Remove EfGenerator, migrated to separate project

.github/workflows/publish-packages.yml

@@ -29,7 +29,7 @@ jobs:
     - name: Publish MapTo
       uses: brandedoutcast/publish-nuget@v2.5.5
       with:
-          PROJECT_FILE_PATH: src/MapTo/MapTo.csproj
+          PROJECT_FILE_PATH: src/BlueWest.MapTo/BlueWest.MapTo.csproj
           NUGET_KEY: ${{secrets.NUGET_API_KEY}}
           NUGET_SOURCE: https://api.nuget.org
           TAG_COMMIT: false

MapTo.sln

@@ -1,6 +1,12 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MapTo", "src\MapTo\MapTo.csproj", "{4DB371AC-48D0-4F01-8EF3-7707D06EF0A7}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MapTo", "src\BlueWest.MapTo\BlueWest.MapTo.csproj", "{4DB371AC-48D0-4F01-8EF3-7707D06EF0A7}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MapToTests", "test\MapTo.Tests\MapTo.Tests.csproj", "{797DA57B-AC7E-468B-8799-44C5A574C0E3}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestConsoleApp", "test\TestConsoleApp\TestConsoleApp.csproj", "{5BE2551A-9EF9-42FA-B6D1-5B5E6A90CC85}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MapTo.Integration.Tests", "test\MapTo.Integration.Tests\MapTo.Integration.Tests.csproj", "{23B46FDF-6A1E-4287-88C9-C8C5D7EECB8C}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

src/BlueWest.MapTo/BlueWest.MapTo.csproj

@@ -4,23 +4,21 @@
         <TargetFramework>netstandard2.0</TargetFramework>
         <Nullable>enable</Nullable>
         <LangVersion>9</LangVersion>
-        <AssemblyName>MapTo</AssemblyName>
         <Description>An object to object mapping generator using Roslyn source generator.</Description>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
         <IncludeSymbols>true</IncludeSymbols>
         <PackageId>MapTo</PackageId>
-        <PackageLicenseFile>LICENSE</PackageLicenseFile>
+        <PackageProjectUrl>https://github.com/mrtaikandi/mapto</PackageProjectUrl>
-        <PackageProjectUrl>https://git.codeliturgy.com/P0/MapTo</PackageProjectUrl>
-        <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
         <PackageVersion>$(Version)</PackageVersion>
         <PublishRepositoryUrl>true</PublishRepositoryUrl>
-        <RepositoryUrl>https://git.codeliturgy.com/P0/MapTo</RepositoryUrl>
+        <RepositoryUrl>https://github.com/mrtaikandi/mapto</RepositoryUrl>
         <SymbolPackageFormat>snupkg</SymbolPackageFormat>
         <RootNamespace>MapTo</RootNamespace>
     </PropertyGroup>
 
     <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
       <DocumentationFile>bin\Release\MapTo.xml</DocumentationFile>
+      <Optimize>false</Optimize>
     </PropertyGroup>
 
     <ItemGroup>
@@ -30,18 +28,17 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.2">
+        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
         <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.8.0" />
         <PackageReference Update="Nerdbank.GitVersioning">
-          <Version>3.6.65-alpha</Version>
+          <Version>3.5.109</Version>
         </PackageReference>
     </ItemGroup>
 
     <ItemGroup>
-        <None Include="..\..\LICENSE" Pack="true" PackagePath="" Visible="false" />
         <None Include="$(OutputPath)\$(AssemblyName).dll" Pack="true" PackagePath="analyzers/dotnet/cs" Visible="false" />
         <None Include="MapTo.props" Pack="true" PackagePath="build" Visible="false" />
     </ItemGroup>

src/BlueWest.MapTo/ClassMappingContext.cs

@@ -0,0 +1,67 @@
+using System.Collections.Immutable;
+using System.Linq;
+using MapTo.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace MapTo
+{
+    internal class ClassMappingContext : MappingContext
+    {
+        internal ClassMappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
+            : base(compilation, sourceGenerationOptions, typeSyntax) { }
+
+        protected override ImmutableArray<MappedMember> GetSourceMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IFieldSymbol>().ToArray();
+
+            return typeSymbol
+                .GetAllMembers()
+                .OfType<IFieldSymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapField(sourceTypeSymbol, sourceProperties, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+        protected override ImmutableArray<MappedMember> GetSourceMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool hasInheritedClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
+
+            return typeSymbol
+                .GetAllMembers()
+                .OfType<IPropertySymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapProperty(sourceTypeSymbol, sourceProperties, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+        protected override ImmutableArray<MappedMember> GetTypeMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IFieldSymbol>().ToArray();
+
+            return sourceTypeSymbol
+                .GetAllMembers()
+                .OfType<IFieldSymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapFieldSimple(typeSymbol, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+        protected override ImmutableArray<MappedMember> GetTypeMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool hasInheritedClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
+
+            return sourceTypeSymbol
+                .GetAllMembers()
+                .OfType<IPropertySymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapPropertySimple(typeSymbol, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+    }
+}

src/BlueWest.MapTo/DiagnosticsFactory.cs

@@ -25,14 +25,10 @@ namespace MapTo
             Create($"{ErrorId}030", location, $"No matching properties found between '{classType.ToDisplayString()}' and '{sourceType.ToDisplayString()}' types.");
 
         internal static Diagnostic NoMatchingPropertyTypeFoundError(ISymbol property) =>
-            Create($"{ErrorId}031", property.Locations.FirstOrDefault(), $"Cannot create a map for '{property.ToDisplayString()}' property because source and destination types are not implicitly convertible. Consider using '{MapTypeConverterAttributeSource.FullyQualifiedName}' to provide a type converter or ignore the property using '{IgnorePropertyAttributeSource.FullyQualifiedName}'.");
+            Create($"{ErrorId}031", property.Locations.FirstOrDefault(), $"Cannot create a map for '{property.ToDisplayString()}' property because source and destination types are not implicitly convertible. Consider using '{MapTypeConverterAttributeSource.FullyQualifiedName}' to provide a type converter or ignore the property using '{IgnoreMemberAttributeSource.FullyQualifiedName}'.");
 
-        internal static Diagnostic InvalidTypeConverterGenericTypesError(ISymbol property, ISymbol memberSymbol)
+        internal static Diagnostic InvalidTypeConverterGenericTypesError(ISymbol property, IPropertySymbol sourceProperty) =>
-        {
+            Create($"{ErrorId}032", property.Locations.FirstOrDefault(), $"Cannot map '{property.ToDisplayString()}' property because the annotated converter does not implement '{RootNamespace}.{ITypeConverterSource.InterfaceName}<{sourceProperty.Type.ToDisplayString()}, {property.GetTypeSymbol()?.ToDisplayString()}>'.");
-
-            return Create($"{ErrorId}032", property.Locations.FirstOrDefault(), $"Cannot map '{property.ToDisplayString()}' property because the annotated converter does not implement '{RootNamespace}.{ITypeConverterSource.InterfaceName}<{memberSymbol.ToString()}, {property.GetTypeSymbol()?.ToDisplayString()}>'.");
-
-        }
 
         internal static Diagnostic ConfigurationParseError(string error) =>
             Create($"{ErrorId}040", Location.None, error);

src/BlueWest.MapTo/Extensions/CommonExtensions.cs

@@ -0,0 +1,86 @@
+using MapTo.Sources;
+using Microsoft.CodeAnalysis;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace MapTo.Extensions
+{
+    internal static class CommonExtensions
+    {
+        internal static SourceBuilder WriteComment(this SourceBuilder builder, string comment = "")
+        {
+            return builder.WriteLine($"// {comment}");
+        }
+        
+        internal static SourceBuilder WriteCommentArray(this SourceBuilder builder, IEnumerable<object> enumerable, string name = "")
+        {
+            builder.WriteComment($"Printing Array: {name}");
+            foreach (var o in enumerable)
+            {
+                if (o != null)
+                {
+                    builder.WriteComment($"     {o.ToString()}");
+                }
+            }
+            builder.WriteComment($"End printing Array: {name}");
+
+            return builder;
+        }
+
+        internal static SourceBuilder WriteModelInfo(this SourceBuilder builder, MappingModel model)
+        {
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                builder
+                    .WriteLine()
+                    .WriteComment($" IsTypeUpdatable                {model.IsTypeUpdatable}")
+                    .WriteComment($" HasMappedBaseClass             {model.HasMappedBaseClass.ToString()}")
+                    .WriteComment($" Namespace                      {model.Namespace}")
+                    .WriteComment($" Options                        {model.Options.ToString()}")
+                    .WriteComment($" Type                           {model.Type}")
+                    .WriteComment($" TypeIdentifierName             {model.TypeIdentifierName}")
+                    .WriteComment($" SourceNamespace                {targetSourceType.SourceNamespace}")
+                    .WriteComment($" SourceTypeFullName             {targetSourceType.SourceTypeFullName}")
+                    .WriteComment($" SourceTypeIdentifierName       {targetSourceType.SourceTypeIdentifierName}");
+            }
+
+            return builder;
+
+        }
+
+        internal static SourceBuilder WriteMappedProperties(this SourceBuilder builder, System.Collections.Immutable.ImmutableArray<MappedMember> mappedProperties)
+        {
+            foreach (var item in mappedProperties)
+            {
+                string str = "";
+
+                if (item.NamedTypeSymbol != null)
+                foreach (var named in item.NamedTypeSymbol?.TypeArguments)
+                    {
+                        str += $"typeToString: {named.ToString()} ";
+                        bool? containedTypeIsJsonEXtension = named?.HasAttribute(MappingContext.JsonExtensionAttributeSymbol);
+                        str += $"typeArgumentTypeIsJsonExtensioN: {containedTypeIsJsonEXtension.ToString()}";
+                    }
+
+                builder .WriteComment($" Name                           {item.Name}")
+                        .WriteComment($" Type                           {item.Type}")
+                        .WriteComment($" MappedSourcePropertyTypeName   {item.MappedSourcePropertyTypeName}")
+                        .WriteComment($" IsEnumerable                   {item.IsEnumerable}")
+                        .WriteComment($" FullyQualifiedType             {item.FullyQualifiedType}")
+                        .WriteComment($" EnumerableTypeArgument         {item.EnumerableTypeArgument}")
+                        .WriteComment($" SourcePropertyName             {item.SourcePropertyName}")
+                        .WriteComment($" TypeSymbol                     {item.FullyQualifiedType.ToString()}")
+                        .WriteComment($" isReadOnly                     {item.isReadOnly.ToString()}")
+                        .WriteComment($" isEnumerable                   {item.isEnumerable.ToString()}")
+                        .WriteComment($" INamedTypeSymbol               {item.NamedTypeSymbol?.ToString()}")
+                        .WriteComment($" INamedTypeSymbolTypeArguments  {str}")
+
+                        .WriteLine();
+            }
+
+            return builder;
+        }
+
+    }
+}

src/BlueWest.MapTo/Extensions/CommonSource.cs

@@ -0,0 +1,379 @@
+using MapTo.Sources;
+using static MapTo.Sources.Constants;
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Collections.Immutable;
+using System.Diagnostics;
+using Microsoft.CodeAnalysis;
+#pragma warning disable CS8602
+
+namespace MapTo.Extensions
+{
+    internal static class CommonSource
+    {
+        internal static SourceCode GenerateStructOrClass(this MappingModel model, string structOrClass)
+        {
+            const bool writeDebugInfo = false;
+            
+            List<string> constructorHeaders = new List<string>();
+
+            using var builder = new SourceBuilder()
+                .WriteLine(GeneratedFilesHeader)
+                .WriteNullableContextOptionIf(model.Options.SupportNullableReferenceTypes)
+                .WriteUsings(model.Usings)
+                .WriteLine()
+                // Namespace declaration
+                .WriteLine($"namespace {model.Namespace}")
+                .WriteOpeningBracket();
+
+            builder
+                // Class declaration
+                .WriteLine($"partial {structOrClass} {model.TypeIdentifierName}")
+                .WriteOpeningBracket()
+                .WriteLine()
+                // Class body
+                .GeneratePublicEmptyConstructor(model, ref constructorHeaders, true)
+                .GeneratePublicConstructor(model, ref constructorHeaders)
+                .GeneratePublicConstructor(model, ref constructorHeaders, true);
+            
+            
+            if (model.IsTypeUpdatable) builder.GenerateUpdateMethod(model);
+            if (model.IsJsonExtension) builder.WriteToJsonMethod(model);
+
+
+            builder
+                .WriteLine()
+                // End class declaration
+                .WriteClosingBracket()
+                .WriteLine()
+                // End namespace declaration
+                .WriteClosingBracket();
+
+            return new(builder.ToString(), $"{model.Namespace}.{model.TypeIdentifierName}.g.cs");
+        }
+
+        private static SourceBuilder GeneratePublicConstructor(this SourceBuilder builder, MappingModel model, ref List<string> constructorHeaders, bool filterNonMapped = false)
+        {
+            const string mappingContextParameterName = "context";
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+                var baseConstructor = /*model.HasMappedBaseClass ? $" : base({mappingContextParameterName}, {sourceClassParameterName})" :*/ string.Empty;
+                var stringBuilder = new StringBuilder();
+                var otherProperties = new List<MappedMember>();
+
+                foreach (var property in targetSourceType.TypeProperties)
+                {
+                    if (!targetSourceType.SourceProperties.IsMappedProperty(property) && !filterNonMapped)
+                    {
+                        stringBuilder.Append(", ");
+                        stringBuilder.Append($"{property.FullyQualifiedType} {property.SourcePropertyName.ToCamelCase()}");
+                        otherProperties.Add(property);
+                    }
+                    
+                }
+                foreach (var property in targetSourceType.TypeFields)
+                {
+                    if (!targetSourceType.SourceFields.IsMappedProperty(property) && !filterNonMapped)
+                    {
+                        stringBuilder.Append(", ");
+                        stringBuilder.Append($"{property.FullyQualifiedType} {property.SourcePropertyName.ToCamelCase()}");
+                        otherProperties.Add(property);
+                    }
+                }
+                
+                var readOnlyPropertiesArguments = stringBuilder.ToString();
+
+                var constructorHeader =
+                    $"public {model.TypeIdentifierName}({targetSourceType.SourceType} {sourceClassParameterName}{readOnlyPropertiesArguments}){baseConstructor}";
+
+
+                bool hasAlreadyConstructor = false;
+                
+                foreach (var header in constructorHeaders)
+                {
+                    if(constructorHeader.Contains(header)) hasAlreadyConstructor = true;
+                }
+
+                if (hasAlreadyConstructor) continue;
+
+                constructorHeaders.Add(constructorHeader);
+                
+                builder
+                    .WriteLine(constructorHeader)
+                    .WriteOpeningBracket()
+                    .WriteAssignmentMethod(model, filterNonMapped ? null : otherProperties.ToArray().ToImmutableArray(), sourceClassParameterName, mappingContextParameterName, filterNonMapped);
+
+                builder.WriteClosingBracket()
+                    .WriteLine();
+            }
+
+            // End constructor declaration
+            return builder;
+        }
+
+        private static SourceBuilder GeneratePublicEmptyConstructor(this SourceBuilder builder, MappingModel model, ref List<string> constructorHeaders, bool filterNonMapped = false)
+        {
+            const string mappingContextParameterName = "context";
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var baseConstructor = /*model.HasMappedBaseClass ? $" : base({mappingContextParameterName}, {sourceClassParameterName})" :*/ string.Empty;
+                
+                var constructorHeader =
+                    $"public {model.TypeIdentifierName}(){baseConstructor}";
+
+
+                bool hasAlreadyConstructor = false;
+                
+                foreach (var header in constructorHeaders)
+                {
+                    if(constructorHeader.Contains(header)) hasAlreadyConstructor = true;
+                }
+
+                if (hasAlreadyConstructor) continue;
+
+                constructorHeaders.Add(constructorHeader);
+                
+                builder
+                    .WriteLine(constructorHeader)
+                    .WriteOpeningBracket()
+                    .WriteClosingBracket()
+                    .WriteLine();
+            }
+
+            // End constructor declaration
+            return builder;
+        }
+
+        private static bool IsMappedProperty(this System.Collections.Immutable.ImmutableArray<MappedMember> properties, MappedMember property)
+        {
+
+            foreach (var prop in properties)
+            {
+                if (prop.Name == property.Name) return true;
+            }
+
+            return false;
+        }
+
+        private static SourceBuilder WriteToJsonMethod(this SourceBuilder builder, MappingModel model)
+        {
+            builder
+                .WriteLine($"public string ToJson()")
+                .WriteOpeningBracket()
+                .WriteLine("var stringBuilder = new System.Text.StringBuilder();")
+                .WriteLine(GetStringBuilderAppendNoInterpolation("{"));
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                foreach (var property in targetSourceType.TypeProperties)
+                {
+                    if (!property.isEnumerable)
+                        HandlePropertyEnumerable(builder, property);
+                    else
+                    {
+                        builder = WriteJsonField(builder, property);
+                    }
+                }
+                foreach (var property in targetSourceType.TypeFields)
+                {
+                    if (!property.isEnumerable)
+                        HandleFieldEnumerable(builder, property);
+                    else
+                    {
+                        builder.WriteLine(GetStringBuilderAppend($"\\\"{property.Name.ToCamelCase()}\\\" : [{GetJsonArrayValue(property, ref builder)}],"));
+                    }
+                }
+                
+                builder.WriteLine(GetStringBuilderAppendNoInterpolation("}"));
+                builder.WriteLine("return stringBuilder.ToString();");
+                builder.WriteClosingBracket();
+            }
+            
+
+            return builder;
+        }
+
+        private static SourceBuilder WriteJsonField(SourceBuilder builder, MappedMember property)
+        {
+            builder.WriteLine(
+                GetStringBuilderAppend(
+                    $"\\\"{property.Name.ToCamelCase()}\\\" : [{GetJsonArrayValue(property, ref builder)}],"));
+            return builder;
+        }
+
+        private static void HandleEnumerable(SourceBuilder builder, MappedMember property)
+        {
+            var symbol = property.ActualSymbol as IPropertySymbol;
+#pragma warning disable CS8602
+            builder.WriteCommentArray(symbol.Parameters, nameof(symbol.Parameters));
+#pragma warning restore CS8602
+            builder.WriteCommentArray(symbol.TypeCustomModifiers, nameof(symbol.TypeCustomModifiers));
+
+            builder.WriteComment($"Is enumerable {(property.ActualSymbol as IPropertySymbol).Parameters}");
+            builder.WriteLine(
+                GetStringBuilderAppend($"\\\"{property.Name.ToCamelCase()}\\\" : {GetJsonValue(property, builder)},"));
+        }
+
+        
+        private static void HandleFieldEnumerable(SourceBuilder builder, MappedMember property)
+        {
+            HandleEnumerable(builder, property);
+        }
+
+        private static void HandlePropertyEnumerable(SourceBuilder builder, MappedMember property)
+        {
+            HandleEnumerable(builder, property);
+        }
+
+        private static string GetJsonArrayValue(MappedMember member, ref SourceBuilder builder)
+        {
+            if (member.isEnumerable)
+            {
+                // get underlying type (check if is a json extension)
+
+                builder.WriteLine("var arrStrBuilder = new StringBuilder();");
+                
+                foreach (var named in member.NamedTypeSymbol?.TypeArguments!)
+                {
+                    bool? containedTypeIsJsonEXtension = named?.HasAttribute(MappingContext.JsonExtensionAttributeSymbol);
+                    if (!containedTypeIsJsonEXtension.HasValue) continue;
+                    builder.WriteLine($"foreach (var v in {member.SourcePropertyName.ToString()})");
+                    builder.WriteOpeningBracket();
+                    builder.WriteLine("arrStrBuilder.Append(v.ToJson());");
+                    builder.WriteLine("arrStrBuilder.Append(\", \");");
+                    builder.WriteClosingBracket();
+                }
+                builder.WriteLine("arrStrBuilder.Remove(arrStrBuilder.Length -1, 1);"); 
+            }
+
+            return "{arrStrBuilder.ToString()}";
+        }
+        private static string GetJsonValue(MappedMember member, SourceBuilder builder)
+        {
+
+            if (member.FullyQualifiedType == "string") return $"\\\"{{{member.SourcePropertyName}}}\\\"";
+            if (member.FullyQualifiedType is "int" or "double" or "float" or "long") return $"{{{member.SourcePropertyName}}}";
+
+            return "";
+        }
+
+        private static string GetStringBuilderAppend(string stringToAppend)
+        {
+            return $"stringBuilder.Append($\"{stringToAppend}\");";
+        }
+        private static string GetStringBuilderAppendNoInterpolation(string stringToAppend)
+        {
+            return $"stringBuilder.Append(\"{stringToAppend}\");";
+        }
+
+        private static SourceBuilder WriteAssignmentMethod(this SourceBuilder builder, MappingModel model, System.Collections.Immutable.ImmutableArray<MappedMember>? otherProperties,
+            string? sourceClassParameterName, string mappingContextParameterName, bool fromUpdate)
+        {
+
+            List<MappedMember> _addedMembers = new List<MappedMember>();
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                foreach (var property in targetSourceType.SourceProperties)
+                {
+                    if (property.isReadOnly && fromUpdate) continue;
+                    if(_addedMembers.Contains(property)) continue;
+                    
+
+                    builder.WriteLine($"{property.Name} = {sourceClassParameterName}.{property.SourcePropertyName};");
+                    _addedMembers.Add(property);
+
+                }
+
+                foreach (var property in targetSourceType.SourceFields)
+                {
+                    if (property.isReadOnly && fromUpdate) continue;
+                    if(_addedMembers.Contains(property)) continue;
+
+                    builder.WriteLine($"{property.Name} = {sourceClassParameterName}.{property.SourcePropertyName};");
+                    _addedMembers.Add(property);
+
+                }
+
+                if (otherProperties == null) return builder;
+
+                foreach (var property in otherProperties)
+                {
+                    if(_addedMembers.Contains(property)) continue;
+
+                    builder.WriteLine(property.MappedSourcePropertyTypeName is null
+                        ? $"{property.Name} = {property.SourcePropertyName.ToCamelCase()};"
+                        : "");
+                    _addedMembers.Add(property);
+
+
+                }
+            }
+
+            
+
+            return builder;
+
+        }
+
+
+        private static SourceBuilder GenerateUpdateMethod(this SourceBuilder builder, MappingModel model)
+        {
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+
+                builder
+                    .GenerateUpdaterMethodsXmlDocs(model, sourceClassParameterName, targetSourceType)
+                    .WriteLine($"public void Update({targetSourceType.SourceType} {sourceClassParameterName})")
+                    .WriteOpeningBracket()
+                    .WriteAssignmentMethod(model, null, sourceClassParameterName, "context", true)
+                    .WriteClosingBracket()
+                    .WriteLine();
+            }
+  
+
+            return builder;
+        }
+
+        private static SourceBuilder GenerateUpdaterMethodsXmlDocs(this SourceBuilder builder, MappingModel model, string sourceClassParameterName,
+            MappedSourceType mappedSourceType)
+        {
+            if (!model.Options.GenerateXmlDocument)
+            {
+                return builder;
+            }
+            builder
+                .WriteLine("/// <summary>")
+                .WriteLine($"/// Updates <see cref=\"{model.TypeIdentifierName}\"/> and sets its participating properties")
+                .WriteLine($"/// using the property values from <paramref name=\"{sourceClassParameterName}\"/>.")
+                .WriteLine("/// </summary>")
+                .WriteLine($"/// <param name=\"{sourceClassParameterName}\">The instance of <see cref=\"{mappedSourceType.SourceType}\"/> to use as source.</param>");
+            return builder;
+        }
+        
+        private static SourceBuilder GenerateEnumerableJsonSourceTypeExtensionMethod(this SourceBuilder builder, MappingModel model)
+        {
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+
+                builder
+                    .WriteLineIf(model.Options.SupportNullableStaticAnalysis, $"[return: NotNullIfNotNull(\"{sourceClassParameterName}\")]")
+                    .WriteLine($"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static string ToJson(this IEnumerable<{targetSourceType.SourceType}{model.Options.NullableReferenceSyntax}> {sourceClassParameterName}List)")
+                    .WriteOpeningBracket()
+                    .WriteLine($"return {sourceClassParameterName} == null ? null : new {model.TypeIdentifierName}({sourceClassParameterName});")
+                    .WriteClosingBracket();
+            }
+
+
+            return builder;
+        }
+    }
+}

src/BlueWest.MapTo/Extensions/RoslynExtensions.cs

@@ -31,13 +31,14 @@ namespace MapTo.Extensions
 
         public static string GetIdentifierName(this TypeDeclarationSyntax typeSyntax) => typeSyntax.Identifier.Text;
 
-        public static AttributeSyntax? GetAttribute(this TypeDeclarationSyntax typeDeclarationSyntax, string attributeName)
+        public static AttributeSyntax? GetAttribute(this MemberDeclarationSyntax typeDeclarationSyntax, string attributeName)
         {
-            return typeDeclarationSyntax.AttributeLists
+            var attributeLists = typeDeclarationSyntax.AttributeLists;
+            var selection = attributeLists
                 .SelectMany(al => al.Attributes)
-                .SingleOrDefault(a =>
+                .FirstOrDefault(x => x.Name.ToString().Contains(attributeName));
-                    (a.Name as IdentifierNameSyntax)?.Identifier.ValueText == attributeName ||
+
-                    ((a.Name as QualifiedNameSyntax)?.Right as IdentifierNameSyntax)?.Identifier.ValueText == attributeName);
+            return selection;
         }
 
         public static bool HasAttribute(this ISymbol symbol, ITypeSymbol attributeSymbol) =>
@@ -49,7 +50,7 @@ namespace MapTo.Extensions
         public static AttributeData? GetAttribute(this ISymbol symbol, ITypeSymbol attributeSymbol) =>
             symbol.GetAttributes(attributeSymbol).FirstOrDefault();
 
