more easy changes

Author: jyn514

compiler/rustc_infer/src/infer/lattice.rs

@@ -55,6 +55,7 @@ where
         return Ok(a);
     }
 
+    let span = this.cause().span;
     let infcx = this.infcx();
     let a = infcx.inner.type_variables().replace_if_possible(a);
     let b = infcx.inner.type_variables().replace_if_possible(b);
@@ -78,18 +79,20 @@ where
         // iterate on the subtype obligations that are returned, but I
         // think this suffices. -nmatsakis
         (&ty::Infer(TyVar(..)), _) => {
-            let v = infcx.next_ty_var(TypeVariableOrigin {
+            let origin = TypeVariableOrigin {
                 kind: TypeVariableOriginKind::LatticeVariable,
-                span: this.cause().span,
-            });
+                span,
+            };
+            let v = infcx.next_ty_var(origin);
             this.relate_bound(v, b, a)?;
             Ok(v)
         }
         (_, &ty::Infer(TyVar(..))) => {
-            let v = infcx.next_ty_var(TypeVariableOrigin {
+            let origin = TypeVariableOrigin {
                 kind: TypeVariableOriginKind::LatticeVariable,
-                span: this.cause().span,
-            });
+                span,
+            };
+            let v = infcx.next_ty_var(origin);
             this.relate_bound(v, a, b)?;
             Ok(v)
         }

compiler/rustc_infer/src/infer/lub.rs

@@ -67,8 +67,9 @@ impl TypeRelation<'tcx> for Lub<'_, 'combine, 'infcx, 'tcx> {
         debug!("{}.regions({:?}, {:?})", self.tag(), a, b);
 
         let origin = Subtype(box self.fields.trace.clone());
+        let tcx = self.tcx();
         Ok(self.fields.infcx.inner.unwrap_region_constraints().lub_regions(
-            self.tcx(),
+            tcx,
             origin,
             a,
             b,

compiler/rustc_infer/src/infer/nll_relate/mod.rs

@@ -314,7 +314,8 @@ where
             }
 
             ty::Projection(projection_ty) if D::normalization() == NormalizationStrategy::Lazy => {
-                return Ok(self.relate_projection_ty(projection_ty, self.delegate.infcx().tcx.mk_ty_var(vid)));
+                let ty_var = self.delegate.infcx().tcx.mk_ty_var(vid);
+                return Ok(self.relate_projection_ty(projection_ty, ty_var));
             }
 
             _ => (),

compiler/rustc_infer/src/infer/sub.rs

@@ -80,7 +80,7 @@ impl TypeRelation<'tcx> for Sub<'_, 'combine, 'infcx, 'tcx> {
             return Ok(a);
         }
 
-        let infcx = self.fields.infcx;
+        let infcx = &mut *self.fields.infcx;
         let a = infcx.inner.type_variables().replace_if_possible(a);
         let b = infcx.inner.type_variables().replace_if_possible(b);
         match (a.kind(), b.kind()) {