diff --git a/examples/project/aggregated/Combined/Combined.csproj b/examples/project/aggregated/Combined/Combined.csproj
index bb5addb..809c7d5 100644
--- a/examples/project/aggregated/Combined/Combined.csproj
+++ b/examples/project/aggregated/Combined/Combined.csproj
@@ -3,5 +3,6 @@
     <ProjectReference Include="../A/A.csproj" />
     <ProjectReference Include="../B/B.csproj" />
     <ProjectReference Include="../C/C.csproj" />
+    <ProjectReference Include="../D/D.csproj" />
   </ItemGroup>
 </Project>
diff --git a/examples/project/aggregated/D/D.csproj b/examples/project/aggregated/D/D.csproj
new file mode 100644
index 0000000..6b512ec
--- /dev/null
+++ b/examples/project/aggregated/D/D.csproj
@@ -0,0 +1 @@
+<Project Sdk="Microsoft.NET.Sdk" />
diff --git a/examples/project/aggregated/D/DTO.cs b/examples/project/aggregated/D/DTO.cs
new file mode 100644
index 0000000..fb3da6b
--- /dev/null
+++ b/examples/project/aggregated/D/DTO.cs
@@ -0,0 +1,3 @@
+namespace D;
+
+public class DTO;
diff --git a/src/LeanCode.ContractsGenerator.Tests/ExampleBased/Project.cs b/src/LeanCode.ContractsGenerator.Tests/ExampleBased/Project.cs
index 705fc6e..392cd2b 100644
--- a/src/LeanCode.ContractsGenerator.Tests/ExampleBased/Project.cs
+++ b/src/LeanCode.ContractsGenerator.Tests/ExampleBased/Project.cs
@@ -27,7 +27,8 @@ public void Aggregated_project_compiles()
             .WithTopic("C.Topic")
             .WithNotification(
                 NotificationTypeRefExtensions.WithTag(TypeRefExtensions.Internal("C.Notification"), "C.Notification")
-            );
+            )
+            .WithDto("D.DTO");
     }
 
     [Fact]
@@ -36,14 +37,16 @@ public void Multiple_separate_projects_compile()
         ProjectsCompile(
                 "project/aggregated/A/A.csproj",
                 "project/aggregated/B/B.csproj",
-                "project/aggregated/C/C.csproj"
+                "project/aggregated/C/C.csproj",
+                "project/aggregated/D/D.csproj"
             )
             .WithCommand("A.Command")
             .WithQuery("B.Query")
             .WithTopic("C.Topic")
             .WithNotification(
                 NotificationTypeRefExtensions.WithTag(TypeRefExtensions.Internal("C.Notification"), "C.Notification")
-            );
+            )
+            .WithDto("D.DTO");
     }
 
     [Fact]
@@ -62,6 +65,7 @@ public void Multiple_separate_projects_compile_even_if_some_references_overlap()
                 "project/aggregated/A/A.csproj",
                 "project/aggregated/B/B.csproj",
                 "project/aggregated/C/C.csproj",
+                "project/aggregated/D/D.csproj",
                 "project/aggregated/Combined/Combined.csproj"
             )
             .WithCommand("A.Command")
@@ -69,20 +73,23 @@ public void Multiple_separate_projects_compile_even_if_some_references_overlap()
             .WithTopic("C.Topic")
             .WithNotification(
                 NotificationTypeRefExtensions.WithTag(TypeRefExtensions.Internal("C.Notification"), "C.Notification")
-            );
+            )
+            .WithDto("D.DTO");
 
         ProjectsCompile(
                 "project/aggregated/Combined/Combined.csproj",
                 "project/aggregated/A/A.csproj",
                 "project/aggregated/B/B.csproj",
-                "project/aggregated/C/C.csproj"
+                "project/aggregated/C/C.csproj",
+                "project/aggregated/D/D.csproj"
             )
             .WithCommand("A.Command")
             .WithQuery("B.Query")
             .WithTopic("C.Topic")
             .WithNotification(
                 NotificationTypeRefExtensions.WithTag(TypeRefExtensions.Internal("C.Notification"), "C.Notification")
-            );
+            )
+            .WithDto("D.DTO");
     }
 
     [Fact]
diff --git a/src/LeanCode.ContractsGenerator/Compilation/ContractTypes.cs b/src/LeanCode.ContractsGenerator/Compilation/ContractTypes.cs
index da88829..06d7754 100644
--- a/src/LeanCode.ContractsGenerator/Compilation/ContractTypes.cs
+++ b/src/LeanCode.ContractsGenerator/Compilation/ContractTypes.cs
@@ -55,19 +55,10 @@ public ContractTypes(IReadOnlyCollection<CSharpCompilation> compilations)
     private static HashSet<INamedTypeSymbol> GetTypeSymbols<T>(IReadOnlyCollection<CSharpCompilation> compilations)
     {
         var name = typeof(T).FullName!;
-        var result = new HashSet<INamedTypeSymbol>(SymbolEqualityComparer.Default);
 
-        foreach (var c in compilations)
-        {
-            var type =
-                c.GetTypeByMetadataName(name)
-                ?? throw new CompilationFailedException(
-                    $"Cannot locate type {name} in compilation unit `{c.AssemblyName ?? "UNKNOWN"}`."
-                );
-            result.Add(type);
-        }
-
-        return result;
+        return compilations
+            .SelectMany(c => c.GetTypesByMetadataName(name))
+            .ToHashSet<INamedTypeSymbol>(SymbolEqualityComparer.Default);
     }
 
     private static HashSet<INamedTypeSymbol> GetUnboundTypeSymbols(
@@ -76,19 +67,11 @@ Type type
     )
     {
         var name = type.FullName!;
-        var result = new HashSet<INamedTypeSymbol>(SymbolEqualityComparer.Default);
-
-        foreach (var c in compilations)
-        {
-            var t =
-                (c.GetTypeByMetadataName(name)?.ConstructUnboundGenericType())
-                ?? throw new CompilationFailedException(
-                    $"Cannot locate generic type {name} in compilation unit `{c.AssemblyName ?? "UNKNOWN"}`."
-                );
-            result.Add(t);
-        }
 
-        return result;
+        return compilations
+            .SelectMany(c => c.GetTypesByMetadataName(name))
+            .Select(nts => nts.ConstructUnboundGenericType())
+            .ToHashSet<INamedTypeSymbol>(SymbolEqualityComparer.Default);
     }
 
     public bool IsQuery(ITypeSymbol symbol) =>