Add at methods to FnCtxt and Coerce to simplify the "inherited" method calls

Author: oli-obk

compiler/rustc_hir_typeck/src/closure.rs

@@ -564,7 +564,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // Check that E' = S'.
                 let cause = self.misc(hir_ty.span);
                 let InferOk { value: (), obligations } = self
-                    .at(&cause, self.param_env)
+                    .at(&cause)
                     .define_opaque_types(self.defining_use_anchor())
                     .eq(*expected_ty, supplied_ty)?;
                 all_obligations.extend(obligations);
@@ -577,7 +577,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             );
             let cause = &self.misc(decl.output.span());
             let InferOk { value: (), obligations } = self
-                .at(cause, self.param_env)
+                .at(cause)
                 .define_opaque_types(self.defining_use_anchor())
                 .eq(expected_sigs.liberated_sig.output(), supplied_output_ty)?;
             all_obligations.extend(obligations);

compiler/rustc_hir_typeck/src/coercion.rs

@@ -44,6 +44,7 @@ use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::Expr;
 use rustc_hir_analysis::astconv::AstConv;
+use rustc_infer::infer::at::At;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{Coercion, DefiningAnchor, InferOk, InferResult};
 use rustc_infer::traits::Obligation;
@@ -140,12 +141,14 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
         Coerce { fcx, cause, allow_two_phase, use_lub: false }
     }
 
+    pub fn at(&self) -> At<'_, 'tcx> {
+        self.infcx.at(&self.cause, self.param_env)
+    }
+
     fn unify(&self, a: Ty<'tcx>, b: Ty<'tcx>) -> InferResult<'tcx, Ty<'tcx>> {
         debug!("unify(a: {:?}, b: {:?}, use_lub: {})", a, b, self.use_lub);
         self.commit_if_ok(|_| {
-            let at = self
-                .at(&self.cause, self.fcx.param_env)
-                .define_opaque_types(self.defining_use_anchor());
+            let at = self.at().define_opaque_types(self.defining_use_anchor());
             if self.use_lub {
                 at.lub(b, a)
             } else {
@@ -177,9 +180,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
             // so this will have the side-effect of making sure we have no ambiguities
             // due to `[type error]` and `_` not coercing together.
             let _ = self.commit_if_ok(|_| {
-                self.at(&self.cause, self.param_env)
-                    .define_opaque_types(self.defining_use_anchor())
-                    .eq(a, b)
+                self.at().define_opaque_types(self.defining_use_anchor()).eq(a, b)
             });
             return success(vec![], self.fcx.tcx.ty_error(guar), vec![]);
         }
@@ -843,8 +844,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
         //! into a closure or a `proc`.
 
         let b = self.shallow_resolve(b);
-        let InferOk { value: b, mut obligations } =
-            self.at(&self.cause, self.param_env).normalize(b);
+        let InferOk { value: b, mut obligations } = self.at().normalize(b);
         debug!("coerce_from_fn_item(a={:?}, b={:?})", a, b);
 
         match b.kind() {
@@ -865,8 +865,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                     }
                 }
 
-                let InferOk { value: a_sig, obligations: o1 } =
-                    self.at(&self.cause, self.param_env).normalize(a_sig);
+                let InferOk { value: a_sig, obligations: o1 } = self.at().normalize(a_sig);
                 obligations.extend(o1);
 
                 let a_fn_pointer = self.tcx.mk_fn_ptr(a_sig);
@@ -1105,9 +1104,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     (ty::FnDef(..), ty::FnDef(..)) => {
                         // Don't reify if the function types have a LUB, i.e., they
                         // are the same function and their parameters have a LUB.
-                        match self
-                            .commit_if_ok(|_| self.at(cause, self.param_env).lub(prev_ty, new_ty))
-                        {
+                        match self.commit_if_ok(|_| self.at(cause).lub(prev_ty, new_ty)) {
                             // We have a LUB of prev_ty and new_ty, just return it.
                             Ok(ok) => return Ok(self.register_infer_ok_obligations(ok)),
                             Err(_) => {
@@ -1155,7 +1152,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // The signature must match.
             let (a_sig, b_sig) = self.normalize(new.span, (a_sig, b_sig));
             let sig = self
-                .at(cause, self.param_env)
+                .at(cause)
                 .trace(prev_ty, new_ty)
                 .lub(a_sig, b_sig)
                 .map(|ok| self.register_infer_ok_obligations(ok))?;
@@ -1241,7 +1238,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 );
 
