Bug 911913 - Squiggle location for Unimplemented Interface Method diagnostic...

 Bug 911913 - Squiggle location for Unimplemented Interface Method diagnostic changed to reflect interface rather than class - matching VB implementation. (changeset 1252208)

Src/Compilers/CSharp/Source/Symbols/Source/ImplicitNamedTypeSymbol.cs

@@ -41,6 +41,13 @@ internal override AttributeUsageInfo GetAttributeUsageInfo()
             return AttributeUsageInfo.Null;
         }
 
+        protected override Location GetCorrespondingBaseListLocation(NamedTypeSymbol @base)
+        {
+            // A script class may implement interfaces in hosted scenarios.
+            // The interface definitions are specified via API, not in compilation source.
+            return NoLocation.Singleton;
+        }
+
         internal override NamedTypeSymbol BaseTypeNoUseSiteDiagnostics
         {
             get

Src/Compilers/CSharp/Source/Symbols/Source/SourceMemberContainerSymbol_ImplementationChecks.cs

-// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
 using System.Collections.Immutable;
@@ -213,7 +213,7 @@ private void CheckAbstractClassImplementations(DiagnosticBag diagnostics)
                                 // Suppress for bogus properties and events and for indexed properties.
                                 if (!interfaceMember.MustCallMethodsDirectly() && !interfaceMember.IsIndexedProperty())
                                 {
-                                    diagnostics.Add(ErrorCode.ERR_UnimplementedInterfaceMember, this.Locations[0], this, interfaceMember);
+                                    diagnostics.Add(ErrorCode.ERR_UnimplementedInterfaceMember, GetImplementsLocation(@interface) ?? this.Locations[0], this, interfaceMember);
                                 }
                             }
                         }
@@ -253,6 +253,47 @@ private void CheckAbstractClassImplementations(DiagnosticBag diagnostics)
             return synthesizedImplementations.ToImmutableAndFree();
         }
 
+        protected abstract Location GetCorrespondingBaseListLocation(NamedTypeSymbol @base);
+
+        private Location GetImplementsLocation(NamedTypeSymbol implementedInterface)
+        {
+            // We ideally want to identify the interface location in the baselist with an exact match but
+            // will fall back and use the first derived interface if exact interface is not present.
+            // this is the similar logic as the VB Implementation.
+            Debug.Assert(this.InterfacesAndTheirBaseInterfacesNoUseSiteDiagnostics.Contains(implementedInterface));
+
+            NamedTypeSymbol directInterface = null;
+            foreach (var iface in this.InterfacesNoUseSiteDiagnostics)
+            {
+                if (iface == implementedInterface)
+                {
+                    directInterface = iface;
+                    break;
+                }
+                else if ((object)directInterface == null && ImplementsInterface(iface, implementedInterface))
+                {
+                    directInterface = iface;
+                }
+            }
+
+            Debug.Assert((object)directInterface != null);
+            return GetCorrespondingBaseListLocation(directInterface);
+        }
+
+        private bool ImplementsInterface(TypeSymbol subType, TypeSymbol superInterface)
+        {
+            HashSet<DiagnosticInfo> unusedDiagnostics = null;
+
+            foreach (NamedTypeSymbol @interface in subType.AllInterfacesWithDefinitionUseSiteDiagnostics(ref unusedDiagnostics))
+            {
+                if (@interface.IsInterface && @interface == superInterface)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         /// <summary>
         /// It's not interesting to report diagnostics on implementation of interface accessors
         /// if the corresponding events or properties are not implemented (i.e. we want to suppress

Src/Compilers/CSharp/Source/Symbols/Source/SourceNamedTypeSymbol.cs

-// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
@@ -32,6 +32,44 @@ internal sealed partial class SourceNamedTypeSymbol : SourceMemberContainerTypeS
 
         private ThreeState lazyIsExplicitDefinitionOfNoPiaLocalType = ThreeState.Unknown;
 
+
+        protected override Location GetCorrespondingBaseListLocation(NamedTypeSymbol @base)
+        {
+            Location backupLocation = null;
+            var unusedDiagnostics = DiagnosticBag.GetInstance();
+
+            foreach (SyntaxReference part in SyntaxReferences)
+            {
+                TypeDeclarationSyntax typeBlock = (TypeDeclarationSyntax)part.GetSyntax();
+                BaseListSyntax bases = typeBlock.BaseList;
+                if (bases == null)
+                {
+                    continue; 
+                }
+                SeparatedSyntaxList<TypeSyntax> inheritedTypeDecls  = typeBlock.BaseList.Types;
+
+                var baseBinder = this.DeclaringCompilation.GetBinder(bases);
+                baseBinder = baseBinder.WithAdditionalFlagsAndContainingMemberOrLambda(BinderFlags.SuppressConstraintChecks, this);
+
+                if ((object) backupLocation == null)
+                {
+                    backupLocation = ((TypeSyntax)inheritedTypeDecls[0]).GetLocation();
+                }
+
+                foreach (TypeSyntax t in inheritedTypeDecls)
+                {
+                    TypeSymbol bt = baseBinder.BindType(t, unusedDiagnostics);
+                    if (bt == @base)
+                    {
+                        unusedDiagnostics.Free();
+                        return t.GetLocation();
+                    }
+                }                
+            }
+            unusedDiagnostics.Free();
+            return backupLocation;
+        }
+
         internal SourceNamedTypeSymbol(NamespaceOrTypeSymbol containingSymbol, MergedTypeDeclaration declaration, DiagnosticBag diagnostics)
             : base(containingSymbol, declaration, diagnostics)
         {

