fix closures GC bug

1 files changed, 6 insertions, 1 deletions

diff --git a/pez.c b/pez.c
index b2e590c..1611770 100644
--- a/pez.c
+++ b/pez.c
@@ -494,6 +494,7 @@ newfn(PezContext *cx, Proto *pr, Val *args, Val *locals, Fn *parent)
 {
     Fn *fn = newobj(cx, PEZ_TFn, sizeof *fn + pr->nupval * sizeof(struct Upval *));
     if (fn) {
+        TRY(push(cx, box_obj(fn))); // gc keep
         fn->proto = pr;
         fn->nupval = pr->nupval;
         for (int i = 0; i < pr->nupval; ++i) {
@@ -510,6 +511,7 @@ newfn(PezContext *cx, Proto *pr, Val *args, Val *locals, Fn *parent)
                     up = newobj(cx, PEZ_TUpval, sizeof *up);
                     if (!up) {
                         cxfree(cx, fn, sizeoffn(fn));
+                        pop(cx);
                         return NULL;
                     }
                     up->ptr = &vals[upinfo->idx];
@@ -522,6 +524,7 @@ newfn(PezContext *cx, Proto *pr, Val *args, Val *locals, Fn *parent)
                 fn->upval[i] = parent->upval[upinfo->idx];
             }
         }
+        pop(cx);
     }
     return fn;
 }
@@ -772,7 +775,9 @@ markfn(PezContext *cx, Fn *fn)
 {
     gcmark(cx, (Obj *)fn->proto);
     for (int i = 0; i < fn->nupval; ++i) {
-        gcmark(cx, (Obj *)fn->upval[i]);
+        if (fn->upval[i]) {
+            gcmark(cx, (Obj *)fn->upval[i]);
+        }
     }
 }