                 return self
-                    .commit_if_ok(|_| self.at(cause, self.param_env).lub(prev_ty, new_ty))
+                    .commit_if_ok(|_| self.at(cause).lub(prev_ty, new_ty))
                     .map(|ok| self.register_infer_ok_obligations(ok));
             }
         }
@@ -1252,7 +1249,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 if let Some(e) = first_error {
                     Err(e)
                 } else {
-                    self.commit_if_ok(|_| self.at(cause, self.param_env).lub(prev_ty, new_ty))
+                    self.commit_if_ok(|_| self.at(cause).lub(prev_ty, new_ty))
                         .map(|ok| self.register_infer_ok_obligations(ok))
                 }
             }
@@ -1489,7 +1486,7 @@ impl<'tcx, 'exprs, E: AsCoercionSite> CoerceMany<'tcx, 'exprs, E> {
             //
             // Another example is `break` with no argument expression.
             assert!(expression_ty.is_unit(), "if let hack without unit type");
-            fcx.at(cause, fcx.param_env)
+            fcx.at(cause)
                 // needed for tests/ui/type-alias-impl-trait/issue-65679-inst-opaque-ty-from-val-twice.rs
                 .define_opaque_types(fcx.defining_use_anchor())
                 .eq_exp(label_expression_as_expected, expression_ty, self.merged_ty())

compiler/rustc_hir_typeck/src/demand.rs

@@ -113,11 +113,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
     ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
-        match self
-            .at(cause, self.param_env)
-            .define_opaque_types(self.defining_use_anchor())
-            .sup(expected, actual)
-        {
+        match self.at(cause).define_opaque_types(self.defining_use_anchor()).sup(expected, actual) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
                 None
@@ -147,11 +143,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         actual: Ty<'tcx>,
     ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
-        match self
-            .at(cause, self.param_env)
-            .define_opaque_types(self.defining_use_anchor())
-            .eq(expected, actual)
-        {
+        match self.at(cause).define_opaque_types(self.defining_use_anchor()).eq(expected, actual) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
                 None

compiler/rustc_hir_typeck/src/expr.rs

@@ -1683,7 +1683,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             if let Some(_) = remaining_fields.remove(&ident) {
                                 let target_ty = self.field_ty(base_expr.span, f, substs);
                                 let cause = self.misc(base_expr.span);
-                                match self.at(&cause, self.param_env).sup(target_ty, fru_ty) {
+                                match self.at(&cause).sup(target_ty, fru_ty) {
                                     Ok(InferOk { obligations, value: () }) => {
                                         self.register_predicates(obligations)
                                     }

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -317,9 +317,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     where
         T: TypeFoldable<TyCtxt<'tcx>>,
     {
-        self.register_infer_ok_obligations(
-            self.at(&self.misc(span), self.param_env).normalize(value),
-        )
+        self.register_infer_ok_obligations(self.at(&self.misc(span)).normalize(value))
     }
 
     pub fn require_type_meets(
@@ -561,7 +559,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // Unify `interior` with `witness` and collect all the resulting obligations.
             let span = self.tcx.hir().body(body_id).value.span;
             let ok = self
-                .at(&self.misc(span), self.param_env)
+                .at(&self.misc(span))
                 .eq(interior, witness)
                 .expect("Failed to unify generator interior type");
             let mut obligations = ok.obligations;
@@ -1319,7 +1317,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             // This also occurs for an enum variant on a type alias.
             let impl_ty = self.normalize(span, tcx.type_of(impl_def_id).subst(tcx, substs));
             let self_ty = self.normalize(span, self_ty);
-            match self.at(&self.misc(span), self.param_env).eq(impl_ty, self_ty) {
+            match self.at(&self.misc(span)).eq(impl_ty, self_ty) {
                 Ok(ok) => self.register_infer_ok_obligations(ok),
                 Err(_) => {
                     self.tcx.sess.delay_span_bug(

