From db8a9a92b3dafcd5a8d7207096c8cbb90db0b013 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Mon, 2 May 2016 11:44:25 -0400
Subject: avoid double panic

---
 src/libsyntax/errors/mod.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src/libsyntax/errors')

diff --git a/src/libsyntax/errors/mod.rs b/src/libsyntax/errors/mod.rs
index 4ade537c8ce..f0c665bcb3c 100644
--- a/src/libsyntax/errors/mod.rs
+++ b/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,
-- 
cgit 1.4.1-3-g733a5