Merge pull request #9476 from jcouv/fix-9167

Fix for #9167: async and iterator rewriters do not require optional attribute types

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenIterators.cs

@@ -2326,5 +2326,73 @@ .maxstack  3
 }");
             Assert.True(expectedIL.IndexOf("<>_", StringComparison.Ordinal) < 0);
         }
+
+        [Fact, WorkItem(9167, "https://github.com/dotnet/roslyn/issues/9167")]
+        public void IteratorShouldCompileWithoutOptionalAttributes()
+        {
+            #region IL for corlib without CompilerGeneratedAttribute or DebuggerNonUserCodeAttribute
+            var corlib = @"
+namespace System
+{
+    public class Object { }
+    public struct Int32 { }
+    public struct Boolean { }
+    public class String { }
+    public class Exception { }
+    public class NotSupportedException : Exception { }
+    public class ValueType { }
+    public class Enum { }
+    public struct Void { }
+
+    public interface IDisposable
+    {
+        void Dispose();
+    }
+}
+
+namespace System.Collections
+{
+    public interface IEnumerable
+    {
+        IEnumerator GetEnumerator();
+    }
+
+    public interface IEnumerator
+    {
+        bool MoveNext();
+        object Current { get; }
+        void Reset();
+    }
+
+    namespace Generic
+    {
+        public interface IEnumerable<T> : IEnumerable
+        {
+            new IEnumerator<T> GetEnumerator();
+        }
+
+        public interface IEnumerator<T> : IEnumerator
+        {
+            new T Current { get; }
+        }
+    }
+}";
+            #endregion
+
+            var source = @"
+public class C
+{
+    public System.Collections.IEnumerable SomeNumbers()
+    {
+        yield return 42;
+    }
+}";
+            // The compilation succeeds even though CompilerGeneratedAttribute and DebuggerNonUserCodeAttribute are not available.
+            var compilation = CreateCompilation(new[] { Parse(source), Parse(corlib) });
+            var verifier = CompileAndVerify(compilation, verify: false);
+            verifier.VerifyDiagnostics(
+                // warning CS8021: No value for RuntimeMetadataVersion found. No assembly containing System.Object was found nor was a value for RuntimeMetadataVersion specified through options.
+                Diagnostic(ErrorCode.WRN_NoRuntimeMetadataVersion).WithLocation(1, 1));
+        }
     }
 }

src/Compilers/VisualBasic/Portable/Lowering/AsyncRewriter/AsyncRewriter.vb

@@ -295,11 +295,6 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         Friend Overrides Function EnsureAllSymbolsAndSignature() As Boolean
             Dim hasErrors As Boolean = MyBase.EnsureAllSymbolsAndSignature
 
-            ' NOTE: in current implementation these attributes must exist
-            ' TODO: change to "don't use if not found"
-            EnsureWellKnownMember(Of MethodSymbol)(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor, hasErrors)
-            EnsureWellKnownMember(Of MethodSymbol)(WellKnownMember.System_Diagnostics_DebuggerHiddenAttribute__ctor, hasErrors)
-
             EnsureSpecialType(SpecialType.System_Object, hasErrors)
             EnsureSpecialType(SpecialType.System_Void, hasErrors)
             EnsureSpecialType(SpecialType.System_ValueType, hasErrors)

src/Compilers/VisualBasic/Portable/Lowering/IteratorRewriter/IteratorRewriter.vb

@@ -86,11 +86,6 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                 hasErrors = True
             End If
 
