Fix a few more borrows

Author: jyn514

compiler/rustc_infer/src/infer/at.rs

@@ -191,9 +191,9 @@ impl<'a, 'b, 'tcx> Trace<'a, 'b, 'tcx> {
         T: Relate<'tcx>,
     {
         debug!("sub({:?} <: {:?})", a, b);
-        let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|infcx, _| {
-            let mut fields = infcx.combine_fields(trace, at.param_env);
+        let Trace { at: At { param_env, infcx, .. }, trace, a_is_expected } = self;
+        infcx.commit_if_ok(|infcx, _| {
+            let mut fields = infcx.combine_fields(trace, param_env);
             fields
                 .sub(a_is_expected)
                 .relate(a, b)
@@ -208,9 +208,9 @@ impl<'a, 'b, 'tcx> Trace<'a, 'b, 'tcx> {
         T: Relate<'tcx>,
     {
         debug!("eq({:?} == {:?})", a, b);
-        let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|infcx, _| {
-            let mut fields = infcx.combine_fields(trace, at.param_env);
+        let Trace { at: At { param_env, infcx, .. }, trace, a_is_expected } = self;
+        infcx.commit_if_ok(|infcx, _| {
+            let mut fields = infcx.combine_fields(trace, param_env);
             fields
                 .equate(a_is_expected)
                 .relate(a, b)
@@ -223,9 +223,9 @@ impl<'a, 'b, 'tcx> Trace<'a, 'b, 'tcx> {
         T: Relate<'tcx>,
     {
         debug!("lub({:?} \\/ {:?})", a, b);
-        let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|infcx, _| {
-            let mut fields = infcx.combine_fields(trace, at.param_env);
+        let Trace { at: At { param_env, infcx, .. }, trace, a_is_expected } = self;
+        infcx.commit_if_ok(|infcx, _| {
+            let mut fields = infcx.combine_fields(trace, param_env);
             fields
                 .lub(a_is_expected)
                 .relate(a, b)
@@ -238,9 +238,9 @@ impl<'a, 'b, 'tcx> Trace<'a, 'b, 'tcx> {
         T: Relate<'tcx>,
     {
         debug!("glb({:?} /\\ {:?})", a, b);
-        let Trace { at, trace, a_is_expected } = self;
-        at.infcx.commit_if_ok(|infcx, _| {
-            let mut fields = infcx.combine_fields(trace, at.param_env);
+        let Trace { at: At { param_env, infcx, .. }, trace, a_is_expected } = self;
+        infcx.commit_if_ok(|infcx, _| {
+            let mut fields = infcx.combine_fields(trace, param_env);
             fields
                 .glb(a_is_expected)
                 .relate(a, b)

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

@@ -51,7 +51,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// for each of the canonical inputs to your query.
 
     pub fn instantiate_canonical_with_fresh_inference_vars<T>(
-        &self,
+        &mut self,
         span: Span,
         canonical: &Canonical<'tcx, T>,
     ) -> (T, CanonicalVarValues<'tcx>)
@@ -80,7 +80,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// details). You can then use `substitute` to instantiate the
     /// canonical variable with these inference variables.
     fn instantiate_canonical_vars(
-        &self,
+        &mut self,
         span: Span,
         variables: &List<CanonicalVarInfo<'tcx>>,
         universe_map: impl Fn(ty::UniverseIndex) -> ty::UniverseIndex,
@@ -137,16 +137,18 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 self.tcx.mk_region(ty::RePlaceholder(placeholder_mapped)).into()
             }
 
-            CanonicalVarKind::Const(ui) => self
-                .next_const_var_in_universe(
-                    self.next_ty_var_in_universe(
-                        TypeVariableOrigin { kind: TypeVariableOriginKind::MiscVariable, span },
-                        universe_map(ui),
-                    ),
+            CanonicalVarKind::Const(ui) => {
+                let ty_var = self.next_ty_var_in_universe(
+                    TypeVariableOrigin { kind: TypeVariableOriginKind::MiscVariable, span },
+                    universe_map(ui),
+                );
+                self.next_const_var_in_universe(
+                    ty_var,
                     ConstVariableOrigin { kind: ConstVariableOriginKind::MiscVariable, span },
                     universe_map(ui),
                 )
-                .into(),
+                .into()
+            }
 
             CanonicalVarKind::PlaceholderConst(ty::PlaceholderConst { universe, name }) => {
                 let universe_mapped = universe_map(universe);

compiler/rustc_infer/src/infer/mod.rs

@@ -570,7 +570,7 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
     where
         T: TypeFoldable<'tcx>,
     {
-        self.enter(|infcx| {
+        self.enter(|mut infcx| {
             let (value, subst) =
                 infcx.instantiate_canonical_with_fresh_inference_vars(span, canonical);
             f(infcx, value, subst)