-        public static string? GetNamespace(this TypeDeclarationSyntax typeDeclarationSyntax) => typeDeclarationSyntax
+        public static string? GetNamespace(this MemberDeclarationSyntax typeDeclarationSyntax) => typeDeclarationSyntax
             .Ancestors()
             .OfType<NamespaceDeclarationSyntax>()
             .FirstOrDefault()
@@ -67,6 +68,7 @@ namespace MapTo.Extensions
                 case IPropertySymbol propertySymbol:
                     typeSymbol = propertySymbol.Type;
                     return true;
+
                 case IFieldSymbol fieldSymbol:
                     typeSymbol = fieldSymbol.Type;
                     return true;
@@ -85,7 +87,7 @@ namespace MapTo.Extensions
 
         public static IPropertySymbol? FindProperty(this IEnumerable<IPropertySymbol> properties, IPropertySymbol targetProperty)
         {
-            return properties.SingleOrDefault(p =>
+            return properties.FirstOrDefault(p =>
                 p.Name == targetProperty.Name &&
                 (p.NullableAnnotation != NullableAnnotation.Annotated ||
                  p.NullableAnnotation == NullableAnnotation.Annotated &&

src/BlueWest.MapTo/MapToGenerator.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Linq;
+using System.Threading;
 using MapTo.Extensions;
 using MapTo.Sources;
 using Microsoft.CodeAnalysis;
@@ -17,7 +19,9 @@ namespace MapTo
         /// <inheritdoc />
         public void Initialize(GeneratorInitializationContext context)
         {
+
             context.RegisterForSyntaxNotifications(() => new MapToSyntaxReceiver());
+            
         }
 
         /// <inheritdoc />
@@ -29,8 +33,9 @@ namespace MapTo
 
                 var compilation = context.Compilation
                     .AddSource(ref context, UseUpdateAttributeSource.Generate(options))
+                    .AddSource(ref context, JsonExtensionAttributeSource.Generate(options))
                     .AddSource(ref context, MapFromAttributeSource.Generate(options))
-                    .AddSource(ref context, IgnorePropertyAttributeSource.Generate(options))
+                    .AddSource(ref context, IgnoreMemberAttributeSource.Generate(options))
                     .AddSource(ref context, ITypeConverterSource.Generate(options))
                     .AddSource(ref context, MapTypeConverterAttributeSource.Generate(options))
                     .AddSource(ref context, MapPropertyAttributeSource.Generate(options))
@@ -53,6 +58,7 @@ namespace MapTo
             foreach (var typeDeclarationSyntax in candidateTypes)
             {
                 var mappingContext = MappingContext.Create(compilation, options, typeDeclarationSyntax);
+
                 mappingContext.Diagnostics.ForEach(context.ReportDiagnostic);
 
                 if (mappingContext.Model is null)

src/BlueWest.MapTo/MapToSyntaxReceiver.cs

@@ -20,7 +20,7 @@ namespace MapTo
 
             var attributeSyntax = attributes
                 .SelectMany(a => a.Attributes)
-                .SingleOrDefault(a => a.Name is
+                .FirstOrDefault(a => a.Name is
                     IdentifierNameSyntax { Identifier: { ValueText: MapFromAttributeSource.AttributeName } } // For: [MapFrom]
                     or
                     QualifiedNameSyntax // For: [MapTo.MapFrom]

src/BlueWest.MapTo/MappingContext.cs

@@ -0,0 +1,630 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using MapTo.Extensions;
+using MapTo.Sources;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+#pragma warning disable CS8602
+
+namespace MapTo
+{
+    internal static class MappingContextExtensions
+    {
+        internal static ImmutableArray<MappedMember> GetReadOnlyMappedProperties(this ImmutableArray<MappedMember> mappedProperties) => mappedProperties.Where(p => p.isReadOnly).ToImmutableArray()!;
+        internal static ImmutableArray<MappedMember> GetWritableMappedProperties(this ImmutableArray<MappedMember> mappedProperties) => mappedProperties.Where(p => !p.isReadOnly).ToImmutableArray()!;
+    }
+
+    internal abstract class MappingContext
+    {
+        private readonly List<SymbolDisplayPart> _ignoredNamespaces;
+
+        protected MappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
+        {
+            _ignoredNamespaces = new();
+            Diagnostics = ImmutableArray<Diagnostic>.Empty;
+            Usings = ImmutableArray.Create("System", Constants.RootNamespace);
+            SourceGenerationOptions = sourceGenerationOptions;
+            TypeSyntax = typeSyntax;
+            Compilation = compilation;
+
+            IgnoreMemberAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(IgnoreMemberAttributeSource.FullyQualifiedName);
+            MapTypeConverterAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MapTypeConverterAttributeSource.FullyQualifiedName);
+            TypeConverterInterfaceTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(ITypeConverterSource.FullyQualifiedName);
+            MapPropertyAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MapPropertyAttributeSource.FullyQualifiedName);
+            MapFromAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MapFromAttributeSource.FullyQualifiedName);
+            UseUpdateAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(UseUpdateAttributeSource.FullyQualifiedName);
+            JsonExtensionAttributeSymbol = compilation.GetTypeByMetadataNameOrThrow(JsonExtensionAttributeSource.FullyQualifiedName);
+            MappingContextTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MappingContextSource.FullyQualifiedName);
+
+            AddUsingIfRequired(sourceGenerationOptions.SupportNullableStaticAnalysis, "System.Diagnostics.CodeAnalysis");
+        }
+
+        public ImmutableArray<Diagnostic> Diagnostics { get; private set; }
+
+        public MappingModel? Model { get; private set; }
+
+        protected Compilation Compilation { get; }
+
+        protected INamedTypeSymbol IgnoreMemberAttributeTypeSymbol { get; }
+
+        protected INamedTypeSymbol MapFromAttributeTypeSymbol { get; }
+        
+        protected INamedTypeSymbol UseUpdateAttributeTypeSymbol { get; }
+
+        public static INamedTypeSymbol JsonExtensionAttributeSymbol { get; set; } = null!;
+
+        protected INamedTypeSymbol MappingContextTypeSymbol { get; }
+
+        protected INamedTypeSymbol MapPropertyAttributeTypeSymbol { get; }
+
+        protected INamedTypeSymbol MapTypeConverterAttributeTypeSymbol { get; }
+
+        protected SourceGenerationOptions SourceGenerationOptions { get; }
+
+        protected INamedTypeSymbol TypeConverterInterfaceTypeSymbol { get; }
+
+        protected TypeDeclarationSyntax TypeSyntax { get; }
+
+        protected ImmutableArray<string> Usings { get; private set; }
+
+        public static MappingContext Create(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
+        {
+
+            MappingContext context = typeSyntax switch
+            {
+                StructDeclarationSyntax => new StructMappingContext(compilation, sourceGenerationOptions, typeSyntax),
+                ClassDeclarationSyntax => new ClassMappingContext(compilation, sourceGenerationOptions, typeSyntax),
+                RecordDeclarationSyntax => new RecordMappingContext(compilation, sourceGenerationOptions, typeSyntax),
+                _ => throw new ArgumentOutOfRangeException()
+            };
+
+            context.Model = context.CreateMappingModel();
+
+            return context;
+        }
+
+        protected void AddDiagnostic(Diagnostic diagnostic)
+        {
+            Diagnostics = Diagnostics.Add(diagnostic);
+        }
+
+        protected void AddUsingIfRequired(ISymbol? namedTypeSymbol) =>
+            AddUsingIfRequired(namedTypeSymbol?.ContainingNamespace.IsGlobalNamespace == false, namedTypeSymbol?.ContainingNamespace);
+
+        protected void AddUsingIfRequired(bool condition, INamespaceSymbol? ns) =>
+            AddUsingIfRequired(condition && ns is not null && !_ignoredNamespaces.Contains(ns.ToDisplayParts().First()), ns?.ToDisplayString());
+
+        protected void AddUsingIfRequired(bool condition, string? ns)
+        {
+            if (ns is not null && condition && ns != TypeSyntax.GetNamespace() && !Usings.Contains(ns))
+            {
+                Usings = Usings.Add(ns);
+            }
+        }
+
+        protected IPropertySymbol? FindSourceProperty(IEnumerable<IPropertySymbol> sourceProperties, ISymbol property)
+        {
+            var propertyName = property
+                .GetAttribute(MapPropertyAttributeTypeSymbol)
+                ?.NamedArguments
+                .FirstOrDefault(a => a.Key == MapPropertyAttributeSource.SourcePropertyNamePropertyName)
+                .Value.Value as string ?? property.Name;
+
+            return sourceProperties.FirstOrDefault(p => p.Name == propertyName);
+        }
+        protected IFieldSymbol? FindSourceField(IEnumerable<IFieldSymbol> sourceProperties, ISymbol property)
+        {
+            var propertyName = property
+                .GetAttribute(MapPropertyAttributeTypeSymbol)
+                ?.NamedArguments
+                .FirstOrDefault(a => a.Key == MapPropertyAttributeSource.SourcePropertyNamePropertyName)
+                .Value.Value as string ?? property.Name;
+
+            return sourceProperties.FirstOrDefault(p => p.Name == propertyName);
+        }
+
+        protected abstract ImmutableArray<MappedMember> GetSourceMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass);
+        protected abstract ImmutableArray<MappedMember> GetTypeMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass);
+
+
+        protected abstract ImmutableArray<MappedMember> GetSourceMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass);
+        protected abstract ImmutableArray<MappedMember> GetTypeMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass);
+
+
+        protected ImmutableArray<INamedTypeSymbol> GetSourceTypeSymbol(TypeDeclarationSyntax typeDeclarationSyntax, SemanticModel? semanticModel = null)
+        {
+            var attributeData = typeDeclarationSyntax.GetAttribute(MapFromAttributeSource.AttributeName);
+            var sourceSymbol = GetSourceTypeSymbol(attributeData, semanticModel);
+            return sourceSymbol;
+        }
+
+        // we need two possible InamedTypeSymbol
+        protected ImmutableArray<INamedTypeSymbol> GetSourceTypeSymbol(SyntaxNode? attributeSyntax, SemanticModel? semanticModel = null)
+        {
+            if (attributeSyntax is null)
+            {
+                return new ImmutableArray<INamedTypeSymbol>(){};
+            }
+
+            semanticModel ??= Compilation.GetSemanticModel(attributeSyntax.SyntaxTree);
+            var descendentNodes = attributeSyntax
+                .DescendantNodes();
+
+            var sourceTypeExpressionSyntax = descendentNodes
+                .OfType<TypeOfExpressionSyntax>()
+                .ToImmutableArray();
+
+            // cast
+            var resultList = new List<INamedTypeSymbol>();
+            for (int i = 0; i < sourceTypeExpressionSyntax.Length; i++)
+            {
+                var sourceTypeExpression = sourceTypeExpressionSyntax[i];
+                if (semanticModel.GetTypeInfo(sourceTypeExpression.Type).Type is INamedTypeSymbol namedTypeSymbol)
+                {
+                    resultList.Add(namedTypeSymbol);
+                }
+            }
+
+            return resultList.ToImmutableArray();
+        }
+
+        protected bool IsTypeInheritFromMappedBaseClass(SemanticModel semanticModel)
+        {
+            return TypeSyntax.BaseList is not null && TypeSyntax.BaseList.Types
+                .Select(t => semanticModel.GetTypeInfo(t.Type).Type)
+                .Any(t => t?.GetAttribute(MapFromAttributeTypeSymbol) != null);
+        }
+
+        protected bool IsTypeUpdatable()
+        {
+            return TypeSyntax.GetAttribute("UseUpdate") != null;
+        }
+        protected bool HasJsonExtension()
+        {
+            return TypeSyntax.GetAttribute("JsonExtension") != null;
+        }
+        protected virtual MappedMember? MapProperty(ISymbol sourceTypeSymbol, IReadOnlyCollection<IPropertySymbol> sourceProperties, ISymbol property)
+        {
+            var sourceProperty = FindSourceProperty(sourceProperties, property);
+            if (sourceProperty is null || !property.TryGetTypeSymbol(out var propertyType))
+            {
+                return null;
+            }
+
+           
+            string? converterFullyQualifiedName = null;
+            var converterParameters = ImmutableArray<string>.Empty;
+            ITypeSymbol? mappedSourcePropertyType = null;
+            ITypeSymbol? enumerableTypeArgumentType = null;
+
+            if (!Compilation.HasCompatibleTypes(sourceProperty, property))
+            {
+                if (!TryGetMapTypeConverterForProperty(property, sourceProperty, out converterFullyQualifiedName, out converterParameters) &&
+                    !TryGetNestedObjectMappings(property, out mappedSourcePropertyType, out enumerableTypeArgumentType))
+                {
+                    return null;
+                }
+            }
+
+            AddUsingIfRequired(propertyType);
+            AddUsingIfRequired(enumerableTypeArgumentType);
+            AddUsingIfRequired(mappedSourcePropertyType);
+
+            INamedTypeSymbol? namedType;
+            var isEnumerable = IsEnumerable(property, out namedType);
+
+
+            return new MappedMember(
+                property.Name,
+                property.GetTypeSymbol().ToString(),
+                ToQualifiedDisplayName(propertyType) ?? propertyType.Name,
+                converterFullyQualifiedName,
+                converterParameters.ToImmutableArray(),
+                sourceProperty.Name,
+                ToQualifiedDisplayName(mappedSourcePropertyType),
+                ToQualifiedDisplayName(enumerableTypeArgumentType),
+                property,
+                namedType,
+                isEnumerable,
+               (property as IPropertySymbol).IsReadOnly);
+;
+        }
+
+        protected virtual MappedMember? MapField(ISymbol sourceTypeSymbol, IReadOnlyCollection<IFieldSymbol> sourceProperties, ISymbol property)
+        {
+            var sourceProperty = FindSourceField(sourceProperties, property);
+            if (sourceProperty is null || !property.TryGetTypeSymbol(out var propertyType))
+            {
+                return null;
+            }
+
+            if (property is IFieldSymbol symbol)
+            {
+                if (symbol.AssociatedSymbol != null) return null;
+            }
+
+            string? converterFullyQualifiedName = null;
+            var converterParameters = ImmutableArray<string>.Empty;
+            ITypeSymbol? mappedSourcePropertyType = null;
+            ITypeSymbol? enumerableTypeArgumentType = null;
+
+            if (!Compilation.HasCompatibleTypes(sourceProperty, property))
+            {
+                if (!TryGetMapTypeConverterForField(property, sourceProperty, out converterFullyQualifiedName, out converterParameters) &&
+                    !TryGetNestedObjectMappings(property, out mappedSourcePropertyType, out enumerableTypeArgumentType))
+                {
+                    return null;
+                }
+            }
+
+            AddUsingIfRequired(propertyType);
+            AddUsingIfRequired(enumerableTypeArgumentType);
+            AddUsingIfRequired(mappedSourcePropertyType);
+
+
+            INamedTypeSymbol? namedType;
+            var isEnumerable = IsEnumerable(property, out namedType);
+
+            return new MappedMember(
+                property.Name,
+                property.GetTypeSymbol()?.ToString() ?? throw new InvalidOperationException(),
+                ToQualifiedDisplayName(propertyType) ?? propertyType.Name,
+                converterFullyQualifiedName,
+                converterParameters.ToImmutableArray(),
+                sourceProperty.Name,
+                ToQualifiedDisplayName(mappedSourcePropertyType),
+                ToQualifiedDisplayName(enumerableTypeArgumentType),
+                property,
+                namedType,
+                isEnumerable,
+               (property as IFieldSymbol).IsReadOnly);
+            ;
+        }
+        protected virtual MappedMember? MapPropertySimple(ISymbol sourceTypeSymbol, ISymbol property)
+        {
+            if (!property.TryGetTypeSymbol(out var propertyType))
+            {
+                return null;
+            }
+
+
+            string? converterFullyQualifiedName = null;
+            var converterParameters = ImmutableArray<string>.Empty;
+            ITypeSymbol? mappedSourcePropertyType = null;
+            ITypeSymbol? enumerableTypeArgumentType = null;
+
+
+            AddUsingIfRequired(propertyType);
+            AddUsingIfRequired(enumerableTypeArgumentType);
+            AddUsingIfRequired(mappedSourcePropertyType);
+
+            INamedTypeSymbol? namedType;
+            var isEnumerable = IsEnumerable(property, out namedType);
+
+            return new MappedMember(
+                property.Name,
+                property.GetTypeSymbol().ToString(),
+                ToQualifiedDisplayName(propertyType) ?? propertyType.Name,
+                converterFullyQualifiedName,
+                converterParameters.ToImmutableArray(),
+                property.Name,
+                ToQualifiedDisplayName(mappedSourcePropertyType),
+                ToQualifiedDisplayName(enumerableTypeArgumentType),
+                property,
+                namedType,
+                isEnumerable,
+#pragma warning disable CS8602
+                (property as IPropertySymbol).IsReadOnly);
+#pragma warning restore CS8602
+            ;
+        }
+
+        protected virtual MappedMember? MapFieldSimple(ISymbol sourceTypeSymbol, ISymbol property)
+        {
+            if (!property.TryGetTypeSymbol(out var propertyType))
+            {
+                return null;
+            }
+
+            if(property is IFieldSymbol symbol)
+            {
+                if (symbol.AssociatedSymbol != null) return null;
+            }
+
+
+            string? converterFullyQualifiedName = null;
+            var converterParameters = ImmutableArray<string>.Empty;
+            ITypeSymbol? mappedSourcePropertyType = null;
+            ITypeSymbol? enumerableTypeArgumentType = null;
+
+
+            AddUsingIfRequired(propertyType);
+            AddUsingIfRequired(enumerableTypeArgumentType);
+            AddUsingIfRequired(mappedSourcePropertyType);
+
+            INamedTypeSymbol? namedType;
+            var isEnumerable = IsEnumerable(property, out namedType);
+
+
+            return new MappedMember(
+                property.Name,
+                property.GetTypeSymbol().ToString(),
+                ToQualifiedDisplayName(propertyType) ?? propertyType.Name,
+                converterFullyQualifiedName,
+                converterParameters.ToImmutableArray(),
+                property.Name,
+                ToQualifiedDisplayName(mappedSourcePropertyType),
+                ToQualifiedDisplayName(enumerableTypeArgumentType),
+                property,
+                namedType,
+                isEnumerable,
+               (property as IFieldSymbol).IsReadOnly);
+            ;
+        }
+        protected bool TryGetMapTypeConverterForProperty(ISymbol property, IPropertySymbol sourceProperty, out string? converterFullyQualifiedName,
+            out ImmutableArray<string> converterParameters)
+        {
+            converterFullyQualifiedName = null;
+            converterParameters = ImmutableArray<string>.Empty;
+
+            if (!Diagnostics.IsEmpty())
+            {
+                return false;
+            }
+
+            var typeConverterAttribute = property.GetAttribute(MapTypeConverterAttributeTypeSymbol);
+            if (typeConverterAttribute?.ConstructorArguments.First().Value is not INamedTypeSymbol converterTypeSymbol)
+            {
+                return false;
+            }
+
+            var baseInterface = GetTypeConverterBaseInterfaceForProperty(converterTypeSymbol, property, sourceProperty);
+            if (baseInterface is null)
+            {
+                AddDiagnostic(DiagnosticsFactory.InvalidTypeConverterGenericTypesError(property, sourceProperty));
+                return false;
+            }
+
+            converterFullyQualifiedName = converterTypeSymbol.ToDisplayString();
+            converterParameters = GetTypeConverterParameters(typeConverterAttribute);
+            return true;
+        }
+        protected bool TryGetMapTypeConverterForField(ISymbol property, IFieldSymbol sourceProperty, out string? converterFullyQualifiedName,
+            out ImmutableArray<string> converterParameters)
+        {
+            converterFullyQualifiedName = null;
+            converterParameters = ImmutableArray<string>.Empty;
+
+            if (!Diagnostics.IsEmpty())
+            {
+                return false;
+            }
+
+            var typeConverterAttribute = property.GetAttribute(MapTypeConverterAttributeTypeSymbol);
+            if (typeConverterAttribute?.ConstructorArguments.First().Value is not INamedTypeSymbol converterTypeSymbol)
+            {
+                return false;
+            }
+
+            var baseInterface = GetTypeConverterBaseInterfaceForField(converterTypeSymbol, property, sourceProperty);
+            if (baseInterface is null)
+            {
+                //AddDiagnostic(DiagnosticsFactory.InvalidTypeConverterGenericTypesError(property, null));
+                return false;
+            }
+
+            converterFullyQualifiedName = converterTypeSymbol.ToDisplayString();
+            converterParameters = GetTypeConverterParameters(typeConverterAttribute);
+            return true;
+        }
+        protected bool TryGetNestedObjectMappings(ISymbol property, out ITypeSymbol? mappedSourcePropertyType, out ITypeSymbol? enumerableTypeArgument)
+        {
+            mappedSourcePropertyType = null;
+            enumerableTypeArgument = null;
+
+            if (!Diagnostics.IsEmpty())
+            {
+                return false;
+            }
+
+            if (!property.TryGetTypeSymbol(out var propertyType))
+            {
+                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyTypeFoundError(property));
+                return false;
+            }
+
+            var mapFromAttribute = propertyType.GetAttribute(MapFromAttributeTypeSymbol);
+            if (mapFromAttribute is null &&
+                propertyType is INamedTypeSymbol namedTypeSymbol &&
+                !propertyType.IsPrimitiveType() &&
+                (Compilation.IsGenericEnumerable(propertyType) || propertyType.AllInterfaces.Any(i => Compilation.IsGenericEnumerable(i))))
+            {
+                enumerableTypeArgument = namedTypeSymbol.TypeArguments.First();
+                mapFromAttribute = enumerableTypeArgument.GetAttribute(MapFromAttributeTypeSymbol);
+            }
+
+            mappedSourcePropertyType = mapFromAttribute?.ConstructorArguments.First().Value as INamedTypeSymbol;
+
+            if (mappedSourcePropertyType is null && enumerableTypeArgument is null)
+            {
+                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyTypeFoundError(property));
+            }
+
+            return Diagnostics.IsEmpty();
+        }
+        protected bool IsEnumerable(ISymbol property, out INamedTypeSymbol? namedTypeSymbolResult)
+        {
+
+            if (!property.TryGetTypeSymbol(out var propertyType))
+            {
+                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyTypeFoundError(property));
+                namedTypeSymbolResult = null;
+                return false;
+            }
+
+            if (
+                propertyType is INamedTypeSymbol namedTypeSymbol &&
+                !propertyType.IsPrimitiveType() &&
+                (Compilation.IsGenericEnumerable(propertyType) || propertyType.AllInterfaces.Any(i => Compilation.IsGenericEnumerable(i))))
+            {
+                namedTypeSymbolResult = namedTypeSymbol;
+                return true;
+            }
+            namedTypeSymbolResult = null;
+            return false;
+        }
+        private static ImmutableArray<string> GetTypeConverterParameters(AttributeData typeConverterAttribute)
+        {
+            var converterParameter = typeConverterAttribute.ConstructorArguments.Skip(1).FirstOrDefault();
+            return converterParameter.IsNull
+                ? ImmutableArray<string>.Empty
+                : converterParameter.Values.Where(v => v.Value is not null).Select(v => v.Value!.ToSourceCodeString()).ToImmutableArray();
+        }
+
+        private MappingModel? CreateMappingModel()
+        {
+            var semanticModel = Compilation.GetSemanticModel(TypeSyntax.SyntaxTree);
+            if (semanticModel.GetDeclaredSymbol(TypeSyntax) is not INamedTypeSymbol typeSymbol)
+            {
+                AddDiagnostic(DiagnosticsFactory.TypeNotFoundError(TypeSyntax.GetLocation(), TypeSyntax.Identifier.ValueText));
+                return null;
+            }
+
+            // We can have 2 sources...
+            
+            var sourceTypeSymbols = GetSourceTypeSymbol(TypeSyntax, semanticModel);
+            
+            
+            // lets pick one for now, and then think what to do with the second one 
+            if (sourceTypeSymbols.IsDefaultOrEmpty)
+            {
+                AddDiagnostic(DiagnosticsFactory.MapFromAttributeNotFoundError(TypeSyntax.GetLocation()));
+                return null;
+            }
+            
+            
+            var typeIdentifierName = TypeSyntax.GetIdentifierName();
+            var isTypeInheritFromMappedBaseClass = IsTypeInheritFromMappedBaseClass(semanticModel);
+            var isTypeUpdatable = true; //IsTypeUpdatable();
+            var hasJsonExtension = false; // HasJsonExtension();
+
+            List<MappedSourceType> mappedSourceTypes = new List<MappedSourceType>();
+            
+            foreach (var sourceTypeSymbol in sourceTypeSymbols)
+            {
+                _ignoredNamespaces.Add(sourceTypeSymbol.ContainingNamespace.ToDisplayParts().First());
+                var sourceTypeIdentifierName = sourceTypeSymbol.Name;
+                var shouldGenerateSecondaryConstructor = ShouldGenerateSecondaryConstructor(semanticModel, sourceTypeSymbol);
+                var mappedProperties = GetSourceMappedProperties(typeSymbol, sourceTypeSymbol, isTypeInheritFromMappedBaseClass);
+                var mappedFields = GetSourceMappedFields(typeSymbol, sourceTypeSymbol, isTypeInheritFromMappedBaseClass);
+                AddUsingIfRequired(mappedProperties.Any(p => p.IsEnumerable), "System.Linq");
+                var allProperties = GetTypeMappedProperties(sourceTypeSymbol, typeSymbol , isTypeInheritFromMappedBaseClass);
+                var allFields = GetTypeMappedFields(sourceTypeSymbol, typeSymbol, isTypeInheritFromMappedBaseClass);
+                
+                mappedSourceTypes.Add(new MappedSourceType(
+                    sourceTypeSymbol.ContainingNamespace.ToDisplayString(), 
+                    sourceTypeIdentifierName, 
+                    sourceTypeSymbol.ToDisplayString(),
+                    mappedProperties, mappedFields, allProperties, allFields, shouldGenerateSecondaryConstructor));
+            }
+
+            //var sourceTypeSymbol = sourceTypeSymbols[0];
+            
+            // Pick first one to avoid errors. TODO: Make possible to use different source types
+
+
+
+
+            /*if (!mappedProperties.Any())
+            {
+                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyFoundError(TypeSyntax.GetLocation(), typeSymbol, sourceTypeSymbol));
+                return null;
+            }*/
+            
+            return new MappingModel(
+                SourceGenerationOptions,
+                TypeSyntax.GetNamespace(),
+                TypeSyntax.Modifiers,
+                TypeSyntax.Keyword.Text,
+                typeIdentifierName,
+                isTypeUpdatable,
+                hasJsonExtension,
+                mappedSourceTypes.ToImmutableArray(),
+                isTypeInheritFromMappedBaseClass,
+                Usings);
+        }
+
+       
+
+        private INamedTypeSymbol? GetTypeConverterBaseInterfaceForProperty(ITypeSymbol converterTypeSymbol, ISymbol property, IPropertySymbol sourceProperty)
+        {
+            if (!property.TryGetTypeSymbol(out var propertyType))
+            {
+                return null;
+            }
+
+            return converterTypeSymbol.AllInterfaces
+                .FirstOrDefault(i =>
+                    i.TypeArguments.Length == 2 &&
+                    SymbolEqualityComparer.Default.Equals(i.ConstructedFrom, TypeConverterInterfaceTypeSymbol) &&
+                    SymbolEqualityComparer.Default.Equals(sourceProperty.Type, i.TypeArguments[0]) &&
+                    SymbolEqualityComparer.Default.Equals(propertyType, i.TypeArguments[1]));
+        }
+        private INamedTypeSymbol? GetTypeConverterBaseInterfaceForField(ITypeSymbol converterTypeSymbol, ISymbol property, IFieldSymbol sourceProperty)
+        {
+            if (!property.TryGetTypeSymbol(out var propertyType))
+            {
+                return null;
+            }
+
+            return converterTypeSymbol.AllInterfaces
+                .FirstOrDefault(i =>
+                    i.TypeArguments.Length == 2 &&
+                    SymbolEqualityComparer.Default.Equals(i.ConstructedFrom, TypeConverterInterfaceTypeSymbol) &&
+                    SymbolEqualityComparer.Default.Equals(sourceProperty.Type, i.TypeArguments[0]) &&
+                    SymbolEqualityComparer.Default.Equals(propertyType, i.TypeArguments[1]));
+        }
+
+        private bool ShouldGenerateSecondaryConstructor(SemanticModel semanticModel, ISymbol sourceTypeSymbol)
+        {
+            var constructorSyntax = TypeSyntax.DescendantNodes()
+                .OfType<ConstructorDeclarationSyntax>()
+                .FirstOrDefault(c =>
+                    c.ParameterList.Parameters.Count == 1 &&
+                    SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeInfo(c.ParameterList.Parameters.Single().Type!).ConvertedType, sourceTypeSymbol));
+
+            if (constructorSyntax is null)
+            {
+                // Secondary constructor is not defined.
+                return true;
+            }
+
+            if (constructorSyntax.Initializer?.ArgumentList.Arguments is not { Count: 2 } arguments ||
+                !SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeInfo(arguments[0].Expression).ConvertedType, MappingContextTypeSymbol) ||
+                !SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeInfo(arguments[1].Expression).ConvertedType, sourceTypeSymbol))
+            {
+                AddDiagnostic(DiagnosticsFactory.MissingConstructorArgument(constructorSyntax));
+            }
+
+            return false;
+        }
+
+        private string? ToQualifiedDisplayName(ISymbol? symbol)
+        {
+            if (symbol is null)
+            {
+                return null;
+            }
+
+            var containingNamespace = TypeSyntax.GetNamespace();
+            var symbolNamespace = symbol.ContainingNamespace.ToDisplayString();
+            return  containingNamespace != symbolNamespace && _ignoredNamespaces.Contains(symbol.ContainingNamespace.ToDisplayParts().First())
+                ? symbol.ToDisplayString()
+                : symbol.Name;
+        }
+    }
+}

