Rollup merge of rust-lang#57703 - m-ou-se:mutexguard-debug, r=cramertj

Centril · web-flow · commit 1e8fde07b6d2 · 2019-01-26T18:21:42.000+01:00
Make MutexGuard's Debug implementation more useful. Fixes rust-lang#57702.
diff --git a/src/libstd/sync/mutex.rs b/src/libstd/sync/mutex.rs
@@ -450,9 +450,7 @@ impl<'a, T: ?Sized> Drop for MutexGuard<'a, T> {
 #[stable(feature = "std_debug", since = "1.16.0")]
 impl<'a, T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.debug_struct("MutexGuard")
-            .field("lock", &self.__lock)
-            .finish()
+        fmt::Debug::fmt(&**self, f)
     }
 }
 

Original file line number	Diff line number	Diff line change
`@@ -450,9 +450,7 @@ impl<'a, T: ?Sized> Drop for MutexGuard<'a, T> {`
`450`	`450`	`#[stable(feature = "std_debug", since = "1.16.0")]`
`451`	`451`	`impl<'a, T: ?Sized + fmt::Debug> fmt::Debug for MutexGuard<'a, T> {`
`452`	`452`	`fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {`
`453`		`- f.debug_struct("MutexGuard")`
`454`		`- .field("lock", &self.__lock)`
`455`		`- .finish()`
	`453`	`+ fmt::Debug::fmt(&**self, f)`
`456`	`454`	`}`
`457`	`455`	`}`
`458`	`456`