fix clippy::clone_on_copy: don't clone types that are copy

Author: matthiaskrgr

src/librustc_infer/infer/glb.rs

@@ -50,7 +50,7 @@ impl TypeRelation<'tcx> for Glb<'combine, 'infcx, 'tcx> {
             ty::Invariant => self.fields.equate(self.a_is_expected).relate(a, b),
             ty::Covariant => self.relate(a, b),
             // FIXME(#41044) -- not correct, need test
-            ty::Bivariant => Ok(a.clone()),
+            ty::Bivariant => Ok(a),
             ty::Contravariant => self.fields.lub(self.a_is_expected).relate(a, b),
         }
     }
@@ -97,7 +97,7 @@ impl TypeRelation<'tcx> for Glb<'combine, 'infcx, 'tcx> {
         // very challenging, switch to invariance. This is obviously
         // overly conservative but works ok in practice.
         self.relate_with_variance(ty::Variance::Invariant, a, b)?;
-        Ok(a.clone())
+        Ok(a)
     }
 }
 

src/librustc_infer/infer/nll_relate/mod.rs

@@ -719,7 +719,7 @@ where
             self.a_scopes.pop().unwrap();
         }
 
-        Ok(a.clone())
+        Ok(a)
     }
 }
 

src/librustc_infer/infer/sub.rs

@@ -68,7 +68,7 @@ impl TypeRelation<'tcx> for Sub<'combine, 'infcx, 'tcx> {
         match variance {
             ty::Invariant => self.fields.equate(self.a_is_expected).relate(a, b),
             ty::Covariant => self.relate(a, b),
-            ty::Bivariant => Ok(a.clone()),
+            ty::Bivariant => Ok(a),
             ty::Contravariant => self.with_expected_switched(|this| this.relate(b, a)),
         }
     }

src/librustc_mir/transform/validate.rs

@@ -115,7 +115,7 @@ pub fn equal_up_to_regions(
             T: Relate<'tcx>,
         {
             self.relate(a.skip_binder(), b.skip_binder())?;
-            Ok(a.clone())
+            Ok(a)
         }
     }
 

src/librustc_trait_selection/autoderef.rs

@@ -187,7 +187,7 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
     }
 
     pub fn span(&self) -> Span {
-        self.span.clone()
+        self.span
     }
 
     pub fn reached_recursion_limit(&self) -> bool {

src/librustc_typeck/check/dropck.rs

@@ -368,6 +368,6 @@ impl TypeRelation<'tcx> for SimpleEqRelation<'tcx> {
         let anon_b = self.tcx.anonymize_late_bound_regions(&b);
         self.relate(anon_a.skip_binder(), anon_b.skip_binder())?;
 
-        Ok(a.clone())
+        Ok(a)
     }
 }