Src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenOverridingAndHiding.cs

@@ -4188,7 +4188,7 @@ public void MissingAssemblyReference01()
                 referencedCompilations: new[] { B, C }).VerifyDiagnostics(
                 // (1,14): error CS0535: 'D' does not implement interface member 'B.M(A)'
                 // public class D : C, B { }
-                    Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "D").WithArguments("D", "B.M(A)")
+                    Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "B").WithArguments("D", "B.M(A)")
                 );
         }
 

Src/Compilers/CSharp/Test/Semantic/Semantics/AmbiguousOverrideTests.cs

@@ -343,9 +343,13 @@ class CBar : IFoo // CS0535 * 2
             var asm = TestReferences.SymbolsTests.CustomModifiers.ModoptTests;
 
             CreateCompilationWithMscorlib(text, new[] { asm }).VerifyDiagnostics(
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CFoo").WithArguments("CFoo", "Metadata.IFooAmbiguous<string, long>.M(?)"),
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CBar").WithArguments("CBar", "Metadata.IFoo.M<T>(T)"),
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CBar").WithArguments("CBar", "Metadata.IFoo.M<T>(T)"));
+                // (4,38): warning CS0473: Explicit interface implementation 'CFoo.Metadata.IFooAmbiguous<string, long>.M(string)' matches more than one interface member. Which interface member is actually chosen is implementation-dependent. Consider using a non-explicit implementation instead.
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IFoo").WithArguments("CBar", "Metadata.IFoo.M<T>(T)"),
+                // (2,14): error CS0535: 'CFoo' does not implement interface member
+                // 'Metadata.IFooAmbiguous<string, long>.M(?)'
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IFoo").WithArguments("CBar", "Metadata.IFoo.M<T>(T)"),
+                // (2,14): error CS0535: 'CFoo' does not implement interface member 'Metadata.IFooAmbiguous<string, long>.M(string)'
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IFooAmbiguous<string, long>").WithArguments("CFoo", "Metadata.IFooAmbiguous<string, long>.M(?)"));
         }
 
         [WorkItem(540518, "DevDiv")]
@@ -362,12 +366,14 @@ public class CFoo : IFooAmbiguous<string, long> // CS0535 *2
 
             CreateCompilationWithMscorlib(text, new[] { asm }).VerifyDiagnostics(
                 // (4,38): warning CS0473: Explicit interface implementation 'CFoo.Metadata.IFooAmbiguous<string, long>.M(string)' matches more than one interface member. Which interface member is actually chosen is implementation-dependent. Consider using a non-explicit implementation instead.
-                Diagnostic(ErrorCode.WRN_ExplicitImplCollision, "M").WithArguments("CFoo.Metadata.IFooAmbiguous<string, long>.M(string)"),
-                // (2,14): error CS0535: 'CFoo' does not implement interface member
-                // 'Metadata.IFooAmbiguous<string, long>.M(?)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CFoo").WithArguments("CFoo", "Metadata.IFooAmbiguous<string, long>.M(?)"),
-                // (2,14): error CS0535: 'CFoo' does not implement interface member 'Metadata.IFooAmbiguous<string, long>.M(string)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CFoo").WithArguments("CFoo", "Metadata.IFooAmbiguous<string, long>.M(string)"));
+                //     long IFooAmbiguous<string, long>.M(string t) { return -128; } // W CS0437
+                Diagnostic(ErrorCode.WRN_ExplicitImplCollision, "M").WithArguments("CFoo.Metadata.IFooAmbiguous<string, long>.M(string)").WithLocation(4, 38),
+                // (2,21): error CS0535: 'CFoo' does not implement interface member 'Metadata.IFooAmbiguous<string, long>.M(string)'
+                // public class CFoo : IFooAmbiguous<string, long> // CS0535 *2
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IFooAmbiguous<string, long>").WithArguments("CFoo", "Metadata.IFooAmbiguous<string, long>.M(string)").WithLocation(2, 21),
+                // (2,21): error CS0535: 'CFoo' does not implement interface member 'Metadata.IFooAmbiguous<string, long>.M(?)'
+                // public class CFoo : IFooAmbiguous<string, long> // CS0535 *2
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IFooAmbiguous<string, long>").WithArguments("CFoo", "Metadata.IFooAmbiguous<string, long>.M(?)").WithLocation(2, 21));
         }
 
         [Fact]

Src/Compilers/CSharp/Test/Semantic/Semantics/BindingTests.cs

@@ -830,6 +830,528 @@ public class Test
             // <fine-name>(4,16): error CS0012: The type 'BaseAssembly.BaseClass' is defined in an assembly that is not referenced. You must add a reference to assembly 'BaseAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
         }
 
