---

yaml
---
r: 277563
b: refs/heads/try
c: db8a9a9
h: refs/heads/master
i:
  277561: b171518
  277559: 844ce88

Author: nikomatsakis

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: 6dbb0e86aec11050480beb76eade6fb805010ba7
 refs/heads/snap-stage3: 235d77457d80b549dad3ac36d94f235208a1eafb
-refs/heads/try: 9d151a71c032b655ca457521730044237c9e130e
+refs/heads/try: db8a9a92b3dafcd5a8d7207096c8cbb90db0b013
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try/src/libsyntax/errors/mod.rs

@@ -20,6 +20,7 @@ use errors::emitter::{Emitter, EmitterWriter};
 use std::cell::{RefCell, Cell};
 use std::{error, fmt};
 use std::rc::Rc;
+use std::thread::panicking;
 use term;
 
 pub mod emitter;
@@ -352,7 +353,7 @@ impl<'a> fmt::Debug for DiagnosticBuilder<'a> {
 /// we emit a bug.
 impl<'a> Drop for DiagnosticBuilder<'a> {
     fn drop(&mut self) {
-        if !self.cancelled() {
+        if !panicking() && !self.cancelled() {
             self.emitter.borrow_mut().emit(&MultiSpan::new(),
                                            "Error constructed but not emitted",
                                            None,