Auto merge of rust-lang#104905 - compiler-errors:normalization-changes, r=spastorino

Some initial normalization method changes

1. Rename `AtExt::normalize` to `QueryNormalizeExt::query_normalize` (using the `QueryNormalizer`)
2. Introduce `NormalizeExt::normalize` to replace `partially_normalize_associated_types_in` (using the `AssocTypeNormalizer`)
3. Rename `FnCtxt::normalize_associated_types_in` to `FnCtxt::normalize`
4. Remove some unused other normalization fns in `Inherited` and `FnCtxt`

Also includes one drive-by where we're no longer creating a `FnCtxt` inside of `check_fn`, but passing it in. This means we don't need such weird `FnCtxt` construction logic.

Stacked on top of rust-lang#104835 for convenience.

r? types

Author: bors

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -291,11 +291,11 @@ where
         // FIXME(lqd): Unify and de-duplicate the following with the actual
         // `rustc_traits::type_op::type_op_normalize` query to allow the span we need in the
         // `ObligationCause`. The normalization results are currently different between
-        // `AtExt::normalize` used in the query and `normalize` called below: the former fails
-        // to normalize the `nll/relate_tys/impl-fn-ignore-binder-via-bottom.rs` test. Check
-        // after #85499 lands to see if its fixes have erased this difference.
+        // `QueryNormalizeExt::query_normalize` used in the query and `normalize` called below:
+        // the former fails to normalize the `nll/relate_tys/impl-fn-ignore-binder-via-bottom.rs` test.
+        // Check after #85499 lands to see if its fixes have erased this difference.
         let (param_env, value) = key.into_parts();
-        let _ = ocx.normalize(cause, param_env, value.value);
+        let _ = ocx.normalize(&cause, param_env, value.value);
 
         try_extract_error_from_fulfill_cx(&ocx, placeholder_region, error_region)
     }

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -761,8 +761,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                             hir_id,
                             ObligationCauseCode::ItemObligation(callee),
                         );
-                        let normalized_predicates =
-                            ocx.normalize(cause.clone(), param_env, predicates);
+                        let normalized_predicates = ocx.normalize(&cause, param_env, predicates);
                         ocx.register_obligations(traits::predicates_for_generics(
                             |_, _| cause.clone(),
                             self.param_env,

compiler/rustc_const_eval/src/util/compare_types.rs

@@ -46,8 +46,8 @@ pub fn is_subtype<'tcx>(
     let infcx = builder.build();
     let ocx = ObligationCtxt::new(&infcx);
     let cause = ObligationCause::dummy();
-    let src = ocx.normalize(cause.clone(), param_env, src);
-    let dest = ocx.normalize(cause.clone(), param_env, dest);
+    let src = ocx.normalize(&cause, param_env, src);
+    let dest = ocx.normalize(&cause, param_env, dest);
     match ocx.sub(&cause, param_env, src, dest) {
         Ok(()) => {}
         Err(_) => return false,

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -109,6 +109,9 @@ pub trait AstConv<'tcx> {
     ) -> Ty<'tcx>;
 
     /// Normalize an associated type coming from the user.
+    ///
+    /// This should only be used by astconv. Use `FnCtxt::normalize`
+    /// or `ObligationCtxt::normalize` in downstream crates.
     fn normalize_ty(&self, span: Span, ty: Ty<'tcx>) -> Ty<'tcx>;
 
     /// Invoked when we encounter an error from some prior pass

compiler/rustc_hir_analysis/src/check/compare_method.rs

@@ -221,7 +221,7 @@ fn compare_predicate_entailment<'tcx>(
     let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs);
     for (predicate, span) in iter::zip(impl_m_own_bounds.predicates, impl_m_own_bounds.spans) {
         let normalize_cause = traits::ObligationCause::misc(span, impl_m_hir_id);
-        let predicate = ocx.normalize(normalize_cause, param_env, predicate);
+        let predicate = ocx.normalize(&normalize_cause, param_env, predicate);
 
         let cause = ObligationCause::new(
             span,
@@ -260,7 +260,7 @@ fn compare_predicate_entailment<'tcx>(
     );
 
     let norm_cause = ObligationCause::misc(impl_m_span, impl_m_hir_id);
-    let impl_sig = ocx.normalize(norm_cause.clone(), param_env, impl_sig);
+    let impl_sig = ocx.normalize(&norm_cause, param_env, impl_sig);
     let impl_fty = tcx.mk_fn_ptr(ty::Binder::dummy(impl_sig));
     debug!("compare_impl_method: impl_fty={:?}", impl_fty);
 
