Fix null escape in character classes (#3192)

Fixes #3001.

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

Author: dbatyai

jerry-core/parser/regexp/re-compiler.c

@@ -452,8 +452,7 @@ re_parse_char_class (re_compiler_ctx_t *re_ctx_p, /**< number of classes */
         re_append_char_class (re_ctx_p, LIT_CHAR_LOWERCASE_Z + 1, LIT_UTF16_CODE_UNIT_MAX);
         ch = LIT_CHAR_UNDEF;
       }
-      else if (lit_char_is_octal_digit ((ecma_char_t) ch)
-               && ch != LIT_CHAR_0)
+      else if (lit_char_is_octal_digit ((ecma_char_t) ch))
       {
         lit_utf8_decr (&parser_ctx_p->input_curr_p);
         ch = (ecma_char_t) re_parse_octal (parser_ctx_p);

tests/jerry/regexp-character-class.js

@@ -133,3 +133,10 @@ assert (r == "abcdefghjklmnopqrstuvwxyz");
 r = new RegExp("[\\u0800-\\uffff]", "g");
 assert (r.test ("\uffff"));
 assert (!r.test ("\uffff"));
+
+r = new RegExp("[\0]");
+assert (r.test ("\0"));
+assert (!r.test ("0"));
+
+r = new RegExp("[\0-\1]");
+assert (r.test ("\1"));