src/BlueWest.MapTo/Models.cs

@@ -0,0 +1,222 @@
+using System;
+using System.Collections.Immutable;
+using MapTo.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace MapTo
+{
+    internal enum AccessModifier
+    {
+        Public,
+        Internal,
+        Private
+    }
+
+    internal enum NullStaticAnalysisState
+    {
+        Default,
+        Enabled,
+        Disabled
+    }
+
+    internal record SourceCode(string Text, string HintName);
+
+    internal record MappedMember(
+        string Name,
+        string FullyQualifiedType,
+        string Type,
+        string? TypeConverter,
+        ImmutableArray<string> TypeConverterParameters,
+        string SourcePropertyName,
+        string? MappedSourcePropertyTypeName,
+        string? EnumerableTypeArgument,
+        ISymbol ActualSymbol,
+        INamedTypeSymbol? NamedTypeSymbol,
+        bool isEnumerable,
+        bool isReadOnly)
+    {
+        public bool IsEnumerable => EnumerableTypeArgument is not null;
+    }
+
+    internal record MappedSourceType
+    (
+        string SourceNamespace,
+        string SourceTypeIdentifierName,
+        string SourceTypeFullName,
+        ImmutableArray<MappedMember> SourceProperties,
+        ImmutableArray<MappedMember> SourceFields,
+        ImmutableArray<MappedMember> TypeProperties,
+        ImmutableArray<MappedMember> TypeFields,
+        bool GenerateSecondaryConstructor
+    )
+    {
+        public string SourceType => SourceTypeFullName;
+    }
+
+
+    internal record MappingModel(
+        SourceGenerationOptions Options,
+        string? Namespace,
+        SyntaxTokenList Modifiers,
+        string Type,
+        string TypeIdentifierName,
+        bool IsTypeUpdatable,
+        bool IsJsonExtension,
+        ImmutableArray<MappedSourceType> MappedSourceTypes,
+        bool HasMappedBaseClass,
+        ImmutableArray<string> Usings
+    );
+
+    internal interface IEfMethodsModel { }
+
+
+
+
+    internal record EfMethodsModel(
+        SourceGenerationOptions Options,
+        string Namespace,
+        string ContextTypeName,
+        string ContextFullType,
+        ImmutableArray<EfEntityDataModel> MethodsModels,
+        ImmutableArray<string> Usings
+    );
+
+    internal class EfEntityDataModel
+    {
+        public string PropertyName { get; set; }
+        public string EntityTypeFullName { get; set; }
+        public string EntityTypeIdentifierName { get; set; }
+
+        public EfEntityDataModel(string propertyName, string entityTypeFullName, string entityTypeIdentifierName)
+        {
+            PropertyName = propertyName;
+            EntityTypeFullName = entityTypeFullName;
+            EntityTypeIdentifierName = entityTypeIdentifierName;
+        }
+    }
+
+
+    internal class EfAddMethodsModel : EfEntityDataModel
+    {
+        public string CreateTypeFullName { get; set; }
+        public string CreateTypeIdentifierName { get; set; }
+        public string ReturnTypeFullName { get; set; }
+        public string ReturnTypeIdentifierName { get; set; }
+
+        public EfAddMethodsModel(EfEntityDataModel entity, string createTypeFullName,
+        string createTypeIdentifierName,
+        string returnTypeFullName,
+        string returnTypeIdentifierName) : base(entity.PropertyName, entity.EntityTypeFullName, entity.EntityTypeIdentifierName)
+        {
+            CreateTypeFullName = createTypeFullName;
+            CreateTypeIdentifierName = createTypeIdentifierName;
+            ReturnTypeIdentifierName = returnTypeIdentifierName;
+            ReturnTypeFullName = returnTypeFullName;
+        }
+    }
+
+    internal class EfGetOneByModel : EfEntityDataModel
+    {
+        public string ByParamPropertyName { get; set; }
+        public string ByParamFullTypeName { get; set; }
+        public string ByParamTypeName { get; set; }
+        public string ReturnTypeIdentifierName { get; set; }
+        public string ReturnTypeFullName { get; set; }
+
+
+        public EfGetOneByModel(EfEntityDataModel entity, string byParamPropertyName,
+        string byParamFullTypeName,
+        string returnTypeFullName,
+        string returnTypeIdentifierName) : base(entity.PropertyName, entity.EntityTypeFullName, entity.EntityTypeIdentifierName)
+        {
+            ByParamPropertyName = byParamPropertyName;
+            ByParamFullTypeName = byParamFullTypeName;
+            ReturnTypeIdentifierName = returnTypeIdentifierName;
+            ReturnTypeFullName = returnTypeFullName;
+            ByParamTypeName = returnTypeFullName;
+        }
+    }
+    
+    internal class EfGetOneWithModel : EfEntityDataModel
+    {
+        public string ReturnTypeIdentifierName { get; set; }
+        public string ReturnTypeFullName { get; set; }
+
+        public EfGetOneWithModel(EfEntityDataModel entity, string returnTypeFullName,
+        string returnTypeIdentifierName) : base(entity.PropertyName, entity.EntityTypeFullName, entity.EntityTypeIdentifierName)
+        {
+            ReturnTypeIdentifierName = returnTypeIdentifierName;
+            ReturnTypeFullName = returnTypeFullName;
+        }
+    }
+        
+    internal class EfGetManyModel : EfEntityDataModel
+    {
+        public string ReturnTypeIdentifierName { get; set; }
+        public string ReturnTypeFullName { get; set; }
+
+        public EfGetManyModel(EfEntityDataModel entity, string returnTypeFullName,
+        string returnTypeIdentifierName) : base(entity.PropertyName, entity.EntityTypeFullName, entity.EntityTypeIdentifierName)
+        {
+            ReturnTypeIdentifierName = returnTypeIdentifierName;
+            ReturnTypeFullName = returnTypeFullName;
+        }
+    }
+
+
+    internal class EfUpdateMethodsModel : EfEntityDataModel
+    {
+        public string UpdateTypeFullName;
+        public string UpdateTypeIdentifierName;
+        public  string ReturnTypeFullName;
+        public string ReturnTypeIdentifierName;
+        public string KeyPropertyName;
+        public string KeyFullTypeName;
+        public EfUpdateMethodsModel(EfEntityDataModel entity,
+        string updateTypeFullName,
+        string updateTypeIdentifierName,
+        string returnTypeFullName,
+        string returnTypeIdentifierName,
+        string keyPropertyName,
+        string keyFullTypeName) : base(entity.PropertyName, entity.EntityTypeFullName, entity.EntityTypeIdentifierName)
+        {
+            UpdateTypeFullName = updateTypeFullName;
+            UpdateTypeIdentifierName = updateTypeIdentifierName;
+            ReturnTypeFullName= returnTypeFullName;
+            ReturnTypeIdentifierName = returnTypeIdentifierName;
+            KeyPropertyName = keyPropertyName;  
+            KeyFullTypeName = keyFullTypeName;
+        }
+    }
+
+    internal record SourceGenerationOptions(
+        AccessModifier ConstructorAccessModifier,
+        AccessModifier GeneratedMethodsAccessModifier,
+        bool GenerateXmlDocument,
+        bool SupportNullableReferenceTypes,
+        bool SupportNullableStaticAnalysis)
+    {
+        internal static SourceGenerationOptions From(GeneratorExecutionContext context)
+        {
+            const string allowNullAttributeName = "System.Diagnostics.CodeAnalysis.AllowNullAttribute";
+            var supportNullableStaticAnalysis = context.GetBuildGlobalOption(propertyName: nameof(SupportNullableStaticAnalysis), NullStaticAnalysisState.Default);
+            var supportNullableReferenceTypes = context.Compilation.Options.NullableContextOptions is NullableContextOptions.Warnings or NullableContextOptions.Enable;
+
+            return new(
+                ConstructorAccessModifier: context.GetBuildGlobalOption(propertyName: nameof(ConstructorAccessModifier), AccessModifier.Public),
+                GeneratedMethodsAccessModifier: context.GetBuildGlobalOption(propertyName: nameof(GeneratedMethodsAccessModifier), AccessModifier.Public),
+                GenerateXmlDocument: context.GetBuildGlobalOption(propertyName: nameof(GenerateXmlDocument), true),
+                SupportNullableReferenceTypes: supportNullableReferenceTypes,
+                SupportNullableStaticAnalysis: supportNullableStaticAnalysis switch
+                {
+                    NullStaticAnalysisState.Enabled => true,
+                    NullStaticAnalysisState.Disabled => false,
+                    _ => context.Compilation is CSharpCompilation { LanguageVersion: >= LanguageVersion.CSharp8 } cs && cs.TypeByMetadataNameExists(allowNullAttributeName)
+                }
+            );
+        }
+
+        public string NullableReferenceSyntax => SupportNullableReferenceTypes ? "?" : string.Empty;
+    }
+}

src/BlueWest.MapTo/RecordMappingContext.cs

@@ -11,7 +11,12 @@ namespace MapTo
         internal RecordMappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
             : base(compilation, sourceGenerationOptions, typeSyntax) { }
 
-        protected override ImmutableArray<MappedProperty> GetSourceMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        protected override ImmutableArray<MappedMember> GetSourceMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        protected override ImmutableArray<MappedMember> GetSourceMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
         {
             var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
             return typeSymbol.GetMembers()
@@ -19,13 +24,18 @@ namespace MapTo
                 .OrderByDescending(s => s.Parameters.Length)
                 .First(s => s.Name == ".ctor")
                 .Parameters
-                .Where(p => !p.HasAttribute(IgnorePropertyAttributeTypeSymbol))
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
                 .Select(property => MapProperty(sourceTypeSymbol, sourceProperties, property))
                 .Where(mappedProperty => mappedProperty is not null)
                 .ToImmutableArray()!;
         }
 
-        protected override ImmutableArray<MappedProperty> GetTypeMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        protected override ImmutableArray<MappedMember> GetTypeMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        protected override ImmutableArray<MappedMember> GetTypeMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
         {
             var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
             return typeSymbol.GetMembers()
@@ -33,7 +43,7 @@ namespace MapTo
                 .OrderByDescending(s => s.Parameters.Length)
                 .First(s => s.Name == ".ctor")
                 .Parameters
-                .Where(p => !p.HasAttribute(IgnorePropertyAttributeTypeSymbol))
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
                 .Select(property => MapProperty(typeSymbol, sourceProperties, property))
                 .Where(mappedProperty => mappedProperty is not null)
                 .ToImmutableArray()!;

src/BlueWest.MapTo/Sources/DictionaryToListAttributeSource.cs

@@ -0,0 +1,60 @@
+using static MapTo.Sources.Constants;
+
+namespace MapTo.Sources
+{
+    internal static class DictionaryToListAttributeSource
+    {
+        internal const string AttributeName = "DictionaryToList";
+        internal const string AttributeClassName = AttributeName + "Attribute";
+        internal const string FullyQualifiedName = RootNamespace + "." + AttributeClassName;
+        internal const string SourceMemberNameFieldOrPropertyName = "SourcePropertyName";
+
+        internal static SourceCode Generate(SourceGenerationOptions options)
+        {
+            using var builder = new SourceBuilder()
+                .WriteLine(GeneratedFilesHeader)
+                .WriteNullableContextOptionIf(options.SupportNullableReferenceTypes)
+                .WriteLine()
+                .WriteLine("using System;")
+                .WriteLine()
+                .WriteLine($"namespace {RootNamespace}")
+                .WriteOpeningBracket();
+
+            if (options.GenerateXmlDocument)
+            {
+                builder
+                    .WriteLine("/// <summary>")
+                    .WriteLine("/// Specifies the mapping behavior of the annotated property.")
+                    .WriteLine("/// </summary>")
+                    .WriteLine("/// <remarks>")
+                    .WriteLine($"/// {AttributeClassName} has a number of uses:")
+                    .WriteLine("/// <list type=\"bullet\">")
+                    .WriteLine("/// <item><description>By default properties with same name will get mapped. This attribute allows the names to be different.</description></item>")
+                    .WriteLine("/// <item><description>Indicates that a property should be mapped when member serialization is set to opt-in.</description></item>")
+                    .WriteLine("/// </list>")
+                    .WriteLine("/// </remarks>");
+            }
+            
+            builder
+                .WriteLine("[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = true)]")
+                .WriteLine($"public sealed class {AttributeClassName} : Attribute")
+                .WriteOpeningBracket();
+         
+            if (options.GenerateXmlDocument)
+            {
+                builder
+                    .WriteLine("/// <summary>")
+                    .WriteLine("/// Gets or sets the property name of the object to mapping from.")
+                    .WriteLine("/// </summary>");
+            }
+
+            builder
+                .WriteLine($"public string{options.NullableReferenceSyntax} {SourceMemberNameFieldOrPropertyName} {{ get; set; }}")
+                .WriteClosingBracket() // class
+                .WriteClosingBracket(); // namespace
+
+            
+            return new(builder.ToString(), $"{AttributeClassName}.g.cs");
+        }
+    }
+}

src/BlueWest.MapTo/Sources/IgnoreMemberAttributeSource.cs

@@ -2,9 +2,9 @@
 
 namespace MapTo.Sources
 {
-    internal static class IgnorePropertyAttributeSource
+    internal static class IgnoreMemberAttributeSource
     {
-        internal const string AttributeName = "IgnoreProperty";
+        internal const string AttributeName = "IgnoreMemberMapTo";
         internal const string AttributeClassName = AttributeName + "Attribute";
         internal const string FullyQualifiedName = RootNamespace + "." + AttributeClassName;
 
@@ -26,7 +26,7 @@ namespace MapTo.Sources
             }
 
             builder
-                .WriteLine("[AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)]")
+                .WriteLine("[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, Inherited = false, AllowMultiple = false)]")
                 .WriteLine($"public sealed class {AttributeClassName} : Attribute {{ }}")
                 .WriteClosingBracket();
 

src/BlueWest.MapTo/Sources/JsonExtensionAttributeSource.cs

@@ -21,7 +21,7 @@ namespace MapTo.Sources
             {
                 builder
                     .WriteLine("/// <summary>")
-                    .WriteLine("/// Specifies that the annotated needs ToJson method")
+                    .WriteLine("/// Specifies that the annotated class has a json extension.")
                     .WriteLine("/// </summary>");
             }
 

src/BlueWest.MapTo/Sources/MapFromAttributeSource.cs

@@ -42,6 +42,13 @@ namespace MapTo.Sources
             builder
                 .WriteLine($"public {AttributeName}Attribute(Type sourceType)")
                 .WriteOpeningBracket()
+                .WriteLine("SourceType = new [] { sourceType };")
+                .WriteClosingBracket()
+                .WriteLine();
+
+            builder
+                .WriteLine($"public {AttributeName}Attribute(Type[] sourceType)")
+                .WriteOpeningBracket()
                 .WriteLine("SourceType = sourceType;")
                 .WriteClosingBracket()
                 .WriteLine();
@@ -55,7 +62,7 @@ namespace MapTo.Sources
             }
 
             builder
-                .WriteLine("public Type SourceType { get; }")
+                .WriteLine("public Type[] SourceType { get; }")
                 .WriteClosingBracket() // class
                 .WriteClosingBracket(); // namespace
 

src/BlueWest.MapTo/Sources/MapPropertyAttributeSource.cs

@@ -23,6 +23,7 @@ namespace MapTo.Sources
             if (options.GenerateXmlDocument)
             {
                 builder
+                    .WriteLine()
                     .WriteLine("/// <summary>")
                     .WriteLine("/// Specifies the mapping behavior of the annotated property.")
                     .WriteLine("/// </summary>")

src/BlueWest.MapTo/Sources/MapRecordSource.cs

@@ -0,0 +1,235 @@
+using System;
+using MapTo.Extensions;
+using static MapTo.Sources.Constants;
+
+namespace MapTo.Sources
+{
+    internal static class MapRecordSource
+    {
+        internal static SourceCode Generate(MappingModel model)
+        {
+            using var builder = new SourceBuilder()
+                .WriteLine(GeneratedFilesHeader)
+                .WriteNullableContextOptionIf(model.Options.SupportNullableReferenceTypes)
+                .WriteUsings(model.Usings)
+                .WriteLine()
+
+                // Namespace declaration
+                .WriteLine($"namespace {model.Namespace}")
+                .WriteOpeningBracket()
+
+                // Class declaration
+                .WriteLine($"partial record {model.TypeIdentifierName}")
+                .WriteOpeningBracket();
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                if (targetSourceType.GenerateSecondaryConstructor)
+                {
+                    builder
+                        .GenerateSecondaryConstructor(model)
+                        .WriteLine();
+                } 
+            }
+
+            // Class body
+            
+
+            builder
+                .GeneratePrivateConstructor(model)
+                
+                .WriteLine()
+                .GenerateFactoryMethod(model)
+
+                // End class declaration
+                .WriteClosingBracket()
+                .WriteLine()
+
+                // Extension class declaration
+                .GenerateSourceTypeExtensionClass(model)
+                
+
+                // End namespace declaration
+                .WriteClosingBracket();
+
+            return new(builder.ToString(), $"{model.Namespace}.{model.TypeIdentifierName}.g.cs");
+        }
+
+        private static SourceBuilder GenerateSecondaryConstructor(this SourceBuilder builder, MappingModel model)
+        {
+            // grab first data from array
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+                if (model.Options.GenerateXmlDocument)
+                {
+                    builder
+                        .WriteLine("/// <summary>")
+                        .WriteLine($"/// Initializes a new instance of the <see cref=\"{model.TypeIdentifierName}\"/> class")
+                        .WriteLine($"/// using the property values from the specified <paramref name=\"{sourceClassParameterName}\"/>.")
+                        .WriteLine("/// </summary>")
+                        .WriteLine($"/// <exception cref=\"ArgumentNullException\">{sourceClassParameterName} is null</exception>");
+                }
+                builder .WriteLine($"{model.Options.ConstructorAccessModifier.ToLowercaseString()} {model.TypeIdentifierName}({targetSourceType.SourceType} {sourceClassParameterName})")
+                    .WriteLine($"    : this(new {MappingContextSource.ClassName}(), {sourceClassParameterName}) {{ }}");
+            }
+
+
+
+            return builder;
+
+        }
+
+        private static SourceBuilder GeneratePrivateConstructor(this SourceBuilder builder, MappingModel model)
+        {
+            const string mappingContextParameterName = "context";
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+                builder
+                    .WriteLine(
+                        $"private protected {model.TypeIdentifierName}({MappingContextSource.ClassName} {mappingContextParameterName}, {targetSourceType.SourceType} {sourceClassParameterName})")
+                    .Indent()
+                    .Write(": this(").WriteProperties(model, sourceClassParameterName, mappingContextParameterName)
+                    .WriteLine(")")
+                    .Unindent()
+                    .WriteOpeningBracket()
+                    .WriteLine($"if ({mappingContextParameterName} == null) throw new ArgumentNullException(nameof({mappingContextParameterName}));")
+                    .WriteLine($"if ({sourceClassParameterName} == null) throw new ArgumentNullException(nameof({sourceClassParameterName}));")
+                    .WriteLine()
+                    .WriteLine($"{mappingContextParameterName}.{MappingContextSource.RegisterMethodName}({sourceClassParameterName}, this);")
+                    .WriteClosingBracket();
+            }
+            // End constructor declaration
+            return builder;
+        }
+
+        private static SourceBuilder WriteProperties(this SourceBuilder builder, MappingModel model, string sourceClassParameterName,
+            string mappingContextParameterName)
+        {
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                for (var i = 0; i < targetSourceType.SourceProperties.Length; i++)
+                {
+                    var property = targetSourceType.SourceProperties[i];
+                    if (property.TypeConverter is null)
+                    {
+                        if (property.IsEnumerable)
+                        {
+                            builder.Write(
+                                $"{property.Name}: {sourceClassParameterName}.{property.SourcePropertyName}.Select({mappingContextParameterName}.{MappingContextSource.MapMethodName}<{property.MappedSourcePropertyTypeName}, {property.EnumerableTypeArgument}>).ToList()");
+                        }
+                        else
+                        {
+                            builder.Write(property.MappedSourcePropertyTypeName is null
+                                ? $"{property.Name}: {sourceClassParameterName}.{property.SourcePropertyName}"
+                                : $"{property.Name}: {mappingContextParameterName}.{MappingContextSource.MapMethodName}<{property.MappedSourcePropertyTypeName}, {property.Type}>({sourceClassParameterName}.{property.SourcePropertyName})");
+                        }
+                    }
+                    else
+                    {
+                        var parameters = property.TypeConverterParameters.IsEmpty
+                            ? "null"
+                            : $"new object[] {{ {string.Join(", ", property.TypeConverterParameters)} }}";
+
+                        builder.Write(
+                            $"{property.Name}: new {property.TypeConverter}().Convert({sourceClassParameterName}.{property.SourcePropertyName}, {parameters})");
+                    }
+
+                    if (i < targetSourceType.SourceProperties.Length - 1)
+                    {
+                        builder.Write(", ");
+                    }
+                }
+            }
+
+            
+
+            return builder;
+        }
+
+        private static SourceBuilder GenerateFactoryMethod(this SourceBuilder builder, MappingModel model)
+        {
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+
+                builder
+                    .GenerateConvertorMethodsXmlDocs(model, sourceClassParameterName)
+                    .WriteLineIf(model.Options.SupportNullableStaticAnalysis, $"[return: NotNullIfNotNull(\"{sourceClassParameterName}\")]")
+                    .WriteLine(
+                        $"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static {model.TypeIdentifierName}{model.Options.NullableReferenceSyntax} From({targetSourceType.SourceType}{model.Options.NullableReferenceSyntax} {sourceClassParameterName})")
+                    .WriteOpeningBracket()
+                    .WriteLine(
+                        $"return {sourceClassParameterName} == null ? null : {MappingContextSource.ClassName}.{MappingContextSource.FactoryMethodName}<{targetSourceType.SourceType}, {model.TypeIdentifierName}>({sourceClassParameterName});")
+                    .WriteClosingBracket();
+            }
+            
+
+            return builder;
+        }
+
+        private static SourceBuilder GenerateConvertorMethodsXmlDocs(this SourceBuilder builder, MappingModel model, string sourceClassParameterName)
+        {
+            if (!model.Options.GenerateXmlDocument)
+            {
+                return builder;
+            }
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                builder
+                    .WriteLine("/// <summary>")
+                    .WriteLine($"/// Creates a new instance of <see cref=\"{model.TypeIdentifierName}\"/> and sets its participating properties")
+                    .WriteLine($"/// using the property values from <paramref name=\"{sourceClassParameterName}\"/>.")
+                    .WriteLine("/// </summary>")
+                    .WriteLine($"/// <param name=\"{sourceClassParameterName}\">The instance of <see cref=\"{targetSourceType.SourceType}\"/> to use as source.</param>")
+                    .WriteLine(
+                        $"/// <returns>A new instance of <see cred=\"{model.TypeIdentifierName}\"/> -or- <c>null</c> if <paramref name=\"{sourceClassParameterName}\"/> is <c>null</c>.</returns>");
+            }
+
+            return builder;
+
+        }
+
+        private static SourceBuilder GenerateSourceTypeExtensionClass(this SourceBuilder builder, MappingModel model)
+        {
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                builder
+                    .WriteLine(
+                        $"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static partial class {targetSourceType.SourceTypeIdentifierName}To{model.TypeIdentifierName}Extensions")
+                    .WriteOpeningBracket()
+                    .GenerateSourceTypeExtensionMethod(model)
+                    .WriteClosingBracket();
+            }
+
+            return builder;
+        }
+
+        private static SourceBuilder GenerateSourceTypeExtensionMethod(this SourceBuilder builder, MappingModel model)
+        {
+
+            foreach (var targetSourceType in model.MappedSourceTypes)
+            {
+                var sourceClassParameterName = targetSourceType.SourceTypeIdentifierName.ToCamelCase();
+
+                builder
+                    .GenerateConvertorMethodsXmlDocs(model, sourceClassParameterName)
+                    .WriteLineIf(model.Options.SupportNullableStaticAnalysis, $"[return: NotNullIfNotNull(\"{sourceClassParameterName}\")]")
+                    .WriteLine(
+                        $"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static {model.TypeIdentifierName}{model.Options.NullableReferenceSyntax} To{model.TypeIdentifierName}(this {targetSourceType.SourceType}{model.Options.NullableReferenceSyntax} {sourceClassParameterName})")
+                    .WriteOpeningBracket()
+                    .WriteLine($"return {sourceClassParameterName} == null ? null : new {model.TypeIdentifierName}({sourceClassParameterName});")
+                    .WriteClosingBracket();
+
+            }
+
+
+            return builder;
+        }
+    }
+}

