diff --git a/MapTo/Extensions/EnumerableExtensions.cs b/MapTo/Extensions/EnumerableExtensions.cs
new file mode 100644
index 0000000..21d0887
--- /dev/null
+++ b/MapTo/Extensions/EnumerableExtensions.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+
+namespace MapTo.Extensions
+{
+    internal static class EnumerableExtensions
+    {
+        internal static void ForEach<T>(this IEnumerable<T> enumerable, Action<T> action)
+        {
+            foreach (var item in enumerable)
+            {
+                action(item);
+            }
+        }    
+    }
+}
\ No newline at end of file
diff --git a/MapTo/MapToGenerator.cs b/MapTo/MapToGenerator.cs
index 8b70066..e3b28a6 100644
--- a/MapTo/MapToGenerator.cs
+++ b/MapTo/MapToGenerator.cs
@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.Linq;
+using MapTo.Extensions;
 using MapTo.Models;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
@@ -28,19 +29,25 @@ namespace MapTo
 
         private static void AddGeneratedMappingsClasses(GeneratorExecutionContext context, IEnumerable<ClassDeclarationSyntax> candidateClasses)
         {
-            foreach (var classDeclarationSyntax in candidateClasses)
+            foreach (var classSyntax in candidateClasses)
             {
-                var (model, diagnostic) = MapModel.Create(context.Compilation, classDeclarationSyntax);
-                if (model is null)
+                var root = classSyntax.GetCompilationUnit();
+                var classSemanticModel = context.Compilation.GetSemanticModel(classSyntax.SyntaxTree);
+                var classSymbol = classSemanticModel.GetDeclaredSymbol(classSyntax) as INamedTypeSymbol;
+                var sourceTypeSymbol = GetSourceTypeSymbol(classSyntax, classSemanticModel);
+
+                var (isValid, diagnostics) = Verify(root, classSyntax, classSemanticModel, classSymbol, sourceTypeSymbol);
+                if (!isValid)
                 {
-                    context.ReportDiagnostic(diagnostic!);
+                    diagnostics.ForEach(context.ReportDiagnostic);
                     continue;
                 }
+                
+                var model = new MapModel(root, classSyntax, classSymbol!, sourceTypeSymbol!);
 
                 var (source, hintName) = SourceBuilder.GenerateSource(model);
-
                 context.AddSource(hintName, source);
-                context.ReportDiagnostic(Diagnostics.ClassMappingsGenerated(classDeclarationSyntax.GetLocation(), model.ClassName));
+                context.ReportDiagnostic(Diagnostics.ClassMappingsGenerated(classSyntax.GetLocation(), model.ClassName));
             }
         }
 
@@ -49,5 +56,33 @@ namespace MapTo
             var (source, hintName) = SourceBuilder.GenerateMapFromAttribute();
             context.AddSource(hintName, source);
         }
+
+        private static INamedTypeSymbol? GetSourceTypeSymbol(ClassDeclarationSyntax classSyntax, SemanticModel model)
+        {
+            var sourceTypeExpressionSyntax = classSyntax
+                .GetAttribute(SourceBuilder.MapFromAttributeName)
+                ?.DescendantNodes()
+                .OfType<TypeOfExpressionSyntax>()
+                .SingleOrDefault();
+
+            return sourceTypeExpressionSyntax is not null ? model.GetTypeInfo(sourceTypeExpressionSyntax.Type).Type as INamedTypeSymbol : null;
+        }
+
+        private static (bool isValid, IEnumerable<Diagnostic> diagnostics) Verify(CompilationUnitSyntax root, ClassDeclarationSyntax classSyntax, SemanticModel classSemanticModel, INamedTypeSymbol? classSymbol, INamedTypeSymbol? sourceTypeSymbol)
+        {
+            var diagnostics = new List<Diagnostic>();
+
+            if (classSymbol is null)
+            {
+                diagnostics.Add(Diagnostics.SymbolNotFound(classSyntax.GetLocation(), classSyntax.Identifier.ValueText));
+            }
+
+            if (sourceTypeSymbol is null)
+            {
+                diagnostics.Add(Diagnostics.SymbolNotFound(classSyntax.GetLocation(), classSyntax.Identifier.ValueText));
+            }
+
+            return (!diagnostics.Any(), diagnostics);
+        }
     }
 }
\ No newline at end of file
diff --git a/MapTo/Models/MapModel.cs b/MapTo/Models/MapModel.cs
index c51bcfb..05ca354 100644
--- a/MapTo/Models/MapModel.cs
+++ b/MapTo/Models/MapModel.cs
@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using System.Linq;
 using MapTo.Extensions;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
@@ -28,6 +27,17 @@ namespace MapTo.Models
             SourceTypeProperties = sourceTypeProperties;
         }
 
+        internal MapModel(CompilationUnitSyntax root, ClassDeclarationSyntax classSyntax, ITypeSymbol classSymbol, ITypeSymbol sourceTypeSymbol)
+            : this(
+                root.GetNamespace(),
+                classSyntax.Modifiers,
+                classSyntax.GetClassName(),
+                classSymbol.GetAllMembersOfType<IPropertySymbol>(),
+                sourceTypeSymbol.ContainingNamespace.ToString(),
+                sourceTypeSymbol.Name,
+                sourceTypeSymbol.ToString(),
+                sourceTypeSymbol.GetAllMembersOfType<IPropertySymbol>()) { }
+
         public string? Namespace { get; }
 
         public SyntaxTokenList ClassModifiers { get; }
@@ -43,45 +53,5 @@ namespace MapTo.Models
         public string SourceClassFullName { get; }
 
         public IEnumerable<IPropertySymbol> SourceTypeProperties { get; }
-
-        internal static (MapModel? model, Diagnostic? diagnostic) Create(Compilation compilation, ClassDeclarationSyntax classSyntax)
-        {
-            var root = classSyntax.GetCompilationUnit();
-            var classSemanticModel = compilation.GetSemanticModel(classSyntax.SyntaxTree);
-
-            if (!(classSemanticModel.GetDeclaredSymbol(classSyntax) is INamedTypeSymbol classSymbol))
-            {
-                return (default, Diagnostics.SymbolNotFound(classSyntax.GetLocation(), classSyntax.Identifier.ValueText));
-            }
-
-            var sourceTypeSymbol = GetSourceTypeSymbol(classSyntax, classSemanticModel);
-            if (sourceTypeSymbol is null)
-            {
-                return (default, Diagnostics.SymbolNotFound(classSyntax.GetLocation(), classSyntax.Identifier.ValueText));
-            }
-
-            var model = new MapModel(
-                root.GetNamespace(),
-                classSyntax.Modifiers,
-                classSyntax.GetClassName(),
-                classSymbol.GetAllMembersOfType<IPropertySymbol>(),
-                sourceTypeSymbol.ContainingNamespace.ToString(),
-                sourceTypeSymbol.Name,
-                sourceTypeSymbol.ToString(),
-                sourceTypeSymbol.GetAllMembersOfType<IPropertySymbol>());
-
-            return (model, default);
-        }
-
-        private static ITypeSymbol? GetSourceTypeSymbol(ClassDeclarationSyntax classSyntax, SemanticModel model)
-        {
-            var sourceTypeExpressionSyntax = classSyntax
-                .GetAttribute(SourceBuilder.MapFromAttributeName)
-                ?.DescendantNodes()
-                .OfType<TypeOfExpressionSyntax>()
-                .SingleOrDefault();
-
-            return sourceTypeExpressionSyntax is not null ? model.GetTypeInfo(sourceTypeExpressionSyntax.Type).Type : null;
-        }
     }
 }
\ No newline at end of file