Simplify more FnCtxt normalization

compiler/rustc_hir_typeck/src/cast.rs

@@ -752,10 +752,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 match *self.expr_ty.kind() {
                     ty::FnDef(..) => {
                         // Attempt a coercion to a fn pointer type.
-                        let f = fcx.normalize(
+                        let f = fcx.normalize(self.expr_span, self.expr_ty.fn_sig(fcx.tcx));
-                            self.expr_span,
-                            self.expr_ty.fn_sig(fcx.tcx),
-                        );
                         let res = fcx.try_coerce(
                             self.expr,
                             self.expr_ty,

compiler/rustc_hir_typeck/src/check.rs

@@ -1,6 +1,6 @@
 use crate::coercion::CoerceMany;
 use crate::gather_locals::GatherLocalsVisitor;
-use crate::{FnCtxt, Inherited};
+use crate::FnCtxt;
 use crate::{GeneratorTypes, UnsafetyState};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
@@ -20,21 +20,16 @@ use std::cell::RefCell;
 ///
 /// * ...
 /// * inherited: other fields inherited from the enclosing fn (if any)
-#[instrument(skip(inherited, body), level = "debug")]
+#[instrument(skip(fcx, body), level = "debug")]
 pub(super) fn check_fn<'a, 'tcx>(
-    inherited: &'a Inherited<'tcx>,
+    fcx: &mut FnCtxt<'a, 'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
     fn_sig: ty::FnSig<'tcx>,
     decl: &'tcx hir::FnDecl<'tcx>,
     fn_def_id: LocalDefId,
     body: &'tcx hir::Body<'tcx>,
     can_be_generator: Option<hir::Movability>,
-) -> (FnCtxt<'a, 'tcx>, Option<GeneratorTypes<'tcx>>) {
+) -> Option<GeneratorTypes<'tcx>> {
-    let fn_id = inherited.tcx.hir().local_def_id_to_hir_id(fn_def_id);
+    let fn_id = fcx.tcx.hir().local_def_id_to_hir_id(fn_def_id);
-
-    // Create the function context. This is either derived from scratch or,
-    // in the case of closures, based on the outer context.
-    let mut fcx = FnCtxt::new(inherited, param_env, body.value.hir_id);
     fcx.ps.set(UnsafetyState::function(fn_sig.unsafety, fn_id));
 
     let tcx = fcx.tcx;
@@ -47,7 +42,7 @@ pub(super) fn check_fn<'a, 'tcx>(
             declared_ret_ty,
             body.value.hir_id,
             decl.output.span(),
-            param_env,
+            fcx.param_env,
         ));
 
     fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(ret_ty)));
@@ -105,7 +100,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         fcx.write_ty(param.hir_id, param_ty);
     }
 
-    inherited.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
+    fcx.typeck_results.borrow_mut().liberated_fn_sigs_mut().insert(fn_id, fn_sig);
 
     if let ty::Dynamic(_, _, ty::Dyn) = declared_ret_ty.kind() {
         // FIXME: We need to verify that the return type is `Sized` after the return expression has
@@ -174,7 +169,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         check_panic_info_fn(tcx, panic_impl_did.expect_local(), fn_sig, decl, declared_ret_ty);
     }
 
-    (fcx, gen_ty)
+    gen_ty
 }
 
 fn check_panic_info_fn(

compiler/rustc_hir_typeck/src/closure.rs

@@ -79,16 +79,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         debug!(?bound_sig, ?liberated_sig);
 
+        let mut fcx = FnCtxt::new(self, self.param_env.without_const(), body.value.hir_id);
         let generator_types = check_fn(
-            self,
+            &mut fcx,
-            self.param_env.without_const(),
             liberated_sig,
             closure.fn_decl,
             expr_def_id,
             body,
             closure.movability,
-        )
+        );
-        .1;
 
         let parent_substs = InternalSubsts::identity_for_item(
             self.tcx,
@@ -797,10 +796,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) -> ClosureSignatures<'tcx> {
         let liberated_sig =
             self.tcx().liberate_late_bound_regions(expr_def_id.to_def_id(), bound_sig);
-        let liberated_sig = self.normalize(
+        let liberated_sig = self.normalize(body.value.span, liberated_sig);
-            body.value.span,
-            liberated_sig,
-        );
         ClosureSignatures { bound_sig, liberated_sig }
     }
 }

