From ba90718bb44fe7e2a5edbcc3e5503ee1f7feebd5 Mon Sep 17 00:00:00 2001
From: achernyak <artemchernyak@gmail.com>
Date: Fri, 28 Apr 2017 22:42:05 -0500
Subject: [PATCH] found the stack overflow culprit

---
 src/librustc/ty/maps.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/librustc/ty/maps.rs b/src/librustc/ty/maps.rs
index 51fc0aa895c..c39417b67d4 100644
--- a/src/librustc/ty/maps.rs
+++ b/src/librustc/ty/maps.rs
@@ -346,8 +346,8 @@ macro_rules! define_maps {
                 }
 
                 // FIXME(eddyb) Get more valid Span's on queries.
-                if span == DUMMY_SP {
-                    span = key.default_span(tcx);
+                if span == DUMMY_SP && stringify!($name) != "def_span" {
+                    span = key.default_span(tcx)
                 }
 
                 let _task = tcx.dep_graph.in_task(Self::to_dep_node(&key));