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -302,9 +302,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
             // 3. Check if the formal type is a supertype of the checked one
             //    and register any such obligations for future type checks
-            let supertype_error = self
-                .at(&self.misc(provided_arg.span), self.param_env)
-                .sup(formal_input_ty, coerced_ty);
+            let supertype_error =
+                self.at(&self.misc(provided_arg.span)).sup(formal_input_ty, coerced_ty);
             let subtyping_error = match supertype_error {
                 Ok(InferOk { obligations, value: () }) => {
                     self.register_predicates(obligations);
@@ -585,9 +584,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
 
             // Using probe here, since we don't want this subtyping to affect inference.
-            let subtyping_error = self.probe(|_| {
-                self.at(&self.misc(arg_span), self.param_env).sup(formal_input_ty, coerced_ty).err()
-            });
+            let subtyping_error = self
+                .probe(|_| self.at(&self.misc(arg_span)).sup(formal_input_ty, coerced_ty).err());
 
             // Same as above: if either the coerce type or the checked type is an error type,
             // consider them *not* compatible.

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -6,6 +6,7 @@ mod suggestions;
 
 pub use _impl::*;
 use rustc_errors::ErrorGuaranteed;
+use rustc_infer::infer::at::At;
 pub use suggestions::*;
 
 use crate::coercion::DynamicCoerceMany;
@@ -145,6 +146,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         self.cause(span, ObligationCauseCode::MiscObligation)
     }
 
+    pub fn at(&'a self, cause: &'a ObligationCause<'tcx>) -> At<'a, 'tcx> {
+        self.infcx.at(cause, self.param_env)
+    }
+
     pub fn sess(&self) -> &Session {
         &self.tcx.sess
     }

compiler/rustc_hir_typeck/src/generator_interior/mod.rs

@@ -327,7 +327,7 @@ pub fn resolve_interior<'a, 'tcx>(
     );
 
     // Unify the type variable inside the generator with the new witness
-    match fcx.at(&fcx.misc(body.value.span), fcx.param_env).eq(interior, witness) {
+    match fcx.at(&fcx.misc(body.value.span)).eq(interior, witness) {
         Ok(ok) => fcx.register_infer_ok_obligations(ok),
         _ => bug!("failed to relate {interior} and {witness}"),
     }

compiler/rustc_hir_typeck/src/method/confirm.rs

@@ -478,7 +478,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                 substs,
             })),
         );
-        match self.at(&cause, self.param_env).sup(method_self_ty, self_ty) {
+        match self.at(&cause).sup(method_self_ty, self_ty) {
             Ok(InferOk { obligations, value: () }) => {
                 self.register_predicates(obligations);
             }

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -409,8 +409,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let fn_sig =
             self.instantiate_binder_with_fresh_vars(obligation.cause.span, infer::FnCall, fn_sig);
 
-        let InferOk { value, obligations: o } =
-            self.at(&obligation.cause, self.param_env).normalize(fn_sig);
+        let InferOk { value, obligations: o } = self.at(&obligation.cause).normalize(fn_sig);
         let fn_sig = {
             obligations.extend(o);
             value
@@ -426,8 +425,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // any late-bound regions appearing in its bounds.
         let bounds = self.tcx.predicates_of(def_id).instantiate(self.tcx, substs);
 
-        let InferOk { value, obligations: o } =
-            self.at(&obligation.cause, self.param_env).normalize(bounds);
+        let InferOk { value, obligations: o } = self.at(&obligation.cause).normalize(bounds);
         let bounds = {
             obligations.extend(o);
             value

