Adjust implementation of...

Adjust implementation of SyntaxTreeExtensions.IsLocalVariableDeclarationContext around Out Variable Declarations.

Fixes #12121.

src/EditorFeatures/CSharpTest2/Recommendations/VarKeywordRecommenderTests.cs

@@ -232,5 +232,13 @@ public async Task TestNotAfterConstField()
 @"class C {
     const $$");
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.KeywordRecommending)]
+        [WorkItem(12121, "https://github.com/dotnet/roslyn/issues/12121")]
+        public async Task TestAfterOutKeywordInArgument()
+        {
+            await VerifyKeywordAsync(AddInsideMethod(
+@"M(out $$"));
+        }
     }
 }

src/Workspaces/CSharp/Portable/Extensions/ContextQuery/SyntaxTreeExtensions.cs

@@ -1201,7 +1201,7 @@ public static bool IsParameterTypeContext(this SyntaxTree syntaxTree, int positi
 
             if (token.IsKind(SyntaxKind.OutKeyword) &&
                 token.Parent.IsKind(SyntaxKind.Argument) &&
-                ((ArgumentSyntax)token.Parent).Declaration != null)
+                ((ArgumentSyntax)token.Parent).RefOrOutKeyword == token)
             {
                 return true;
             }