Assign temporary ID to anonymous ID [Bug #18250]

Dumped iseq binary can not have unnamed symbols/IDs, and ID 0 is
stored instead.  As `struct rb_id_table` disallows ID 0, also for
the distinction, re-assign a new temporary ID based on the local
variable table index when loading from the binary, as well as the
parser.

1 files changed, 11 insertions, 0 deletions

diff --git a/symbol.c b/symbol.c
index 79ec4de502..5ce95f5b07 100644
--- a/symbol.c
+++ b/symbol.c
@@ -952,6 +952,17 @@ rb_make_internal_id(void)
     return next_id_base() | ID_INTERNAL | ID_STATIC_SYM;
 }
 
+ID
+rb_make_temporary_id(size_t n)
+{
+    const ID max_id = RB_ID_SERIAL_MAX & ~0xffff;
+    const ID id = max_id - (ID)n;
+    if (id <= ruby_global_symbols.last_id) {
+	rb_raise(rb_eRuntimeError, "too big to make temporary ID: %" PRIdSIZE, n);
+    }
+    return (id << ID_SCOPE_SHIFT) | ID_STATIC_SYM | ID_INTERNAL;
+}
+
 static int
 symbols_i(st_data_t key, st_data_t value, st_data_t arg)
 {