diff --git a/ruby_parser.c b/ruby_parser.c
index ded17b0a42..191f9dcdda 100644
--- a/ruby_parser.c
+++ b/ruby_parser.c
@@ -349,7 +349,6 @@ enc_mbc_to_codepoint(const char *p, const char *e, void *enc)
     return ONIGENC_MBC_TO_CODE((rb_encoding *)enc, up, ue);
 }
 
-VALUE rb_io_gets_internal(VALUE io);
 extern VALUE rb_eArgError;
 
 static const rb_parser_config_t rb_global_parser_config = {
@@ -396,8 +395,6 @@ static const rb_parser_config_t rb_global_parser_config = {
 
     .str_catf = rb_str_catf,
     .str_cat_cstr = rb_str_cat_cstr,
-    .str_subseq = rb_str_subseq,
-    .str_new_frozen = rb_str_new_frozen,
     .str_modify = rb_str_modify,
     .str_set_len = rb_str_set_len,
     .str_cat = rb_str_cat,
@@ -413,7 +410,6 @@ static const rb_parser_config_t rb_global_parser_config = {
     .rstring_ptr = RSTRING_PTR,
     .rstring_end = RSTRING_END,
     .rstring_len = RSTRING_LEN,
-    .filesystem_str_new_cstr = rb_filesystem_str_new_cstr,
     .obj_as_string = rb_obj_as_string,
 
     .int2num = rb_int2num_inline,
@@ -423,7 +419,6 @@ static const rb_parser_config_t rb_global_parser_config = {
     .io_write = rb_io_write,
     .io_flush = rb_io_flush,
     .io_puts = rb_io_puts,
-    .io_gets_internal = rb_io_gets_internal,
 
     .debug_output_stdout = rb_ractor_stdout,
     .debug_output_stderr = rb_ractor_stderr,
diff --git a/rubyparser.h b/rubyparser.h
index 5bf9c9aa1b..80e20884ae 100644
--- a/rubyparser.h
+++ b/rubyparser.h
@@ -1289,8 +1289,6 @@ typedef struct rb_parser_config_struct {
     RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 2, 3)
     VALUE (*str_catf)(VALUE str, const char *format, ...);
     VALUE (*str_cat_cstr)(VALUE str, const char *ptr);
-    VALUE (*str_subseq)(VALUE str, long beg, long len);
-    VALUE (*str_new_frozen)(VALUE orig);
     void (*str_modify)(VALUE str);
     void (*str_set_len)(VALUE str, long len);
     VALUE (*str_cat)(VALUE str, const char *ptr, long len);
@@ -1308,7 +1306,6 @@ typedef struct rb_parser_config_struct {
     char *(*rstring_ptr)(VALUE str);
     char *(*rstring_end)(VALUE str);
     long (*rstring_len)(VALUE str);
-    VALUE (*filesystem_str_new_cstr)(const char *ptr);
     VALUE (*obj_as_string)(VALUE);
 
     /* Numeric */
@@ -1320,7 +1317,6 @@ typedef struct rb_parser_config_struct {
     VALUE (*io_write)(VALUE io, VALUE str);
     VALUE (*io_flush)(VALUE io);
     VALUE (*io_puts)(int argc, const VALUE *argv, VALUE out);
-    VALUE (*io_gets_internal)(VALUE io);
 
     /* IO (Ractor) */
     VALUE (*debug_output_stdout)(void);
diff --git a/universal_parser.c b/universal_parser.c
index 6c90803625..d34adbec33 100644
--- a/universal_parser.c
+++ b/universal_parser.c
@@ -119,8 +119,6 @@
 #define rb_str_catf                       p->config->str_catf
 #undef rb_str_cat_cstr
 #define rb_str_cat_cstr                   p->config->str_cat_cstr
-#define rb_str_subseq                     p->config->str_subseq
-#define rb_str_new_frozen                 p->config->str_new_frozen
 #define rb_str_modify                     p->config->str_modify
 #define rb_str_set_len                    p->config->str_set_len
 #define rb_str_cat                        p->config->str_cat
@@ -142,7 +140,6 @@
 #define RSTRING_END                       p->config->rstring_end
 #undef RSTRING_LEN
 #define RSTRING_LEN                       p->config->rstring_len
-#define rb_filesystem_str_new_cstr        p->config->filesystem_str_new_cstr
 #define rb_obj_as_string                  p->config->obj_as_string
 
 #undef INT2NUM
@@ -153,7 +150,6 @@
 #define rb_io_write        p->config->io_write
 #define rb_io_flush        p->config->io_flush
 #define rb_io_puts         p->config->io_puts
-#define rb_io_gets_internal p->config->io_gets_internal
 
 #define rb_ractor_stdout   p->config->debug_output_stdout
 #define rb_ractor_stderr   p->config->debug_output_stderr