Don't clone in UnificationTable::probe().

nnethercote · nnethercote · commit f0c9a9f4749c · 2016-11-18T14:26:22.000+11:00
This speeds up compilation of rustc-benchmarks/inflate-0.1.0 by 1%.
diff --git a/src/librustc_data_structures/unify/mod.rs b/src/librustc_data_structures/unify/mod.rs
@@ -344,7 +344,7 @@ impl<'tcx, K, V> UnificationTable<K>
     }
 
     pub fn probe(&mut self, a_id: K) -> Option<V> {
-        self.get(a_id).value.clone()
+        self.get(a_id).value
     }
 
     pub fn unsolved_variables(&mut self) -> Vec<K> {

Original file line number	Diff line number	Diff line change
`@@ -344,7 +344,7 @@ impl<'tcx, K, V> UnificationTable<K>`
`344`	`344`	`}`
`345`	`345`
`346`	`346`	`pub fn probe(&mut self, a_id: K) -> Option<V> {`
`347`		`- self.get(a_id).value.clone()`
	`347`	`+ self.get(a_id).value`
`348`	`348`	`}`
`349`	`349`
`350`	`350`	`pub fn unsolved_variables(&mut self) -> Vec<K> {`