src/BlueWest.MapTo/StructMappingContext.cs

@@ -0,0 +1,67 @@
+using System.Collections.Immutable;
+using System.Linq;
+using MapTo.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace MapTo
+{
+    internal class StructMappingContext : MappingContext
+    {
+        internal StructMappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
+            : base(compilation, sourceGenerationOptions, typeSyntax) { }
+
+        protected override ImmutableArray<MappedMember> GetSourceMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IFieldSymbol>().ToArray();
+
+            return typeSymbol
+                .GetAllMembers()
+                .OfType<IFieldSymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapField(sourceTypeSymbol, sourceProperties, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+        protected override ImmutableArray<MappedMember> GetSourceMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool hasInheritedClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
+
+            return typeSymbol
+                .GetAllMembers()
+                .OfType<IPropertySymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapProperty(sourceTypeSymbol, sourceProperties, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+        protected override ImmutableArray<MappedMember> GetTypeMappedFields(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IFieldSymbol>().ToArray();
+
+            return sourceTypeSymbol
+                .GetAllMembers()
+                .OfType<IFieldSymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapFieldSimple(typeSymbol, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+        protected override ImmutableArray<MappedMember> GetTypeMappedProperties(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool hasInheritedClass)
+        {
+            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
+
+            return sourceTypeSymbol
+                .GetAllMembers()
+                .OfType<IPropertySymbol>()
+                .Where(p => !p.HasAttribute(IgnoreMemberAttributeTypeSymbol))
+                .Select(property => MapPropertySimple(typeSymbol, property))
+                .Where(mappedProperty => mappedProperty is not null)
+                .ToImmutableArray()!;
+        }
+
+    }
+}

src/MapTo/ClassMappingContext.cs

@@ -1,39 +0,0 @@
-using System.Collections.Immutable;
-using System.Linq;
-using MapTo.Extensions;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp.Syntax;
-
-namespace MapTo
-{
-    internal class ClassMappingContext : MappingContext
-    {
-        internal ClassMappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
-            : base(compilation, sourceGenerationOptions, typeSyntax) { }
-
-        protected override ImmutableArray<MappedProperty> GetSourceMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
-        {
-            var sourceProperties = sourceTypeSymbol.GetAllMembers().ToArray();
-
-            return typeSymbol
-                .GetAllMembers(!isInheritFromMappedBaseClass)
-                .Where(p => !p.HasAttribute(IgnorePropertyAttributeTypeSymbol))
-                .Select(property => MapProperty(sourceTypeSymbol, sourceProperties, property))
-                .Where(mappedProperty => mappedProperty is not null)
-                .ToImmutableArray()!;
-        }
-
-        protected override ImmutableArray<MappedProperty> GetTypeMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass)
-        {
-            var sourceProperties = sourceTypeSymbol.GetAllMembers().ToArray();
-           
-
-            return typeSymbol
-                .GetAllMembers()
-                .Where(p => !p.HasAttribute(IgnorePropertyAttributeTypeSymbol))
-                .Select(property => MapProperty(typeSymbol, sourceProperties, property))
-                .Where(mappedProperty => mappedProperty is not null)
-                .ToImmutableArray()!;
-        }
-    }
-}

src/MapTo/Extensions/CommonExtensions.cs

@@ -1,51 +0,0 @@
-using MapTo.Sources;
-using System;
-using System.Collections.Generic;
-using System.Text;
-
-namespace MapTo.Extensions
-{
-    internal static class CommonExtensions
-    {
-        internal static SourceBuilder WriteComment(this SourceBuilder builder, string comment = "")
-        {
-            return builder.WriteLine($"// {comment}");
-        }
-
-        internal static SourceBuilder WriteModelInfo(this SourceBuilder builder, MappingModel model)
-        {
-            return builder
-                        .WriteLine()
-                        .WriteComment($" IsTypeUpdatable                {model.IsTypeUpdatable}")
-                        .WriteComment($" HasMappedBaseClass             {model.HasMappedBaseClass.ToString()}")
-                        .WriteComment($" Namespace                      {model.Namespace}")
-                        .WriteComment($" Options                        {model.Options.ToString()}")
-                        .WriteComment($" Type                           {model.Type}")
-                        .WriteComment($" TypeIdentifierName             {model.TypeIdentifierName}")
-                        .WriteComment($" SourceNamespace                {model.SourceNamespace}")
-                        .WriteComment($" SourceTypeFullName             {model.SourceTypeFullName}")
-                        .WriteComment($" SourceTypeIdentifierName       {model.SourceTypeIdentifierName}");
-
-        }
-
-        internal static SourceBuilder WriteMappedProperties(this SourceBuilder builder, System.Collections.Immutable.ImmutableArray<MappedProperty> mappedProperties)
-        {
-            foreach (var item in mappedProperties)
-            {
-                builder .WriteComment($" Name                           {item.Name}")
-                        .WriteComment($" Type                           {item.Type}")
-                        .WriteComment($" MappedSourcePropertyTypeName   {item.MappedSourcePropertyTypeName}")
-                        .WriteComment($" IsEnumerable                   {item.IsEnumerable}")
-                        .WriteComment($" FullyQualifiedType             {item.FullyQualifiedType}")
-                        .WriteComment($" EnumerableTypeArgument         {item.EnumerableTypeArgument}")
-                        .WriteComment($" SourcePropertyName             {item.SourcePropertyName}")
-                        .WriteComment($" TypeSymbol                     {item.FullyQualifiedType.ToString()}")
-                        .WriteComment($" isReadOnly                     {item.isReadOnly.ToString()}")
-                        .WriteLine();
-            }
-
-            return builder;
-        }
-
-    }
-}

src/MapTo/Extensions/CommonSource.cs

@@ -1,184 +0,0 @@
-using MapTo.Sources;
-using static MapTo.Sources.Constants;
-using System;
-using System.Collections.Generic;
-using System.Text;
-using System.Collections.Immutable;
-
-namespace MapTo.Extensions
-{
-    internal static class CommonSource
-    {
-        internal static SourceCode GenerateStructOrClass(this MappingModel model, string structOrClass)
-        {
-            const bool writeDebugInfo = true;
-
-            using var builder = new SourceBuilder()
-                .WriteLine(GeneratedFilesHeader)
-                .WriteNullableContextOptionIf(model.Options.SupportNullableReferenceTypes)
-                .WriteUsings(model.Usings)
-                .WriteLine()
-
-                // Namespace declaration
-                .WriteLine($"namespace {model.Namespace}")
-                .WriteOpeningBracket();
-
-            if(writeDebugInfo)
-            builder
-                .WriteModelInfo(model)
-                .WriteLine()
-                .WriteComment("Type properties")
-                .WriteComment()
-                .WriteMappedProperties(model.TypeProperties)
-                .WriteLine()
-                .WriteComment("Source properties")
-                .WriteMappedProperties(model.SourceProperties)
-                .WriteLine();
-
-            builder
-                // Class declaration
-                .WriteLine($"partial {structOrClass} {model.TypeIdentifierName}")
-                .WriteOpeningBracket()
-                .WriteLine()
-                // Class body
-                .GeneratePublicConstructor(model);
-
-            if (model.IsTypeUpdatable && model.TypeProperties.GetWritableMappedProperties().Length > 0) builder.GenerateUpdateMethod(model);
-
-            builder
-                .WriteLine()
-                // End class declaration
-                .WriteClosingBracket()
-                .WriteLine()
-                // End namespace declaration
-                .WriteClosingBracket();
-
-            return new(builder.ToString(), $"{model.Namespace}.{model.TypeIdentifierName}.g.cs");
-        }
-
-        private static SourceBuilder GeneratePublicConstructor(this SourceBuilder builder, MappingModel model)
-        {
-            var sourceClassParameterName = model.SourceTypeIdentifierName.ToCamelCase();
-            const string mappingContextParameterName = "context";
-
-            var baseConstructor = /*model.HasMappedBaseClass ? $" : base({mappingContextParameterName}, {sourceClassParameterName})" :*/ string.Empty;
-
-            var stringBuilder = new StringBuilder();
-
-            var otherProperties = new List<MappedProperty>();
-
-            foreach (var property in model.TypeProperties)
-            {
-                if (!model.SourceProperties.IsMappedProperty(property))
-                {
-                    stringBuilder.Append(", ");
-                    stringBuilder.Append($"{property.FullyQualifiedType} {property.SourcePropertyName.ToCamelCase()}");
-                    otherProperties.Add(property);
-                }
-            }
-   
-            var readOnlyPropertiesArguments = stringBuilder.ToString();
-
-            builder
-                .WriteLine($"public {model.TypeIdentifierName}({model.SourceType} {sourceClassParameterName}{readOnlyPropertiesArguments}){baseConstructor}")
-                .WriteOpeningBracket()
-                .TryWriteProperties(model.SourceProperties, otherProperties.ToArray().ToImmutableArray(), sourceClassParameterName, mappingContextParameterName, false);
-
-            // End constructor declaration
-            return builder.WriteClosingBracket();
-        }
-
-        private static bool IsMappedProperty(this ImmutableArray<MappedProperty> properties, MappedProperty property) {
-
-            foreach(var prop in properties)
-            {
-                if (prop.Name == property.Name) return true;
-            }
-
-            return false;
-        }
-
-        private static SourceBuilder TryWriteProperties(this SourceBuilder builder, ImmutableArray<MappedProperty> properties, System.Collections.Immutable.ImmutableArray<MappedProperty>? otherProperties,
-            string? sourceClassParameterName, string mappingContextParameterName, bool fromUpdate)
-        {
-            if (fromUpdate)
-            {
-                properties = properties.GetWritableMappedProperties();
-            }
-
-            foreach (var property in properties)
-            {
-                if (property.isReadOnly && fromUpdate) continue;
-
-                if (property.TypeConverter is null)
-                {
-                    if (property.IsEnumerable)
-                    {
-                        builder.WriteLine(
-                            $"{property.Name} = {sourceClassParameterName}.{property.SourcePropertyName}.Select({mappingContextParameterName}.{MappingContextSource.MapMethodName}<{property.MappedSourcePropertyTypeName}, {property.EnumerableTypeArgument}>).ToList();");
-                    }
-                    else
-                    {
-                        builder.WriteLine(property.MappedSourcePropertyTypeName is null
-                            ? $"{property.Name} = {sourceClassParameterName}.{property.SourcePropertyName};"
-                            : "");
-                    }
-                }
-                else
-                {
-                    var parameters = property.TypeConverterParameters.IsEmpty
-                        ? "null"
-                        : $"new object[] {{ {string.Join(", ", property.TypeConverterParameters)} }}";
-
-                    builder.WriteLine(
-                        $"{property.Name} = new {property.TypeConverter}().Convert({sourceClassParameterName}.{property.SourcePropertyName}, {parameters});");
-                }
-
-            }
-
-
-            if (otherProperties == null) return builder;
-
-            foreach (var property in otherProperties)
-            {
-                    builder.WriteLine(property.MappedSourcePropertyTypeName is null
-                    ? $"{property.Name} = {property.SourcePropertyName.ToCamelCase()};"
-                    : "");
-
-            }
-
-            return builder;
-
-        }
-
-
-        private static SourceBuilder GenerateUpdateMethod(this SourceBuilder builder, MappingModel model)
-        {
-            var sourceClassParameterName = model.SourceTypeIdentifierName.ToCamelCase();
-
-            builder
-               .GenerateUpdaterMethodsXmlDocs(model, sourceClassParameterName)
-               .WriteLine($"public void Update({model.SourceType} {sourceClassParameterName})")
-               .WriteOpeningBracket()
-               .TryWriteProperties(model.SourceProperties, null, sourceClassParameterName, "context", true)
-               .WriteClosingBracket();
-
-            return builder;
-        }
-
-        private static SourceBuilder GenerateUpdaterMethodsXmlDocs(this SourceBuilder builder, MappingModel model, string sourceClassParameterName)
-        {
-            if (!model.Options.GenerateXmlDocument)
-            {
-                return builder;
-            }
-
-            return builder
-                .WriteLine("/// <summary>")
-                .WriteLine($"/// Updates <see cref=\"{model.TypeIdentifierName}\"/> and sets its participating properties")
-                .WriteLine($"/// using the property values from <paramref name=\"{sourceClassParameterName}\"/>.")
-                .WriteLine("/// </summary>")
-                .WriteLine($"/// <param name=\"{sourceClassParameterName}\">The instance of <see cref=\"{model.SourceType}\"/> to use as source.</param>");
-        }
-    }
-}