compiler/rustc_hir_typeck/src/coercion.rs

@@ -62,7 +62,9 @@ use rustc_span::{self, BytePos, DesugaringKind, Span};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
-use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode, ObligationCtxt};
+use rustc_trait_selection::traits::{
+    self, NormalizeExt, ObligationCause, ObligationCauseCode, ObligationCtxt,
+};
 
 use smallvec::{smallvec, SmallVec};
 use std::ops::Deref;
@@ -832,7 +834,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
 
         let b = self.shallow_resolve(b);
         let InferOk { value: b, mut obligations } =
-            self.normalize_associated_types_in_as_infer_ok(self.cause.span, b);
+            self.at(&self.cause, self.param_env).normalize(b);
         debug!("coerce_from_fn_item(a={:?}, b={:?})", a, b);
 
         match b.kind() {
@@ -854,7 +856,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
                 }
 
                 let InferOk { value: a_sig, obligations: o1 } =
-                    self.normalize_associated_types_in_as_infer_ok(self.cause.span, a_sig);
+                    self.at(&self.cause, self.param_env).normalize(a_sig);
                 obligations.extend(o1);
 
                 let a_fn_pointer = self.tcx.mk_fn_ptr(a_sig);

compiler/rustc_hir_typeck/src/expr.rs

@@ -1748,9 +1748,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     ty::Adt(adt, substs) if adt.is_struct() => variant
                         .fields
                         .iter()
-                        .map(|f| {
+                        .map(|f| self.normalize(expr_span, f.ty(self.tcx, substs)))
-                            self.normalize(expr_span, f.ty(self.tcx, substs))
-                        })
                         .collect(),
                     _ => {
                         self.tcx

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -16,7 +16,7 @@ use rustc_hir_analysis::astconv::{
 };
 use rustc_infer::infer::canonical::{Canonical, OriginalQueryValues, QueryResponse};
 use rustc_infer::infer::error_reporting::TypeAnnotationNeeded::E0282;
-use rustc_infer::infer::{InferOk, InferResult};
+use rustc_infer::infer::InferResult;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::fold::TypeFoldable;
@@ -31,9 +31,7 @@ use rustc_span::hygiene::DesugaringKind;
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
-use rustc_trait_selection::traits::{
+use rustc_trait_selection::traits::{self, NormalizeExt, ObligationCauseCode, ObligationCtxt};
-    self, NormalizeExt, ObligationCause, ObligationCauseCode, ObligationCtxt,
-};
 
 use std::collections::hash_map::Entry;
 use std::slice;
@@ -377,42 +375,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         )
     }
 
-    pub(in super::super) fn normalize_associated_types_in_as_infer_ok<T>(
-        &self,
-        span: Span,
-        value: T,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        self.at(&ObligationCause::misc(span, self.body_id), self.param_env).normalize(value)
-    }
-
-    pub(in super::super) fn normalize_op_associated_types_in_as_infer_ok<T>(
-        &self,
-        span: Span,
-        value: T,
-        opt_input_expr: Option<&hir::Expr<'_>>,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        self.at(
-            &ObligationCause::new(
-                span,
-                self.body_id,
-                traits::BinOp {
-                    rhs_span: opt_input_expr.map(|expr| expr.span),
-                    is_lit: opt_input_expr
-                        .map_or(false, |expr| matches!(expr.kind, ExprKind::Lit(_))),
-                    output_ty: None,
-                },
-            ),
-            self.param_env,
-        )
-        .normalize(value)
-    }
-
     pub fn require_type_meets(
         &self,
         ty: Ty<'tcx>,

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -20,6 +20,7 @@ use rustc_span::Span;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::error_reporting::DefIdOrName;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
+use rustc_trait_selection::traits::NormalizeExt;
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub(crate) fn body_fn_sig(&self) -> Option<ty::FnSig<'tcx>> {
@@ -245,7 +246,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // implied by wf, but also because that would possibly result in
         // erroneous errors later on.
         let infer::InferOk { value: output, obligations: _ } =
-            self.normalize_associated_types_in_as_infer_ok(expr.span, output);
+            self.at(&self.misc(expr.span), self.param_env).normalize(output);
 
         if output.is_ty_var() { None } else { Some((def_id_or_name, output, inputs)) }
     }

compiler/rustc_hir_typeck/src/lib.rs

@@ -48,8 +48,6 @@ pub use diverges::Diverges;
 pub use expectation::Expectation;
 pub use fn_ctxt::*;
 pub use inherited::{Inherited, InheritedBuilder};
-use rustc_infer::traits::ObligationCause;
-use rustc_trait_selection::traits::NormalizeExt;
 
