codegen.c: no integer overflow error in `codegen`; close #5376

Add new pool value type `IREP_TT_BIGINT` and generate integer overflow
error in the VM. In the future, `mruby` will support `Bignum` for
integers bigger than `mrb_int` (probably using `mpz`).

1 files changed, 2 insertions, 0 deletions

diff --git a/src/vm.c b/src/vm.c
index 2607ba308..1009fb638 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1143,6 +1143,8 @@ RETRY_TRY_BLOCK:
 #endif
         goto L_INT_OVERFLOW;
 #endif
+      case IREP_TT_BIGINT:
+        goto L_INT_OVERFLOW;
 #ifndef MRB_NO_FLOAT
       case IREP_TT_FLOAT:
         regs[a] = mrb_float_value(mrb, pool[b].u.f);