Merge pull request #24679 from VSadov/fix24348

Produce an error when a bridge method must be variadic

src/Compilers/CSharp/Portable/CSharpResources.Designer.cs

@@ -5578,6 +5578,15 @@ internal class CSharpResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; cannot implement interface member &apos;{1}&apos; in type &apos;{2}&apos; because it has an __arglist parameter..
+        /// </summary>
+        internal static string ERR_InterfaceImplementedImplicitlyByVariadic {
+            get {
+                return ResourceManager.GetString("ERR_InterfaceImplementedImplicitlyByVariadic", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to &apos;{0}&apos;: interface members cannot have a definition.
         /// </summary>

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -1755,6 +1755,9 @@ If such a class is used as a base class and if the deriving class defines a dest
   <data name="ERR_InterfaceImplementedByConditional" xml:space="preserve">
     <value>Conditional member '{0}' cannot implement interface member '{1}' in type '{2}'</value>
   </data>
+  <data name="ERR_InterfaceImplementedImplicitlyByVariadic" xml:space="preserve">
+    <value>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</value>
+  </data>
   <data name="ERR_IllegalRefParam" xml:space="preserve">
     <value>ref and out are not valid in this context</value>
   </data>

src/Compilers/CSharp/Portable/Errors/ErrorCode.cs

@@ -427,6 +427,7 @@ internal enum ErrorCode
         WRN_ExternMethodNoImplementation = 626,
         WRN_ProtectedInSealed = 628,
         ERR_InterfaceImplementedByConditional = 629,
+        ERR_InterfaceImplementedImplicitlyByVariadic = 630,
         ERR_IllegalRefParam = 631,
         ERR_BadArgumentToAttribute = 633,
         //ERR_MissingComTypeOrMarshaller = 635,

src/Compilers/CSharp/Portable/Symbols/Source/SourceMemberContainerSymbol_ImplementationChecks.cs

@@ -141,7 +141,16 @@ private void CheckAbstractClassImplementations(DiagnosticBag diagnostics)
 
                     if ((object)synthesizedImplementation != null)
                     {
-                        synthesizedImplementations.Add(synthesizedImplementation);
+                        if (synthesizedImplementation.IsVararg)
+                        {
+                            diagnostics.Add(
+                                ErrorCode.ERR_InterfaceImplementedImplicitlyByVariadic, 
+                                GetImplicitImplementationDiagnosticLocation(interfaceMember, this, implementingMember), implementingMember, interfaceMember, this);
+                        }
+                        else
+                        {
+                            synthesizedImplementations.Add(synthesizedImplementation);
+                        }
                     }
 
                     if (wasImplementingMemberFound && interfaceMemberKind == SymbolKind.Event)

src/Compilers/CSharp/Portable/Symbols/TypeSymbol.cs

@@ -1213,7 +1213,7 @@ private static void ReportAnyMismatchedConstraints(MethodSymbol interfaceMethod,
             }
         }
 
-        private static Location GetImplicitImplementationDiagnosticLocation(Symbol interfaceMember, TypeSymbol implementingType, Symbol member)
+        internal static Location GetImplicitImplementationDiagnosticLocation(Symbol interfaceMember, TypeSymbol implementingType, Symbol member)
         {
             if (member.ContainingType == implementingType)
             {

src/Compilers/CSharp/Portable/xlf/CSharpResources.cs.xlf

@@ -8595,6 +8595,11 @@ Pokud chcete odstranit toto varování, můžete místo toho použít /reference
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.de.xlf

@@ -8595,6 +8595,11 @@ Um die Warnung zu beheben, können Sie stattdessen /reference verwenden (Einbett
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.es.xlf

@@ -8595,6 +8595,11 @@ Para eliminar la advertencia puede usar /reference (establezca la propiedad Embe
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.fr.xlf

@@ -8595,6 +8595,11 @@ Pour supprimer l'avertissement, vous pouvez utiliser la commande /reference (dé
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.it.xlf

@@ -8595,6 +8595,11 @@ Per rimuovere l'avviso, è invece possibile usare /reference (impostare la propr
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.ja.xlf

@@ -8595,6 +8595,11 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.ko.xlf

@@ -8595,6 +8595,11 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.pl.xlf

@@ -8595,6 +8595,11 @@ Aby usunąć ostrzeżenie, możesz zamiast tego użyć opcji /reference (ustaw w
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.pt-BR.xlf

@@ -8595,6 +8595,11 @@ Para incorporar informações de tipo de interoperabilidade para os dois assembl
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.ru.xlf

@@ -8595,6 +8595,11 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.tr.xlf

@@ -8595,6 +8595,11 @@ Uyarıyı kaldırmak için, /reference kullanabilirsiniz (Birlikte Çalışma T
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hans.xlf

@@ -8595,6 +8595,11 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

src/Compilers/CSharp/Portable/xlf/CSharpResources.zh-Hant.xlf

@@ -8595,6 +8595,11 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
         <target state="new">ref conditional expression</target>
         <note />
       </trans-unit>
+      <trans-unit id="ERR_InterfaceImplementedImplicitlyByVariadic">
+        <source>'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</source>
+        <target state="new">'{0}' cannot implement interface member '{1}' in type '{2}' because it has an __arglist parameter</target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>
\ No newline at end of file

