Fix duplicated argument validation for default arguments (#3178)

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik [email protected]

Author: rerobika

jerry-core/parser/js/js-parser.c

@@ -2272,7 +2272,7 @@ parser_parse_function_arguments (parser_context_t *context_p, /**< context */
       lexer_literal_t *literal_p;
 
 #if ENABLED (JERRY_ES2015_FUNCTION_PARAMETER_INITIALIZER)
-      if (initializer_found)
+      if (initializer_found && (context_p->lit_object.literal_p->status_flags & LEXER_FLAG_FUNCTION_ARGUMENT))
       {
         parser_raise_error (context_p, PARSER_ERR_DUPLICATED_ARGUMENT_NAMES);
       }
@@ -2296,6 +2296,9 @@ parser_parse_function_arguments (parser_context_t *context_p, /**< context */
        * since no byte code has been emitted yet. Therefore there is no
        * need to set the index field. */
       context_p->lit_object.literal_p->type = LEXER_UNUSED_LITERAL;
+#if ENABLED (JERRY_ES2015_FUNCTION_PARAMETER_INITIALIZER)
+      context_p->lit_object.literal_p->prop.index = context_p->literal_count;
+#endif /* ENABLED (JERRY_ES2015_FUNCTION_PARAMETER_INITIALIZER) */
 
       /* Only the LEXER_FLAG_FUNCTION_ARGUMENT flag is kept. */
       context_p->lit_object.literal_p->status_flags &= LEXER_FLAG_FUNCTION_ARGUMENT;

tests/jerry/es2015/function-param-init.js

@@ -88,3 +88,11 @@ f();
 
 var f = new Function (str, "return (a + c) * (b == undefined ? 1 : 0)");
 assert (f() == 9);
+
+function duplicatedArg (a = c, b = d, c) {
+  assert(a === 1);
+  assert(b === 2);
+  assert(c === 3);
+}
+
+duplicatedArg(1, 2, 3);