src/MapTo/MappingContext.cs

@@ -1,453 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Linq;
-using MapTo.Extensions;
-using MapTo.Sources;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp.Syntax;
-
-namespace MapTo
-{
-    internal static class MappingContextExtensions
-    {
-        internal static ImmutableArray<MappedProperty> GetReadOnlyMappedProperties(this ImmutableArray<MappedProperty> mappedProperties) => mappedProperties.Where(p => p.isReadOnly).ToImmutableArray()!;
-        internal static ImmutableArray<MappedProperty> GetWritableMappedProperties(this ImmutableArray<MappedProperty> mappedProperties) => mappedProperties.Where(p => !p.isReadOnly).ToImmutableArray()!;
-    }
-
-    internal abstract class MappingContext
-    {
-        private readonly List<SymbolDisplayPart> _ignoredNamespaces;
-
-        protected MappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
-        {
-            _ignoredNamespaces = new();
-            Diagnostics = ImmutableArray<Diagnostic>.Empty;
-            Usings = ImmutableArray.Create("System", Constants.RootNamespace);
-            SourceGenerationOptions = sourceGenerationOptions;
-            TypeSyntax = typeSyntax;
-            Compilation = compilation;
-
-            IgnorePropertyAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(IgnorePropertyAttributeSource.FullyQualifiedName);
-            MapTypeConverterAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MapTypeConverterAttributeSource.FullyQualifiedName);
-            TypeConverterInterfaceTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(ITypeConverterSource.FullyQualifiedName);
-            MapPropertyAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MapPropertyAttributeSource.FullyQualifiedName);
-            MapFromAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MapFromAttributeSource.FullyQualifiedName);
-            UseUpdateAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(UseUpdateAttributeSource.FullyQualifiedName);
-            JsonExtensionAttributeTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(UseUpdateAttributeSource.FullyQualifiedName);
-
-            MappingContextTypeSymbol = compilation.GetTypeByMetadataNameOrThrow(MappingContextSource.FullyQualifiedName);
-
-            AddUsingIfRequired(sourceGenerationOptions.SupportNullableStaticAnalysis, "System.Diagnostics.CodeAnalysis");
-        }
-
-        public ImmutableArray<Diagnostic> Diagnostics { get; private set; }
-
-        public MappingModel? Model { get; private set; }
-
-        protected Compilation Compilation { get; }
-
-        protected INamedTypeSymbol IgnorePropertyAttributeTypeSymbol { get; }
-
-        protected INamedTypeSymbol MapFromAttributeTypeSymbol { get; }
-        
-        protected INamedTypeSymbol UseUpdateAttributeTypeSymbol { get; }
-
-        protected INamedTypeSymbol JsonExtensionAttributeTypeSymbol { get; }
-
-        protected INamedTypeSymbol MappingContextTypeSymbol { get; }
-
-        protected INamedTypeSymbol MapPropertyAttributeTypeSymbol { get; }
-
-        protected INamedTypeSymbol MapTypeConverterAttributeTypeSymbol { get; }
-
-        protected SourceGenerationOptions SourceGenerationOptions { get; }
-
-        protected INamedTypeSymbol TypeConverterInterfaceTypeSymbol { get; }
-
-        protected TypeDeclarationSyntax TypeSyntax { get; }
-
-        protected ImmutableArray<string> Usings { get; private set; }
-
-        public static MappingContext Create(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
-        {
-            MappingContext context = typeSyntax switch
-            {
-                StructDeclarationSyntax => new StructMappingContext(compilation, sourceGenerationOptions, typeSyntax),
-                ClassDeclarationSyntax => new ClassMappingContext(compilation, sourceGenerationOptions, typeSyntax),
-                RecordDeclarationSyntax => new RecordMappingContext(compilation, sourceGenerationOptions, typeSyntax),
-                _ => throw new ArgumentOutOfRangeException()
-            };
-
-            context.Model = context.CreateMappingModel();
-
-            return context;
-        }
-
-        protected void AddDiagnostic(Diagnostic diagnostic)
-        {
-            Diagnostics = Diagnostics.Add(diagnostic);
-        }
-
-        protected void AddUsingIfRequired(ISymbol? namedTypeSymbol) =>
-            AddUsingIfRequired(namedTypeSymbol?.ContainingNamespace.IsGlobalNamespace == false, namedTypeSymbol?.ContainingNamespace);
-
-        protected void AddUsingIfRequired(bool condition, INamespaceSymbol? ns) =>
-            AddUsingIfRequired(condition && ns is not null && !_ignoredNamespaces.Contains(ns.ToDisplayParts().First()), ns?.ToDisplayString());
-
-        protected void AddUsingIfRequired(bool condition, string? ns)
-        {
-            if (ns is not null && condition && ns != TypeSyntax.GetNamespace() && !Usings.Contains(ns))
-            {
-                Usings = Usings.Add(ns);
-            }
-        }
-
-        protected ISymbol? FindSourceProperty(IEnumerable<ISymbol> sourceMembers, ISymbol member)
-        {
-            var propertyName = member
-                .GetAttribute(MapPropertyAttributeTypeSymbol)
-                ?.NamedArguments
-                .SingleOrDefault(a => a.Key == MapPropertyAttributeSource.SourcePropertyNamePropertyName)
-                .Value.Value as string ?? member.Name;
-            foreach(var sourceProperty in sourceMembers)
-            {
-                if(sourceProperty is IPropertySymbol propertySymbol)
-                {
-                    if (propertySymbol.Name == propertyName) return sourceProperty;
-                }
-                if (sourceProperty is IFieldSymbol fieldSymbol)
-                {
-                    if (fieldSymbol.Name == propertyName) return sourceProperty;
-                }
-
-            }
-
-            return sourceMembers.SingleOrDefault(p => p.Name == propertyName);
-        }
-
-        protected abstract ImmutableArray<MappedProperty> GetSourceMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass);
-        protected abstract ImmutableArray<MappedProperty> GetTypeMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool isInheritFromMappedBaseClass);
-
-        protected INamedTypeSymbol? GetSourceTypeSymbol(TypeDeclarationSyntax typeDeclarationSyntax, SemanticModel? semanticModel = null) =>
-            GetSourceTypeSymbol(typeDeclarationSyntax.GetAttribute(MapFromAttributeSource.AttributeName), semanticModel);
-
-        protected INamedTypeSymbol? GetSourceTypeSymbol(SyntaxNode? attributeSyntax, SemanticModel? semanticModel = null)
-        {
-            if (attributeSyntax is null)
-            {
-                return null;
-            }
-
-            semanticModel ??= Compilation.GetSemanticModel(attributeSyntax.SyntaxTree);
-            var sourceTypeExpressionSyntax = attributeSyntax
-                .DescendantNodes()
-                .OfType<TypeOfExpressionSyntax>()
-                .SingleOrDefault();
-
-            return sourceTypeExpressionSyntax is not null ? semanticModel.GetTypeInfo(sourceTypeExpressionSyntax.Type).Type as INamedTypeSymbol : null;
-        }
-
-        protected bool IsTypeInheritFromMappedBaseClass(SemanticModel semanticModel)
-        {
-            return TypeSyntax.BaseList is not null && TypeSyntax.BaseList.Types
-                .Select(t => semanticModel.GetTypeInfo(t.Type).Type)
-                .Any(t => t?.GetAttribute(MapFromAttributeTypeSymbol) != null);
-        }
-
-        protected bool IsTypeUpdatable()
-        {
-            return TypeSyntax.GetAttribute("UseUpdate") != null;
-        }
-
-        protected bool IsJsonExtension()
-        {
-            return TypeSyntax.GetAttribute("JsonExtension") != null;
-        }
-
-        protected virtual MappedProperty? MapProperty(ISymbol sourceTypeSymbol, IReadOnlyCollection<ISymbol> sourceProperties, ISymbol property)
-        {
-            var sourceProperty = FindSourceProperty(sourceProperties, property);
-            if (sourceProperty is null || !property.TryGetTypeSymbol(out var propertyType))
-            {
-                return null;
-            }
-
-           
-            string? converterFullyQualifiedName = null;
-            var converterParameters = ImmutableArray<string>.Empty;
-            ITypeSymbol? mappedSourcePropertyType = null;
-            ITypeSymbol? enumerableTypeArgumentType = null;
-
-            if (!Compilation.HasCompatibleTypes(sourceProperty, property))
-            {
-                if (!TryGetMapTypeConverter(property, sourceProperty, out converterFullyQualifiedName, out converterParameters) &&
-                    !TryGetNestedObjectMappings(property, out mappedSourcePropertyType, out enumerableTypeArgumentType))
-                {
-                    return null;
-                }
-            }
-
-            AddUsingIfRequired(propertyType);
-            AddUsingIfRequired(enumerableTypeArgumentType);
-            AddUsingIfRequired(mappedSourcePropertyType);
-
-            bool isReadOnly = false;
-
-            if(property is IPropertySymbol pSymbol)
-            {
-                isReadOnly = pSymbol.IsReadOnly;
-            }
-            if (property is IFieldSymbol fSymbol)
-            {
-                isReadOnly = fSymbol.IsReadOnly;
-            }
-
-            return new MappedProperty(
-                property.Name,
-                property.GetTypeSymbol().ToString(),
-                ToQualifiedDisplayName(propertyType) ?? propertyType.Name,
-                converterFullyQualifiedName,
-                converterParameters.ToImmutableArray(),
-                sourceProperty.Name,
-                ToQualifiedDisplayName(mappedSourcePropertyType),
-                ToQualifiedDisplayName(enumerableTypeArgumentType),
-               isReadOnly);
-;
-        }
-        protected virtual MappedProperty? MapPropertySimple(ISymbol sourceTypeSymbol, ISymbol property)
-        {
-            if (!property.TryGetTypeSymbol(out var propertyType))
-            {
-                return null;
-            }
-
-
-            string? converterFullyQualifiedName = null;
-            var converterParameters = ImmutableArray<string>.Empty;
-            ITypeSymbol? mappedSourcePropertyType = null;
-            ITypeSymbol? enumerableTypeArgumentType = null;
-
-
-            AddUsingIfRequired(propertyType);
-            AddUsingIfRequired(enumerableTypeArgumentType);
-            AddUsingIfRequired(mappedSourcePropertyType);
-
-            bool isReadOnly = false;
-
-            if (property is IPropertySymbol pSymbol)
-            {
-                isReadOnly = pSymbol.IsReadOnly;
-            }
-            if (property is IFieldSymbol fSymbol)
-            {
-                isReadOnly = fSymbol.IsReadOnly;
-            }
-            return new MappedProperty(
-                property.Name,
-                property.GetTypeSymbol().ToString(),
-                ToQualifiedDisplayName(propertyType) ?? propertyType.Name,
-                converterFullyQualifiedName,
-                converterParameters.ToImmutableArray(),
-                property.Name,
-                ToQualifiedDisplayName(mappedSourcePropertyType),
-                ToQualifiedDisplayName(enumerableTypeArgumentType),
-               isReadOnly);
-            ;
-        }
-        protected bool TryGetMapTypeConverter(ISymbol property, ISymbol sourceMember, out string? converterFullyQualifiedName,
-            out ImmutableArray<string> converterParameters)
-        {
-            converterFullyQualifiedName = null;
-            converterParameters = ImmutableArray<string>.Empty;
-
-            if (!Diagnostics.IsEmpty())
-            {
-                return false;
-            }
-
-            var typeConverterAttribute = property.GetAttribute(MapTypeConverterAttributeTypeSymbol);
-            if (typeConverterAttribute?.ConstructorArguments.First().Value is not INamedTypeSymbol converterTypeSymbol)
-            {
-                return false;
-            }
-
-            var baseInterface = GetTypeConverterBaseInterface(converterTypeSymbol, property, sourceMember);
-            if (baseInterface is null)
-            {
-                AddDiagnostic(DiagnosticsFactory.InvalidTypeConverterGenericTypesError(property, sourceMember));
-                return false;
-            }
-
-            converterFullyQualifiedName = converterTypeSymbol.ToDisplayString();
-            converterParameters = GetTypeConverterParameters(typeConverterAttribute);
-            return true;
-        }
-
-        protected bool TryGetNestedObjectMappings(ISymbol property, out ITypeSymbol? mappedSourcePropertyType, out ITypeSymbol? enumerableTypeArgument)
-        {
-            mappedSourcePropertyType = null;
-            enumerableTypeArgument = null;
-
-            if (!Diagnostics.IsEmpty())
-            {
-                return false;
-            }
-
-            if (!property.TryGetTypeSymbol(out var propertyType))
-            {
-                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyTypeFoundError(property));
-                return false;
-            }
-
-            var mapFromAttribute = propertyType.GetAttribute(MapFromAttributeTypeSymbol);
-            if (mapFromAttribute is null &&
-                propertyType is INamedTypeSymbol namedTypeSymbol &&
-                !propertyType.IsPrimitiveType() &&
-                (Compilation.IsGenericEnumerable(propertyType) || propertyType.AllInterfaces.Any(i => Compilation.IsGenericEnumerable(i))))
-            {
-                enumerableTypeArgument = namedTypeSymbol.TypeArguments.First();
-                mapFromAttribute = enumerableTypeArgument.GetAttribute(MapFromAttributeTypeSymbol);
-            }
-
-            mappedSourcePropertyType = mapFromAttribute?.ConstructorArguments.First().Value as INamedTypeSymbol;
-
-            if (mappedSourcePropertyType is null && enumerableTypeArgument is null)
-            {
-                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyTypeFoundError(property));
-            }
-
-            return Diagnostics.IsEmpty();
-        }
-
-        private static ImmutableArray<string> GetTypeConverterParameters(AttributeData typeConverterAttribute)
-        {
-            var converterParameter = typeConverterAttribute.ConstructorArguments.Skip(1).FirstOrDefault();
-            return converterParameter.IsNull
-                ? ImmutableArray<string>.Empty
-                : converterParameter.Values.Where(v => v.Value is not null).Select(v => v.Value!.ToSourceCodeString()).ToImmutableArray();
-        }
-
-        private MappingModel? CreateMappingModel()
-        {
-            var semanticModel = Compilation.GetSemanticModel(TypeSyntax.SyntaxTree);
-            if (semanticModel.GetDeclaredSymbol(TypeSyntax) is not INamedTypeSymbol typeSymbol)
-            {
-                AddDiagnostic(DiagnosticsFactory.TypeNotFoundError(TypeSyntax.GetLocation(), TypeSyntax.Identifier.ValueText));
-                return null;
-            }
-
-            var sourceTypeSymbol = GetSourceTypeSymbol(TypeSyntax, semanticModel);
-            if (sourceTypeSymbol is null)
-            {
-                AddDiagnostic(DiagnosticsFactory.MapFromAttributeNotFoundError(TypeSyntax.GetLocation()));
-                return null;
-            }
-
-            _ignoredNamespaces.Add(sourceTypeSymbol.ContainingNamespace.ToDisplayParts().First());
-
-            var typeIdentifierName = TypeSyntax.GetIdentifierName();
-            var sourceTypeIdentifierName = sourceTypeSymbol.Name;
-            var isTypeInheritFromMappedBaseClass = IsTypeInheritFromMappedBaseClass(semanticModel);
-            var isTypeUpdatable = IsTypeUpdatable();
-            var isJsonExtension = IsJsonExtension();
-            var shouldGenerateSecondaryConstructor = ShouldGenerateSecondaryConstructor(semanticModel, sourceTypeSymbol);
-
-            var mappedProperties = GetSourceMappedMembers(typeSymbol, sourceTypeSymbol, isTypeInheritFromMappedBaseClass);
-          /*  if (!mappedProperties.Any())
-            {
-                AddDiagnostic(DiagnosticsFactory.NoMatchingPropertyFoundError(TypeSyntax.GetLocation(), typeSymbol, sourceTypeSymbol));
-                return null;
-            }*/
-
-            AddUsingIfRequired(mappedProperties.Any(p => p.IsEnumerable), "System.Linq");
-
-            var allProperties = GetTypeMappedMembers(sourceTypeSymbol, typeSymbol , isTypeInheritFromMappedBaseClass);
-
-            return new MappingModel(
-                SourceGenerationOptions,
-                TypeSyntax.GetNamespace(),
-                TypeSyntax.Modifiers,
-                TypeSyntax.Keyword.Text,
-                typeIdentifierName,
-                sourceTypeSymbol.ContainingNamespace.ToDisplayString(),
-                sourceTypeIdentifierName,
-                sourceTypeSymbol.ToDisplayString(),
-                isTypeUpdatable,
-                isJsonExtension,
-                mappedProperties,
-                allProperties,
-                isTypeInheritFromMappedBaseClass,
-                Usings,
-                shouldGenerateSecondaryConstructor);
-        }
-
-       
-
-        private INamedTypeSymbol? GetTypeConverterBaseInterface(ITypeSymbol converterTypeSymbol, ISymbol property, ISymbol sourceMember)
-        {
-            if (!property.TryGetTypeSymbol(out var propertyType))
-            {
-                return null;
-            }
-            ISymbol? type = null;
-
-            if(sourceMember is IPropertySymbol propertySymbol)
-            {
-                type = propertySymbol.Type;
-            }
-
-            if (sourceMember is IFieldSymbol fieldSymbol)
-            {
-                type = fieldSymbol.Type;
-            }
-
-            if (type == null) return null;
-
-            return converterTypeSymbol.AllInterfaces
-                .SingleOrDefault(i =>
-                    i.TypeArguments.Length == 2 &&
-                    SymbolEqualityComparer.Default.Equals(i.ConstructedFrom, TypeConverterInterfaceTypeSymbol) &&
-                    SymbolEqualityComparer.Default.Equals(type, i.TypeArguments[0]) &&
-                    SymbolEqualityComparer.Default.Equals(propertyType, i.TypeArguments[1]));
-        }
-
-        private bool ShouldGenerateSecondaryConstructor(SemanticModel semanticModel, ISymbol sourceTypeSymbol)
-        {
-            var constructorSyntax = TypeSyntax.DescendantNodes()
-                .OfType<ConstructorDeclarationSyntax>()
-                .SingleOrDefault(c =>
-                    c.ParameterList.Parameters.Count == 1 &&
-                    SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeInfo(c.ParameterList.Parameters.Single().Type!).ConvertedType, sourceTypeSymbol));
-
-            if (constructorSyntax is null)
-            {
-                // Secondary constructor is not defined.
-                return true;
-            }
-
-            if (constructorSyntax.Initializer?.ArgumentList.Arguments is not { Count: 2 } arguments ||
-                !SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeInfo(arguments[0].Expression).ConvertedType, MappingContextTypeSymbol) ||
-                !SymbolEqualityComparer.Default.Equals(semanticModel.GetTypeInfo(arguments[1].Expression).ConvertedType, sourceTypeSymbol))
-            {
-                AddDiagnostic(DiagnosticsFactory.MissingConstructorArgument(constructorSyntax));
-            }
-
-            return false;
-        }
-
-        private string? ToQualifiedDisplayName(ISymbol? symbol)
-        {
-            if (symbol is null)
-            {
-                return null;
-            }
-
-            var containingNamespace = TypeSyntax.GetNamespace();
-            var symbolNamespace = symbol.ContainingNamespace.ToDisplayString();
-            return  containingNamespace != symbolNamespace && _ignoredNamespaces.Contains(symbol.ContainingNamespace.ToDisplayParts().First())
-                ? symbol.ToDisplayString()
-                : symbol.Name;
-        }
-    }
-}

src/MapTo/Models.cs

@@ -1,89 +0,0 @@
-using System;
-using System.Collections.Immutable;
-using MapTo.Extensions;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp;
-
-namespace MapTo
-{
-    internal enum AccessModifier
-    {
-        Public,
-        Internal,
-        Private
-    }
-
-    internal enum NullStaticAnalysisState
-    {
-        Default,
-        Enabled,
-        Disabled
-    }
-
-    internal record SourceCode(string Text, string HintName);
-
-    internal record MappedProperty(
-        string Name,
-        string FullyQualifiedType,
-        string Type,
-        string? TypeConverter,
-        ImmutableArray<string> TypeConverterParameters,
-        string SourcePropertyName,
-        string? MappedSourcePropertyTypeName,
-        string? EnumerableTypeArgument,
-        bool isReadOnly)
-    {
-        public bool IsEnumerable => EnumerableTypeArgument is not null;
-    }
-
-    internal record MappingModel (
-        SourceGenerationOptions Options,
-        string? Namespace,
-        SyntaxTokenList Modifiers,
-        string Type,
-        string TypeIdentifierName,
-        string SourceNamespace,
-        string SourceTypeIdentifierName,
-        string SourceTypeFullName,
-        bool IsTypeUpdatable,
-        bool IsJsonExtension,
-        ImmutableArray<MappedProperty> SourceProperties,
-        ImmutableArray<MappedProperty> TypeProperties,
-        bool HasMappedBaseClass,
-        ImmutableArray<string> Usings,
-        bool GenerateSecondaryConstructor
-    )
-    {
-        public string SourceType => SourceTypeFullName;
-    }
-
-    internal record SourceGenerationOptions(
-        AccessModifier ConstructorAccessModifier,
-        AccessModifier GeneratedMethodsAccessModifier,
-        bool GenerateXmlDocument,
-        bool SupportNullableReferenceTypes,
-        bool SupportNullableStaticAnalysis)
-    {
-        internal static SourceGenerationOptions From(GeneratorExecutionContext context)
-        {
-            const string allowNullAttributeName = "System.Diagnostics.CodeAnalysis.AllowNullAttribute";
-            var supportNullableStaticAnalysis = context.GetBuildGlobalOption(propertyName: nameof(SupportNullableStaticAnalysis), NullStaticAnalysisState.Default);
-            var supportNullableReferenceTypes = context.Compilation.Options.NullableContextOptions is NullableContextOptions.Warnings or NullableContextOptions.Enable;
-
-            return new(
-                ConstructorAccessModifier: context.GetBuildGlobalOption(propertyName: nameof(ConstructorAccessModifier), AccessModifier.Public),
-                GeneratedMethodsAccessModifier: context.GetBuildGlobalOption(propertyName: nameof(GeneratedMethodsAccessModifier), AccessModifier.Public),
-                GenerateXmlDocument: context.GetBuildGlobalOption(propertyName: nameof(GenerateXmlDocument), true),
-                SupportNullableReferenceTypes: supportNullableReferenceTypes,
-                SupportNullableStaticAnalysis: supportNullableStaticAnalysis switch
-                {
-                    NullStaticAnalysisState.Enabled => true,
-                    NullStaticAnalysisState.Disabled => false,
-                    _ => context.Compilation is CSharpCompilation { LanguageVersion: >= LanguageVersion.CSharp8 } cs && cs.TypeByMetadataNameExists(allowNullAttributeName)
-                }
-            );
-        }
-
-        public string NullableReferenceSyntax => SupportNullableReferenceTypes ? "?" : string.Empty;
-    }
-}

src/MapTo/Nuget.Config

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<configuration>
-  <packageSources>
-    <add key="BlueWest.EfGenerator" value="https://git.codeliturgy.com/api/packages/P0/nuget/index.json" />
-  </packageSources>
-</configuration>

src/MapTo/Sources/MapRecordSource.cs

@@ -1,191 +0,0 @@
-using System;
-using MapTo.Extensions;
-using static MapTo.Sources.Constants;
-
-namespace MapTo.Sources
-{
-    internal static class MapRecordSource
-    {
-        internal static SourceCode Generate(MappingModel model)
-        {
-            using var builder = new SourceBuilder()
-                .WriteLine(GeneratedFilesHeader)
-                .WriteNullableContextOptionIf(model.Options.SupportNullableReferenceTypes)
-                .WriteUsings(model.Usings)
-                .WriteLine()
-
-                // Namespace declaration
-                .WriteLine($"namespace {model.Namespace}")
-                .WriteOpeningBracket()
-
-                // Class declaration
-                .WriteLine($"partial record {model.TypeIdentifierName}")
-                .WriteOpeningBracket();
-
-            // Class body
-            if (model.GenerateSecondaryConstructor)
-            {
-                builder
-                    .GenerateSecondaryConstructor(model)
-                    .WriteLine();
-            }
-
-            builder
-                .GeneratePrivateConstructor(model)
-                
-                .WriteLine()
-                .GenerateFactoryMethod(model)
-
-                // End class declaration
-                .WriteClosingBracket()
-                .WriteLine()
-
-                // Extension class declaration
-                .GenerateSourceTypeExtensionClass(model)
-                
-
-                // End namespace declaration
-                .WriteClosingBracket();
-
-            return new(builder.ToString(), $"{model.Namespace}.{model.TypeIdentifierName}.g.cs");
-        }
-
-        private static SourceBuilder GenerateSecondaryConstructor(this SourceBuilder builder, MappingModel model)
-        {
-            var sourceClassParameterName = model.SourceTypeIdentifierName.ToCamelCase();
-
-            if (model.Options.GenerateXmlDocument)
-            {
-                builder
-                    .WriteLine("/// <summary>")
-                    .WriteLine($"/// Initializes a new instance of the <see cref=\"{model.TypeIdentifierName}\"/> class")
-                    .WriteLine($"/// using the property values from the specified <paramref name=\"{sourceClassParameterName}\"/>.")
-                    .WriteLine("/// </summary>")
-                    .WriteLine($"/// <exception cref=\"ArgumentNullException\">{sourceClassParameterName} is null</exception>");
-            }
-
-            return builder
-                .WriteLine($"{model.Options.ConstructorAccessModifier.ToLowercaseString()} {model.TypeIdentifierName}({model.SourceType} {sourceClassParameterName})")
-                .WriteLine($"    : this(new {MappingContextSource.ClassName}(), {sourceClassParameterName}) {{ }}");
-        }
-
-        private static SourceBuilder GeneratePrivateConstructor(this SourceBuilder builder, MappingModel model)
-        {
-            var sourceClassParameterName = model.SourceTypeIdentifierName.ToCamelCase();
-            const string mappingContextParameterName = "context";
-
-            builder
-                .WriteLine($"private protected {model.TypeIdentifierName}({MappingContextSource.ClassName} {mappingContextParameterName}, {model.SourceType} {sourceClassParameterName})")
-                .Indent()
-                .Write(": this(").
-
-            WriteProperties(model, sourceClassParameterName, mappingContextParameterName)
-
-            .WriteLine(")")
-                .Unindent()
-                .WriteOpeningBracket()
-                .WriteLine($"if ({mappingContextParameterName} == null) throw new ArgumentNullException(nameof({mappingContextParameterName}));")
-                .WriteLine($"if ({sourceClassParameterName} == null) throw new ArgumentNullException(nameof({sourceClassParameterName}));")
-                .WriteLine()
-                .WriteLine($"{mappingContextParameterName}.{MappingContextSource.RegisterMethodName}({sourceClassParameterName}, this);");
-
-            // End constructor declaration
-            return builder.WriteClosingBracket();
-        }
-
-        private static SourceBuilder WriteProperties(this SourceBuilder builder, MappingModel model, string sourceClassParameterName,
-            string mappingContextParameterName)
-        {
-            for (var i = 0; i < model.SourceProperties.Length; i++)
-            {
-                var property = model.SourceProperties[i];
-                if (property.TypeConverter is null)
-                {
-                    if (property.IsEnumerable)
-                    {
-                        builder.Write(
-                            $"{property.Name}: {sourceClassParameterName}.{property.SourcePropertyName}.Select({mappingContextParameterName}.{MappingContextSource.MapMethodName}<{property.MappedSourcePropertyTypeName}, {property.EnumerableTypeArgument}>).ToList()");
-                    }
-                    else
-                    {
-                        builder.Write(property.MappedSourcePropertyTypeName is null
-                            ? $"{property.Name}: {sourceClassParameterName}.{property.SourcePropertyName}"
-                            : $"{property.Name}: {mappingContextParameterName}.{MappingContextSource.MapMethodName}<{property.MappedSourcePropertyTypeName}, {property.Type}>({sourceClassParameterName}.{property.SourcePropertyName})");
-                    }
-                }
-                else
-                {
-                    var parameters = property.TypeConverterParameters.IsEmpty
-                        ? "null"
-                        : $"new object[] {{ {string.Join(", ", property.TypeConverterParameters)} }}";
-
-                    builder.Write(
-                        $"{property.Name}: new {property.TypeConverter}().Convert({sourceClassParameterName}.{property.SourcePropertyName}, {parameters})");
-                }
-
-                if (i < model.SourceProperties.Length - 1)
-                {
-                    builder.Write(", ");
-                }
-            }
-
-            return builder;
-        }
-
-        private static SourceBuilder GenerateFactoryMethod(this SourceBuilder builder, MappingModel model)
-        {
-            var sourceClassParameterName = model.SourceTypeIdentifierName.ToCamelCase();
-
-            return builder
-                .GenerateConvertorMethodsXmlDocs(model, sourceClassParameterName)
-                .WriteLineIf(model.Options.SupportNullableStaticAnalysis, $"[return: NotNullIfNotNull(\"{sourceClassParameterName}\")]")
-                .WriteLine(
-                    $"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static {model.TypeIdentifierName}{model.Options.NullableReferenceSyntax} From({model.SourceType}{model.Options.NullableReferenceSyntax} {sourceClassParameterName})")
-                .WriteOpeningBracket()
-                .WriteLine(
-                    $"return {sourceClassParameterName} == null ? null : {MappingContextSource.ClassName}.{MappingContextSource.FactoryMethodName}<{model.SourceType}, {model.TypeIdentifierName}>({sourceClassParameterName});")
-                .WriteClosingBracket();
-        }
-
-        private static SourceBuilder GenerateConvertorMethodsXmlDocs(this SourceBuilder builder, MappingModel model, string sourceClassParameterName)
-        {
-            if (!model.Options.GenerateXmlDocument)
-            {
-                return builder;
-            }
-
-            return builder
-                .WriteLine("/// <summary>")
-                .WriteLine($"/// Creates a new instance of <see cref=\"{model.TypeIdentifierName}\"/> and sets its participating properties")
-                .WriteLine($"/// using the property values from <paramref name=\"{sourceClassParameterName}\"/>.")
-                .WriteLine("/// </summary>")
-                .WriteLine($"/// <param name=\"{sourceClassParameterName}\">The instance of <see cref=\"{model.SourceType}\"/> to use as source.</param>")
-                .WriteLine(
-                    $"/// <returns>A new instance of <see cred=\"{model.TypeIdentifierName}\"/> -or- <c>null</c> if <paramref name=\"{sourceClassParameterName}\"/> is <c>null</c>.</returns>");
-        }
-
-        private static SourceBuilder GenerateSourceTypeExtensionClass(this SourceBuilder builder, MappingModel model)
-        {
-            return builder
-                .WriteLine(
-                    $"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static partial class {model.SourceTypeIdentifierName}To{model.TypeIdentifierName}Extensions")
-                .WriteOpeningBracket()
-                .GenerateSourceTypeExtensionMethod(model)
-                .WriteClosingBracket();
-        }
-
-        private static SourceBuilder GenerateSourceTypeExtensionMethod(this SourceBuilder builder, MappingModel model)
-        {
-            var sourceClassParameterName = model.SourceTypeIdentifierName.ToCamelCase();
-
-            return builder
-                .GenerateConvertorMethodsXmlDocs(model, sourceClassParameterName)
-                .WriteLineIf(model.Options.SupportNullableStaticAnalysis, $"[return: NotNullIfNotNull(\"{sourceClassParameterName}\")]")
-                .WriteLine(
-                    $"{model.Options.GeneratedMethodsAccessModifier.ToLowercaseString()} static {model.TypeIdentifierName}{model.Options.NullableReferenceSyntax} To{model.TypeIdentifierName}(this {model.SourceType}{model.Options.NullableReferenceSyntax} {sourceClassParameterName})")
-                .WriteOpeningBracket()
-                .WriteLine($"return {sourceClassParameterName} == null ? null : new {model.TypeIdentifierName}({sourceClassParameterName});")
-                .WriteClosingBracket();
-        }
-    }
-}

src/MapTo/StructMappingContext.cs

@@ -1,38 +0,0 @@
-using System.Collections.Immutable;
-using System.Linq;
-using MapTo.Extensions;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.CSharp.Syntax;
-
-namespace MapTo
-{
-    internal class StructMappingContext : MappingContext
-    {
-        internal StructMappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
-            : base(compilation, sourceGenerationOptions, typeSyntax) { }
-
-        protected override ImmutableArray<MappedProperty> GetSourceMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool hasInheritedClass)
-        {
-            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
-
-            return typeSymbol
-                .GetAllMembers()
-                .Where(p => !p.HasAttribute(IgnorePropertyAttributeTypeSymbol))
-                .Select(property => MapProperty(sourceTypeSymbol, sourceProperties, property))
-                .Where(mappedProperty => mappedProperty is not null)
-                .ToImmutableArray()!;
-        }
-        protected override ImmutableArray<MappedProperty> GetTypeMappedMembers(ITypeSymbol typeSymbol, ITypeSymbol sourceTypeSymbol, bool hasInheritedClass)
-        {
-            var sourceProperties = sourceTypeSymbol.GetAllMembers().OfType<IPropertySymbol>().ToArray();
-
-            return sourceTypeSymbol
-                .GetAllMembers()
-                .Where(p => !p.HasAttribute(IgnorePropertyAttributeTypeSymbol))
-                .Select(property => MapPropertySimple(typeSymbol, property))
-                .Where(mappedProperty => mappedProperty is not null)
-                .ToImmutableArray()!;
-        }
-
-    }
-}

test/BlueWest.MapTo.Tests/BlueWest.MapTo.Tests.csproj

@@ -0,0 +1,42 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net6.0</TargetFramework>
+
+        <IsPackable>false</IsPackable>
+
+        <Nullable>enable</Nullable>
+
+        <RootNamespace>MapTo.Tests</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.3">
+            <PrivateAssets>all</PrivateAssets>
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+        </PackageReference>
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.2.0" />
+        <PackageReference Update="Nerdbank.GitVersioning">
+          <Version>3.5.109</Version>
+        </PackageReference>
+    </ItemGroup>
+    
+    <ItemGroup>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.3.0" />
+        <PackageReference Include="Shouldly" Version="4.0.3" />
+        <PackageReference Include="xunit" Version="2.4.2" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="coverlet.collector" Version="3.1.2">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\BlueWest.MapTo\BlueWest.MapTo.csproj" />
+    </ItemGroup>
+
+</Project>