@@ -271,7 +271,7 @@ fn compare_predicate_entailment<'tcx>(
     // we have to do this before normalization, since the normalized ty may
     // not contain the input parameters. See issue #87748.
     wf_tys.extend(trait_sig.inputs_and_output.iter());
-    let trait_sig = ocx.normalize(norm_cause, param_env, trait_sig);
+    let trait_sig = ocx.normalize(&norm_cause, param_env, trait_sig);
     // We also have to add the normalized trait signature
     // as we don't normalize during implied bounds computation.
     wf_tys.extend(trait_sig.inputs_and_output.iter());
@@ -366,7 +366,7 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
     // Normalize the impl signature with fresh variables for lifetime inference.
     let norm_cause = ObligationCause::misc(return_span, impl_m_hir_id);
     let impl_sig = ocx.normalize(
-        norm_cause.clone(),
+        &norm_cause,
         param_env,
         infcx.replace_bound_vars_with_fresh_vars(
             return_span,
@@ -387,7 +387,7 @@ pub fn collect_trait_impl_trait_tys<'tcx>(
             tcx.bound_fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs),
         )
         .fold_with(&mut collector);
-    let trait_sig = ocx.normalize(norm_cause.clone(), param_env, unnormalized_trait_sig);
+    let trait_sig = ocx.normalize(&norm_cause, param_env, unnormalized_trait_sig);
     let trait_return_ty = trait_sig.output();
 
     let wf_tys = FxIndexSet::from_iter(
@@ -592,7 +592,7 @@ impl<'tcx> TypeFolder<'tcx> for ImplTraitInTraitCollector<'_, 'tcx> {
             for (pred, pred_span) in self.tcx().bound_explicit_item_bounds(proj.item_def_id).subst_iter_copied(self.tcx(), proj.substs) {
                 let pred = pred.fold_with(self);
                 let pred = self.ocx.normalize(
-                    ObligationCause::misc(self.span, self.body_id),
+                    &ObligationCause::misc(self.span, self.body_id),
                     self.param_env,
                     pred,
                 );
@@ -1403,11 +1403,11 @@ pub(crate) fn raw_compare_const_impl<'tcx>(
     );
 
     // There is no "body" here, so just pass dummy id.
-    let impl_ty = ocx.normalize(cause.clone(), param_env, impl_ty);
+    let impl_ty = ocx.normalize(&cause, param_env, impl_ty);
 
     debug!("compare_const_impl: impl_ty={:?}", impl_ty);
 
-    let trait_ty = ocx.normalize(cause.clone(), param_env, trait_ty);
+    let trait_ty = ocx.normalize(&cause, param_env, trait_ty);
 
     debug!("compare_const_impl: trait_ty={:?}", trait_ty);
 
@@ -1556,7 +1556,7 @@ fn compare_type_predicate_entailment<'tcx>(
     for (span, predicate) in std::iter::zip(impl_ty_own_bounds.spans, impl_ty_own_bounds.predicates)
     {
         let cause = ObligationCause::misc(span, impl_ty_hir_id);
-        let predicate = ocx.normalize(cause, param_env, predicate);
+        let predicate = ocx.normalize(&cause, param_env, predicate);
 
         let cause = ObligationCause::new(
             span,
@@ -1778,7 +1778,7 @@ pub fn check_type_bounds<'tcx>(
 
     for mut obligation in util::elaborate_obligations(tcx, obligations) {
         let normalized_predicate =
-            ocx.normalize(normalize_cause.clone(), normalize_param_env, obligation.predicate);
+            ocx.normalize(&normalize_cause, normalize_param_env, obligation.predicate);
         debug!("compare_projection_bounds: normalized predicate = {:?}", normalized_predicate);
         obligation.predicate = normalized_predicate;
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -53,12 +53,14 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
         self.ocx.infcx.tcx
     }
 
+    // Convenience function to normalize during wfcheck. This performs
+    // `ObligationCtxt::normalize`, but provides a nice `ObligationCauseCode`.
     fn normalize<T>(&self, span: Span, loc: Option<WellFormedLoc>, value: T) -> T
     where
         T: TypeFoldable<'tcx>,
     {
         self.ocx.normalize(
-            ObligationCause::new(span, self.body_id, ObligationCauseCode::WellFormed(loc)),
+            &ObligationCause::new(span, self.body_id, ObligationCauseCode::WellFormed(loc)),
             self.param_env,
             value,
         )

compiler/rustc_hir_analysis/src/lib.rs

@@ -332,7 +332,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
             ObligationCauseCode::MainFunctionType,
         );
         let ocx = traits::ObligationCtxt::new(&infcx);
-        let norm_return_ty = ocx.normalize(cause.clone(), param_env, return_ty);
+        let norm_return_ty = ocx.normalize(&cause, param_env, return_ty);
         ocx.register_bound(cause, param_env, norm_return_ty, term_did);
         let errors = ocx.select_all_or_error();
         if !errors.is_empty() {

compiler/rustc_hir_typeck/src/callee.rs

@@ -448,7 +448,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // previously appeared within a `Binder<>` and hence would not
         // have been normalized before.
         let fn_sig = self.replace_bound_vars_with_fresh_vars(call_expr.span, infer::FnCall, fn_sig);
-        let fn_sig = self.normalize_associated_types_in(call_expr.span, fn_sig);
+        let fn_sig = self.normalize(call_expr.span, fn_sig);
 
         // Call the generic checker.
         let expected_arg_tys = self.expected_inputs_for_expected_output(

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_associated_types_in(
-                            self.expr_span,
-                            self.expr_ty.fn_sig(fcx.tcx),
-                        );
+                        let f = fcx.normalize(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>,
-    param_env: ty::ParamEnv<'tcx>,
+    fcx: &mut FnCtxt<'a, '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>>) {
-    let fn_id = inherited.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);
+) -> Option<GeneratorTypes<'tcx>> {
+    let fn_id = fcx.tcx.hir().local_def_id_to_hir_id(fn_def_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(