From a07d2c88bbeac21b78745ffc660ff2a98f1f09bb Mon Sep 17 00:00:00 2001
From: Neal Gafter <neal@gafter.com>
Date: Thu, 17 Dec 2015 14:39:09 -0800
Subject: [PATCH] A method may have the same name as its type parameter. Fixes
 #7506

---
 .../Symbols/Source/SourceMemberMethodSymbol.cs  |  5 +----
 .../Symbols/Source/TypeParameterBuilder.cs      |  3 ++-
 .../Test/Symbol/Symbols/SymbolErrorTests.cs     | 17 +++++++++--------
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberMethodSymbol.cs b/src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberMethodSymbol.cs
index 7eae1e9bbba..00c5587c1b4 100644
--- a/src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberMethodSymbol.cs
+++ b/src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberMethodSymbol.cs
@@ -822,10 +822,7 @@ private ImmutableArray<TypeParameterSymbol> MakeTypeParameters(MethodDeclaration
                 var location = identifier.GetLocation();
                 var name = identifier.ValueText;
 
-                if (name == this.Name)
-                {
-                    diagnostics.Add(ErrorCode.ERR_TypeVariableSameAsParent, location, name);
-                }
+                // Note: It is not an error to have a type parameter named the same as its enclosing method: void M<M>() {}
 
                 for (int i = 0; i < result.Count; i++)
                 {
diff --git a/src/Compilers/CSharp/Portable/Symbols/Source/TypeParameterBuilder.cs b/src/Compilers/CSharp/Portable/Symbols/Source/TypeParameterBuilder.cs
index 84b14bd0fbb..673d3fbe097 100644
--- a/src/Compilers/CSharp/Portable/Symbols/Source/TypeParameterBuilder.cs
+++ b/src/Compilers/CSharp/Portable/Symbols/Source/TypeParameterBuilder.cs
@@ -10,7 +10,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.Symbols
 {
     /// <summary>
-    /// A context for binding type parameter symbols.
+    /// A context for binding type parameter symbols of named types.
     /// </summary>
     internal sealed class TypeParameterBuilder
     {
@@ -37,6 +37,7 @@ internal TypeParameterSymbol MakeSymbol(int ordinal, IList<TypeParameterBuilder>
                 ToLocations(builders),
                 ToSyntaxRefs(builders));
 
+            // SPEC: A type parameter [of a type] cannot have the same name as the type itself.
             if (result.Name == result.ContainingSymbol.Name)
             {
                 diagnostics.Add(ErrorCode.ERR_TypeVariableSameAsParent, result.Locations[0], result.Name);
diff --git a/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs b/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs
index 58a8760959f..61e4c1cfdf2 100644
--- a/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs
+++ b/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs
@@ -11961,7 +11961,7 @@ public void CS0694ERR_TypeVariableSameAsParent01()
 {
     interface IFoo
     {
-        void M<M>(M m);
+        void M<M>(M m); // OK (constraint applies to types but not methods)
     }
     
     class C<C>
@@ -11972,13 +11972,14 @@ public struct S<T, S>
     }
 }
 ";
-            var comp = DiagnosticsUtils.VerifyErrorsAndGetCompilationWithMscorlib(text,
-                new ErrorDescription { Code = (int)ErrorCode.ERR_TypeVariableSameAsParent, Line = 5, Column = 16 }, // Dev10 not report this if there next 2 errors
-                new ErrorDescription { Code = (int)ErrorCode.ERR_TypeVariableSameAsParent, Line = 8, Column = 13 },
-                new ErrorDescription { Code = (int)ErrorCode.ERR_TypeVariableSameAsParent, Line = 10, Column = 28 });
-
-            var ns = comp.SourceModule.GlobalNamespace.GetMembers("NS").Single() as NamespaceSymbol;
-            // TODO...
+            CreateCompilationWithMscorlib(text).VerifyDiagnostics(
+                // (8,13): error CS0694: Type parameter 'C' has the same name as the containing type, or method
+                //     class C<C>
+                Diagnostic(ErrorCode.ERR_TypeVariableSameAsParent, "C").WithArguments("C").WithLocation(8, 13),
+                // (10,28): error CS0694: Type parameter 'S' has the same name as the containing type, or method
+                //         public struct S<T, S>
+                Diagnostic(ErrorCode.ERR_TypeVariableSameAsParent, "S").WithArguments("S").WithLocation(10, 28)
+                );
         }
 
         [Fact]
-- 
GitLab