Fix segfault

src/compiler.pr

@@ -1428,6 +1428,17 @@ def convert_ref_to_ref(tpe: &typechecking::Type, value: Value, loc: &Value, stat
     // Convert weak ref to strong reference
     // Need to check the ref count and return a null reference if its 0
     if is_weak_ref(value.tpe) and is_ref(tpe) {
+        let ref_value = state.ptr_to_int(extract1_ret, loc)
+        let isnull = state.icmp(CompareInt::eq, ref_value, 
+            [ kind = ValueKind::INT, tpe = builtins::int64_, i = 0 ] !Value, loc)
+
+        let br1 = make_insn_dbg(InsnKind::BR, loc)
+        br1.value.br = [ cond = isnull ] !InsnBr
+        push_insn(br1, state)
+        let nonnull = make_label(state)
+        push_label(nonnull, state)
+        br1.value.br.if_false = nonnull
+
         let meta = state.load(ref_meta, extract1_ret, loc)
         let refcount = state.extract_value(builtins::int64_, meta, [0], loc)
         let iszero = state.icmp(CompareInt::sle, refcount, 
@@ -1439,6 +1450,7 @@ def convert_ref_to_ref(tpe: &typechecking::Type, value: Value, loc: &Value, stat
         push_insn(br, state)
         let if_true = make_label(state)
         push_label(if_true, state)
+        br1.value.br.if_true = if_true
         br.value.br.if_true = if_true
 
         // Null reference