Use fully qualified name of the source type instead of adding usings if necessary.

src/MapTo/MappingContext.cs

@@ -11,8 +11,11 @@ namespace MapTo
 {
     internal abstract class MappingContext
     {
+        private readonly List<string> _ignoredNamespaces;
+
         protected MappingContext(Compilation compilation, SourceGenerationOptions sourceGenerationOptions, TypeDeclarationSyntax typeSyntax)
         {
+            _ignoredNamespaces = new();
             Diagnostics = ImmutableArray<Diagnostic>.Empty;
             Usings = ImmutableArray.Create("System", Constants.RootNamespace);
             SourceGenerationOptions = sourceGenerationOptions;
@@ -77,7 +80,10 @@ namespace MapTo
 
         protected void AddUsingIfRequired(bool condition, string? ns)
         {
-            if (condition && ns is not null && ns != TypeSyntax.GetNamespace() && !Usings.Contains(ns))
+            if (condition && ns is not null &&
+                ns != TypeSyntax.GetNamespace() &&
+                !_ignoredNamespaces.Contains(ns) &&
+                !Usings.Contains(ns))
             {
                 Usings = Usings.Add(ns);
             }
@@ -145,7 +151,6 @@ namespace MapTo
             }
 
             AddUsingIfRequired(propertyType);
-            AddUsingIfRequired(sourceTypeSymbol);
             AddUsingIfRequired(enumerableTypeArgumentType);
             AddUsingIfRequired(mappedSourcePropertyType);
 
@@ -155,8 +160,8 @@ namespace MapTo
                 converterFullyQualifiedName,
                 converterParameters.ToImmutableArray(),
                 sourceProperty.Name,
-                mappedSourcePropertyType?.Name,
-                enumerableTypeArgumentType?.Name);
+                ToQualifiedDisplayName(mappedSourcePropertyType),
+                ToQualifiedDisplayName(enumerableTypeArgumentType));
         }
 
         protected bool TryGetMapTypeConverter(ISymbol property, IPropertySymbol sourceProperty, out string? converterFullyQualifiedName,
@@ -171,7 +176,7 @@ namespace MapTo
             }
 
             var typeConverterAttribute = property.GetAttribute(MapTypeConverterAttributeTypeSymbol);
-            if (!(typeConverterAttribute?.ConstructorArguments.First().Value is INamedTypeSymbol converterTypeSymbol))
+            if (typeConverterAttribute?.ConstructorArguments.First().Value is not INamedTypeSymbol converterTypeSymbol)
             {
                 return false;
             }
@@ -248,6 +253,9 @@ namespace MapTo
                 return null;
             }
 
+            var sourceTypeNamespace = sourceTypeSymbol.ContainingNamespace.ToDisplayString();
+            _ignoredNamespaces.Add(sourceTypeNamespace);
+
             var typeIdentifierName = TypeSyntax.GetIdentifierName();
             var sourceTypeIdentifierName = sourceTypeSymbol.Name;
             var isTypeInheritFromMappedBaseClass = IsTypeInheritFromMappedBaseClass(semanticModel);
@@ -260,7 +268,6 @@ namespace MapTo
                 return null;
             }
 
-            AddUsingIfRequired(sourceTypeSymbol);
             AddUsingIfRequired(mappedProperties.Any(p => p.IsEnumerable), "System.Linq");
 
             return new MappingModel(
@@ -269,7 +276,7 @@ namespace MapTo
                 TypeSyntax.Modifiers,
                 TypeSyntax.Keyword.Text,
                 typeIdentifierName,
-                sourceTypeSymbol.ContainingNamespace.ToString(),
+                sourceTypeNamespace,
                 sourceTypeIdentifierName,
                 sourceTypeSymbol.ToDisplayString(),
                 mappedProperties,
@@ -316,5 +323,16 @@ namespace MapTo
 
             return false;
         }
+
+        private string? ToQualifiedDisplayName(ISymbol? typeSymbol)
+        {
+            if (typeSymbol is null)
+            {
+                return null;
+            }
+
+            var typeNamespace = typeSymbol.ContainingNamespace.ToDisplayString();
+            return _ignoredNamespaces.Contains(typeNamespace) ? typeSymbol.ToDisplayString() : typeSymbol.Name;
+        }
     }
 }

src/MapTo/Models.cs

@@ -34,7 +34,7 @@ namespace MapTo
         bool GenerateSecondaryConstructor
     )
     {
-        public string SourceType => SourceTypeIdentifierName == TypeIdentifierName ? SourceTypeFullName : SourceTypeIdentifierName;
+        public string SourceType => SourceTypeFullName;
     }
 
     internal record SourceGenerationOptions(

test/MapTo.Tests/MappedClassesTests.cs

@@ -172,6 +172,142 @@ namespace SaleModel
             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)