Check if m->env is NULL before dereferencing it; fix #3436

1 files changed, 3 insertions, 1 deletions

diff --git a/src/vm.c b/src/vm.c
index c174c0b43..287b18518 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -1309,7 +1309,9 @@ RETRY_TRY_BLOCK:
         else {
           stack_extend(mrb, irep->nregs, ci->argc+2);
         }
-        regs[0] = m->env->stack[0];
+        if(m->env) {
+          regs[0] = m->env->stack[0];
+        }
         pc = irep->iseq;
         JUMP;
       }