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -754,7 +754,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             // see issue #89650
             let cause = traits::ObligationCause::misc(self.span, self.body_id);
             let InferOk { value: xform_self_ty, obligations } =
-                self.fcx.at(&cause, self.param_env).normalize(xform_self_ty);
+                self.fcx.at(&cause).normalize(xform_self_ty);
 
             debug!(
                 "assemble_inherent_impl_probe after normalization: xform_self_ty = {:?}/{:?}",
@@ -933,11 +933,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 let fty = self.instantiate_binder_with_fresh_vars(self.span, infer::FnCall, fty);
 
                 if let Some(self_ty) = self_ty {
-                    if self
-                        .at(&ObligationCause::dummy(), self.param_env)
-                        .sup(fty.inputs()[0], self_ty)
-                        .is_err()
-                    {
+                    if self.at(&ObligationCause::dummy()).sup(fty.inputs()[0], self_ty).is_err() {
                         return false;
                     }
                 }
@@ -1440,9 +1436,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 CandidateSource::Trait(candidate.item.container_id(self.tcx))
             }
             TraitCandidate(trait_ref) => self.probe(|_| {
-                let _ = self
-                    .at(&ObligationCause::dummy(), self.param_env)
-                    .sup(candidate.xform_self_ty, self_ty);
+                let _ = self.at(&ObligationCause::dummy()).sup(candidate.xform_self_ty, self_ty);
                 match self.select_trait_candidate(trait_ref) {
                     Ok(Some(traits::ImplSource::UserDefined(ref impl_data))) => {
                         // If only a single impl matches, make the error message point
@@ -1469,16 +1463,14 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 
         self.probe(|_| {
             // First check that the self type can be related.
-            let sub_obligations = match self
-                .at(&ObligationCause::dummy(), self.param_env)
-                .sup(probe.xform_self_ty, self_ty)
-            {
-                Ok(InferOk { obligations, value: () }) => obligations,
-                Err(err) => {
-                    debug!("--> cannot relate self-types {:?}", err);
-                    return ProbeResult::NoMatch;
-                }
-            };
+            let sub_obligations =
+                match self.at(&ObligationCause::dummy()).sup(probe.xform_self_ty, self_ty) {
+                    Ok(InferOk { obligations, value: () }) => obligations,
+                    Err(err) => {
+                        debug!("--> cannot relate self-types {:?}", err);
+                        return ProbeResult::NoMatch;
+                    }
+                };
 
             let mut result = ProbeResult::Match;
             let mut xform_ret_ty = probe.xform_ret_ty;
@@ -1500,7 +1492,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     let InferOk {
                         value: normalized_xform_ret_ty,
                         obligations: normalization_obligations,
-                    } = self.fcx.at(&cause, self.param_env).normalize(xform_ret_ty);
+                    } = self.fcx.at(&cause).normalize(xform_ret_ty);
                     xform_ret_ty = normalized_xform_ret_ty;
                     debug!("xform_ret_ty after normalization: {:?}", xform_ret_ty);
 
@@ -1510,7 +1502,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     let impl_bounds = impl_bounds.instantiate(self.tcx, substs);
 
                     let InferOk { value: impl_bounds, obligations: norm_obligations } =
-                        self.fcx.at(&cause, self.param_env).normalize(impl_bounds);
+                        self.fcx.at(&cause).normalize(impl_bounds);
 
                     // Convert the bounds into obligations.
                     let impl_obligations = traits::predicates_for_generics(
@@ -1663,7 +1655,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                     let InferOk {
                         value: normalized_xform_ret_ty,
                         obligations: normalization_obligations,
-                    } = self.fcx.at(&cause, self.param_env).normalize(xform_ret_ty);
+                    } = self.fcx.at(&cause).normalize(xform_ret_ty);
                     xform_ret_ty = normalized_xform_ret_ty;
                     debug!("xform_ret_ty after normalization: {:?}", xform_ret_ty);
                     // Evaluate those obligations to see if they might possibly hold.
@@ -1686,7 +1678,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
                 );
                 if let ProbeResult::Match = result
                     && self
-                    .at(&ObligationCause::dummy(), self.param_env)
+                    .at(&ObligationCause::dummy())
                     .sup(return_ty, xform_ret_ty)
                     .is_err()
                 {