Merge pull request #5952 from AlekseyTs/Issue2544

Preserve LookupResult methods in a BoundMethodGroup even if they are not viable.

src/Compilers/CSharp/Portable/Binder/Binder_Expressions.cs

@@ -4753,7 +4753,7 @@ private BoundExpression MakeMemberAccessValue(BoundExpression expr, DiagnosticBa
                         typeArguments,
                         boundLeft,
                         rightName,
-                        ImmutableArray<MethodSymbol>.Empty,
+                        lookupResult.Symbols.All(s => s.Kind == SymbolKind.Method) ? lookupResult.Symbols.SelectAsArray(s_toMethodSymbolFunc) : ImmutableArray<MethodSymbol>.Empty,
                         lookupResult,
                         flags);
                 }

src/Compilers/CSharp/Test/Semantic/Semantics/ObjectAndCollectionInitializerTests.cs

@@ -1987,6 +1987,18 @@ static void Main()
 ";
             var compilation = CreateCompilationWithMscorlib(source);
 
+            compilation.VerifyDiagnostics(
+    // (5,14): error CS0535: 'Base' does not implement interface member 'IEnumerable<int>.GetEnumerator()'
+    // class Base : IEnumerable<int>
+    Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IEnumerable<int>").WithArguments("Base", "System.Collections.Generic.IEnumerable<int>.GetEnumerator()").WithLocation(5, 14),
+    // (5,14): error CS0535: 'Base' does not implement interface member 'IEnumerable.GetEnumerator()'
+    // class Base : IEnumerable<int>
+    Diagnostic(ErrorCode.ERR_UnimplementedInterfaceMember, "IEnumerable<int>").WithArguments("Base", "System.Collections.IEnumerable.GetEnumerator()").WithLocation(5, 14),
+    // (17,32): error CS0122: 'X.Add(string)' is inaccessible due to its protection level
+    //         var z = new X { String.Empty };
+    Diagnostic(ErrorCode.ERR_BadAccess, "Empty").WithArguments("X.Add(string)").WithLocation(17, 32)
+                );
+
             var tree = compilation.SyntaxTrees.Single();
             var semanticModel = compilation.GetSemanticModel(tree);
 
@@ -1999,8 +2011,8 @@ where node.IsKind(SyntaxKind.CollectionInitializerExpression)
             symbolInfo = semanticModel.GetCollectionInitializerSymbolInfo(nodes[0]);
 
             Assert.Null(symbolInfo.Symbol);
-            Assert.Equal(CandidateReason.None, symbolInfo.CandidateReason);
-            Assert.Equal(0, symbolInfo.CandidateSymbols.Length);
+            Assert.Equal(CandidateReason.Inaccessible, symbolInfo.CandidateReason);
+            Assert.Equal("void X.Add(System.String x)", symbolInfo.CandidateSymbols.Single().ToTestDisplayString());
         }
 
         [WorkItem(529787, "DevDiv")]

src/Compilers/CSharp/Test/Semantic/Semantics/OverloadResolutionTests.cs

@@ -8237,5 +8237,47 @@ public static class Class
 RemoveDetail
 RemoveDetail");
         }
+
+        [Fact, WorkItem(2544, "https://github.com/dotnet/roslyn/issues/2544")]
+        public void GetSymbolOnfo_Inaccessible()
+        {
+            var source =
+@"
+class C
+{
+    private void M(D d)
+    {
+        d.M(1);
+    }
+}
+
+class D
+{
+    private void M(int i) { }
+    private void M(double d) { }
+}
+";
+            var compilation = CreateCompilationWithMscorlib(source, options: TestOptions.ReleaseDll);
+
+            compilation.VerifyDiagnostics(
+    // (6,11): error CS0122: 'D.M(int)' is inaccessible due to its protection level
+    //         d.M(1);
+    Diagnostic(ErrorCode.ERR_BadAccess, "M").WithArguments("D.M(int)").WithLocation(6, 11)
+                );
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var callSyntax = tree.GetRoot().DescendantNodes().OfType<InvocationExpressionSyntax>().Single();
+
+            var symbolInfo = model.GetSymbolInfo(callSyntax);
+
+            Assert.Equal(CandidateReason.Inaccessible, symbolInfo.CandidateReason);
+            var candidates = symbolInfo.CandidateSymbols;
+            Assert.Equal(2, candidates.Length);
+            Assert.Equal("void D.M(System.Int32 i)", candidates[0].ToTestDisplayString());
+            Assert.Equal("void D.M(System.Double d)", candidates[1].ToTestDisplayString());
+        }
+
     }
 }

src/EditorFeatures/Test2/FindReferences/FindReferencesTests.OrdinaryMethodSymbols.vb

@@ -891,7 +891,7 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.FindReferences
         End Sub
 
         <WorkItem(2544, "https://github.com/dotnet/roslyn/issues/2544")>
-        <WpfFact(Skip:="2544"), Trait(Traits.Feature, Traits.Features.FindReferences)>
+        <WpfFact, Trait(Traits.Feature, Traits.Features.FindReferences)>
         Public Sub TestInaccessibleMemberOverrideCS()
             Dim workspace =
 <Workspace>