OHI tests for ref readonly

src/Compilers/CSharp/Portable/CSharpResources.resx

@@ -288,6 +288,9 @@
   <data name="IDS_SK_EXTERNALIAS" xml:space="preserve">
     <value>extern alias</value>
   </data>
+  <data name="IDS_SK_CONSTRUCTOR" xml:space="preserve">
+    <value>constructor</value>
+  </data>
   <data name="IDS_FOREACHLOCAL" xml:space="preserve">
     <value>foreach iteration variable</value>
   </data>
@@ -1817,8 +1820,8 @@ If such a class is used as a base class and if the deriving class defines a dest
   <data name="ERR_OutAttrOnRefParam" xml:space="preserve">
     <value>Cannot specify only Out attribute on a ref parameter. Use both In and Out attributes, or neither.</value>
   </data>
-  <data name="ERR_OverloadRefOut" xml:space="preserve">
-    <value>'{0}' cannot define overloaded methods that differ only on ref and out</value>
+  <data name="ERR_OverloadRefKind" xml:space="preserve">
+    <value>'{0}' cannot define an overloaded {1} that differs only on parameter modifiers '{2}' and '{3}'</value>
   </data>
   <data name="ERR_LiteralDoubleCast" xml:space="preserve">
     <value>Literal of type double cannot be implicitly converted to type '{1}'; use an '{0}' suffix to create a literal of this type</value>
@@ -3731,9 +3734,6 @@ You should consider suppressing the warning only if you're sure that you don't w
   <data name="WRN_IsDynamicIsConfusing_Title" xml:space="preserve">
     <value>Using 'is' to test compatibility with 'dynamic' is essentially identical to testing compatibility with 'Object'</value>
   </data>
-  <data name="ERR_OverloadRefOutCtor" xml:space="preserve">
-    <value>Cannot define overloaded constructor '{0}' because it differs from another constructor only on ref and out</value>
-  </data>
   <data name="ERR_YieldNotAllowedInScript" xml:space="preserve">
     <value>Cannot use 'yield' in top-level script code</value>
   </data>

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

@@ -452,7 +452,7 @@ internal enum ErrorCode
         WRN_EqualityOpWithoutEquals = 660,
         WRN_EqualityOpWithoutGetHashCode = 661,
         ERR_OutAttrOnRefParam = 662,
-        ERR_OverloadRefOut = 663,
+        ERR_OverloadRefKind = 663,
         ERR_LiteralDoubleCast = 664,
         WRN_IncorrectBooleanAssg = 665,
         ERR_ProtectedInStruct = 666,
@@ -584,7 +584,7 @@ internal enum ErrorCode
         ERR_ExpressionTreeContainsBadCoalesce = 845,
         ERR_ArrayInitializerExpected = 846,
         ERR_ArrayInitializerIncorrectLength = 847,
-        ERR_OverloadRefOutCtor = 851,
+        // ERR_OverloadRefOutCtor = 851,                                Replaced By ERR_OverloadRefKind
         ERR_ExpressionTreeContainsNamedArgument = 853,
         ERR_ExpressionTreeContainsOptionalArgument = 854,
         ERR_ExpressionTreeContainsIndexedProperty = 855,

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

@@ -10,6 +10,7 @@ internal enum MessageID
     {
         None = 0,
         MessageBase = 1200,
+
         IDS_SK_METHOD = MessageBase + 2000,
         IDS_SK_TYPE = MessageBase + 2001,
         IDS_SK_NAMESPACE = MessageBase + 2002,
@@ -23,6 +24,8 @@ internal enum MessageID
         IDS_SK_ALIAS = MessageBase + 2010,
         //IDS_SK_EXTERNALIAS = MessageBase + 2011,
         IDS_SK_LABEL = MessageBase + 2012,
+        IDS_SK_CONSTRUCTOR = MessageBase + 2013,
+
         IDS_NULL = MessageBase + 10001,
         //IDS_RELATEDERROR = MessageBase + 10002,
         //IDS_RELATEDWARNING = MessageBase + 10003,
@@ -129,7 +132,6 @@ internal enum MessageID
         IDS_ThrowExpression = MessageBase + 12717,
 
         IDS_FeatureReadonlyReferences = MessageBase + 12718,
-
     }
 
     // Message IDs may refer to strings that need to be localized.

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

@@ -1538,23 +1538,29 @@ private void ReportMethodSignatureCollision(DiagnosticBag diagnostics, SourceMet
                 return;
             }
 
-            if (DifferByOutOrRef(method1, method2))
-            {
-                // '{0}' cannot define overloaded methods that differ only on ref and out
-                ErrorCode errorCode = method1.MethodKind == MethodKind.Constructor ?
-                    ErrorCode.ERR_OverloadRefOutCtor :
-                    ErrorCode.ERR_OverloadRefOut;
-                diagnostics.Add(errorCode, method1.Locations[0], this);
-            }
-            else
+            Debug.Assert(method1.ParameterCount == method2.ParameterCount);
+
+            for (int i = 0; i < method1.ParameterCount; i++)
             {
-                // Special case: if there are two destructors, use the destructor syntax instead of "Finalize"
-                var methodName = (method1.MethodKind == MethodKind.Destructor && method2.MethodKind == MethodKind.Destructor) ?
-                    "~" + this.Name :
-                    method1.Name;
-                // Type '{1}' already defines a member called '{0}' with the same parameter types
-                diagnostics.Add(ErrorCode.ERR_MemberAlreadyExists, method1.Locations[0], methodName, this);
+                var refKind1 = method1.Parameters[i].RefKind;
+                var refKind2 = method2.Parameters[i].RefKind;
+
+                if (refKind1 != refKind2)
+                {
+                    // '{0}' cannot define an overloaded {1} that differs only on parameter modifiers '{2}' and '{3}'
+                    var methodKind = method1.MethodKind == MethodKind.Constructor ? MessageID.IDS_SK_CONSTRUCTOR : MessageID.IDS_SK_METHOD;
+                    diagnostics.Add(ErrorCode.ERR_OverloadRefKind, method1.Locations[0], this, methodKind.Localize(), refKind1.ToDisplayString(), refKind2.ToDisplayString());
+
+                    return;
+                }
             }
+
+            // Special case: if there are two destructors, use the destructor syntax instead of "Finalize"
+            var methodName = (method1.MethodKind == MethodKind.Destructor && method2.MethodKind == MethodKind.Destructor) ?
+                "~" + this.Name :
+                method1.Name;
+            // Type '{1}' already defines a member called '{0}' with the same parameter types
+            diagnostics.Add(ErrorCode.ERR_MemberAlreadyExists, method1.Locations[0], methodName, this);
         }
 
