clarify intent in returnType creation

Author: jwunderl

src/services/codefixes/helpers.ts

@@ -156,7 +156,7 @@ namespace ts.codefix {
             isIdentifier(arg) ? arg.text :
                 isPropertyAccessExpression(arg) ? arg.name.text : undefined);
         const contextualType = checker.getContextualType(call);
-        const returnType = inJs ? undefined : contextualType && checker.typeToTypeNode(contextualType, contextNode, /*flags*/ undefined, tracker);
+        const returnType = (inJs || !contextualType) ? undefined : checker.typeToTypeNode(contextualType, contextNode, /*flags*/ undefined, tracker);
         return createMethod(
             /*decorators*/ undefined,
             /*modifiers*/ makeStatic ? [createToken(SyntaxKind.StaticKeyword)] : undefined,