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_Typical()
+        {
+            string scenarioCode = @"
+public class ITT
+    : IInterfaceBase
+{ }
+public interface IInterfaceBase
+{
+    void bar();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (3,7): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase.bar()'
+                //     : IInterfaceBase
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase").WithArguments("ITT", "IInterfaceBase.bar()").WithLocation(3, 7));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_FullyQualified()
+        {
+
+            // Using fully Qualified names
+            string scenarioCode = @"
+public class ITT
+    : test.IInterfaceBase
+{ }
+
+namespace test
+{
+    public interface IInterfaceBase
+    {
+        void bar();
+    }
+}";
+
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (3,7): error CS0535: 'ITT' does not implement interface member 'test.IInterfaceBase.bar()'
+                //     : test.IInterfaceBase
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "test.IInterfaceBase").WithArguments("ITT", "test.IInterfaceBase.bar()").WithLocation(3, 7));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_WithAlias()
+        {
+            // Using Alias            
+            string scenarioCode = @"
+using a1 = test;
+
+public class ITT
+    : a1.IInterfaceBase
+{ }
+
+namespace test 
+{
+    public interface IInterfaceBase
+    {
+        void bar();
+    }
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (5,7): error CS0535: 'ITT' does not implement interface member 'test.IInterfaceBase.bar()'
+                //     : a1.IInterfaceBase
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "a1.IInterfaceBase").WithArguments("ITT", "test.IInterfaceBase.bar()").WithLocation(5, 7));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario01()
+        {
+            // Two interfaces, neither implemented with alias - should have 2 errors each squiggling a different interface type.            
+            string scenarioCode = @"
+using a1 = test;
+
+public class ITT
+    : a1.IInterfaceBase, a1.IInterfaceBase2 
+{ }
+
+namespace test 
+{
+    public interface IInterfaceBase
+    {
+        void xyz();
+    }
+
+    public interface IInterfaceBase2
+    {
+        void xyz();
+    }
+}";
+
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (5,7): error CS0535: 'ITT' does not implement interface member 'test.IInterfaceBase.xyz()'
+                //     : a1.IInterfaceBase, a1.IInterfaceBase2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "a1.IInterfaceBase").WithArguments("ITT", "test.IInterfaceBase.xyz()").WithLocation(5, 7),
+                // (5,26): error CS0535: 'ITT' does not implement interface member 'test.IInterfaceBase2.xyz()'
+                //     : a1.IInterfaceBase, a1.IInterfaceBase2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "a1.IInterfaceBase2").WithArguments("ITT", "test.IInterfaceBase2.xyz()").WithLocation(5, 26));
+        }
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario02()
+        {
+
+            // Two interfaces, only the  second is implemented 
+            string scenarioCode = @"
+public class ITT
+    : IInterfaceBase, IInterfaceBase2 
+{
+    void IInterfaceBase2.abc()
+    { }
+}
+
+public interface IInterfaceBase
+{
+        void xyz();
+}
+
+public interface IInterfaceBase2
+{
+        void abc();
+}";
+
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (3,7): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase.xyz()'
+                //     : IInterfaceBase, IInterfaceBase2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase").WithArguments("ITT", "IInterfaceBase.xyz()").WithLocation(3, 7));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario03()
+        {
+            // Two interfaces, only the first is implemented
+            string scenarioCode = @"
+public class ITT
+    : IInterfaceBase, IInterfaceBase2 
+{
+    void IInterfaceBase.xyz()
+    { }
+}
+
+public interface IInterfaceBase
+{
+    void xyz();
+}
+
+public interface IInterfaceBase2
+{
+    void abc();
+}
+";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (3,23): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase2.abc()'
+                //     : IInterfaceBase, IInterfaceBase2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase2").WithArguments("ITT", "IInterfaceBase2.abc()").WithLocation(3, 23));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario04()
+        {
+            // Two interfaces, neither implemented but formatting of interfaces are on different lines
+            string scenarioCode = @"
+public class ITT
+    : IInterfaceBase, 
+     IInterfaceBase2 
+{ }
+
+public interface IInterfaceBase
+{
+    void xyz();
+}
+
+public interface IInterfaceBase2
+{
+    void xyz();
+}
+";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (3,7): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase.xyz()'
+                //     : IInterfaceBase, 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase").WithArguments("ITT", "IInterfaceBase.xyz()").WithLocation(3, 7),
+                // (4,6): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase2.xyz()'
+                //      IInterfaceBase2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase2").WithArguments("ITT", "IInterfaceBase2.xyz()").WithLocation(4, 6));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario05()
+        {
+            // Inherited Interface scenario 
+            // With methods not implemented in both base and derived.
+            // Should reflect 2 diagnostics but both with be squiggling the derived as we are not 
+            // explicitly implementing base.
+            string scenarioCode = @"
+public class ITT: IDerived
+{ }
+
+interface IInterfaceBase
+{
+    void xyzb();
+}
+
+interface IDerived : IInterfaceBase
+{
+    void xyzd();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,19): error CS0535: 'ITT' does not implement interface member 'IDerived.xyzd()'
+                // public class ITT: IDerived
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived").WithArguments("ITT", "IDerived.xyzd()").WithLocation(2, 19),
+                // (2,19): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase.xyzb()'
+                // public class ITT: IDerived
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived").WithArguments("ITT", "IInterfaceBase.xyzb()").WithLocation(2, 19));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario06()
+        {
+            // Inherited Interface scenario 
+            string scenarioCode = @"
+public class ITT: IDerived, IInterfaceBase
+{ }
+
+interface IInterfaceBase
+{
+    void xyz();
+}
+
+interface IDerived : IInterfaceBase
+{
+    void xyzd();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,19): error CS0535: 'ITT' does not implement interface member 'IDerived.xyzd()'
+                // public class ITT: IDerived, IInterfaceBase
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived").WithArguments("ITT", "IDerived.xyzd()").WithLocation(2, 19),
+                // (2,29): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase.xyz()'
+                // public class ITT: IDerived, IInterfaceBase