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

@@ -13292,6 +13292,162 @@ .maxstack  4
 ");
         }
 
+        [WorkItem(24348, "https://github.com/dotnet/roslyn/issues/24348")]
+        [Fact]
+        public void VarargBridgeSource()
+        {
+
+            var code = @"
+public class VarArgs
+{
+    public void Invoke(__arglist)
+    {
+        var ai = new System.ArgIterator(__arglist);
+        System.Console.WriteLine(ai.GetRemainingCount());
+    }
+}
+
+interface IVarArgs
+{
+    void Invoke(__arglist);
+}
+
+class MyVarArgs : VarArgs, IVarArgs
+{
+
+}
+
+public static class P
+{
+    public static void Main()
+    {
+        IVarArgs iv = new MyVarArgs();
+
+        iv.Invoke(__arglist(1, 2, 3, 4));
+    }
+}
+";
+
+            var compilation = CompileAndVerify(code, expectedOutput: "4");
+        }
+
+        [WorkItem(24348, "https://github.com/dotnet/roslyn/issues/24348")]
+        [Fact]
+        public void VarargBridgeMeta()
+        {
+            var reference = CreateStandardCompilation(@"
+public class VarArgs
+{
+    public void Invoke(__arglist)
+    {
+        var ai = new System.ArgIterator(__arglist);
+        System.Console.WriteLine(ai.GetRemainingCount());
+    }
+}");
+
+            var code = @"
+interface IVarArgs
+{
+    void Invoke(__arglist);
+}
+
+class MyVarArgs : VarArgs, IVarArgs
+{
+
+}
+
+public static class P
+{
+    public static void Main()
+    {
+        IVarArgs iv = new MyVarArgs();
+
+        iv.Invoke(__arglist(1, 2, 3, 4));
+    }
+}
+";
+
+            var comp = CreateStandardCompilation(code, references: new[] { reference.ToMetadataReference() });
+            comp.VerifyDiagnostics(
+                // (7,28): error CS0630: 'VarArgs.Invoke(__arglist)' cannot implement interface member 'IVarArgs.Invoke(__arglist)' in type 'MyVarArgs' because it has an __arglist parameter.
+                // class MyVarArgs : VarArgs, IVarArgs
+                Diagnostic(ErrorCode.ERR_InterfaceImplementedImplicitlyByVariadic, "IVarArgs").WithArguments("VarArgs.Invoke(__arglist)", "IVarArgs.Invoke(__arglist)", "MyVarArgs").WithLocation(7, 28)
+                );
+
+            comp = CreateStandardCompilation(code, references: new[] { reference.EmitToImageReference() });
+            comp.VerifyDiagnostics(
+                // (7,28): error CS0630: 'VarArgs.Invoke(__arglist)' cannot implement interface member 'IVarArgs.Invoke(__arglist)' in type 'MyVarArgs' because it has an __arglist parameter.
+                // class MyVarArgs : VarArgs, IVarArgs
+                Diagnostic(ErrorCode.ERR_InterfaceImplementedImplicitlyByVariadic, "IVarArgs").WithArguments("VarArgs.Invoke(__arglist)", "IVarArgs.Invoke(__arglist)", "MyVarArgs").WithLocation(7, 28)
+                );
+        }
+
+        [WorkItem(24348, "https://github.com/dotnet/roslyn/issues/24348")]
+        [ClrOnlyFact(ClrOnlyReason.Ilasm)]
+        public void VarargBridgeSourceModopt()
+        {
+
+            var il = @"
+.class interface public auto ansi abstract IVarArgs
+{
+	// Methods
+	.method public hidebysig newslot abstract virtual 
+		instance vararg int32 modopt(int64) Invoke () cil managed 
+	{
+	} // end of method IVarArgs::Invoke
+
+} // end of class IVarArgs
+
+
+";
+
+            var reference = CompileIL(il);
+
+            var code = @"
+
+public class VarArgs
+{
+    public int Invoke(__arglist) => throw null;
+}
+
+class MyVarArgs : VarArgs, IVarArgs
+{
+
+}
+
+class MyVarArgs2 : IVarArgs
+{
+    public int Invoke(__arglist) => throw null;
+}
+
+class MyVarArgs3 : IVarArgs
+{
+    // this is ok, modifiers are copied
+    int IVarArgs.Invoke(__arglist) => throw null;
+}
+
+public static class P
+{
+    public static void Main()
+    {
+        IVarArgs iv = new MyVarArgs3();
+
+        iv.Invoke(__arglist(1, 2, 3, 4));
+    }
+}
+";
+
+            var comp = CreateStandardCompilation(code, references: new[] { reference});
+            comp.VerifyDiagnostics(
+                // (15,16): error CS0630: 'MyVarArgs2.Invoke(__arglist)' cannot implement interface member 'IVarArgs.Invoke(__arglist)' in type 'MyVarArgs2' because it has an __arglist parameter
+                //     public int Invoke(__arglist) => throw null;
+                Diagnostic(ErrorCode.ERR_InterfaceImplementedImplicitlyByVariadic, "Invoke").WithArguments("MyVarArgs2.Invoke(__arglist)", "IVarArgs.Invoke(__arglist)", "MyVarArgs2").WithLocation(15, 16),
+                // (8,28): error CS0630: 'VarArgs.Invoke(__arglist)' cannot implement interface member 'IVarArgs.Invoke(__arglist)' in type 'MyVarArgs' because it has an __arglist parameter
+                // class MyVarArgs : VarArgs, IVarArgs
+                Diagnostic(ErrorCode.ERR_InterfaceImplementedImplicitlyByVariadic, "IVarArgs").WithArguments("VarArgs.Invoke(__arglist)", "IVarArgs.Invoke(__arglist)", "MyVarArgs").WithLocation(8, 28)
+                );
+        }
+
         [WorkItem(530067, "http://vstfdevdiv:8080/DevDiv2/DevDiv/_workitems/edit/530067")]
         [Fact]
         public void NopAfterCall()