Auto merge of rust-lang#108237 - GuillaumeGomez:rollup-olxq5dt, r=GuillaumeGomez

Rollup of 5 pull requests

Successful merges:

 - rust-lang#107766 (Fix json reexports of different items with same name)
 - rust-lang#108129 (Correctly handle links starting with whitespace)
 - rust-lang#108188 (Change src/etc/vscode_settings.json to always treat ./library as the sysroot source)
 - rust-lang#108203 (Fix RPITITs in default trait methods (by assuming projection predicates in param-env))
 - rust-lang#108212 (Download rustfmt regardless of rustc being set in config.toml)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -1599,7 +1599,7 @@ fn check_return_position_impl_trait_in_trait_bounds<'tcx>(
     {
         for arg in fn_output.walk() {
             if let ty::GenericArgKind::Type(ty) = arg.unpack()
-                && let ty::Alias(ty::Projection, proj) = ty.kind()
+                && let ty::Alias(ty::Opaque, proj) = ty.kind()
                 && tcx.def_kind(proj.def_id) == DefKind::ImplTraitPlaceholder
                 && tcx.impl_trait_in_trait_parent(proj.def_id) == fn_def_id.to_def_id()
             {

compiler/rustc_middle/src/ty/util.rs

@@ -4,7 +4,7 @@ use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use crate::mir;
 use crate::ty::layout::IntegerExt;
 use crate::ty::{
-    self, ir::TypeFolder, DefIdTree, FallibleTypeFolder, Ty, TyCtxt, TypeFoldable,
+    self, ir::TypeFolder, DefIdTree, FallibleTypeFolder, ToPredicate, Ty, TyCtxt, TypeFoldable,
     TypeSuperFoldable,
 };
 use crate::ty::{GenericArgKind, SubstsRef};
@@ -865,6 +865,26 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for OpaqueTypeExpander<'tcx> {
         }
         t
     }
+
+    fn fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> ty::Predicate<'tcx> {
+        if let ty::PredicateKind::Clause(clause) = p.kind().skip_binder()
+            && let ty::Clause::Projection(projection_pred) = clause
+        {
+            p.kind()
+                .rebind(ty::ProjectionPredicate {
+                    projection_ty: projection_pred.projection_ty.fold_with(self),
+                    // Don't fold the term on the RHS of the projection predicate.
+                    // This is because for default trait methods with RPITITs, we
+                    // install a `NormalizesTo(Projection(RPITIT) -> Opaque(RPITIT))`
+                    // predicate, which would trivially cause a cycle when we do
+                    // anything that requires `ParamEnv::with_reveal_all_normalized`.
+                    term: projection_pred.term,
+                })
+                .to_predicate(self.tcx)
+        } else {
+            p.super_fold_with(self)
+        }
+    }
 }
 
 impl<'tcx> Ty<'tcx> {

compiler/rustc_resolve/src/rustdoc.rs

@@ -339,6 +339,7 @@ pub fn inner_docs(attrs: &[ast::Attribute]) -> bool {
 fn preprocess_link(link: &str) -> String {
     let link = link.replace('`', "");
     let link = link.split('#').next().unwrap();
+    let link = link.trim();
     let link = link.rsplit('@').next().unwrap();
     let link = link.strip_suffix("()").unwrap_or(link);
     let link = link.strip_suffix("{}").unwrap_or(link);

compiler/rustc_trait_selection/src/traits/project.rs

@@ -90,15 +90,7 @@ enum ProjectionCandidate<'tcx> {
     /// From an "impl" (or a "pseudo-impl" returned by select)
     Select(Selection<'tcx>),
 