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase").WithArguments("ITT", "IInterfaceBase.xyz()").WithLocation(2, 29));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario07()
+        {
+            // Inherited Interface scenario - different order. 
+            string scenarioCode = @"
+public class ITT: IInterfaceBase, IDerived 
+{ }
+
+interface IDerived : IInterfaceBase
+{
+    void xyzd();
+}
+interface IInterfaceBase
+{
+    void xyz();
+}
+";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,35): error CS0535: 'ITT' does not implement interface member 'IDerived.xyzd()'
+                // public class ITT: IInterfaceBase, IDerived 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived").WithArguments("ITT", "IDerived.xyzd()").WithLocation(2, 35),
+                // (2,19): error CS0535: 'ITT' does not implement interface member 'IInterfaceBase.xyz()'
+                // public class ITT: IInterfaceBase, IDerived 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IInterfaceBase").WithArguments("ITT", "IInterfaceBase.xyz()").WithLocation(2, 19));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario08()
+        {
+            // Inherited Interface scenario
+            string scenarioCode = @"
+public class ITT: IDerived2 
+{}
+
+interface IBase
+{
+    void method1();
+}
+interface IBase2
+{
+    void Method2();
+}
+interface IDerived2: IBase, IBase2
+{}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,19): error CS0535: 'ITT' does not implement interface member 'IBase.method1()'
+                // public class ITT: IDerived2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived2").WithArguments("ITT", "IBase.method1()").WithLocation(2, 19),
+                // (2,19): error CS0535: 'ITT' does not implement interface member 'IBase2.Method2()'
+                // public class ITT: IDerived2 
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived2").WithArguments("ITT", "IBase2.Method2()").WithLocation(2, 19));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation13UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario09()
+        {
+            // Inherited Interface scenario.           
+            string scenarioCode = @"
+public class ITT : IDerived
+{
+    void IBase2.method2()
+    { }
+
+    void IDerived.method3()
+    { }
+}
+
+public interface IBase
+{
+    void method1();
+}
+
+public interface IBase2
+{
+    void method2();
+}
+public interface IDerived : IBase, IBase2
+{
+    void method3();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,20): error CS0535: 'ITT' does not implement interface member 'IBase.method1()'
+                // public class ITT : IDerived
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived").WithArguments("ITT", "IBase.method1()").WithLocation(2, 20));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_InterfaceInheritenceScenario10()
+        {
+            // Inherited Interface scenario.
+            string scenarioCode = @"
+public class ITT : IDerived
+{
+    void IBase2.method2()
+    { }    
+    void IBase3.method3()
+    { }
+    void IDerived.method4()
+    { }
+}
+
+public interface IBase
+{
+    void method1();
+}
+
+public interface IBase2 : IBase
+{    
+    void method2();
+}
+
+public interface IBase3 : IBase
+{
+    void method3();
+}
+public interface IDerived : IBase2, IBase3
+{
+    void method4();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,20): error CS0535: 'ITT' does not implement interface member 'IBase.method1()'
+                // public class ITT : IDerived
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IDerived").WithArguments("ITT", "IBase.method1()").WithLocation(2, 20));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_WithPartialClass01()
+        {
+            // partial class - missing method. 
+            // each partial implements interface but one is missing method.
+            string scenarioCode = @"
+ public partial class Foo : IBase
+{
+    void IBase.method1()
+    { }
+
+    void IBase2.method2()
+    { }
+}
+
+public partial class Foo : IBase2
+{
+}
+
+public partial class Foo : IBase3
+{
+}
+
+public interface IBase
+{
+    void method1();
+}
+
+public interface IBase2
+{    
+    void method2();
+}
+
+public interface IBase3
+{
+    void method3();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (15,28): error CS0535: 'Foo' does not implement interface member 'IBase3.method3()'
+                // public partial class Foo : IBase3
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IBase3").WithArguments("Foo", "IBase3.method3()").WithLocation(15, 28));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_WithPartialClass02()
+        {
+            // partial class - missing method. diagnostic is reported in correct partial class
+            // one partial class specifically does include any inherited interface 
+            string scenarioCode = @"
+public partial class Foo : IBase, IBase2
+{
+    void IBase.method1()
+    { }
+
+}
+
+public partial class Foo
+{
+}
+
+public partial class Foo : IBase3
+{
+}
+
+public interface IBase
+{
+    void method1();
+}
+
+public interface IBase2
+{
+    void method2();
+}
+
+public interface IBase3
+{
+    void method3();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,35): error CS0535: 'Foo' does not implement interface member 'IBase2.method2()'
+                // public partial class Foo : IBase, IBase2
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IBase2").WithArguments("Foo", "IBase2.method2()").WithLocation(2, 35),
+                // (13,28): error CS0535: 'Foo' does not implement interface member 'IBase3.method3()'
+                // public partial class Foo : IBase3
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IBase3").WithArguments("Foo", "IBase3.method3()").WithLocation(13, 28));
+        }
+
+        [WorkItem(911913, "DevDiv")]
+        [Fact]
+        public void UnimplementedInterfaceSquiggleLocation_WithPartialClass03()
+        {
+            // Partial class scenario
+            // One class implements multiple interfaces and is missing method.             
+            string scenarioCode = @" 
+public partial class Foo : IBase, IBase2
+{
+    void IBase.method1()
+    { }
+
+}
+
+public partial class Foo : IBase3
+{
+}
+
+public interface IBase
+{
+    void method1();
+}
+
+public interface IBase2
+{    
+    void method2();
+}
+
+public interface IBase3
+{
+    void method3();
+}";
+            var testAssembly = CreateCompilationWithMscorlib(scenarioCode);
+            testAssembly.VerifyDiagnostics(
+                // (2,35): error CS0535: 'Foo' does not implement interface member 'IBase2.method2()'
+                // public partial class Foo : IBase, IBase2
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IBase2").WithArguments("Foo", "IBase2.method2()").WithLocation(2, 35),
+                // (9,28): error CS0535: 'Foo' does not implement interface member 'IBase3.method3()'
+                // public partial class Foo : IBase3
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IBase3").WithArguments("Foo", "IBase3.method3()").WithLocation(9, 28)
+ );
+        }
         [WorkItem(541466, "DevDiv")]
         [Fact]
         public void UseSiteErrorViaAliasTest04()

