diff --git a/src/libjsparser/parser.c b/src/libjsparser/parser.c
index fbed1a5d0..b59845b9b 100644
--- a/src/libjsparser/parser.c
+++ b/src/libjsparser/parser.c
@@ -2662,7 +2662,14 @@ preparse_scope (bool is_global)
     skip_newlines ();
   }
 
-  lexer_seek (start_loc);
+  if (start_loc != tok.loc)
+  {
+    lexer_seek (start_loc);
+  }
+  else
+  {
+    lexer_save_token (tok);
+  }
 }
 
 /* source_element_list
diff --git a/src/libjsparser/syntax-errors.c b/src/libjsparser/syntax-errors.c
index 637d9bf3e..c0a156c3c 100644
--- a/src/libjsparser/syntax-errors.c
+++ b/src/libjsparser/syntax-errors.c
@@ -63,7 +63,7 @@ syntax_add_prop_name (operand op, prop_type pt)
 }
 
 void
-syntax_check_for_duplication_of_prop_names (bool is_strict, locus loc)
+syntax_check_for_duplication_of_prop_names (bool is_strict, locus loc __unused)
 {
   if (STACK_SIZE (props) - STACK_TOP (U8) < 2)
   {
@@ -144,7 +144,7 @@ void syntax_add_varg (operand op)
 }
 
 static void
-emit_error_on_eval_and_arguments (operand op, locus loc)
+emit_error_on_eval_and_arguments (operand op, locus loc __unused)
 {
   if (op.type == OPERAND_LITERAL)
   {
@@ -169,7 +169,7 @@ syntax_check_for_eval_and_arguments_in_strict_mode (operand op, bool is_strict,
 
 /* 13.1, 15.3.2 */
 void
-syntax_check_for_syntax_errors_in_formal_param_list (bool is_strict, locus loc)
+syntax_check_for_syntax_errors_in_formal_param_list (bool is_strict, locus loc __unused)
 {
   if (STACK_SIZE (props) - STACK_TOP (U8) < 2 || !is_strict)
   {
@@ -199,7 +199,7 @@ syntax_check_for_syntax_errors_in_formal_param_list (bool is_strict, locus loc)
 }
 
 void
-syntax_check_delete (bool is_strict, locus loc)
+syntax_check_delete (bool is_strict, locus loc __unused)
 {
   if (is_strict)
   {
diff --git a/src/libjsparser/syntax-errors.h b/src/libjsparser/syntax-errors.h
index 33a12d23b..ca25287f8 100644
--- a/src/libjsparser/syntax-errors.h
+++ b/src/libjsparser/syntax-errors.h
@@ -20,6 +20,7 @@
 #include "opcodes-dumper.h"
 #include "lexer.h"
 
+#ifndef JERRY_NDEBUG
 #define PARSE_ERROR(MESSAGE, LOCUS) do { \
   size_t line, column; \
   lexer_locus_to_line_and_column ((locus) (LOCUS), &line, &column); \
@@ -63,6 +64,19 @@
   __printf ("SORRY, Unimplemented: Ln %d, Col %d: %s\n", line + 1, column + 1, MESSAGE); \
   __exit (-1); \
 } while (0)
+#else /* JERRY_NDEBUG */
+#define PARSE_ERROR(MESSAGE, LOCUS) do { \
+  __exit (-1); \
+} while (0)
+#define PARSE_WARN(MESSAGE, LOCUS) do { \
+} while (0)
+#define PARSE_ERROR_VARG(MESSAGE, LOCUS, ...) do { \
+  __exit (-1); \
+} while (0)
+#define PARSE_SORRY(MESSAGE, LOCUS) do { \
+  __exit (-1); \
+} while (0)
+#endif /* JERRY_NDEBUG */
 
 typedef enum
 {