Fix type forwarding

dotnet · Nov 25, 2024 · ee5d655 · ee5d655
1 parent a983cab
commit ee5d655
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Showing 3 changed files with 10 additions and 0 deletions.
diff --git a/src/libraries/System.Collections/ref/System.Collections.Forwards.cs b/src/libraries/System.Collections/ref/System.Collections.Forwards.cs
@@ -0,0 +1,7 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// ------------------------------------------------------------------------------
+// Changes to this file must follow the https://aka.ms/api-review process.
+// ------------------------------------------------------------------------------
+
+[assembly: System.Runtime.CompilerServices.TypeForwardedTo(typeof(System.Collections.ObjectModel.ReadOnlySet<>))]
diff --git a/src/libraries/System.Collections/ref/System.Collections.csproj b/src/libraries/System.Collections/ref/System.Collections.csproj
@@ -4,6 +4,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="System.Collections.cs" />
+    <Compile Include="System.Collections.Forwards.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\System.Runtime\ref\System.Runtime.csproj" />

diff --git a/src/libraries/System.Collections/tests/Generic/CollectionExtensionsTests.cs b/src/libraries/System.Collections/tests/Generic/CollectionExtensionsTests.cs
@@ -122,6 +122,8 @@ public void AsReadOnly_TurnsISetIntoReadOnlySet()
             ISet<string> set = new HashSet<string> { "A", "B" };
             ReadOnlySet<string> readOnlySet = set.AsReadOnly();
             Assert.NotNull(readOnlySet);
+            Assert.NotSame(set, readOnlySet);
+            Assert.NotSame(readOnlySet, set.AsReadOnly());
             CollectionAsserts.Equal(set, readOnlySet);
         }