         private void CheckIndexerNameConflicts(DiagnosticBag diagnostics, Dictionary<string, ImmutableArray<Symbol>> membersByName)
@@ -2436,23 +2442,7 @@ private static ImmutableArray<Symbol> Remove(ImmutableArray<Symbol> symbols, Sym
             }
             return builder.ToImmutableAndFree();
         }
-
-        private static bool DifferByOutOrRef(SourceMethodSymbol m1, SourceMethodSymbol m2)
-        {
-            var pl1 = m1.Parameters;
-            var pl2 = m2.Parameters;
-            int n = pl1.Length;
-            for (int i = 0; i < n; i++)
-            {
-                if (pl1[i].RefKind != pl2[i].RefKind)
-                {
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
+
         /// <summary>
         /// Report an error if a member (other than a method) exists with the same name
         /// as the property accessor, or if a method exists with the same name and signature.

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

@@ -4955,7 +4955,7 @@ internal enum ErrorCode
             WRN_EqualityOpWithoutEquals = 660,
             WRN_EqualityOpWithoutGetHashCode = 661,
             ERR_OutAttrOnRefParam = 662,
-            ERR_OverloadRefOut = 663,
+            ERR_OverloadRefKind = 663,
             ERR_LiteralDoubleCast = 664,
             WRN_IncorrectBooleanAssg = 665,
             ERR_ProtectedInStruct = 666,
@@ -5084,7 +5084,7 @@ internal enum ErrorCode
             ERR_ExpressionTreeContainsBadCoalesce = 845,
             ERR_ArrayInitializerExpected = 846,
             ERR_ArrayInitializerIncorrectLength = 847,
-            ERR_OverloadRefOutCtor = 851,
+            // ERR_OverloadRefOutCtor = 851,                                Replaced By ERR_OverloadRefKind
             ERR_ExpressionTreeContainsNamedArgument = 853,
             ERR_ExpressionTreeContainsOptionalArgument = 854,
             ERR_ExpressionTreeContainsIndexedProperty = 855,

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

@@ -1321,5 +1321,39 @@ public static void Main(string[] args)
             // since the runtime can distinguish signatures with different modopts.
             verifier.VerifyDiagnostics();
         }
+
+        [Fact]
+        [CompilerTrait(CompilerFeature.ReadonlyReferences)]
+        public void OverloadsWithDifferentParameterModifiers_Ref_RefReadOnly()
+        {
+            var text = @"
+abstract class TestClass
+{
+    public virtual void Method(ref int x) { }
+    public virtual void Method(ref readonly int x) { }
+}";
+
+            var comp = CreateCompilationWithMscorlib(text).VerifyDiagnostics(
+                // (5,25): error CS0663: 'TestClass' cannot define an overloaded method that differs only on parameter modifiers 'ref readonly' and 'ref'
+                //     public virtual void Method(ref readonly int x) { }
+                Diagnostic(ErrorCode.ERR_OverloadRefKind, "Method").WithArguments("TestClass", "method", "ref readonly", "ref").WithLocation(5, 25));
+        }
+
+        [Fact]
+        [CompilerTrait(CompilerFeature.ReadonlyReferences)]
+        public void OverloadsWithDifferentParameterModifiers_Out_RefReadOnly()
+        {
+            var text = @"
+abstract class TestClass
+{
+    public virtual void Method(out int x) { x = 0; }
+    public virtual void Method(ref readonly int x) { }
+}";
+
+            var comp = CreateCompilationWithMscorlib(text).VerifyDiagnostics(
+                // (5,25): error CS0663: 'TestClass' cannot define an overloaded method that differs only on parameter modifiers 'ref readonly' and 'out'
+                //     public virtual void Method(ref readonly int x) { }
+                Diagnostic(ErrorCode.ERR_OverloadRefKind, "Method").WithArguments("TestClass", "method", "ref readonly", "out").WithLocation(5, 25));
+        }
     }
 }

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

@@ -5453,8 +5453,9 @@ class Derived2 : Base2
 }";
 
             CreateCompilationWithMscorlib(text).VerifyDiagnostics(
-                // (14,26): error CS0663: 'Derived2' cannot define overloaded methods that differ only on ref and out
-                Diagnostic(ErrorCode.ERR_OverloadRefOut, "Method").WithArguments("Derived2"));
+                // (14,26): error CS0663: 'Derived2' cannot define an overloaded method that differs only on parameter modifiers 'ref' and 'out'
+                //     public override void Method(int x, ref int y, out Exception z) { z = null; }
+                Diagnostic(ErrorCode.ERR_OverloadRefKind, "Method").WithArguments("Derived2", "method", "ref", "out").WithLocation(14, 26));
         }
 
         [Fact]