test/BlueWest.MapTo.Tests/Common.cs

@@ -0,0 +1,252 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using MapTo.Extensions;
+using MapTo.Sources;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Shouldly;
+
+namespace MapTo.Tests
+{
+    internal static class Common
+    {
+        internal const int Indent1 = 4;
+        internal const int Indent2 = Indent1 * 2;
+        internal const int Indent3 = Indent1 * 3;
+        internal static readonly Location IgnoreLocation = Location.None;
+
+        internal static readonly Dictionary<string, string> DefaultAnalyzerOptions = new()
+        {
+            [GeneratorExecutionContextExtensions.GetBuildPropertyName(nameof(SourceGenerationOptions.GenerateXmlDocument))] = "false"
+        };
+
+        internal static string GetSourceText(SourceGeneratorOptions? options = null)
+        {
+            const string ns = "Test";
+            options ??= new SourceGeneratorOptions();
+            var hasDifferentSourceNamespace = options.SourceClassNamespace != ns;
+            var builder = new SourceBuilder();
+
+            builder.WriteLine("//");
+            builder.WriteLine("// Test source code.");
+            builder.WriteLine("//");
+            builder.WriteLine();
+
+            options.Usings?.ForEach(s => builder.WriteLine($"using {s};"));
+
+            if (options.UseMapToNamespace)
+            {
+                builder.WriteLine($"using {Constants.RootNamespace};");
+            }
+
+            builder
+                .WriteLine($"using {options.SourceClassNamespace};")
+                .WriteLine()
+                .WriteLine();
+
+            builder
+                .WriteLine($"namespace {ns}")
+                .WriteOpeningBracket();
+
+            if (hasDifferentSourceNamespace && options.UseMapToNamespace)
+            {
+                builder
+                    .WriteLine($"using {options.SourceClassNamespace};")
+                    .WriteLine()
+                    .WriteLine();
+            }
+
+            builder
+                .WriteLine(options.UseMapToNamespace ? "[MapFrom(typeof(Baz))]" : "[MapTo.MapFrom(typeof(Baz))]")
+                .WriteLine("public partial class Foo")
+                .WriteOpeningBracket();
+
+            for (var i = 1; i <= options.ClassPropertiesCount; i++)
+            {
+                builder.WriteLine(i % 2 == 0 ? $"public int Prop{i} {{ get; set; }}" : $"public int Prop{i} {{ get; }}");
+            }
+
+            options.PropertyBuilder?.Invoke(builder);
+
+            builder
+                .WriteClosingBracket()
+                .WriteClosingBracket()
+                .WriteLine()
+                .WriteLine();
+
+            builder
+                .WriteLine($"namespace {options.SourceClassNamespace}")
+                .WriteOpeningBracket()
+                .WriteLine("public class Baz")
+                .WriteOpeningBracket();
+
+            for (var i = 1; i <= options.SourceClassPropertiesCount; i++)
+            {
+                builder.WriteLine(i % 2 == 0 ? $"public int Prop{i} {{ get; set; }}" : $"public int Prop{i} {{ get; }}");
+            }
+
+            options.SourcePropertyBuilder?.Invoke(builder);
+
+            builder
+                .WriteClosingBracket()
+                .WriteClosingBracket();
+
+            return builder.ToString();
+        }
+
+        internal static string[] GetEmployeeManagerSourceText(
+            Func<string>? employeeClassSource = null,
+            Func<string>? managerClassSource = null,
+            Func<string>? employeeViewModelSource = null,
+            Func<string>? managerViewModelSource = null,
+            bool useDifferentViewModelNamespace = false)
+        {
+            return new[]
+            {
+                employeeClassSource?.Invoke() ?? DefaultEmployeeClassSource(),
+                managerClassSource?.Invoke() ?? DefaultManagerClassSource(),
+                employeeViewModelSource?.Invoke() ??
+                DefaultEmployeeViewModelSource(useDifferentViewModelNamespace),
+                managerViewModelSource?.Invoke() ?? DefaultManagerViewModelSource(useDifferentViewModelNamespace)
+            };
+
+            static string DefaultEmployeeClassSource() =>
+                @"
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Test.Data.Models
+{
+    public class Employee
+    {
+        public int Id { get; set; }
+
+        public string EmployeeCode { get; set; }
+
+        public Manager Manager { get; set; }
+    }
+}".Trim();
+
+            static string DefaultManagerClassSource() =>
+                @"using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Test.Data.Models
+{
+    public class Manager: Employee
+    {
+        public int Level { get; set; }
+
+        public IEnumerable<Employee> Employees { get; set; } = Array.Empty<Employee>();
+    }
+}
+".Trim();
+
+            static string DefaultEmployeeViewModelSource(bool useDifferentNamespace) => useDifferentNamespace
+                ? @"
+using MapTo;
+using Test.Data.Models;
+using Test.ViewModels2;
+
+namespace Test.ViewModels
+{
+    [MapFrom(typeof(Employee))]
+    public partial class EmployeeViewModel
+    {
+        public int Id { get; set; }
+
+        public string EmployeeCode { get; set; }
+
+        public ManagerViewModel Manager { get; set; }
+    }
+}
+".Trim()
+                : @"
+using MapTo;
+using Test.Data.Models;
+
+namespace Test.ViewModels
+{
+    [MapFrom(typeof(Employee))]
+    public partial class EmployeeViewModel
+    {
+        public int Id { get; set; }
+
+        public string EmployeeCode { get; set; }
+
+        public ManagerViewModel Manager { get; set; }
+    }
+}
+".Trim();
+
+            static string DefaultManagerViewModelSource(bool useDifferentNamespace) => useDifferentNamespace
+                ? @"
+using System;
+using System.Collections.Generic;
+using MapTo;
+using Test.Data.Models;
+using Test.ViewModels;
+
+namespace Test.ViewModels2
+{
+    [MapFrom(typeof(Manager))]
+    public partial class ManagerViewModel : EmployeeViewModel
+    {
+        public int Level { get; set; }
+
+        public IEnumerable<EmployeeViewModel> Employees { get; set; } = Array.Empty<EmployeeViewModel>();
+    }
+}
+".Trim()
+                : @"
+using System;
+using System.Collections.Generic;
+using MapTo;
+using Test.Data.Models;
+
+namespace Test.ViewModels
+{
+    [MapFrom(typeof(Manager))]
+    public partial class ManagerViewModel : EmployeeViewModel
+    {
+        public int Level { get; set; }
+
+        public IEnumerable<EmployeeViewModel> Employees { get; set; } = Array.Empty<EmployeeViewModel>();
+    }
+}".Trim();
+        }
+
+        internal static PropertyDeclarationSyntax GetPropertyDeclarationSyntax(SyntaxTree syntaxTree, string targetPropertyName, string targetClass = "Foo")
+        {
+            return syntaxTree.GetRoot()
+                .DescendantNodes()
+                .OfType<ClassDeclarationSyntax>()
+                .Single(c => c.Identifier.ValueText == targetClass)
+                .DescendantNodes()
+                .OfType<PropertyDeclarationSyntax>()
+                .Single(p => p.Identifier.ValueText == targetPropertyName);
+        }
+
+        internal static IPropertySymbol GetSourcePropertySymbol(string propertyName, Compilation compilation, string targetClass = "Foo")
+        {
+            var syntaxTree = compilation.SyntaxTrees.First();
+            var propSyntax = GetPropertyDeclarationSyntax(syntaxTree, propertyName, targetClass);
+
+            var semanticModel = compilation.GetSemanticModel(syntaxTree);
+            return semanticModel.GetDeclaredSymbol(propSyntax).ShouldNotBeNull();
+        }
+
+        internal record SourceGeneratorOptions(
+            bool UseMapToNamespace = false,
+            string SourceClassNamespace = "Test.Models",
+            int ClassPropertiesCount = 3,
+            int SourceClassPropertiesCount = 3,
+            Action<SourceBuilder>? PropertyBuilder = null,
+            Action<SourceBuilder>? SourcePropertyBuilder = null,
+            IEnumerable<string>? Usings = null);
+    }
+}

test/BlueWest.MapTo.Tests/CompilerServices/IsExternalInit.cs

@@ -0,0 +1,16 @@
+// ReSharper disable UnusedType.Global
+// ReSharper disable CheckNamespace
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.ComponentModel;
+
+namespace System.Runtime.CompilerServices
+{
+    /// <summary>
+    /// Reserved to be used by the compiler for tracking metadata.
+    /// This class should not be used by developers in source code.
+    /// </summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    internal static class IsExternalInit { }
+}

test/BlueWest.MapTo.Tests/Extensions/RoslynExtensions.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Linq;
+using System.Text;
+using Microsoft.CodeAnalysis;
+
+namespace MapTo.Tests.Extensions
+{
+    internal static class RoslynExtensions
+    {
+        internal static SyntaxTree? GetGeneratedSyntaxTree(this Compilation compilation, string className) =>
+            compilation.SyntaxTrees.FirstOrDefault(s => s.FilePath.EndsWith($"{className}.g.cs"));
+
+        internal static string PrintSyntaxTree(this Compilation compilation)
+        {
+            var builder = new StringBuilder();
+            
+            return string.Join(
+                Environment.NewLine,
+                compilation.SyntaxTrees
+                    .Reverse()
+                    .Select((s, i) =>
+                    {
+                        builder
+                            .Clear()
+                            .AppendLine("----------------------------------------")
+                            .AppendFormat("File Path: \"{0}\"", s.FilePath).AppendLine()
+                            .AppendFormat("Index: \"{0}\"", i).AppendLine()
+                            .AppendLine();
+
+                        var lines = s.ToString().Split(Environment.NewLine);
+                        var lineNumber = 0;
+                        foreach (var line in lines)
+                        {
+                            builder.AppendFormat("{0:00}: {1}", lineNumber, line).AppendLine();
+                            lineNumber++;
+                        }
+
+                        return builder.ToString();
+                    }));
+        }
+    }
+}

test/BlueWest.MapTo.Tests/Extensions/ShouldlyExtensions.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Shouldly;
+using Xunit;
+
+namespace MapTo.Tests.Extensions
+{
+    internal static class ShouldlyExtensions
+    {
+        internal static void ShouldContainSource(this IEnumerable<SyntaxTree> syntaxTree, string typeName, string expectedSource, string? customMessage = null)
+        {
+            var syntax = syntaxTree
+                .Select(s => s.ToString().Trim())
+                .FirstOrDefault(s => s.Contains(typeName));
+
+            syntax.ShouldNotBeNullOrWhiteSpace();
+            syntax.ShouldBe(expectedSource, customMessage);
+        }
+        
+        internal static void ShouldContainPartialSource(this IEnumerable<SyntaxTree> syntaxTree, string typeName, string expectedSource, string? customMessage = null)
+        {
+            var syntax = syntaxTree
+                .Select(s => s.ToString().Trim())
+                .FirstOrDefault(s => s.Contains(typeName));
+            
+            syntax.ShouldNotBeNullOrWhiteSpace();
+            syntax.ShouldContainWithoutWhitespace(expectedSource, customMessage);
+        }
+        
+        internal static void ShouldContainPartialSource(this SyntaxTree syntaxTree, string expectedSource, string? customMessage = null)
+        {
+            var syntax = syntaxTree.ToString();
+            syntax.ShouldNotBeNullOrWhiteSpace();
+            syntax.ShouldContainWithoutWhitespace(expectedSource, customMessage);
+        }
+        
+        internal static void ShouldBeSuccessful(this IEnumerable<Diagnostic> diagnostics, Compilation? compilation = null, IEnumerable<string>? ignoreDiagnosticsIds = null)
+        {
+            var actual = diagnostics
+                .Where(d => (ignoreDiagnosticsIds is null || ignoreDiagnosticsIds.All(i => !d.Id.StartsWith(i) )) && (d.Severity is DiagnosticSeverity.Warning or DiagnosticSeverity.Error))
+                .Select(c => $"{c.Severity}: {c.Location.GetLineSpan()} - {c.GetMessage()}").ToArray();
+
+            if (!actual.Any())
+            {
+                return;
+            }
+
+            var builder = new StringBuilder();
+            builder.AppendLine("Failed");
+
+            foreach (var d in actual)
+            {
+                builder.AppendFormat("- {0}", d).AppendLine();
+            }
+
+            if (compilation is not null)
+            {
+                builder.AppendLine("Generated Sources:");
+                builder.AppendLine(compilation.PrintSyntaxTree());
+            }
+            
+            Assert.False(true, builder.ToString());
+        }
+
+        internal static void ShouldNotBeSuccessful(this ImmutableArray<Diagnostic> diagnostics, Diagnostic expectedError)
+        {
+            var actualDiagnostics = diagnostics.FirstOrDefault(d => d.Id == expectedError.Id);
+            var compilationDiagnostics = actualDiagnostics == null ? diagnostics : diagnostics.Except(new[] { actualDiagnostics });
+            
+            compilationDiagnostics.ShouldBeSuccessful();
+            
+            Assert.NotNull(actualDiagnostics);
+            Assert.Equal(expectedError.Id, actualDiagnostics?.Id);
+            Assert.Equal(expectedError.Descriptor.Id, actualDiagnostics?.Descriptor.Id);
+            Assert.Equal(expectedError.Descriptor.Description, actualDiagnostics?.Descriptor.Description);
+            Assert.Equal(expectedError.Descriptor.Title, actualDiagnostics?.Descriptor.Title);
+            
+            if (expectedError.Location != Location.None)
+            {
+                Assert.Equal(expectedError.Location, actualDiagnostics?.Location);
+            }
+        }
+    }
+}

test/BlueWest.MapTo.Tests/IgnorePropertyAttributeTests.cs

@@ -0,0 +1,81 @@
+using System.Linq;
+using MapTo.Extensions;
+using MapTo.Sources;
+using MapTo.Tests.Extensions;
+using MapTo.Tests.Infrastructure;
+using Shouldly;
+using Xunit;
+using static MapTo.Tests.Common;
+
+namespace MapTo.Tests
+{
+    public class IgnorePropertyAttributeTests
+    {
+        /*
+        [Fact]
+        public void VerifyIgnorePropertyAttribute()
+        {
+            // Arrange
+            const string source = "";
+            var expectedAttribute = $@"
+{Constants.GeneratedFilesHeader}
+using System;
+
+namespace MapTo
+{{
+    [AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)]
+    public sealed class IgnorePropertyAttribute : Attribute {{ }}
+}}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(IgnorePropertyAttributeSource.AttributeName, expectedAttribute);
+        }
+        */
+
+        [Fact]
+        public void When_IgnorePropertyAttributeIsSpecified_Should_NotGenerateMappingsForThatProperty()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder =>
+                {
+                    builder
+                        .WriteLine("[IgnoreProperty]")
+                        .WriteLine("public int Prop4 { get; set; }");
+                },
+                SourcePropertyBuilder: builder => builder.WriteLine("public int Prop4 { get; set; }")));
+
+            var expectedResult = @"
+    partial class Foo
+    {
+        public Foo(Test.Models.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Models.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+            Prop2 = baz.Prop2;
+            Prop3 = baz.Prop3;
+        }
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+    }
+}

test/BlueWest.MapTo.Tests/Infrastructure/CSharpGenerator.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using MapTo.Tests.Extensions;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+
+namespace MapTo.Tests.Infrastructure
+{
+    internal static class CSharpGenerator
+    {
+        internal static (Compilation compilation, ImmutableArray<Diagnostic> diagnostics) GetOutputCompilation(
+            string source,
+            bool assertCompilation = false,
+            IDictionary<string, string>? analyzerConfigOptions = null,
+            NullableContextOptions nullableContextOptions = NullableContextOptions.Disable,
+            LanguageVersion languageVersion = LanguageVersion.CSharp7_3) =>
+            GetOutputCompilation(
+                new[] { source },
+                assertCompilation,
+                analyzerConfigOptions,
+                nullableContextOptions,
+                languageVersion);
+        
+        internal static (Compilation compilation, ImmutableArray<Diagnostic> diagnostics) GetOutputCompilation(
+            IEnumerable<string> sources, 
+            bool assertCompilation = false, 
+            IDictionary<string, string>? analyzerConfigOptions = null,
+            NullableContextOptions nullableContextOptions = NullableContextOptions.Disable, 
+            LanguageVersion languageVersion = LanguageVersion.CSharp7_3)
+        {
+            var references = AppDomain.CurrentDomain.GetAssemblies()
+                .Where(a => !a.IsDynamic && !string.IsNullOrWhiteSpace(a.Location))
+                .Select(a => MetadataReference.CreateFromFile(a.Location))
+                .ToList();
+            
+            var compilation = CSharpCompilation.Create(
+                $"{typeof(CSharpGenerator).Assembly.GetName().Name}.Dynamic",
+                sources.Select((source, index) => CSharpSyntaxTree.ParseText(source, path: $"Test{index:00}.g.cs", options: new CSharpParseOptions(languageVersion))),
+                references,
+                new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary, nullableContextOptions: nullableContextOptions));
+            
+            if (assertCompilation)
+            {
+                // NB: fail tests when the injected program isn't valid _before_ running generators
+                compilation.GetDiagnostics().ShouldBeSuccessful();
+            }
+
+            var driver = CSharpGeneratorDriver.Create(
+                new List<ISourceGenerator>() { new MapToGenerator()},
+                optionsProvider: new TestAnalyzerConfigOptionsProvider(analyzerConfigOptions),
+                parseOptions: new CSharpParseOptions(languageVersion)
+            );
+
+            driver.RunGeneratorsAndUpdateCompilation(compilation, out var outputCompilation, out var generateDiagnostics);
+            
+            generateDiagnostics.ShouldBeSuccessful(ignoreDiagnosticsIds: new[] { "MT" });
+            outputCompilation.GetDiagnostics().ShouldBeSuccessful(outputCompilation);
+
+            return (outputCompilation, generateDiagnostics);
+        }
+    }
+}

test/BlueWest.MapTo.Tests/Infrastructure/TestAnalyzerConfigOptions.cs

@@ -0,0 +1,19 @@
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace MapTo.Tests.Infrastructure
+{
+    internal sealed class TestAnalyzerConfigOptions : AnalyzerConfigOptions
+    {
+        private readonly ImmutableDictionary<string, string> _backing;
+
+        public TestAnalyzerConfigOptions(IDictionary<string, string>? properties)
+        {
+            _backing = properties?.ToImmutableDictionary(KeyComparer) ?? ImmutableDictionary.Create<string, string>(KeyComparer);
+        }
+
+        public override bool TryGetValue(string key, out string? value) => _backing.TryGetValue(key, out value);
+    }
+}

test/BlueWest.MapTo.Tests/Infrastructure/TestAnalyzerConfigOptionsProvider.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.Diagnostics;
+
+namespace MapTo.Tests.Infrastructure
+{
+    internal sealed class TestAnalyzerConfigOptionsProvider : AnalyzerConfigOptionsProvider
+    {
+        public TestAnalyzerConfigOptionsProvider(IDictionary<string, string>? options)
+        {
+            GlobalOptions = new TestAnalyzerConfigOptions(options);
+        }
+
+        /// <inheritdoc />
+        public override AnalyzerConfigOptions GlobalOptions { get; }
+
+        /// <inheritdoc />
+        public override AnalyzerConfigOptions GetOptions(SyntaxTree tree) => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public override AnalyzerConfigOptions GetOptions(AdditionalText textFile) => throw new NotImplementedException();
+    }
+}

test/BlueWest.MapTo.Tests/MapPropertyTests.cs

@@ -0,0 +1,202 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using MapTo.Sources;
+using MapTo.Tests.Extensions;
+using MapTo.Tests.Infrastructure;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Xunit;
+using static MapTo.Tests.Common;
+
+namespace MapTo.Tests
+{
+    public class MapPropertyTests
+    {
+        [Theory]
+        [InlineData(NullableContextOptions.Disable)]
+        [InlineData(NullableContextOptions.Enable)]
+        public void VerifyMapPropertyAttribute(NullableContextOptions nullableContextOptions)
+        {
+            // Arrange
+            const string source = "";
+            var nullableSyntax = nullableContextOptions == NullableContextOptions.Enable ? "?" : string.Empty;
+            var languageVersion = nullableContextOptions == NullableContextOptions.Enable ? LanguageVersion.CSharp8 : LanguageVersion.CSharp7_3;
+            var expectedInterface = $@"
+{Constants.GeneratedFilesHeader}
+{(nullableContextOptions == NullableContextOptions.Enable ? $"#nullable enable{Environment.NewLine}" : string.Empty)}
+using System;
+
+namespace MapTo
+{{
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Parameter, AllowMultiple = true)]
+    public sealed class MapPropertyAttribute : Attribute
+    {{
+        public string{nullableSyntax} SourcePropertyName {{ get; set; }}
+    }}
+}}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, nullableContextOptions: nullableContextOptions, languageVersion: languageVersion);
+
+            
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(MapPropertyAttributeSource.AttributeName, expectedInterface);
+        }
+
+        [Fact]
+        public void When_MapPropertyFound_Should_UseItToMapToSourceProperty()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder =>
+                {
+                    builder
+                        .WriteLine("[MapProperty(SourcePropertyName = nameof(Baz.Prop3))]")
+                        .WriteLine("public int Prop4 { get; set; }");
+                },
+                SourcePropertyBuilder: builder => builder.WriteLine("public int Prop4 { get; set; }")));
+
+            var expectedResult = @"
+    partial class Foo
+    {
+        public Foo(Test.Models.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Models.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+            Prop2 = baz.Prop2;
+            Prop3 = baz.Prop3;
+            Prop4 = baz.Prop3;
+        }
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+
+        [Theory]
+        [MemberData(nameof(MapPropertyWithImplicitConversionFoundData))]
+        public void When_MapPropertyWithImplicitConversionFound_Should_UseItToMapToSourceProperty(string source, string expectedResult, LanguageVersion languageVersion)
+        {
+            // Arrange
+            source = source.Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: languageVersion);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+
+        public static IEnumerable<object[]> MapPropertyWithImplicitConversionFoundData => new List<object[]>
+        {
+            new object[]
+            {
+                @"
+namespace Test
+{
+    using System.Collections.Generic;
+
+    public class InnerClass { public int Prop1 { get; set; } }
+    public class OuterClass
+    {
+        public int Id { get; set; }
+        public List<InnerClass> InnerProp { get; set; }
+    }
+}
+
+namespace Test.Models
+{
+    using MapTo;
+    using System.Collections.Generic;
+
+    [MapFrom(typeof(Test.InnerClass))]
+    public partial class InnerClass { public int Prop1 { get; set; } }
+
+    [MapFrom(typeof(Test.OuterClass))]
+    public partial class OuterClass
+    {
+        public int Id { get; set; }
+        public IReadOnlyList<InnerClass> InnerProp { get; set; }
+    }
+}
+",
+                @"
+        private protected OuterClass(MappingContext context, Test.OuterClass outerClass)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (outerClass == null) throw new ArgumentNullException(nameof(outerClass));
+
+            context.Register(outerClass, this);
+
+            Id = outerClass.Id;
+            InnerProp = outerClass.InnerProp.Select(context.MapFromWithContext<Test.InnerClass, InnerClass>).ToList();
+        }
+",
+                LanguageVersion.CSharp7_3
+            },
+            new object[]
+            {
+                @"
+namespace Test 
+{
+    using System;
+    using System.Collections.Generic;
+
+    public class InnerClass
+    {      
+        public int Id { get; set; }
+        public string Name { get; set; }
+    }
+
+    public class OuterClass
+    {
+        public int Id { get; set; }
+        public List<InnerClass> InnerClasses { get; set; }
+        public DateTime? SomeDate { get; set; }
+    }  
+}
+
+namespace Test.Models
+{
+    using MapTo;
+    using System;
+    using System.Collections.Generic;
+
+    [MapFrom(typeof(Test.InnerClass))]
+    public partial record InnerClass(int Id, string Name);
+
+    [MapFrom(typeof(Test.OuterClass))]
+    public partial record OuterClass(int Id, DateTime? SomeDate, IReadOnlyList<InnerClass> InnerClasses);
+}
+",
+                @"
+        private protected OuterClass(MappingContext context, Test.OuterClass outerClass)
+            : this(Id: outerClass.Id, SomeDate: outerClass.SomeDate, InnerClasses: outerClass.InnerClasses.Select(context.MapFromWithContext<Test.InnerClass, InnerClass>).ToList())
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (outerClass == null) throw new ArgumentNullException(nameof(outerClass));
+
+            context.Register(outerClass, this);
+        }
+",
+                LanguageVersion.CSharp9
+            }
+        };
+    }
+}

