Rename explicit method implementations where needed - fixes #492

Author: GrahamTheCoder

CHANGELOG.md

@@ -17,7 +17,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 * Fix conversion for string implicitly converted to enum [#476](https://github.com/icsharpcode/CodeConverter/issues/476)
 
 ### C# -> VB
-
+* Rename explicit method implementations where needed [#492](https://github.com/icsharpcode/CodeConverter/issues/492)
 
 ## [8.1.4] - 2020-06-26
 

CodeConverter/VB/ClashingMemberRenamer.cs

@@ -28,7 +28,8 @@ public static async Task<Project> RenameClashingSymbolsAsync(Project project)
 
         private static IEnumerable<(ISymbol Original, string NewName)> GetSymbolsWithNewNames(INamespaceOrTypeSymbol containerSymbol, Compilation compilation)
         {
-            var members = containerSymbol.GetMembers().Where(m => m.Locations.Any(loc => loc.SourceTree != null && compilation.ContainsSyntaxTree(loc.SourceTree))).ToArray();
+            var members = containerSymbol.GetMembers()
+                .Where(m => m.Locations.Any(loc => loc.SourceTree != null && compilation.ContainsSyntaxTree(loc.SourceTree))).ToArray();
             var symbolSets = GetLocalSymbolSets(containerSymbol, compilation, members).Concat(members.AsEnumerable().Yield());
             return symbolSets.SelectMany(GetUniqueNamesForSymbolSet);
         }

CodeConverter/VB/NodesVisitor.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
 using ICSharpCode.CodeConverter.Shared;
 using ICSharpCode.CodeConverter.Util;
@@ -50,6 +51,7 @@ internal class NodesVisitor : CS.CSharpSyntaxVisitor<VisualBasicSyntaxNode>
         private readonly HashSet<string> _extraImports = new HashSet<string>();
         private readonly CSharpHelperMethodDefinition _cSharpHelperMethodDefinition;
         private readonly CommonConversions _commonConversions;
+        private readonly HashSet<string> _addedNames = new HashSet<string>();
 
         private int _placeholder = 1;
         public CommentConvertingVisitorWrapper<VisualBasicSyntaxNode> TriviaConvertingVisitor { get; }
@@ -432,7 +434,7 @@ public override VisualBasicSyntaxNode VisitMethodDeclaration(CSS.MethodDeclarati
             if (needsOverloads == true) {
                 modifiers = modifiers.Add(SyntaxFactory.Token(SyntaxKind.OverloadsKeyword));
             }
-            var implementsClause = methodInfo == null ? null : CreateImplementsClauseSyntaxOrNull(methodInfo, id);
+            var implementsClause = methodInfo == null ? null : CreateImplementsClauseSyntaxOrNull(methodInfo, ref id);
             if (isVoidSub) {
                 var stmt = SyntaxFactory.SubStatement(
                     attributes,
@@ -459,20 +461,33 @@ public override VisualBasicSyntaxNode VisitMethodDeclaration(CSS.MethodDeclarati
         /// <remarks>
         /// PERF: Computational complexity high due to starting with all members and narrowing down
         /// </remarks>
-        private ImplementsClauseSyntax CreateImplementsClauseSyntaxOrNull(ISymbol memberInfo, SyntaxToken id)
+        private ImplementsClauseSyntax CreateImplementsClauseSyntaxOrNull(ISymbol memberInfo, ref SyntaxToken id)
         {
+            var originalId = id;
             var explicitImplementors = memberInfo.ExplicitInterfaceImplementations();
-            if (explicitImplementors.Any())
-                return CreateImplementsClauseSyntax(explicitImplementors, id);
-            var containingType = memberInfo.ContainingType;
-            var baseClassesAndInterfaces = containingType.GetAllBaseClassesAndInterfaces(true);
-            var implementors = baseClassesAndInterfaces.Except(new[] { containingType })
-                .SelectMany(t => t.GetMembers().Where(m => memberInfo.Name.EndsWith(m.Name)))
-                .Where(m => containingType.FindImplementationForInterfaceMember(m)?.Equals(memberInfo) == true)
-                .ToList();
+            if (explicitImplementors.Any()) {
+                //https://github.com/icsharpcode/CodeConverter/issues/492
+                var memberNames = memberInfo.ContainingType.GetMembers().ToLookup(s => UndottedMemberName(s.Name), StringComparer.OrdinalIgnoreCase);
+                string explicitMemberName = UndottedMemberName(memberInfo.Name);
+                var hasDuplicateNames = memberNames[explicitMemberName].Count() > 1;
+                if (hasDuplicateNames) id = SyntaxFactory.Identifier(NameGenerator.GenerateUniqueName(explicitMemberName, n => !memberNames.Contains(n) && _addedNames.Add(n)));
+            } else {
+                var containingType = memberInfo.ContainingType;
+                var baseClassesAndInterfaces = containingType.GetAllBaseClassesAndInterfaces(true);
+                explicitImplementors = baseClassesAndInterfaces.Except(new[] { containingType })
+                    .SelectMany(t => t.GetMembers().Where(m => memberInfo.Name.EndsWith(m.Name)))
+                    .Where(m => containingType.FindImplementationForInterfaceMember(m)?.Equals(memberInfo) == true)
+                    .ToImmutableArray();
+            }
+
+            return !explicitImplementors.Any() ? null : CreateImplementsClauseSyntax(explicitImplementors, originalId);
+        }
 
