Fix for 8402

member declaration parse should not be considered not advanced when "ref" keyword was consumed.

Fixes dotnet#8402

src/Compilers/CSharp/Portable/Parser/LanguageParser.cs

@@ -1668,7 +1668,7 @@ private TypeDeclarationSyntax ParseClassOrStructOrInterfaceDeclaration(SyntaxLis
                             var saveTerm2 = _termState;
                             _termState |= TerminatorState.IsPossibleMemberStartOrStop;
 
-                            var memberOrStatement = this.ParseMemberDeclarationOrStatement(kind, name.ValueText);
+                            var memberOrStatement = this.ParseMemberDeclarationOrStatement(classOrStructOrInterface.Kind, name.ValueText);
                             if (memberOrStatement != null)
                             {
                                 // statements are accepted here, a semantic error will be reported later
@@ -2500,7 +2500,7 @@ private MemberDeclarationSyntax ParseMemberDeclarationOrStatement(SyntaxKind par
                 // We need to consume a bad member and try again.
                 if (explicitInterfaceOpt == null && identifierOrThisOpt == null && typeParameterListOpt == null)
                 {
-                    if (attributes.Count == 0 && modifiers.Count == 0 && type.IsMissing)
+                    if (attributes.Count == 0 && modifiers.Count == 0 && type.IsMissing && refKeyword == null)
                     {
                         // we haven't advanced, the caller needs to consume the tokens ahead
                         return null;

src/Compilers/CSharp/Test/Syntax/Parsing/DeclarationParsingTests.cs

@@ -2475,6 +2475,34 @@ public void TestClassMethodWithRefReturn()
             Assert.Equal(SyntaxKind.None, ms.SemicolonToken.Kind());
         }
 
+        public void TestClassMethodWithRef()
+        {
+            var text = "class a { ref }";
+            var file = this.ParseFileExperimental(text);
+
+            Assert.NotNull(file);
+            Assert.Equal(1, file.Members.Count);
+            Assert.Equal(text, file.ToString());
+            Assert.Equal(1, file.Errors().Length);
+
+            Assert.Equal(SyntaxKind.ClassDeclaration, file.Members[0].Kind());
+            var cs = (TypeDeclarationSyntax)file.Members[0];
+            Assert.Equal(0, cs.AttributeLists.Count);
+            Assert.Equal(0, cs.Modifiers.Count);
+            Assert.NotNull(cs.Keyword);
+            Assert.Equal(SyntaxKind.ClassKeyword, cs.Keyword.Kind());
+            Assert.NotNull(cs.Identifier);
+            Assert.Equal("a", cs.Identifier.ToString());
+            Assert.Null(cs.BaseList);
+            Assert.Equal(0, cs.ConstraintClauses.Count);
+            Assert.NotNull(cs.OpenBraceToken);
+            Assert.NotNull(cs.CloseBraceToken);
+
+            Assert.Equal(1, cs.Members.Count);
+
+            Assert.Equal(SyntaxKind.IncompleteMember, cs.Members[0].Kind());
+        }
+
         private void TestClassMethodModifiers(params SyntaxKind[] modifiers)
         {
             var text = "class a { " + string.Join(" ", modifiers.Select(SyntaxFacts.GetText)) + " b X() { } }";