Src/Compilers/CSharp/Test/Semantic/Semantics/UseSiteErrorTests.cs

@@ -167,10 +167,10 @@ class C : CSharpErrors.InterfaceMethods
 
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceMethods.ParameterType1(UnavailableClass)'
                 // class C : CSharpErrors.InterfaceMethods
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType1(UnavailableClass)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceMethods").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType1(UnavailableClass)"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceMethods.ParameterType2(UnavailableClass[])'
                 // class C : CSharpErrors.InterfaceMethods
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType2(UnavailableClass[])"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceMethods").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType2(UnavailableClass[])"));
         }
 
         [Fact]
@@ -244,16 +244,16 @@ class C : CSharpErrors.InterfaceMethods
 
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceMethods.ReturnType1()'
                 // class C : CSharpErrors.InterfaceMethods
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceMethods.ReturnType1()"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceMethods").WithArguments("C", "CSharpErrors.InterfaceMethods.ReturnType1()"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceMethods.ReturnType2()'
                 // class C : CSharpErrors.InterfaceMethods
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceMethods.ReturnType2()"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceMethods").WithArguments("C", "CSharpErrors.InterfaceMethods.ReturnType2()"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceMethods.ParameterType1(UnavailableClass)'
                 // class C : CSharpErrors.InterfaceMethods
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType1(UnavailableClass)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceMethods").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType1(UnavailableClass)"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceMethods.ParameterType2(UnavailableClass[])'
                 // class C : CSharpErrors.InterfaceMethods
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType2(UnavailableClass[])"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceMethods").WithArguments("C", "CSharpErrors.InterfaceMethods.ParameterType2(UnavailableClass[])"));
         }
 
         [Fact]
@@ -559,22 +559,22 @@ class C : CSharpErrors.InterfaceProperties
 
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceProperties.GetSet1'
                 // class C : CSharpErrors.InterfaceProperties
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceProperties.GetSet1"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceProperties").WithArguments("C", "CSharpErrors.InterfaceProperties.GetSet1"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceProperties.GetSet2'
                 // class C : CSharpErrors.InterfaceProperties
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceProperties.GetSet2"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceProperties").WithArguments("C", "CSharpErrors.InterfaceProperties.GetSet2"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceProperties.Get1'
                 // class C : CSharpErrors.InterfaceProperties
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceProperties.Get1"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceProperties").WithArguments("C", "CSharpErrors.InterfaceProperties.Get1"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceProperties.Get2'
                 // class C : CSharpErrors.InterfaceProperties
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceProperties.Get2"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceProperties").WithArguments("C", "CSharpErrors.InterfaceProperties.Get2"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceProperties.Set1'
                 // class C : CSharpErrors.InterfaceProperties
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceProperties.Set1"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceProperties").WithArguments("C", "CSharpErrors.InterfaceProperties.Set1"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceProperties.Set2'
                 // class C : CSharpErrors.InterfaceProperties
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceProperties.Set2"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceProperties").WithArguments("C", "CSharpErrors.InterfaceProperties.Set2"));
         }
 
         [Fact]
@@ -927,16 +927,15 @@ class C : CSharpErrors.InterfaceEvents
                 // (6,87): error CS0539: 'C.Event3' in explicit interface declaration is not a member of interface
                 //     event CSharpErrors.EventDelegate<UnavailableClass[]> CSharpErrors.InterfaceEvents.Event3 { add { } remove { } }
                 Diagnostic(ErrorCode.ERR_InterfaceMemberNotFound, "Event3").WithArguments("C.Event3"),
-
-                // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceEvents.Event1'
+                // (2,11): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceEvents.Event3'
                 // class C : CSharpErrors.InterfaceEvents
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceEvents.Event1"),
-                // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceEvents.Event2'
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceEvents").WithArguments("C", "CSharpErrors.InterfaceEvents.Event3"),
+                // (2,11): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceEvents.Event1'
                 // class C : CSharpErrors.InterfaceEvents
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceEvents.Event2"),
-                // (2,7): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceEvents.Event3'
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceEvents").WithArguments("C", "CSharpErrors.InterfaceEvents.Event1"),
+                // (2,11): error CS0535: 'C' does not implement interface member 'CSharpErrors.InterfaceEvents.Event2'
                 // class C : CSharpErrors.InterfaceEvents
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "CSharpErrors.InterfaceEvents.Event3"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CSharpErrors.InterfaceEvents").WithArguments("C", "CSharpErrors.InterfaceEvents.Event2"));
         }
 
         [Fact]
@@ -1279,10 +1278,10 @@ class B : ILErrors.ModReqClassEventsNonVirtual, ILErrors.ModReqInterfaceEvents {
                 Diagnostic(ErrorCode.ERR_CloseUnimplementedInterfaceMemberWrongReturnType, "B").WithArguments("B", "ILErrors.ModReqInterfaceEvents.Event1", "ILErrors.ModReqClassEventsNonVirtual.Event1", "?"),
                 // (2,7): error CS0535: 'B' does not implement interface member 'ILErrors.ModReqInterfaceEvents.remove_Event1(?)'
                 // class B : ILErrors.ModReqClassEventsNonVirtual, ILErrors.ModReqInterfaceEvents { }
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "B").WithArguments("B", "ILErrors.ModReqInterfaceEvents.remove_Event1(?)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "ILErrors.ModReqInterfaceEvents").WithArguments("B", "ILErrors.ModReqInterfaceEvents.remove_Event1(?)"),
                 // (2,7): error CS0535: 'B' does not implement interface member 'ILErrors.ModReqInterfaceEvents.add_Event1(?)'
                 // class B : ILErrors.ModReqClassEventsNonVirtual, ILErrors.ModReqInterfaceEvents { }
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "B").WithArguments("B", "ILErrors.ModReqInterfaceEvents.add_Event1(?)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "ILErrors.ModReqInterfaceEvents").WithArguments("B", "ILErrors.ModReqInterfaceEvents.add_Event1(?)"));
         }
 