-            return !implementors.Any() ? null: CreateImplementsClauseSyntax(implementors, id);
+        private static string UndottedMemberName(string n)
+        {
+            return n.Split('.').Last();
         }
+
         private ImplementsClauseSyntax CreateImplementsClauseSyntax(IEnumerable<ISymbol> implementors, SyntaxToken id) {
             return SyntaxFactory.ImplementsClause(implementors.Select(x => {
                     NameSyntax nameSyntax = _commonConversions.GetFullyQualifiedNameSyntax(x.ContainingSymbol as INamedTypeSymbol);
@@ -515,14 +530,15 @@ private VisualBasicSyntaxNode ConvertPropertyBlock(CSS.BasePropertyDeclarationSy
             IPropertySymbol declaredSymbol = _semanticModel.GetDeclaredSymbol(node) as IPropertySymbol;
             modifiers = modifiers.AddRange(GetAccessLimitationSyntaxKinds(declaredSymbol).Select(x => SyntaxFactory.Token(x)));
             Func<PropertyStatementSyntax> getStatementSyntax = () => {
+                var implementsClauseSyntaxOrNull = declaredSymbol == null ? null : CreateImplementsClauseSyntaxOrNull(declaredSymbol, ref id);
                 return SyntaxFactory.PropertyStatement(
                     attributes,
                     modifiers,
                     id,
                     parameterListSyntax,
                     SyntaxFactory.SimpleAsClause(returnAttributes, (TypeSyntax)node.Type.Accept(TriviaConvertingVisitor)),
                     initializerOrNull,
-                    declaredSymbol == null ? null : CreateImplementsClauseSyntaxOrNull(declaredSymbol, id)
+                    implementsClauseSyntaxOrNull
                 );
             };
 
