Replace inaccurate error messages

When Bison reports "memory exhausted", it means the parser stack
depth reached the limit `YYMAXDEPTH` which is defaulted to 10_000,
but not memory allocation failed.

1 files changed, 3 insertions, 0 deletions

diff --git a/parse.y b/parse.y
index d7261a008d..3d5ba3b1ea 100644
--- a/parse.y
+++ b/parse.y
@@ -105,6 +105,9 @@ struct lex_context {
           (Current).end_pos = YYRHSLOC(Rhs, 0).end_pos;                 \
         }                                                               \
     while (0)
+#define YY_(Msgid) \
+    (((Msgid)[0] == 'm') && (strcmp((Msgid), "memory exhausted") == 0) ? \
+     "nesting too deep" : (Msgid))
 
 #define RUBY_SET_YYLLOC_FROM_STRTERM_HEREDOC(Current)			\
     rb_parser_set_location_from_strterm_heredoc(p, &p->lex.strterm->u.heredoc, &(Current))