         [Fact]

Src/Compilers/CSharp/Test/Symbol/Symbols/AccessorOverriddenOrHiddenMembersTests.cs

@@ -519,7 +519,7 @@ class Derived : Base, I //CS0535
 
             compilation.VerifyDiagnostics(
                 // (12,7): error CS0535: 'Derived' does not implement interface member 'I.P.set'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Derived").WithArguments("Derived", "I.P.set"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "I").WithArguments("Derived", "I.P.set"));
 
             var global = compilation.GlobalNamespace;
 

Src/Compilers/CSharp/Test/Symbol/Symbols/GenericConstraintTests.cs

@@ -536,9 +536,9 @@ class C : I<string>
 }";
             CreateCompilationWithMscorlib(source).VerifyDiagnostics(
                 // (7,20): error CS0539: 'C.M2<U>()' in explicit interface declaration is not a member of interface
-                Diagnostic(ErrorCode.ERR_InterfaceMemberNotFound, "M2").WithArguments("C.M2<U>()").WithLocation(7, 20),
-                // (5,7): error CS0535: 'C' does not implement interface member 'I<string>.M1<U>()'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "I<string>.M1<U>()").WithLocation(5, 7));
+                Diagnostic(ErrorCode.ERR_InterfaceMemberNotFound, "M2").WithArguments("C.M2<U>()"),
+                // (5,11): error CS0535: 'C' does not implement interface member 'I<string>.M1<U>()'
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "I<string>").WithArguments("C", "I<string>.M1<U>()"));
         }
 
         /// <summary>
@@ -2011,13 +2011,13 @@ class B4 : A4, I { }
 class B5 : A5, I { }";
             CreateCompilationWithCustomILSource(csharpSource, ilSource).VerifyDiagnostics(
                 // (2,7): error CS0425: The constraints for type parameter 'T' of method 'A2.M<T>()' must match the constraints for type parameter 'T' of interface method 'I.M<T>()'. Consider using an explicit interface implementation instead.
-                Diagnostic(ErrorCode.ERR_ImplBadConstraints, "B2").WithArguments("T", "A2.M<T>()", "T", "I.M<T>()").WithLocation(2, 7),
+                Diagnostic(ErrorCode.ERR_ImplBadConstraints, "B2").WithArguments("T", "A2.M<T>()", "T", "I.M<T>()"),
                 // (3,7): error CS0425: The constraints for type parameter 'T' of method 'A3.M<T>()' must match the constraints for type parameter 'T' of interface method 'I.M<T>()'. Consider using an explicit interface implementation instead.
-                Diagnostic(ErrorCode.ERR_ImplBadConstraints, "B3").WithArguments("T", "A3.M<T>()", "T", "I.M<T>()").WithLocation(3, 7),
+                Diagnostic(ErrorCode.ERR_ImplBadConstraints, "B3").WithArguments("T", "A3.M<T>()", "T", "I.M<T>()"),
                 // (4,7): error CS0425: The constraints for type parameter 'T' of method 'A4.M<T>()' must match the constraints for type parameter 'T' of interface method 'I.M<T>()'. Consider using an explicit interface implementation instead.
-                Diagnostic(ErrorCode.ERR_ImplBadConstraints, "B4").WithArguments("T", "A4.M<T>()", "T", "I.M<T>()").WithLocation(4, 7),
+                Diagnostic(ErrorCode.ERR_ImplBadConstraints, "B4").WithArguments("T", "A4.M<T>()", "T", "I.M<T>()"),
                 // (5,7): error CS0535: 'B5' does not implement interface member 'I.M<T>()'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "B5").WithArguments("B5", "I.M<T>()").WithLocation(5, 7));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "I").WithArguments("B5", "I.M<T>()"));
         }
 
         /// <summary>

Src/Compilers/CSharp/Test/Symbol/Symbols/IndexedPropertyTests.cs

@@ -2503,7 +2503,7 @@ class D : CodeModule
             comp.VerifyDiagnostics(
                 // (4,7): error CS0535: 'C' does not implement interface member 'Microsoft.Vbe.Interop._CodeModule.ProcOfLine[int, out Microsoft.Vbe.Interop.vbext_ProcKind].get'
                 // class C : CodeModule
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "Microsoft.Vbe.Interop._CodeModule.ProcOfLine[int, out Microsoft.Vbe.Interop.vbext_ProcKind].get"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "CodeModule").WithArguments("C", "Microsoft.Vbe.Interop._CodeModule.ProcOfLine[int, out Microsoft.Vbe.Interop.vbext_ProcKind].get"));
 
             var interfaceProperty = comp.GlobalNamespace
                 .GetMember<NamespaceSymbol>("Microsoft")

Src/Compilers/CSharp/Test/Symbol/Symbols/IndexerTests.cs

-// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+// Copyright (c) Microsoft Open Technologies, Inc.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
 using System.Collections.Generic;
@@ -536,7 +536,7 @@ class C : I1
                 // (4,12): warning CS0473: Explicit interface implementation 'C.I1.this[int]' matches more than one interface member. Which interface member is actually chosen is implementation-dependent. Consider using a non-explicit implementation instead.
                 Diagnostic(ErrorCode.WRN_ExplicitImplCollision, "this").WithArguments("C.I1.this[int]"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'I1.this[int]'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "I1.this[int]"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "I1").WithArguments("C", "I1.this[int]"));
 
             var @interface = compilation.GlobalNamespace.GetMember<NamedTypeSymbol>("I1");
             var interfaceIndexers = @interface.Indexers;
@@ -1371,9 +1371,9 @@ class Test : IRefIndexer
             // Normally, we wouldn't see errors for the accessors, but here we do because the indexer is bogus.
             compilation.VerifyDiagnostics(
                 // (2,7): error CS0535: 'Test' does not implement interface member 'IRefIndexer.get_Item(ref int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Test").WithArguments("Test", "IRefIndexer.get_Item(ref int)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IRefIndexer").WithArguments("Test", "IRefIndexer.get_Item(ref int)"),
                 // (2,7): error CS0535: 'Test' does not implement interface member 'IRefIndexer.set_Item(ref int, int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Test").WithArguments("Test", "IRefIndexer.set_Item(ref int, int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IRefIndexer").WithArguments("Test", "IRefIndexer.set_Item(ref int, int)"));
         }
 
