From 0649942a46d29a4782b4bfcce1c6fe006ad63dc6 Mon Sep 17 00:00:00 2001
From: Jeffrey Seyfried <jeffrey.seyfried@gmail.com>
Date: Sat, 30 Apr 2016 04:08:49 +0000
Subject: [PATCH] Panic on relowering an AST node with a cached node id

---
 src/librustc/hir/lowering.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 6f30553e2663..ea92cfd9ee07 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -213,6 +213,8 @@ fn cache_ids<'a, OP, R>(lctx: &LoweringContext, expr_id: NodeId, op: OP) -> R
         let id_cache: &mut HashMap<_, _> = &mut lctx.id_cache.borrow_mut();
 
         if id_cache.contains_key(&expr_id) {
+            panic!("relowering!!!");
+            /*
             let cached_id = lctx.cached_id.get();
             if cached_id == 0 {
                 // We're entering a node where we need to track ids, but are not
@@ -224,6 +226,7 @@ fn cache_ids<'a, OP, R>(lctx: &LoweringContext, expr_id: NodeId, op: OP) -> R
                 assert!(cached_id == id_cache[&expr_id], "id mismatch");
             }
             lctx.gensym_key.set(id_cache[&expr_id]);
+            */
         } else {
             // We've never lowered this node before, remember it for next time.
             let next_id = lctx.id_assigner.peek_node_id();