Fixes:dotnet#20226

VSadov · Jun 15, 2017 · 2faad6f · 2faad6f
1 parent ae941fc
commit 2faad6f
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diff --git a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
diff --git a/src/Compilers/CSharp/Portable/CSharpResources.resx b/src/Compilers/CSharp/Portable/CSharpResources.resx
@@ -1957,6 +1957,9 @@ If such a class is used as a base class and if the deriving class defines a dest
   </data>
   <data name="ERR_StaticClassInterfaceImpl" xml:space="preserve">
     <value>'{0}': static classes cannot implement interfaces</value>
+  </data>
+    <data name="ERR_RefStructInterfaceImpl" xml:space="preserve">
+    <value>'{0}': ref structs cannot implement interfaces</value>
   </data>
   <data name="ERR_OperatorInStaticClass" xml:space="preserve">
     <value>'{0}': static classes cannot contain user-defined operators</value>

diff --git a/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs b/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs
@@ -1513,5 +1513,6 @@ internal enum ErrorCode
         ERR_FieldsInRoStruct = 8514,
         ERR_AutoPropsInRoStruct = 8515,
         ERR_FieldlikeEventsInRoStruct = 8516,
+        ERR_RefStructInterfaceImpl = 8517,
     }
 }
diff --git a/src/Compilers/CSharp/Portable/Symbols/Source/SourceNamedTypeSymbol_Bases.cs b/src/Compilers/CSharp/Portable/Symbols/Source/SourceNamedTypeSymbol_Bases.cs
@@ -459,6 +459,12 @@ private Tuple<NamedTypeSymbol, ImmutableArray<NamedTypeSymbol>> MakeOneDeclaredB
                             diagnostics.Add(ErrorCode.ERR_StaticClassInterfaceImpl, location, this, baseType);
                         }
 
+                        if (this.IsByRefLikeType)
+                        {
+                            // '{0}': static classes cannot implement interfaces
+                            diagnostics.Add(ErrorCode.ERR_RefStructInterfaceImpl, location, this, baseType);
+                        }
+
                         if (baseType.ContainsDynamic())
                         {
                             diagnostics.Add(ErrorCode.ERR_DeriveFromConstructedDynamic, location, this, baseType);

diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/SpanStackSafetyTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/SpanStackSafetyTests.cs
@@ -414,6 +414,43 @@ public struct S2
             );
         }
 
+        [WorkItem(20226, "https://github.com/dotnet/roslyn/issues/20226")]
+        [Fact]
+        public void InterfaceImpl()
+        {
+            var text = @"
+using System;
+
+public class Program
+{
+    static void Main(string[] args)
+    {
+        using (new S1())
+        {
+
+        }
+    }
+
+    public ref struct S1 : IDisposable
+    {
+        public void Dispose() { }
+    }
+}
+";
+
+            CSharpCompilation comp = CreateCompilationWithMscorlibAndSpan(text);
+
+            comp.VerifyDiagnostics(
+                // (14,28): error CS8517: 'Program.S1': ref structs cannot implement interfaces
+                //     public ref struct S1 : IDisposable
+                Diagnostic(ErrorCode.ERR_RefStructInterfaceImpl, "IDisposable").WithArguments("Program.S1", "System.IDisposable").WithLocation(14, 28),
+                // (8,16): error CS1674: 'Program.S1': type used in a using statement must be implicitly convertible to 'System.IDisposable'
+                //         using (new S1())
+                Diagnostic(ErrorCode.ERR_NoConvToIDisp, "new S1()").WithArguments("Program.S1").WithLocation(8, 16)
+            );
+        }
+
+
         [Fact]
         public void Properties()
         {