         /// <summary>
@@ -1395,9 +1395,9 @@ class Test : IRefIndexer
                 // (4,21): error CS0539: 'Test.this[int]' in explicit interface declaration is not a member of interface
                 Diagnostic(ErrorCode.ERR_InterfaceMemberNotFound, "this").WithArguments("Test.this[int]"),
                 // (2,7): error CS0535: 'Test' does not implement interface member 'IRefIndexer.get_Item(ref int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Test").WithArguments("Test", "IRefIndexer.get_Item(ref int)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IRefIndexer").WithArguments("Test", "IRefIndexer.get_Item(ref int)"),
                 // (2,7): error CS0535: 'Test' does not implement interface member 'IRefIndexer.set_Item(ref int, int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Test").WithArguments("Test", "IRefIndexer.set_Item(ref int, int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IRefIndexer").WithArguments("Test", "IRefIndexer.set_Item(ref int, int)"));
         }
 
         [Fact]

Src/Compilers/CSharp/Test/Symbol/Symbols/InterfaceImplementationTests.cs

@@ -1213,7 +1213,7 @@ static void Main()
             var comp = CreateCompilationWithMscorlib(csharp);
             comp.VerifyDiagnostics(
                 // (15,7): error CS0535: 'Derived' does not implement interface member 'Interface.M(ref int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Derived").WithArguments("Derived", "Interface.M(ref int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Derived", "Interface.M(ref int)"));
             var global = comp.GlobalNamespace;
             Assert.Null(global.GetMember<NamedTypeSymbol>("Derived").FindImplementationForInterfaceMember(
                 global.GetMember<NamedTypeSymbol>("Interface").GetMember<MethodSymbol>("M")));
@@ -1284,7 +1284,7 @@ .maxstack  8
             var comp = CreateCompilationWithCustomILSource(csharp, il);
             comp.VerifyDiagnostics(
                 // (7,7): error CS0535: 'Derived' does not implement interface member 'Interface.M(ref int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Derived").WithArguments("Derived", "Interface.M(ref int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Derived", "Interface.M(ref int)"));
             var global = comp.GlobalNamespace;
             Assert.Null(global.GetMember<NamedTypeSymbol>("Derived").FindImplementationForInterfaceMember(
                 global.GetMember<NamedTypeSymbol>("Interface").GetMember<MethodSymbol>("M")));
@@ -1340,7 +1340,7 @@ static void Main()
             var comp = CreateCompilationWithCustomILSource(csharp, il);
             comp.VerifyDiagnostics(
                 // (10,7): error CS0535: 'Derived' does not implement interface member 'Interface.M(ref int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Derived").WithArguments("Derived", "Interface.M(ref int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Derived", "Interface.M(ref int)"));
             var global = comp.GlobalNamespace;
             Assert.Null(global.GetMember<NamedTypeSymbol>("Derived").FindImplementationForInterfaceMember(
                 global.GetMember<NamedTypeSymbol>("Interface").GetMember<MethodSymbol>("M")));
@@ -1415,7 +1415,7 @@ .maxstack  8
             var comp = CreateCompilationWithCustomILSource(csharp, il);
             comp.VerifyDiagnostics(
                 // (2,7): error CS0535: 'Derived' does not implement interface member 'Interface.M(ref int)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Derived").WithArguments("Derived", "Interface.M(ref int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Derived", "Interface.M(ref int)"));
             var global = comp.GlobalNamespace;
             Assert.Null(global.GetMember<NamedTypeSymbol>("Derived").FindImplementationForInterfaceMember(
                 global.GetMember<NamedTypeSymbol>("Interface").GetMember<MethodSymbol>("M")));
@@ -1558,7 +1558,7 @@ class C1 : I1
 }
 ";
             CreateCompilationWithMscorlib(text).VerifyDiagnostics(
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C1").WithArguments("C1", "I1.Foo(out int)"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "I1").WithArguments("C1", "I1.Foo(out int)"));
         }
 
         [Fact]
@@ -2108,10 +2108,10 @@ class Derived2 : Base2, Interface
             CreateCompilationWithMscorlib(source, new[] { ilRef }).VerifyDiagnostics(
                 // (6,7): error CS0535: 'Base2' does not implement interface member 'Interface.M()'
                 // class Base2 : Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Base2").WithArguments("Base2", "Interface.M()"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Base2", "Interface.M()"),
                 // (10,7): error CS0535: 'Derived2' does not implement interface member 'Interface.M()'
                 // class Derived2 : Base2, Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Derived2").WithArguments("Derived2", "Interface.M()"));
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Derived2", "Interface.M()"));
         }
 
         [WorkItem(718115, "DevDiv")]

