Get rid of imemo_ast

It has been marked as obsolete for a while and I see no reason
to keep it.

Author: byroot

debug_counter.h

@@ -305,7 +305,6 @@ RB_DEBUG_COUNTER(obj_imemo_ment)
 RB_DEBUG_COUNTER(obj_imemo_iseq)
 RB_DEBUG_COUNTER(obj_imemo_env)
 RB_DEBUG_COUNTER(obj_imemo_tmpbuf)
-RB_DEBUG_COUNTER(obj_imemo_ast)
 RB_DEBUG_COUNTER(obj_imemo_cref)
 RB_DEBUG_COUNTER(obj_imemo_svar)
 RB_DEBUG_COUNTER(obj_imemo_throw_data)

ext/objspace/objspace.c

@@ -500,7 +500,6 @@ count_imemo_objects(int argc, VALUE *argv, VALUE self)
         INIT_IMEMO_TYPE_ID(imemo_ment);
         INIT_IMEMO_TYPE_ID(imemo_iseq);
         INIT_IMEMO_TYPE_ID(imemo_tmpbuf);
-        INIT_IMEMO_TYPE_ID(imemo_ast);
         INIT_IMEMO_TYPE_ID(imemo_callinfo);
         INIT_IMEMO_TYPE_ID(imemo_callcache);
         INIT_IMEMO_TYPE_ID(imemo_constcache);

imemo.c

@@ -16,7 +16,6 @@ rb_imemo_name(enum imemo_type type)
     // put no default case to get a warning if an imemo type is missing
     switch (type) {
 #define IMEMO_NAME(x) case imemo_##x: return #x;
-        IMEMO_NAME(ast);
         IMEMO_NAME(callcache);
         IMEMO_NAME(callinfo);
         IMEMO_NAME(constcache);
@@ -220,10 +219,6 @@ rb_imemo_memsize(VALUE obj)
 {
     size_t size = 0;
     switch (imemo_type(obj)) {
-      case imemo_ast:
-        rb_bug("imemo_ast is obsolete");
-
-        break;
       case imemo_callcache:
         break;
       case imemo_callinfo:
@@ -336,10 +331,6 @@ void
 rb_imemo_mark_and_move(VALUE obj, bool reference_updating)
 {
     switch (imemo_type(obj)) {
-      case imemo_ast:
-        rb_bug("imemo_ast is obsolete");
-
-        break;
       case imemo_callcache: {
         /* cc is callcache.
          *
@@ -600,10 +591,6 @@ void
 rb_imemo_free(VALUE obj)
 {
     switch (imemo_type(obj)) {
-      case imemo_ast:
-        rb_bug("imemo_ast is obsolete");
-
-        break;
       case imemo_callcache:
         RB_DEBUG_COUNTER_INC(obj_imemo_callcache);
 

internal/imemo.h

@@ -37,7 +37,6 @@ enum imemo_type {
     imemo_ment           =  6,
     imemo_iseq           =  7,
     imemo_tmpbuf         =  8,
-    imemo_ast            =  9, // Obsolete due to the universal parser
     imemo_callinfo       = 10,
     imemo_callcache      = 11,
     imemo_constcache     = 12,