register<nlocals may not have a local variable name (e.g. a block arg); fix #2258

1 files changed, 6 insertions, 1 deletions

diff --git a/src/codegen.c b/src/codegen.c
index a1564d955..cec0d226f 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -2503,7 +2503,12 @@ scope_new(mrb_state *mrb, codegen_scope *prev, node *lv)
     p->irep->lv = (struct mrb_locals*)mrb_malloc(mrb, sizeof(struct mrb_locals) * (p->nlocals - 1));
     for (i=0, n=lv; n; i++,n=n->cdr) {
       p->irep->lv[i].name = lv_name(n);
-      p->irep->lv[i].r = lv_idx(p, lv_name(n));
+      if (lv_name(n)) {
+        p->irep->lv[i].r = lv_idx(p, lv_name(n));
+      }
+      else {
+        p->irep->lv[i].r = 0;
+      }
     }
     mrb_assert(i + 1 == p->nlocals);
   }