-            ' NOTE: in current implementation these attributes must exist
-            ' TODO: change to "don't use if not found"
-            EnsureWellKnownMember(Of MethodSymbol)(WellKnownMember.System_Runtime_CompilerServices_CompilerGeneratedAttribute__ctor, hasErrors)
-            EnsureWellKnownMember(Of MethodSymbol)(WellKnownMember.System_Diagnostics_DebuggerNonUserCodeAttribute__ctor, hasErrors)
-
             ' NOTE: We don't ensure DebuggerStepThroughAttribute, it is just not emitted if not found
             ' EnsureWellKnownMember(Of MethodSymbol)(WellKnownMember.System_Diagnostics_DebuggerStepThroughAttribute__ctor, hasErrors)
 

src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenIterators.vb

@@ -1618,5 +1618,75 @@ End Module
             CompileAndVerify(source, expectedOutput:="420420")
         End Sub
 
+        <Fact, WorkItem(9167, "https://github.com/dotnet/roslyn/issues/9167")>
+        Public Sub IteratorShouldCompileWithoutOptionalAttributes()
+
+#Region "IL For corlib without CompilerGeneratedAttribute Or DebuggerNonUserCodeAttribute"
+            Dim corlib = "
+Namespace System
+    Public Class [Object]
+    End Class
+    Public Class [Int32]
+    End Class
+    Public Class [Boolean]
+    End Class
+    Public Class [String]
+    End Class
+    Public Class Exception
+    End Class
+    Public Class NotSupportedException
+        Inherits Exception
+    End Class
+    Public Class ValueType
+    End Class
+    Public Class [Enum]
+    End Class
+    Public Class Void
+    End Class
+    Public Interface IDisposable
+        Sub Dispose()
+    End Interface
+End Namespace
+Namespace System.Collections
+    Public Interface IEnumerable
+        Function GetEnumerator() As IEnumerator
+    End Interface
+    Public Interface IEnumerator
+        Function MoveNext() As Boolean
+        Property Current As Object
+        Sub Reset()
+    End Interface
+    Namespace Generic
+        Public Interface IEnumerable(Of T)
+            Inherits IEnumerable
+            Overloads Function GetEnumerator() As IEnumerator(Of T)
+        End Interface
+        Public Interface IEnumerator(Of T)
+            Inherits IEnumerator
+            Overloads Property Current As T
+        End Interface
+    End Namespace
+End Namespace
+Namespace System.Threading
+    Public Class Thread
+        Shared Property CurrentThread As Thread
+        Property ManagedThreadId As Integer
+    End Class
+End Namespace
+"
+#End Region
+
+            Dim source = "
+Class C
+    Public Iterator Function SomeNumbers() As System.Collections.IEnumerable
+        Yield Nothing
+    End Function
+End Class
+"
+            ' The compilation succeeds even though CompilerGeneratedAttribute and DebuggerNonUserCodeAttribute are not available.
+            Dim compilation = CompilationUtils.CreateCompilation({Parse(source), Parse(corlib)})
+            Dim verifier = CompileAndVerify(compilation, verify:=False)
+            verifier.VerifyDiagnostics()
+        End Sub
     End Class
 End Namespace

src/Compilers/VisualBasic/Test/Emit/Emit/EditAndContinue/EditAndContinueStateMachineTests.vb

@@ -4456,26 +4456,6 @@ End Class
 Imports System
 Imports System.Threading.Tasks
 
-' TODO: the attribute shouldn't be needed (https://github.com/dotnet/roslyn/issues/9167)
-Namespace System.Runtime.CompilerServices
-    <AttributeUsage(AttributeTargets.All)>
-    Public Class CompilerGeneratedAttribute
-        Inherits Attribute
-        Public Sub New()
-        End Sub
-    End Class
-End Namespace
-
-' TODO: the attribute shouldn't be needed  (https://github.com/dotnet/roslyn/issues/9167)
-Namespace System.Diagnostics
-    <AttributeUsage(AttributeTargets.All)>
-    Public Class DebuggerHiddenAttribute
-        Inherits Attribute
-        Public Sub New()
-        End Sub
-    End Class
-End Namespace
-
 Namespace Microsoft.VisualBasic.CompilerServices
     Class ProjectData
         Shared Sub  SetProjectError(e As Exception)