@@ -591,10 +607,11 @@ public override VisualBasicSyntaxNode VisitEventDeclaration(CSS.EventDeclaration
             var id = _commonConversions.ConvertIdentifier(node.Identifier);
             var modifiers = CommonConversions.ConvertModifiers(node.Modifiers, GetMemberContext(node))
                 .Add(SyntaxFactory.Token(SyntaxKind.CustomKeyword));
+            var implementsClauseSyntaxOrNull = declaredSymbol == null ? null : CreateImplementsClauseSyntaxOrNull(declaredSymbol, ref id);
             var stmt = SyntaxFactory.EventStatement(
                 attributes, modifiers, id, null,
                 SyntaxFactory.SimpleAsClause(returnAttributes, (TypeSyntax)node.Type.Accept(TriviaConvertingVisitor)),
-                declaredSymbol == null ? null : CreateImplementsClauseSyntaxOrNull(declaredSymbol, id)
+                implementsClauseSyntaxOrNull
             );
             if (!RequiresAccessorBody(node.AccessorList))
                 return stmt;
@@ -650,14 +667,15 @@ public override VisualBasicSyntaxNode VisitEventFieldDeclaration(CSS.EventFieldD
             var id = SyntaxFactory.Identifier(decl.Identifier.ValueText, SyntaxFacts.IsKeywordKind(decl.Identifier.Kind()), decl.Identifier.GetIdentifierText(), TypeCharacter.None);
             ConvertAndSplitAttributes(node.AttributeLists, out SyntaxList<AttributeListSyntax> attributes, out SyntaxList<AttributeListSyntax> returnAttributes);
             var declaredSymbol = _semanticModel.GetDeclaredSymbol(decl);
+            var implementsClauseSyntaxOrNull = declaredSymbol == null ? null : CreateImplementsClauseSyntaxOrNull(declaredSymbol, ref id);
             return SyntaxFactory.EventStatement(
                 attributes,
                 CommonConversions.ConvertModifiers(node.Modifiers, GetMemberContext(node)),
                 id,
                 null,
                 SyntaxFactory.SimpleAsClause(returnAttributes,
                 (TypeSyntax)node.Declaration.Type.Accept(TriviaConvertingVisitor)),
-                declaredSymbol == null ? null : CreateImplementsClauseSyntaxOrNull(declaredSymbol, id));
+                implementsClauseSyntaxOrNull);
         }
         private TypeSyntax GetTypeSyntax(ITypeSymbol typeInfo) {
             return (TypeSyntax) _vbSyntaxGenerator.TypeExpression(typeInfo);

Tests/VB/SpecialConversionTests.cs

@@ -660,6 +660,44 @@ Public Sub Method()
         Dim vbLf As String = Microsoft.VisualBasic.vbLf
         Dim vbCrLf As String = Microsoft.VisualBasic.vbCrLf
     End Sub
+End Class", conversionOptions: EmptyNamespaceOptionStrictOff);
+        }
+
+        [Fact]
+        public async Task ExplicitImplementationsMustNotDifferOnlyByReturnTypeAsync() {
+            await TestConversionCSharpToVisualBasicAsync(
+@"using System.Collections;
+using System.Collections.Generic;
+
+public class AdditionalLocals : IEnumerable<KeyValuePair<string, int>>
+{
+    private readonly Stack<Dictionary<string, int>> _additionalLocals = new Stack<Dictionary<string, int>>();
+
+    public IEnumerator<KeyValuePair<string, int>> GetEnumerator()
+    {
+        return _additionalLocals.Peek().GetEnumerator();
+    }
+
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+        return _additionalLocals.Peek().GetEnumerator();
+    }
+}",
+@"Imports System.Collections
+Imports System.Collections.Generic
+
+Public Class AdditionalLocals
+    Implements IEnumerable(Of KeyValuePair(Of String, Integer))
+
+    Private ReadOnly _additionalLocals As Stack(Of Dictionary(Of String, Integer)) = New Stack(Of Dictionary(Of String, Integer))()
+
+    Public Function GetEnumerator() As IEnumerator(Of KeyValuePair(Of String, Integer)) Implements IEnumerable(Of KeyValuePair(Of String, Integer)).GetEnumerator
+        Return _additionalLocals.Peek().GetEnumerator()
+    End Function
+
+    Private Function GetEnumerator1() As IEnumerator Implements IEnumerable.GetEnumerator
+        Return _additionalLocals.Peek().GetEnumerator()
+    End Function
 End Class", conversionOptions: EmptyNamespaceOptionStrictOff);
         }
     }