test/BlueWest.MapTo.Tests/MapToTests.cs

@@ -0,0 +1,601 @@
+using System.Collections.Generic;
+using System.Linq;
+using MapTo.Sources;
+using MapTo.Tests.Extensions;
+using MapTo.Tests.Infrastructure;
+using Shouldly;
+using Xunit;
+using static MapTo.Extensions.GeneratorExecutionContextExtensions;
+using static MapTo.Tests.Common;
+
+namespace MapTo.Tests
+{
+    public class MapToTests
+    {
+        private static readonly string ExpectedAttribute = $@"{Constants.GeneratedFilesHeader}
+using System;
+
+namespace MapTo
+{{
+    [AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
+    public sealed class MapFromAttribute : Attribute
+    {{
+        public MapFromAttribute(Type sourceType)
+        {{
+            SourceType = sourceType;
+        }}
+
+        public Type SourceType {{ get; }}
+    }}
+}}";
+
+        [Fact]
+        public void VerifyMapToAttribute()
+        {
+            // Arrange
+            const string source = "";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(MapFromAttributeSource.AttributeClassName, ExpectedAttribute);
+        }
+
+        [Fact]
+        public void When_FoundMatchingPropertyNameWithDifferentTypes_Should_ReportError()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder => { builder.WriteLine("public string Prop4 { get; set; }"); },
+                SourcePropertyBuilder: builder => builder.WriteLine("public int Prop4 { get; set; }")));
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            var expectedError = DiagnosticsFactory.NoMatchingPropertyTypeFoundError(GetSourcePropertySymbol("Prop4", compilation));
+
+            diagnostics.ShouldNotBeSuccessful(expectedError);
+        }
+
+        [Fact]
+        public void When_MappingsModifierOptionIsSetToInternal_Should_GenerateThoseMethodsWithInternalAccessModifier()
+        {
+            // Arrange
+            var source = GetSourceText();
+            var configOptions = new Dictionary<string, string>
+            {
+                [GetBuildPropertyName(nameof(SourceGenerationOptions.GeneratedMethodsAccessModifier))] = "Internal",
+                [GetBuildPropertyName(nameof(SourceGenerationOptions.GenerateXmlDocument))] = "false"
+            };
+
+            var expectedExtension = @"    
+    internal static partial class BazToFooExtensions
+    {
+        internal static Foo ToFoo(this Test.Models.Baz baz)
+        {
+            return baz == null ? null : new Foo(baz);
+        }
+    }".Trim();
+
+            var expectedFactory = @"
+        internal static Foo From(Test.Models.Baz baz)
+        {
+            return baz == null ? null : MappingContext.Create<Test.Models.Baz, Foo>(baz);
+        }".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: configOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+
+            var syntaxTree = compilation.SyntaxTrees.Last().ToString();
+            syntaxTree.ShouldContain(expectedFactory);
+            syntaxTree.ShouldContain(expectedExtension);
+        }
+
+        [Fact]
+        public void When_MapToAttributeFound_Should_GenerateTheClass()
+        {
+            // Arrange
+            const string source = @"
+using MapTo;
+
+namespace Test
+{
+    [MapFrom(typeof(Baz))]
+    public partial class Foo
+    {
+        public int Prop1 { get; set; }
+    }
+
+    public class Baz 
+    {
+        public int Prop1 { get; set; }
+    }
+}
+";
+
+            const string expectedResult = @"
+// <auto-generated />
+using MapTo;
+using System;
+
+namespace Test
+{
+    partial class Foo
+    {
+        public Foo(Test.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ToString().ShouldStartWith(expectedResult.Trim());
+        }
+
+        [Fact]
+        public void When_MapToAttributeFoundWithoutMatchingProperties_Should_ReportError()
+        {
+            // Arrange
+            const string source = @"
+using MapTo;
+
+namespace Test
+{
+    [MapFrom(typeof(Baz))]
+    public partial class Foo { }
+
+    public class Baz { public int Prop1 { get; set; } }
+}
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source);
+
+            // Assert
+            var fooType = compilation.GetTypeByMetadataName("Test.Foo");
+            fooType.ShouldNotBeNull();
+
+            var bazType = compilation.GetTypeByMetadataName("Test.Baz");
+            bazType.ShouldNotBeNull();
+
+            var expectedDiagnostic = DiagnosticsFactory.NoMatchingPropertyFoundError(fooType.Locations.Single(), fooType, bazType);
+            var error = diagnostics.FirstOrDefault(d => d.Id == expectedDiagnostic.Id);
+            error.ShouldNotBeNull();
+        }
+
+        [Fact]
+        public void When_MapToAttributeWithNamespaceFound_Should_GenerateTheClass()
+        {
+            // Arrange
+            const string source = @"
+namespace Test
+{
+    [MapTo.MapFrom(typeof(Baz))]
+    public partial class Foo { public int Prop1 { get; set; } }
+
+    public class Baz { public int Prop1 { get; set; } }
+}
+";
+
+            const string expectedResult = @"
+// <auto-generated />
+using MapTo;
+using System;
+
+namespace Test
+{
+    partial class Foo
+    {
+        public Foo(Test.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ToString().ShouldStartWith(expectedResult.Trim());
+        }
+
+        [Fact]
+        public void When_NoMapToAttributeFound_Should_GenerateOnlyTheAttribute()
+        {
+            // Arrange
+            const string source = "";
+            var expectedTypes = new[]
+            {
+                //IgnorePropertyAttributeSource.AttributeName,
+                MapFromAttributeSource.AttributeName,
+                ITypeConverterSource.InterfaceName,
+                MapPropertyAttributeSource.AttributeName
+            };
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees
+                .Select(s => s.ToString())
+                .Where(s => !string.IsNullOrWhiteSpace(s.ToString()))
+                .All(s => expectedTypes.Any(s.Contains))
+                .ShouldBeTrue();
+        }
+
+        [Fact]
+        public void When_SourceTypeHasDifferentNamespace_Should_NotAddToUsings()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(SourceClassNamespace: "Bazaar"));
+
+            const string expectedResult = @"
+// <auto-generated />
+using MapTo;
+using System;
+
+namespace Test
+{
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ToString().ShouldStartWith(expectedResult.Trim());
+        }
+
+        [Fact]
+        public void When_SourceTypeHasMatchingProperties_Should_CreateConstructorAndAssignSrcToDest()
+        {
+            // Arrange
+            var source = GetSourceText();
+
+            const string expectedResult = @"
+    partial class Foo
+    {
+        public Foo(Test.Models.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Models.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+            Prop2 = baz.Prop2;
+            Prop3 = baz.Prop3;
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult.Trim());
+        }
+
+        [Fact]
+        public void When_SourceTypeHasMatchingProperties_Should_CreateFromStaticMethod()
+        {
+            // Arrange
+            var source = GetSourceText();
+
+            const string expectedResult = @"
+        public static Foo From(Test.Models.Baz baz)
+        {
+            return baz == null ? null : MappingContext.Create<Test.Models.Baz, Foo>(baz);
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult.Trim());
+        }
+
+        [Fact]
+        public void When_SourceTypeHasMatchingProperties_Should_GenerateToExtensionMethodOnSourceType()
+        {
+            // Arrange
+            var source = GetSourceText();
+
+            const string expectedResult = @"
+    public static partial class BazToFooExtensions
+    {
+        public static Foo ToFoo(this Test.Models.Baz baz)
+        {
+            return baz == null ? null : new Foo(baz);
+        }
+    }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult.Trim());
+        }
+
+        [Fact]
+        public void When_HasNestedObjectPropertyTypeHasMapFromAttribute_Should_UseContinueToMap()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                SourceClassNamespace: "Test",
+                PropertyBuilder: b => b.WriteLine("public B InnerProp1 { get; }"),
+                SourcePropertyBuilder: b => b.WriteLine("public A InnerProp1 { get; }")));
+
+            source += @"
+namespace Test
+{
+    public class A { public int Prop1 { get; } }
+
+    [MapTo.MapFrom(typeof(A))]
+    public partial class B { public int Prop1 { get; }}
+}
+".Trim();
+            
+            var expectedResult = @"
+    partial class Foo
+    {
+        public Foo(Test.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+            Prop2 = baz.Prop2;
+            Prop3 = baz.Prop3;
+            InnerProp1 = context.MapFromWithContext<A, B>(baz.InnerProp1);
+        }
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ToArray()[^2].ShouldContainPartialSource(expectedResult);
+        }
+        
+        [Fact]
+        public void When_HasNestedObjectPropertyTypeDoesNotHaveMapFromAttribute_Should_ReportError()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                SourceClassNamespace: "Test",
+                PropertyBuilder: b => b.WriteLine("public FooInner1 InnerProp1 { get; }"),
+                SourcePropertyBuilder: b => b.WriteLine("public BazInner1 InnerProp1 { get; }")));
+
+            source += @"
+namespace Test
+{
+    public class FooInner1 { public int Prop1 { get; } }
+    
+    public partial class BazInner1 { public int Prop1 { get; }}
+}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            var expectedError = DiagnosticsFactory.NoMatchingPropertyTypeFoundError(GetSourcePropertySymbol("InnerProp1", compilation));
+            diagnostics.ShouldNotBeSuccessful(expectedError);
+        }
+        
+        [Fact]
+        public void When_HasNestedObjectPropertyTypeHasMapFromAttributeToDifferentType_Should_ReportError()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                SourceClassNamespace: "Test",
+                PropertyBuilder: b => b.WriteLine("public FooInner1 InnerProp1 { get; }"),
+                SourcePropertyBuilder: b => b.WriteLine("public BazInner1 InnerProp1 { get; }")));
+
+            source += @"
+namespace Test
+{
+    public class FooInner1 { public int Prop1 { get; } }
+
+    public class FooInner2 { public int Prop1 { get; } }
+
+    [MapTo.MapFrom(typeof(FooInner2))]
+    public partial class BazInner1 { public int Prop1 { get; }}
+}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            var expectedError = DiagnosticsFactory.NoMatchingPropertyTypeFoundError(GetSourcePropertySymbol("InnerProp1", compilation));
+            diagnostics.ShouldNotBeSuccessful(expectedError);
+        }
+        
+        [Fact]
+        public void When_SourceTypeEnumerableProperties_Should_CreateConstructorAndAssignSrcToDest()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                Usings: new[] { "System.Collections.Generic"}, 
+                PropertyBuilder: builder => builder.WriteLine("public IEnumerable<int> Prop4 { get; }"),
+                SourcePropertyBuilder: builder => builder.WriteLine("public IEnumerable<int> Prop4 { get; }")));
+
+            const string expectedResult = @"
+    partial class Foo
+    {
+        public Foo(Test.Models.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Models.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+            Prop2 = baz.Prop2;
+            Prop3 = baz.Prop3;
+            Prop4 = baz.Prop4;
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult.Trim());
+        }
+        
+        [Fact]
+        public void When_DestinationTypeHasBaseClass_Should_CallBaseConstructor()
+        {
+            // Arrange
+            var sources = GetEmployeeManagerSourceText();
+
+            const string expectedResult = @"
+private protected ManagerViewModel(MappingContext context, Test.Data.Models.Manager manager) : base(context, manager)
+{
+    if (context == null) throw new ArgumentNullException(nameof(context));
+    if (manager == null) throw new ArgumentNullException(nameof(manager));
+
+    context.Register(manager, this);
+
+    Level = manager.Level;
+    Employees = manager.Employees.Select(context.MapFromWithContext<Test.Data.Models.Employee, EmployeeViewModel>).ToList();
+}
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(sources, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+        
+        [Fact]
+        public void When_SourceTypeHasEnumerablePropertiesWithMapFromAttribute_Should_CreateANewEnumerableWithMappedObjects()
+        {
+            // Arrange
+            var sources = GetEmployeeManagerSourceText();
+
+            const string expectedResult = @"
+// <auto-generated />
+using MapTo;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Test.ViewModels
+{
+    partial class ManagerViewModel
+    {
+        public ManagerViewModel(Test.Data.Models.Manager manager)
+            : this(new MappingContext(), manager) { }
+
+        private protected ManagerViewModel(MappingContext context, Test.Data.Models.Manager manager) : base(context, manager)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (manager == null) throw new ArgumentNullException(nameof(manager));
+
+            context.Register(manager, this);
+
+            Level = manager.Level;
+            Employees = manager.Employees.Select(context.MapFromWithContext<Test.Data.Models.Employee, EmployeeViewModel>).ToList();
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(sources, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+        
+        [Fact]
+        public void When_SourceTypeHasEnumerablePropertiesWithMapFromAttributeInDifferentNamespaces_Should_CreateANewEnumerableWithMappedObjectsAndImportNamespace()
+        {
+            // Arrange
+            var sources = GetEmployeeManagerSourceText(useDifferentViewModelNamespace: true);
+
+            const string expectedResult = @"
+using MapTo;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Test.ViewModels2
+{
+    partial class ManagerViewModel
+    {
+        public ManagerViewModel(Test.Data.Models.Manager manager)
+            : this(new MappingContext(), manager) { }
+
+        private protected ManagerViewModel(MappingContext context, Test.Data.Models.Manager manager) : base(context, manager)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (manager == null) throw new ArgumentNullException(nameof(manager));
+
+            context.Register(manager, this);
+
+            Level = manager.Level;
+            Employees = manager.Employees.Select(context.MapFromWithContext<Test.Data.Models.Employee, Test.ViewModels.EmployeeViewModel>).ToList();
+        }
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(sources, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+    }
+}

test/BlueWest.MapTo.Tests/MapTypeConverterTests.cs

@@ -0,0 +1,283 @@
+using System.Linq;
+using MapTo.Sources;
+using MapTo.Tests.Extensions;
+using MapTo.Tests.Infrastructure;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Xunit;
+using static MapTo.Tests.Common;
+
+namespace MapTo.Tests
+{
+    public class MapTypeConverterTests
+    {
+        [Fact]
+        public void VerifyMapTypeConverterAttribute()
+        {
+            // Arrange
+            const string source = "";
+            var expectedInterface = $@"
+{Constants.GeneratedFilesHeader}
+
+using System;
+
+namespace MapTo
+{{
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Parameter, AllowMultiple = false)]
+    public sealed class MapTypeConverterAttribute : Attribute
+    {{
+        public MapTypeConverterAttribute(Type converter, object[] converterParameters = null)
+        {{
+            Converter = converter;
+            ConverterParameters = converterParameters;
+        }}
+
+        public Type Converter {{ get; }}
+
+        public object[] ConverterParameters {{ get; }}
+    }}
+}}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(MapTypeConverterAttributeSource.AttributeName, expectedInterface);
+        }
+
+        [Fact]
+        public void VerifyMapTypeConverterAttributeWithNullableOptionOn()
+        {
+            // Arrange
+            const string source = "";
+            var expectedInterface = $@"
+{Constants.GeneratedFilesHeader}
+#nullable enable
+
+using System;
+
+namespace MapTo
+{{
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Parameter, AllowMultiple = false)]
+    public sealed class MapTypeConverterAttribute : Attribute
+    {{
+        public MapTypeConverterAttribute(Type converter, object[]? converterParameters = null)
+        {{
+            Converter = converter;
+            ConverterParameters = converterParameters;
+        }}
+
+        public Type Converter {{ get; }}
+
+        public object[]? ConverterParameters {{ get; }}
+    }}
+}}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, nullableContextOptions: NullableContextOptions.Enable, languageVersion: LanguageVersion.CSharp8);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(MapTypeConverterAttributeSource.AttributeName, expectedInterface);
+        }
+
+        [Fact]
+        public void VerifyTypeConverterInterface()
+        {
+            // Arrange
+            const string source = "";
+            var expectedInterface = $@"
+{Constants.GeneratedFilesHeader}
+
+namespace MapTo
+{{
+    public interface ITypeConverter<in TSource, out TDestination>
+    {{
+        TDestination Convert(TSource source, object[] converterParameters);
+    }}
+}}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(ITypeConverterSource.InterfaceName, expectedInterface);
+        }
+
+        [Fact]
+        public void VerifyTypeConverterInterfaceWithNullableOptionOn()
+        {
+            // Arrange
+            const string source = "";
+            var expectedInterface = $@"
+{Constants.GeneratedFilesHeader}
+#nullable enable
+
+namespace MapTo
+{{
+    public interface ITypeConverter<in TSource, out TDestination>
+    {{
+        TDestination Convert(TSource source, object[]? converterParameters);
+    }}
+}}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, nullableContextOptions: NullableContextOptions.Enable, languageVersion: LanguageVersion.CSharp8);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(ITypeConverterSource.InterfaceName, expectedInterface);
+        }
+
+        [Fact]
+        public void When_FoundMatchingPropertyNameWithConverterType_ShouldUseTheConverterAndItsParametersToAssignProperties()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder =>
+                {
+                    builder
+                        .WriteLine("[MapTypeConverter(typeof(Prop4Converter), new object[]{\"G\", 'C', 10})]")
+                        .WriteLine("public string Prop4 { get; set; }");
+                },
+                SourcePropertyBuilder: builder => builder.WriteLine("public long Prop4 { get; set; }")));
+
+            source += @"
+namespace Test
+{
+    using MapTo;
+
+    public class Prop4Converter: ITypeConverter<long, string>
+    {
+        public string Convert(long source, object[] converterParameters) => source.ToString(converterParameters[0] as string);
+    }
+}
+";
+
+            const string expectedSyntax = "Prop4 = new Test.Prop4Converter().Convert(baz.Prop4, new object[] { \"G\", 'C', 10 });";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedSyntax);
+        }
+
+        [Fact]
+        public void When_FoundMatchingPropertyNameWithConverterType_ShouldUseTheConverterToAssignProperties()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder =>
+                {
+                    builder
+                        .WriteLine("[MapTypeConverter(typeof(Prop4Converter))]")
+                        .WriteLine("public long Prop4 { get; set; }");
+                },
+                SourcePropertyBuilder: builder => builder.WriteLine("public string Prop4 { get; set; }")));
+
+            source += @"
+namespace Test
+{
+    using MapTo;
+
+    public class Prop4Converter: ITypeConverter<string, long>
+    {
+        public long Convert(string source, object[] converterParameters) => long.Parse(source);
+    }
+}
+";
+
+            const string expectedSyntax = "Prop4 = new Test.Prop4Converter().Convert(baz.Prop4, null);";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedSyntax);
+        }
+
+        [Fact]
+        public void When_FoundMatchingPropertyNameWithDifferentImplicitlyConvertibleType_Should_GenerateTheProperty()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder => { builder.WriteLine("public long Prop4 { get; set; }"); },
+                SourcePropertyBuilder: builder => builder.WriteLine("public int Prop4 { get; set; }")));
+
+            var expectedResult = @"
+    partial class Foo
+    {
+        public Foo(Test.Models.Baz baz)
+            : this(new MappingContext(), baz) { }
+
+        private protected Foo(MappingContext context, Test.Models.Baz baz)
+        {
+            if (context == null) throw new ArgumentNullException(nameof(context));
+            if (baz == null) throw new ArgumentNullException(nameof(baz));
+
+            context.Register(baz, this);
+
+            Prop1 = baz.Prop1;
+            Prop2 = baz.Prop2;
+            Prop3 = baz.Prop3;
+            Prop4 = baz.Prop4;
+        }
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.Last().ShouldContainPartialSource(expectedResult);
+        }
+
+        [Fact]
+        public void When_FoundMatchingPropertyNameWithIncorrectConverterType_ShouldReportError()
+        {
+            // Arrange
+            var source = GetSourceText(new SourceGeneratorOptions(
+                true,
+                PropertyBuilder: builder =>
+                {
+                    builder
+                        .WriteLine("[IgnoreProperty]")
+                        .WriteLine("public long IgnoreMe { get; set; }")
+                        .WriteLine("[MapTypeConverter(typeof(Prop4Converter))]")
+                        .WriteLine("public long Prop4 { get; set; }");
+                },
+                SourcePropertyBuilder: builder => builder.WriteLine("public string Prop4 { get; set; }")));
+
+            source += @"
+namespace Test
+{
+    using MapTo;
+
+    public class Prop4Converter: ITypeConverter<string, int>
+    {
+        public int Convert(string source, object[] converterParameters) => int.Parse(source);
+    }
+}
+";
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            var expectedError = DiagnosticsFactory.InvalidTypeConverterGenericTypesError(GetSourcePropertySymbol("Prop4", compilation), GetSourcePropertySymbol("Prop4", compilation, "Baz"));
+            diagnostics.ShouldNotBeSuccessful(expectedError);
+        }
+    }
+}