Src/Compilers/CSharp/Test/Symbol/Symbols/Metadata/MetadataMemberTests.cs

@@ -569,10 +569,10 @@ class Explicit : Interface
             comp.VerifyDiagnostics(
                 // (2,7): error CS0535: 'Empty' does not implement interface member 'Interface.SetterIsGap'
                 // class Empty : Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Empty").WithArguments("Empty", "Interface.SetterIsGap"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Empty", "Interface.SetterIsGap"),
                 // (2,7): error CS0535: 'Empty' does not implement interface member 'Interface.GetterIsGap'
                 // class Empty : Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Empty").WithArguments("Empty", "Interface.GetterIsGap"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("Empty", "Interface.GetterIsGap"),
                 // (17,33): error CS0550: 'Explicit.Interface.GetterIsGap.get' adds an accessor not found in interface member 'Interface.GetterIsGap'
                 //     int Interface.GetterIsGap { get; set; }
                 Diagnostic(ErrorCode.ERR_ExplicitPropertyAddingAccessor, "get").WithArguments("Explicit.Interface.GetterIsGap.get", "Interface.GetterIsGap"),

Src/Compilers/CSharp/Test/Symbol/Symbols/Source/EventTests.cs

@@ -606,13 +606,13 @@ class E : Interface
             CreateCompilationWithCustomILSource(csharpSource, ilSource).VerifyDiagnostics(
                 // (2,7): error CS0535: 'C' does not implement interface member 'Interface.raise_e(object, object)'
                 // class C : Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "Interface.raise_e(object, object)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("C", "Interface.raise_e(object, object)"),
                 // (2,7): error CS0535: 'C' does not implement interface member 'Interface.e'
                 // class C : Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "C").WithArguments("C", "Interface.e"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("C", "Interface.e"),
                 // (7,7): error CS0535: 'D' does not implement interface member 'Interface.raise_e(object, object)'
                 // class D : Interface
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "D").WithArguments("D", "Interface.raise_e(object, object)"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "Interface").WithArguments("D", "Interface.raise_e(object, object)"),
 
                 // (15,32): warning CS0067: The event 'E.e' is never used
                 //     public event System.Action e;

Src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs

@@ -7456,7 +7456,7 @@ class MyClass : I
 }
 ";
             var comp = DiagnosticsUtils.VerifyErrorsAndGetCompilationWithMscorlib(text,
-                new ErrorDescription { Code = (int)ErrorCode.ERR_UnimplementedInterfaceMember, Line = 6, Column = 7 }, //Dev10 doesn't include this
+                new ErrorDescription { Code = (int)ErrorCode.ERR_UnimplementedInterfaceMember, Line = 6, Column = 17 }, //Dev10 doesn't include this
                 new ErrorDescription { Code = (int)ErrorCode.ERR_MethodImplementingAccessor, Line = 8, Column = 16 });
         }
 
@@ -8913,7 +8913,7 @@ public void CS0535ERR_UnimplementedInterfaceMember()
 public class B : A { }   // CS0535 A::F is not implemented
 ";
             var comp = DiagnosticsUtils.VerifyErrorsAndGetCompilationWithMscorlib(text,
-                new ErrorDescription { Code = (int)ErrorCode.ERR_UnimplementedInterfaceMember, Line = 6, Column = 14 });
+                new ErrorDescription { Code = (int)ErrorCode.ERR_UnimplementedInterfaceMember, Line = 6, Column = 18 });
         }
 
         [Fact]
@@ -9737,7 +9737,7 @@ public static void Main()
 }
 ";
             var comp = DiagnosticsUtils.VerifyErrorsAndGetCompilationWithMscorlib(text,
-                new ErrorDescription { Code = (int)ErrorCode.ERR_UnimplementedInterfaceMember, Line = 10, Column = 14 }, //CONSIDER: dev10 suppresses this
+                new ErrorDescription { Code = (int)ErrorCode.ERR_UnimplementedInterfaceMember, Line = 10, Column = 18 }, //CONSIDER: dev10 suppresses this
                 new ErrorDescription { Code = (int)ErrorCode.ERR_ExplicitPropertyMissingAccessor, Line = 12, Column = 12 });
         }
 
@@ -11442,16 +11442,11 @@ struct SFoo : IFoo<Void>
     }
 }";
             CreateCompilationWithMscorlib(source).VerifyDiagnostics(
-                // (14,28): error CS0673: System.Void cannot be used from C# -- use typeof(void) to get the void type object
-                Diagnostic(ErrorCode.ERR_SystemVoid, "Void").WithLocation(14, 28),
-                // (7,9): error CS0673: System.Void cannot be used from C# -- use typeof(void) to get the void type object
-                Diagnostic(ErrorCode.ERR_SystemVoid, "Void").WithLocation(7, 9),
-                // (12,16): error CS0673: System.Void cannot be used from C# -- use typeof(void) to get the void type object
-                Diagnostic(ErrorCode.ERR_SystemVoid, "Void").WithLocation(12, 16),
-                // (14,16): error CS0535: 'NS.Foo.SFoo' does not implement interface member 'NS.IFoo<System.Void>.M(System.Void)'
-                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "SFoo").WithArguments("NS.Foo.SFoo", "NS.IFoo<System.Void>.M(System.Void)").WithLocation(14, 16),
-                // (12,21): warning CS0626: Method, operator, or accessor 'NS.Foo.GetVoid()' is marked external and has no attributes on it. Consider adding a DllImport attribute to specify the external implementation.
-                Diagnostic(ErrorCode.WRN_ExternMethodNoImplementation, "GetVoid").WithArguments("NS.Foo.GetVoid()").WithLocation(12, 21));
+                Diagnostic(ErrorCode.ERR_SystemVoid, "Void"),
+                Diagnostic(ErrorCode.ERR_SystemVoid, "Void"),
+                Diagnostic(ErrorCode.ERR_SystemVoid, "Void"),
+                Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IFoo<Void>").WithArguments("NS.Foo.SFoo", "NS.IFoo<System.Void>.M(System.Void)"),
+                Diagnostic(ErrorCode.WRN_ExternMethodNoImplementation, "GetVoid").WithArguments("NS.Foo.GetVoid()")) ;
         }
 
         [Fact]