 use crate::check::check_fn;
 use crate::coercion::DynamicCoerceMany;
@@ -235,9 +233,10 @@ fn typeck_with_fallback<'tcx>(
 
     let typeck_results = Inherited::build(tcx, def_id).enter(|inh| {
         let param_env = tcx.param_env(def_id);
-        let mut fcx = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
+        let mut fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
+
+        if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
             let fn_sig = if rustc_hir_analysis::collect::get_infer_ret_ty(&decl.output).is_some() {
-                let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
                 <dyn AstConv<'_>>::ty_of_fn(&fcx, id, header.unsafety, header.abi, decl, None, None)
             } else {
                 tcx.fn_sig(def_id)
@@ -247,16 +246,10 @@ fn typeck_with_fallback<'tcx>(
 
             // Compute the function signature from point of view of inside the fn.
             let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig);
-            // FIXME(compiler-errors): Remove
+            let fn_sig = fcx.normalize(body.value.span, fn_sig);
-            let fn_sig = inh
+
-                .register_infer_ok_obligations(
+            check_fn(&mut fcx, fn_sig, decl, def_id, body, None);
-                    inh.at(&ObligationCause::misc(body.value.span, body_id.hir_id),
-                    param_env,
-                )
-                .normalize(fn_sig));
-            check_fn(&inh, param_env, fn_sig, decl, def_id, body, None).0
         } else {
-            let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
             let expected_type = body_ty
                 .and_then(|ty| match ty.kind {
                     hir::TyKind::Infer => Some(<dyn AstConv<'_>>::ast_ty_to_ty(&fcx, ty)),
@@ -316,8 +309,6 @@ fn typeck_with_fallback<'tcx>(
             fcx.check_expr_coercable_to_type(&body.value, expected_type, None);
 
             fcx.write_ty(id, expected_type);
-
-            fcx
         };
 
         fcx.type_inference_fallback();

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -23,8 +23,8 @@ use rustc_middle::ty::subst::{InternalSubsts, SubstsRef};
 use rustc_middle::ty::{self, DefIdTree, GenericParamDefKind, Ty, TypeVisitable};
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
-use rustc_trait_selection::traits;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt;
+use rustc_trait_selection::traits::{self, NormalizeExt};
 
 use self::probe::{IsSuggestion, ProbeScope};
 
@@ -465,11 +465,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let fn_sig = fn_sig.subst(self.tcx, substs);
         let fn_sig = self.replace_bound_vars_with_fresh_vars(span, infer::FnCall, fn_sig);
 
-        let InferOk { value, obligations: o } = if is_op {
+        let cause = if is_op {
-            self.normalize_op_associated_types_in_as_infer_ok(span, fn_sig, opt_input_expr)
+            ObligationCause::new(
+                span,
+                self.body_id,
+                traits::BinOp {
+                    rhs_span: opt_input_expr.map(|expr| expr.span),
+                    is_lit: opt_input_expr
+                        .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
+                    output_ty: None,
+                },
+            )
         } else {
-            self.normalize_associated_types_in_as_infer_ok(span, fn_sig)
+            traits::ObligationCause::misc(span, self.body_id)
         };
+
+        let InferOk { value, obligations: o } = self.at(&cause, self.param_env).normalize(fn_sig);
         let fn_sig = {
             obligations.extend(o);
             value
@@ -485,11 +496,7 @@ 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 } = if is_op {
+        let InferOk { value, obligations: o } = self.at(&cause, self.param_env).normalize(bounds);
-            self.normalize_op_associated_types_in_as_infer_ok(span, bounds, opt_input_expr)
-        } else {
-            self.normalize_associated_types_in_as_infer_ok(span, bounds)
-        };
         let bounds = {
             obligations.extend(o);
             value
@@ -497,20 +504,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         assert!(!bounds.has_escaping_bound_vars());
 
-        let cause = if is_op {
-            ObligationCause::new(
-                span,
-                self.body_id,
-                traits::BinOp {
-                    rhs_span: opt_input_expr.map(|expr| expr.span),
-                    is_lit: opt_input_expr
-                        .map_or(false, |expr| matches!(expr.kind, hir::ExprKind::Lit(_))),
-                    output_ty: None,
-                },
-            )
-        } else {
-            traits::ObligationCause::misc(span, self.body_id)
-        };
         let predicates_cause = cause.clone();
         obligations.extend(traits::predicates_for_generics(
             move |_, _| predicates_cause.clone(),