test/BlueWest.MapTo.Tests/MappedClassesTests.cs

@@ -0,0 +1,562 @@
+using System.Collections.Generic;
+using System.Linq;
+using MapTo.Tests.Extensions;
+using MapTo.Tests.Infrastructure;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Shouldly;
+using Xunit;
+using Xunit.Abstractions;
+using static MapTo.Tests.Common;
+
+namespace MapTo.Tests
+{
+    public class MappedClassesTests
+    {
+        private readonly ITestOutputHelper _output;
+
+        public MappedClassesTests(ITestOutputHelper output)
+        {
+            _output = output;
+        }
+
+        [Theory]
+        [MemberData(nameof(SecondaryConstructorCheckData))]
+        public void When_SecondaryConstructorExists_Should_NotGenerateOne(string source, LanguageVersion languageVersion)
+        {
+            // Arrange
+            source = source.Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: languageVersion);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation
+                .GetGeneratedSyntaxTree("DestinationClass")
+                .ShouldNotBeNull()
+                .GetRoot()
+                .DescendantNodes()
+                .OfType<ConstructorDeclarationSyntax>()
+                .Count()
+                .ShouldBe(1);
+        }
+
+        public static IEnumerable<object[]> SecondaryConstructorCheckData => new List<object[]>
+        {
+            new object[]
+            {
+                @"
+using MapTo;
+namespace Test.Data.Models
+{
+    public class SourceClass { public string Prop1 { get; set; } }
+
+    [MapFrom(typeof(SourceClass))]
+    public partial class DestinationClass
+    {
+        public DestinationClass(SourceClass source) : this(new MappingContext(), source) { }
+        public string Prop1 { get; set; }
+    }
+}
+",
+                LanguageVersion.CSharp7_3
+            },
+            new object[]
+            {
+                @"
+using MapTo;
+namespace Test.Data.Models
+{
+    public record SourceClass(string Prop1);
+
+    [MapFrom(typeof(SourceClass))]
+    public partial record DestinationClass(string Prop1)
+    {
+        public DestinationClass(SourceClass source) : this(new MappingContext(), source) { }
+    }
+}
+",
+                LanguageVersion.CSharp9
+            }
+        };
+
+        [Theory]
+        [MemberData(nameof(SecondaryCtorWithoutPrivateCtorData))]
+        public void When_SecondaryConstructorExistsButDoNotReferencePrivateConstructor_Should_ReportError(string source, LanguageVersion languageVersion)
+        {
+            // Arrange
+            source = source.Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: languageVersion);
+
+            // Assert
+            var constructorSyntax = compilation.SyntaxTrees
+                .First()
+                .GetRoot()
+                .DescendantNodes()
+                .OfType<ConstructorDeclarationSyntax>()
+                .Single();
+
+            diagnostics.ShouldNotBeSuccessful(DiagnosticsFactory.MissingConstructorArgument(constructorSyntax));
+        }
+
+        public static IEnumerable<object[]> SecondaryCtorWithoutPrivateCtorData => new List<object[]>
+        {
+            new object[]
+            {
+                @"
+using MapTo;
+namespace Test.Data.Models
+{
+    public class SourceClass { public string Prop1 { get; set; } }
+
+    [MapFrom(typeof(SourceClass))]
+    public partial class DestinationClass
+    {
+        public DestinationClass(SourceClass source) { }
+        public string Prop1 { get; set; }
+    }
+}
+",
+                LanguageVersion.CSharp7_3
+            },
+            new object[]
+            {
+                @"
+using MapTo;
+namespace Test.Data.Models
+{
+    public record SourceClass(string Prop1);
+
+    [MapFrom(typeof(SourceClass))]
+    public partial record DestinationClass(string Prop1)
+    {
+        public DestinationClass(SourceClass source) : this(""invalid"") { }
+    }
+}
+",
+                LanguageVersion.CSharp9
+            }
+        };
+
+        [Fact]
+        public void When_PropertyNameIsTheSameAsClassName_Should_MapAccordingly()
+        {
+            // Arrange
+            var source = @"
+namespace Sale
+{
+    public class Sale { public Sale Prop1 { get; set; } }
+}
+
+namespace SaleModel
+{
+    using MapTo;
+    using Sale;
+
+    [MapFrom(typeof(Sale))]
+    public partial class SaleModel
+    {
+        [MapProperty(SourcePropertyName = nameof(global::Sale.Sale.Prop1))]
+        public Sale Sale { get; set; }
+    }
+}
+".Trim();
+
+            // Act
+            var (_, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+        }
+
+        [Theory]
+        [MemberData(nameof(SameSourceAndDestinationTypeNameData))]
+        public void When_SourceAndDestinationNamesAreTheSame_Should_MapAccordingly(string source, LanguageVersion languageVersion)
+        {
+            // Arrange
+            source = source.Trim();
+
+            // Act
+            var (_, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: languageVersion);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+        }
+
+        public static IEnumerable<object[]> SameSourceAndDestinationTypeNameData => new List<object[]>
+        {
+            new object[]
+            {
+                @"
+namespace Test
+{
+    public class TypeName { public int Prop2 { get; set; } }
+}
+
+namespace Test2
+{
+    using MapTo;    
+
+    [MapFrom(typeof(Test.TypeName))]
+    public partial class TypeName
+    {
+        [MapProperty(SourcePropertyName=""Prop2"")]
+        public int Prop1 { get; set; }
+    }
+}",
+                LanguageVersion.CSharp7_3
+            },
+            new object[]
+            {
+                @"
+namespace Test
+{
+    public record TypeName(int Prop2);
+}
+
+namespace Test2
+{
+    using MapTo;    
+
+    [MapFrom(typeof(Test.TypeName))]
+    public partial record TypeName([MapProperty(SourcePropertyName=""Prop2"")] int Prop1);
+}",
+                LanguageVersion.CSharp9
+            },
+            new object[]
+            {
+                @"
+namespace Test
+{
+    using System.Collections.Generic; 
+
+    public class SourceType2 { public int Id { get; set; } }
+    public class SourceType 
+    { 
+        public int Id { get; set; }
+        public List<SourceType2> Prop1 { get; set; } 
+    }
+}
+
+namespace Test2
+{
+    using MapTo; 
+    using System.Collections.Generic;   
+
+    [MapFrom(typeof(Test.SourceType2))]
+    public partial class SourceType2 { public int Id { get; set; } }
+
+    [MapFrom(typeof(Test.SourceType))]
+    public partial class SourceType
+    {        
+        public int Id { get; set; }
+        public IReadOnlyList<SourceType2> Prop1 { get; set; }
+    }
+}",
+                LanguageVersion.CSharp7_3
+            },
+            new object[]
+            {
+                @"
+namespace Test
+{
+    using System.Collections.Generic;
+
+    public record SourceType(int Id, List<SourceType2> Prop1);
+    public record SourceType2(int Id);
+}
+
+namespace Test2
+{
+    using MapTo; 
+    using System.Collections.Generic;   
+
+    [MapFrom(typeof(Test.SourceType2))]
+    public partial record SourceType2(int Id);
+
+    [MapFrom(typeof(Test.SourceType))]
+    public partial record SourceType(int Id, IReadOnlyList<SourceType2> Prop1);
+}",
+                LanguageVersion.CSharp9
+            },
+            new object[]
+            {
+                @"
+namespace Test
+{
+    using System.Collections.Generic;
+
+    public record SourceType1(int Id);
+    public record SourceType2(int Id, List<SourceType1> Prop1);
+}
+
+namespace Test
+{
+    using MapTo; 
+    using System.Collections.Generic;   
+
+    [MapFrom(typeof(Test.SourceType1))]
+    public partial record SourceType3(int Id);
+
+    [MapFrom(typeof(Test.SourceType2))]
+    public partial record SourceType4(int Id, IReadOnlyList<SourceType3> Prop1);
+}",
+                LanguageVersion.CSharp9
+            }
+        };
+
+        [Theory]
+        [MemberData(nameof(VerifyMappedTypesData))]
+        public void VerifyMappedTypes(string[] sources, LanguageVersion languageVersion)
+        {
+            // Arrange
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(sources, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: languageVersion);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            _output.WriteLine(compilation.PrintSyntaxTree());
+        }
+
+        public static IEnumerable<object[]> VerifyMappedTypesData => new List<object[]>
+        {
+            new object[] { new[] { MainSourceClass, NestedSourceClass, MainDestinationClass, NestedDestinationClass }, LanguageVersion.CSharp7_3 },
+            new object[] { new[] { MainSourceRecord, NestedSourceRecord, MainDestinationRecord, NestedDestinationRecord }, LanguageVersion.CSharp9 },
+            new object[]
+            {
+                new[]
+                {
+                    @"
+namespace Test.Classes.Classes1
+{
+    public class Class1
+    {      
+        public int Id { get; set; }
+        public string Name { get; set; }
+    }  
+}",
+                    @"
+using System;
+using System.Collections.Generic;
+using Test.Classes.Classes1;
+
+namespace Test.Classes.Classes2
+{    
+    public class Class2
+    {
+        public int Id { get; set; }
+        public List<Class1> Genres { get; set; }
+        public DateTime? ReleaseDate { get; set; }
+    }  
+}",
+                    @"
+using MapTo;
+using System;
+using System.Collections.Generic;
+using TC = Test.Classes;
+
+namespace Tests.Records
+{
+    [MapFrom(typeof(Test.Classes.Classes1.Class1))]
+    public partial record Class1(int Id, string Name);
+
+   [MapFrom(typeof(Test.Classes.Classes2.Class2))]
+    public partial record Class2(int Id, IReadOnlyList<Class1> Genres);
+}"
+                },
+                LanguageVersion.CSharp9
+            }
+        };
+
+        [Fact]
+        public void VerifySelfReferencingRecords()
+        {
+            // Arrange
+            var source = @"
+namespace Tests.Data.Models
+{
+    using System.Collections.Generic;
+    
+    public record Employee(int Id, string EmployeeCode, Manager Manager);
+
+    public record Manager(int Id, string EmployeeCode, Manager Manager, int Level, List<Employee> Employees) : Employee(Id, EmployeeCode, Manager);
+}
+
+namespace Tests.Data.ViewModels
+{
+    using System.Collections.Generic;
+    using Tests.Data.Models;
+    using MapTo;
+    
+    [MapFrom(typeof(Employee))]
+    public partial record EmployeeViewModel(int Id, string EmployeeCode, ManagerViewModel Manager);
+
+    [MapFrom(typeof(Manager))]
+    public partial record ManagerViewModel(int Id, string EmployeeCode, ManagerViewModel Manager, int Level, List<EmployeeViewModel> Employees) : EmployeeViewModel(Id, EmployeeCode, Manager);
+}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: LanguageVersion.CSharp9);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            _output.WriteLine(compilation.PrintSyntaxTree());
+        }
+
+        [Fact]
+        public void VerifySystemNamespaceConflict()
+        {
+            // Arrange
+            var source = @"
+namespace Test
+{
+    public record SomeRecord(int Id);
+}
+
+namespace Test.Models
+{
+    using MapTo;
+
+    [MapFrom(typeof(Test.SomeRecord))]
+    public partial record SomeRecordModel(int Id);
+}
+
+namespace Test.System
+{
+    public interface IMyInterface { }
+}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions, languageVersion: LanguageVersion.CSharp9);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            _output.WriteLine(compilation.PrintSyntaxTree());
+        }
+
+        private static string MainSourceClass => @"
+using System;
+
+namespace Test.Data.Models
+{
+    public class User
+    {
+        public int Id { get; set; }
+
+        public DateTimeOffset RegisteredAt { get; set; }
+
+        public Profile Profile { get; set; }
+    }
+}
+".Trim();
+        
+        private static string NestedSourceClass => @"
+namespace Test.Data.Models
+{
+    public class Profile
+    {
+        public string FirstName { get; set; }
+
+        public string LastName { get; set; }
+
+        public string FullName => $""{FirstName} {LastName}"";
+    }
+}
+".Trim();
+        
+        private static string MainDestinationClass => @"
+using System;
+using MapTo;
+using Test.Data.Models;
+
+namespace Test.ViewModels
+{
+    [MapFrom(typeof(User))]
+    public partial class UserViewModel
+    {
+        [MapProperty(SourcePropertyName = nameof(User.Id))]
+        [MapTypeConverter(typeof(IdConverter))]
+        public string Key { get; }
+
+        public DateTimeOffset RegisteredAt { get; set; }
+        
+        // [IgnoreProperty]
+        public ProfileViewModel Profile { get; set; }
+
+        private class IdConverter : ITypeConverter<int, string>
+        {
+            public string Convert(int source, object[] converterParameters) => $""{source:X}"";
+        }
+    }
+}
+".Trim();
+        
+        private static string NestedDestinationClass => @"
+using MapTo;
+using Test.Data.Models;
+
+namespace Test.ViewModels
+{
+    [MapFrom(typeof(Profile))]
+    public partial class ProfileViewModel
+    {
+        public string FirstName { get; }
+
+        public string LastName { get; }
+    }
+}
+".Trim();
+
+        private static string MainSourceRecord => BuildSourceRecord("public record User(int Id, DateTimeOffset RegisteredAt, Profile Profile);");
+        
+        private static string MainDestinationRecord => BuildDestinationRecord(@"
+[MapFrom(typeof(User))] 
+public partial record UserViewModel(
+    [MapProperty(SourcePropertyName = nameof(User.Id))] 
+    [MapTypeConverter(typeof(UserViewModel.IdConverter))] 
+    string Key, 
+    DateTimeOffset RegisteredAt,
+    Profile Profile)
+{
+    private class IdConverter : ITypeConverter<int, string>
+    {
+        public string Convert(int source, object[] converterParameters) => $""{source:X}"";
+    }
+}");
+        
+        private static string NestedSourceRecord => BuildSourceRecord("public record Profile(string FirstName, string LastName) { public string FullName => $\"{FirstName} {LastName}\"; }");
+        
+        private static string NestedDestinationRecord => BuildDestinationRecord("[MapFrom(typeof(Profile))] public partial record ProfileViewModel(string FirstName, string LastName);");
+        
+        private static string BuildSourceRecord(string record)
+        {
+            return $@"
+using System;
+
+namespace RecordTest.Data.Models
+{{
+    {record}        
+}}
+".Trim();
+        }
+        
+        private static string BuildDestinationRecord(string record)
+        {
+            return $@"
+using System;
+using MapTo;
+using RecordTest.Data.Models;
+
+namespace RecordTest.ViewModels
+{{
+    {record}        
+}}
+".Trim();
+        }
+    }
+}

test/BlueWest.MapTo.Tests/MappingContextTests.cs

@@ -0,0 +1,102 @@
+using MapTo.Sources;
+using MapTo.Tests.Extensions;
+using MapTo.Tests.Infrastructure;
+using Xunit;
+using static MapTo.Tests.Common;
+
+namespace MapTo.Tests
+{
+    public class MappingContextTests
+    {
+        [Fact]
+        public void VerifyMappingContextSource()
+        {
+            // Arrange
+            const string source = "";
+            var expected = @"
+// <auto-generated />
+
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+
+namespace MapTo
+{
+    internal sealed class MappingContext
+    {
+        private readonly Dictionary<object, object> _cache;
+
+        internal MappingContext()
+        {
+            _cache = new Dictionary<object, object>(1);
+        }
+
+        internal static TMapped Create<TOriginal, TMapped>(TOriginal original)
+        {
+            if (original == null) throw new ArgumentNullException(nameof(original));
+
+            var context = new MappingContext();
+            var mapped = context.MapFromWithContext<TOriginal, TMapped>(original);
+
+            if (mapped == null)
+            {
+                throw new InvalidOperationException();
+            }
+
+            return mapped;
+        }
+
+        internal TMapped MapFromWithContext<TOriginal, TMapped>(TOriginal original)
+        {
+            if (original == null)
+            {
+                return default(TMapped);
+            }
+
+            if (!TryGetValue<TOriginal, TMapped>(original, out var mapped))
+            {
+                var instance = Activator.CreateInstance(typeof(TMapped), BindingFlags.Instance | BindingFlags.NonPublic, null, new object[] { this, original }, null);
+                if (instance != null)
+                {
+                    mapped = (TMapped)instance;
+                }
+            }
+
+            return mapped;
+        }
+
+        internal void Register<TOriginal, TMapped>(TOriginal original, TMapped mapped)
+        {
+            if (original == null) throw new ArgumentNullException(nameof(original));
+            if (mapped == null) throw new ArgumentNullException(nameof(mapped));
+
+            if (!_cache.ContainsKey(original))
+            {
+                _cache.Add(original, mapped);
+            }
+        }
+
+        private bool TryGetValue<TOriginal, TMapped>(TOriginal original, out TMapped mapped)
+        {
+            if (original != null && _cache.TryGetValue(original, out var value))
+            {
+                mapped = (TMapped)value;
+                return true;
+            }
+
+            mapped = default(TMapped);
+            return false;
+        }
+    }
+}
+".Trim();
+
+            // Act
+            var (compilation, diagnostics) = CSharpGenerator.GetOutputCompilation(source, analyzerConfigOptions: DefaultAnalyzerOptions);
+
+            // Assert
+            diagnostics.ShouldBeSuccessful();
+            compilation.SyntaxTrees.ShouldContainSource(MappingContextSource.ClassName, expected);
+        }
+    }
+}

test/MapTo.Integration.Tests/CyclicReferenceTests.cs

@@ -0,0 +1,85 @@
+using System.Linq;
+using MapTo.Integration.Tests.Data.Models;
+using MapTo.Integration.Tests.Data.ViewModels;
+using Shouldly;
+using Xunit;
+
+namespace MapTo.Integration.Tests
+{
+    public class CyclicReferenceTests
+    {
+        [Fact]
+        public void VerifySelfReference()
+        {
+            // Arrange
+            var manager = new Manager { Id = 1, EmployeeCode = "M001", Level = 100 };
+            manager.Manager = manager;
+            
+            // Act
+            var result = manager.ToManagerViewModel();
+            
+            // Assert
+            result.Id.ShouldBe(manager.Id);
+            result.EmployeeCode.ShouldBe(manager.EmployeeCode);
+            result.Level.ShouldBe(manager.Level);
+            result.Manager.ShouldBeSameAs(result);
+        }
+
+        [Fact]
+        public void VerifyNestedReference()
+        {
+            // Arrange
+            var manager1 = new Manager { Id = 100, EmployeeCode = "M001", Level = 100 };
+            var manager2 = new Manager { Id = 102, EmployeeCode = "M002", Level = 100 };
+            
+            var employee1 = new Employee { Id = 200, EmployeeCode = "E001"};
+            var employee2 = new Employee { Id = 201, EmployeeCode = "E002"};
+            
+            employee1.Manager = manager1;
+            employee2.Manager = manager2;
+
+            manager2.Manager = manager1;
+            
+            // Act
+            var manager1ViewModel = manager1.ToManagerViewModel();
+            
+            // Assert
+            manager1ViewModel.Id.ShouldBe(manager1.Id);
+            manager1ViewModel.Manager.ShouldBeNull();
+            manager1ViewModel.Employees.Count.ShouldBe(2);
+            manager1ViewModel.Employees[0].Id.ShouldBe(employee1.Id);
+            manager1ViewModel.Employees[0].Manager.ShouldBeSameAs(manager1ViewModel);
+            manager1ViewModel.Employees[1].Id.ShouldBe(manager2.Id);
+            manager1ViewModel.Employees[1].Manager.ShouldBeSameAs(manager1ViewModel);
+        }
+        
+        [Fact]
+        public void VerifyNestedSelfReference()
+        {
+            // Arrange
+            var manager1 = new Manager { Id = 100, EmployeeCode = "M001", Level = 100 };
+            var manager3 = new Manager { Id = 101, EmployeeCode = "M003", Level = 100 };
+            var manager2 = new Manager { Id = 102, EmployeeCode = "M002", Level = 100 };
+            
+            var employee1 = new Employee { Id = 200, EmployeeCode = "E001"};
+            var employee2 = new Employee { Id = 201, EmployeeCode = "E002"};
+            var employee3 = new Employee { Id = 202, EmployeeCode = "E003"};
+            
+            employee1.Manager = manager1;
+            employee2.Manager = manager2;
+            employee3.Manager = manager3;
+
+            manager2.Manager = manager1;
+            manager3.Manager = manager2;
+            
+            // Act
+            var manager3ViewModel = manager3.ToManagerViewModel();
+            
+            // Assert
+            manager3ViewModel.Manager.ShouldNotBeNull();
+            manager3ViewModel.Manager.Id.ShouldBe(manager2.Id);
+            manager3ViewModel.Manager.Manager.Id.ShouldBe(manager1.Id);
+            manager3ViewModel.Employees.All(e => ReferenceEquals(e.Manager, manager3ViewModel)).ShouldBeTrue();
+        }
+    }
+}

test/MapTo.Integration.Tests/Data/Models/Employee.cs

@@ -0,0 +1,29 @@
+namespace MapTo.Integration.Tests.Data.Models
+{
+    public class Employee
+    {
+        private Manager _manager;
+
+        public int Id { get; set; }
+
+        public string EmployeeCode { get; set; }
+
+        public Manager Manager
+        {
+            get => _manager;
+            set
+            {
+                if (value == null)
+                {
+                    _manager.Employees.Remove(this);
+                }
+                else
+                {
+                    value.Employees.Add(this);
+                }
+
+                _manager = value;
+            }
+        }
+    }
+}

test/MapTo.Integration.Tests/Data/Models/Manager.cs

@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+
+namespace MapTo.Integration.Tests.Data.Models
+{
+    public class Manager : Employee
+    {
+        public int Level { get; set; }
+
+        public List<Employee> Employees { get; set; } = new();
+    }
+}

test/MapTo.Integration.Tests/Data/ViewModels/EmployeeViewModel.cs

@@ -0,0 +1,14 @@
+using MapTo.Integration.Tests.Data.Models;
+
+namespace MapTo.Integration.Tests.Data.ViewModels
+{
+    [MapFrom(typeof(Employee))]
+    public partial class EmployeeViewModel
+    {
+        public int Id { get; set; }
+
+        public string EmployeeCode { get; set; }
+
+        public ManagerViewModel Manager { get; set; }
+    }
+}

test/MapTo.Integration.Tests/Data/ViewModels/ManagerViewModel.cs

@@ -0,0 +1,13 @@
+using System.Collections.Generic;
+using MapTo.Integration.Tests.Data.Models;
+
+namespace MapTo.Integration.Tests.Data.ViewModels
+{
+    [MapFrom(typeof(Manager))]
+    public partial class ManagerViewModel : EmployeeViewModel
+    {
+        public int Level { get; set; }
+
+        public List<EmployeeViewModel> Employees { get; set;  } = new();
+    }
+}

test/MapTo.Integration.Tests/MapTo.Integration.Tests.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net5.0</TargetFramework>
+        <IsPackable>false</IsPackable>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\BlueWest.MapTo\BlueWest.MapTo.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    </ItemGroup>
+    
+    <ItemGroup>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.10.0" />
+        <PackageReference Include="Shouldly" Version="4.0.3" />
+        <PackageReference Include="xunit" Version="2.4.1" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+        <PackageReference Include="coverlet.collector" Version="3.0.3">
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+            <PrivateAssets>all</PrivateAssets>
+        </PackageReference>
+    </ItemGroup>
+
+</Project>

test/TestConsoleApp/Data/FinanceTransaction.cs

@@ -0,0 +1,59 @@
+using System;
+using MapTo;
+
+namespace BlueWest.Data
+{
+    public enum FinanceSymbol
+    {
+        BTC_EUR,
+        BTC_BUSD,
+        BTC_USD,
+        BTC_USDT,
+        LTC_EUR,
+        LTC_BUSD,
+        LTC_USDT
+
+
+
+
+
+
+
+
+
+    }
+
+    public enum FinanceTransactionType
+    {
+        Buy,
+        Sell
+    }
+
+    [JsonExtension]
+    [MapFrom(typeof(FinanceTransactionInsertDto))]
+    public partial struct FinanceTransaction
+    {
+       public readonly int  Id;
+       public readonly int UserId;
+        public readonly FinanceTransactionType FinanceTransactionType;
+        public readonly FinanceSymbol FinanceSymbol;
+        public readonly double Amount; // To Buy
+        public readonly double Quantity; // Bought
+        public readonly double Fee;
+        public readonly DateTime DateTime;
+
+
+        public FinanceTransaction(int id, int userId, FinanceTransactionType financeTransactionType,
+            FinanceSymbol financeSymbol, double amount, double quantity, double fee, DateTime dateTime)
+        {
+            Id = id;
+            UserId = userId;
+            FinanceTransactionType = financeTransactionType;
+            FinanceSymbol = financeSymbol;
+            Amount = amount;
+            Quantity = quantity;
+            Fee = fee;
+            DateTime = dateTime;
+        }
+    }
+}

test/TestConsoleApp/Data/FinanceTransactionInsertDto.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace BlueWest.Data
+{
+    
+    public partial struct FinanceTransactionInsertDto
+    {
+        public readonly int UserId;
+        public readonly FinanceTransactionType FinanceTransactionType;
+        public readonly FinanceSymbol FinanceSymbol;
+        public readonly double Amount; // To Buy
+        public readonly double Quantity; // Bought
+        public readonly double Fee;
+        public readonly DateTime DateTime;
+    }
+}

test/TestConsoleApp/Data/FinanceTransactionReadDto.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using MapTo;
+
+namespace BlueWest.Data
+{
+    [MapFrom(typeof(FinanceTransaction))]
+
+     partial struct FinanceTransactionReadDto
+    {
+        public readonly int UserId;
+        public readonly FinanceTransactionType FinanceTransactionType;
+        public readonly FinanceSymbol FinanceSymbol;
+        public readonly double Amount; // To Buy
+        public readonly double Quantity; // Bought
+        public readonly double Fee;
+        public readonly DateTime DateTime;
+
+        public readonly string ReadData;
+    }
+}

test/TestConsoleApp/Data/Models/Car.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using MapTo;
+using TestConsoleApp.ViewModels;
+
+namespace TestConsoleApp.Data.Models
+{
+    [MapFrom(typeof(CarReadDto))]
+    [UseUpdate]
+    partial class Car
+    {
+        public int Size { get; }
+        public int Id { get; }
+
+        public string Brand { get; }
+
+        public Car(int size, int id, string brand)
+        {
+            Size = size;
+            Id = id;
+            Brand = brand;
+        }
+    }
+}

test/TestConsoleApp/Data/Models/Employee.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace TestConsoleApp.Data.Models
+{
+   
+    public class Employee
+    {
+        public int Id { get;  }
+
+        public string EmployeeCode { get; }
+
+        public Employee(int id, string employeeCode)
+        {
+            Id = id;
+            EmployeeCode = employeeCode;
+        }
+
+    }
+}

test/TestConsoleApp/Data/Models/MyStruct.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using TestConsoleApp.ViewModels;
+using MapTo;
+
+namespace TestConsoleApp.Data.Models
+{
+    [MapFrom(typeof(MyStructViewModel))]
+    [UseUpdate]
+    public partial struct MyStruct
+    {
+        public int SomeInt { get; set; }
+
+        public string ReadOnlyString { get; }
+
+        public MyStruct(int someInt, string readOnlyString)
+        {
+            SomeInt = someInt;
+            ReadOnlyString = readOnlyString;
+        }
+
+    }
+}

test/TestConsoleApp/Data/User.cs

@@ -0,0 +1,44 @@
+
+using System.Collections.Generic;
+using MapTo;
+
+
+namespace BlueWest.Data
+{
+    [MapFrom(typeof(UserUpdateDto))]
+    [JsonExtension]
+    public partial class User 
+    {
+        public readonly int Id;
+        public string Name;
+        public string Address;
+
+        public string BTCAddress;
+        public string LTCAddress;
+
+        public double BTCAmount;
+        public double LTCAmount;
+
+        public readonly List<FinanceTransaction> FinanceTransactions;
+
+        public User(int id, string name, string address, string btcAddress, string ltcAddress, double btcAmount, double ltcAmount, List<FinanceTransaction> financeTransactions)
+        {
+            Id = id;
+            Name = name;
+            Address = address;
+            BTCAddress = btcAddress;
+            LTCAddress = ltcAddress;
+            BTCAmount = btcAmount;
+            LTCAmount = ltcAmount;
+            FinanceTransactions = financeTransactions;
+        }
+
+        public void AddTransaction(FinanceTransaction financeTransaction)
+        {
+            FinanceTransactions.Add(financeTransaction);
+        }
+
+    }
+}
+    
+

test/TestConsoleApp/Data/UserList.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+
+namespace BlueWest.Data
+{
+    public class UserList
+    {
+        public List<User> Users;
+
+        public UserList(List<User> users)
+        {
+            Users = users;
+        }
+
+        public int Length => Users.Count;
+    }
+}

test/TestConsoleApp/Data/UserUpdateDto.cs

@@ -0,0 +1,19 @@
+using MapTo;
+
+namespace BlueWest.Data
+{
+    [MapFrom(typeof(User))]
+
+    public partial class UserUpdateDto
+    {
+        public string Name;
+        public string Address;
+
+        public string BTCAddress;
+        public string LTCAddress;
+
+        public double BTCAmount;
+        public double LTCAmount;
+
+    }
+}

test/TestConsoleApp/Program.cs

@@ -0,0 +1,32 @@
+using System;
+using MapTo;
+using TestConsoleApp.Data.Models;
+using TestConsoleApp.ViewModels;
+
+namespace TestConsoleApp
+{
+    internal class Program
+    {
+        private static void Main(string[] args)
+        {
+            //UserTest();
+             
+            // EmployeeManagerTest();
+            Console.WriteLine("done");
+        }
+
+        private static void EmployeeManagerTest()
+        {
+
+
+            var employee = new Employee(1, "hello");
+
+
+
+
+        }
+
+
+ 
+    }
+}

test/TestConsoleApp/TestConsoleApp.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net471</TargetFramework>
+        <LangVersion>latest</LangVersion>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\BlueWest.MapTo\BlueWest.MapTo.csproj" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
+    </ItemGroup>
+
+    <Import Project="..\..\src\BlueWest.MapTo\MapTo.props" />
+    <PropertyGroup>
+        <MapTo_ConstructorAccessModifier>Internal</MapTo_ConstructorAccessModifier>
+    </PropertyGroup>
+</Project>

test/TestConsoleApp/ViewModels/CarReadDto.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using MapTo;
+using TestConsoleApp.Data.Models;
+
+namespace TestConsoleApp.ViewModels
+{
+    [MapFrom(typeof(Car))]
+    partial class CarReadDto
+    {
+        public int Size { get; }
+        public string Brand { get; }
+
+        public CarReadDto(int size, string brand)
+        {
+            Size = size;
+            Brand = brand;
+        }
+    }
+}

test/TestConsoleApp/ViewModels/EmployeeViewModel.cs

@@ -0,0 +1,13 @@
+using MapTo;
+using TestConsoleApp.Data.Models;
+
+namespace TestConsoleApp.ViewModels
+{
+    [MapFrom(typeof(Employee))]
+    public partial class EmployeeViewModel
+    {
+        public int Id { get; }
+
+
+    }
+}

test/TestConsoleApp/ViewModels/MyStructViewModel.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using TestConsoleApp.Data.Models;
+using MapTo;
+
+namespace TestConsoleApp.ViewModels
+{
+    [MapFrom(typeof(MyStruct))]
+
+    public partial struct MyStructViewModel
+    {
+        public int SomeInt { get; set; }
+
+        public MyStructViewModel(int someInt)
+        {
+            SomeInt = someInt;
+        }
+    }
+}