[Bug #20504] Remove regexp fragment checks in the parser

parse.y

@@ -1480,9 +1480,6 @@ static rb_ast_id_table_t *local_tbl(struct parser_params*);
 
 static VALUE reg_compile(struct parser_params*, rb_parser_string_t*, int);
 static void reg_fragment_setenc(struct parser_params*, rb_parser_string_t*, int);
-int rb_parser_reg_fragment_check(struct parser_params*, rb_parser_string_t*, int, rb_parser_reg_fragment_error_func);
-static void reg_fragment_error(struct parser_params *, VALUE);
-#define reg_fragment_check(p, str, option) rb_parser_reg_fragment_check(p, str, option, reg_fragment_error)
 
 static int literal_concat0(struct parser_params *p, rb_parser_string_t *head, rb_parser_string_t *tail);
 static NODE *heredoc_dedent(struct parser_params*,NODE*);
@@ -13190,16 +13187,13 @@ new_regexp(struct parser_params *p, NODE *node, int options, const YYLTYPE *loc)
             /* Check string is valid regex */
             reg_compile(p, dreg->string, options);
         }
-        else if (dreg->string) {
-            reg_fragment_check(p, dreg->string, options);
-        }
         prev = node;
         for (list = dreg->nd_next; list; list = RNODE_LIST(list->nd_next)) {
             NODE *frag = list->nd_head;
             enum node_type type = nd_type(frag);
             if (type == NODE_STR || (type == NODE_DSTR && !RNODE_DSTR(frag)->nd_next)) {
                 rb_parser_string_t *tail = RNODE_STR(frag)->string;
-                if (reg_fragment_check(p, tail, options) && prev && RNODE_DREGX(prev)->string) {
+                if (prev && RNODE_DREGX(prev)->string) {
                     rb_parser_string_t *lit = prev == node ? dreg->string : RNODE_STR(RNODE_LIST(prev)->nd_head)->string;
                     if (!literal_concat0(p, lit, tail)) {
                         return NEW_NIL(loc); /* dummy node on error */
@@ -15381,30 +15375,6 @@ reg_fragment_setenc(struct parser_params* p, rb_parser_string_t *str, int option
     if (c) reg_fragment_enc_error(p, str, c);
 }
 
-static void
-reg_fragment_error(struct parser_params* p, VALUE err)
-{
-    compile_error(p, "%"PRIsVALUE, err);
-}
-
-#ifndef RIPPER
-int
-rb_parser_reg_fragment_check(struct parser_params* p, rb_parser_string_t *str, int options, rb_parser_reg_fragment_error_func error)
-{
-    VALUE err, str2;
-    reg_fragment_setenc(p, str, options);
-    /* TODO */
-    str2 = rb_str_new_parser_string(str);
-    err = rb_reg_check_preprocess(str2);
-    if (err != Qnil) {
-        err = rb_obj_as_string(err);
-        error(p, err);
-        return 0;
-    }
-    return 1;
-}
-#endif
-
 #ifndef UNIVERSAL_PARSER
 typedef struct {
     struct parser_params* parser;
@@ -15503,7 +15473,7 @@ reg_compile(struct parser_params* p, rb_parser_string_t *str, int options)
     if (NIL_P(re)) {
         VALUE m = rb_attr_get(rb_errinfo(), idMesg);
         rb_set_errinfo(err);
-        reg_fragment_error(p, m);
+        compile_error(p, "%"PRIsVALUE, m);
         return Qnil;
     }
     return re;