-    ImplTraitInTrait(ImplTraitInTraitCandidate<'tcx>),
-}
-
-#[derive(PartialEq, Eq, Debug)]
-enum ImplTraitInTraitCandidate<'tcx> {
-    // The `impl Trait` from a trait function's default body
-    Trait,
-    // A concrete type provided from a trait's `impl Trait` from an impl
-    Impl(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>),
+    ImplTraitInTrait(ImplSourceUserDefinedData<'tcx, PredicateObligation<'tcx>>),
 }
 
 enum ProjectionCandidateSet<'tcx> {
@@ -1292,17 +1284,6 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
     let tcx = selcx.tcx();
     if tcx.def_kind(obligation.predicate.def_id) == DefKind::ImplTraitPlaceholder {
         let trait_fn_def_id = tcx.impl_trait_in_trait_parent(obligation.predicate.def_id);
-        // If we are trying to project an RPITIT with trait's default `Self` parameter,
-        // then we must be within a default trait body.
-        if obligation.predicate.self_ty()
-            == ty::InternalSubsts::identity_for_item(tcx, obligation.predicate.def_id).type_at(0)
-            && tcx.associated_item(trait_fn_def_id).defaultness(tcx).has_value()
-        {
-            candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(
-                ImplTraitInTraitCandidate::Trait,
-            ));
-            return;
-        }
 
         let trait_def_id = tcx.parent(trait_fn_def_id);
         let trait_substs =
@@ -1313,9 +1294,7 @@ fn assemble_candidate_for_impl_trait_in_trait<'cx, 'tcx>(
         let _ = selcx.infcx.commit_if_ok(|_| {
             match selcx.select(&obligation.with(tcx, trait_predicate)) {
                 Ok(Some(super::ImplSource::UserDefined(data))) => {
-                    candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(
-                        ImplTraitInTraitCandidate::Impl(data),
-                    ));
+                    candidate_set.push_candidate(ProjectionCandidate::ImplTraitInTrait(data));
                     Ok(())
                 }
                 Ok(None) => {
@@ -1777,18 +1756,9 @@ fn confirm_candidate<'cx, 'tcx>(
         ProjectionCandidate::Select(impl_source) => {
             confirm_select_candidate(selcx, obligation, impl_source)
         }
-        ProjectionCandidate::ImplTraitInTrait(ImplTraitInTraitCandidate::Impl(data)) => {
+        ProjectionCandidate::ImplTraitInTrait(data) => {
             confirm_impl_trait_in_trait_candidate(selcx, obligation, data)
         }
-        // If we're projecting an RPITIT for a default trait body, that's just
-        // the same def-id, but as an opaque type (with regular RPIT semantics).
-        ProjectionCandidate::ImplTraitInTrait(ImplTraitInTraitCandidate::Trait) => Progress {
-            term: selcx
-                .tcx()
-                .mk_opaque(obligation.predicate.def_id, obligation.predicate.substs)
-                .into(),
-            obligations: vec![],
-        },
     };
 
     // When checking for cycle during evaluation, we compare predicates with

compiler/rustc_ty_utils/src/ty.rs

@@ -1,8 +1,12 @@
-use rustc_data_structures::fx::FxIndexSet;
+use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_index::bit_set::BitSet;
+#[cfg(not(bootstrap))]
+use rustc_middle::ty::ir::TypeVisitable;
 use rustc_middle::ty::{
-    self, Binder, EarlyBinder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt,
+    self, ir::TypeVisitor, Binder, EarlyBinder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt,
+    TypeSuperVisitable,
 };
 use rustc_session::config::TraitSolver;
 use rustc_span::def_id::{DefId, CRATE_DEF_ID};
@@ -136,6 +140,19 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
         predicates.extend(environment);
     }
 
+    if tcx.def_kind(def_id) == DefKind::AssocFn
+        && tcx.associated_item(def_id).container == ty::AssocItemContainer::TraitContainer
+    {
+        let sig = tcx.fn_sig(def_id).subst_identity();
+        sig.visit_with(&mut ImplTraitInTraitFinder {
+            tcx,
+            fn_def_id: def_id,
+            bound_vars: sig.bound_vars(),
+            predicates: &mut predicates,
+            seen: FxHashSet::default(),
+        });
+    }
+
     let local_did = def_id.as_local();
     let hir_id = local_did.map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id));
 
@@ -222,6 +239,46 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
     traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
 }
 
+/// Walk through a function type, gathering all RPITITs and installing a
+/// `NormalizesTo(Projection(RPITIT) -> Opaque(RPITIT))` predicate into the
+/// predicates list. This allows us to observe that an RPITIT projects to
+/// its corresponding opaque within the body of a default-body trait method.
+struct ImplTraitInTraitFinder<'a, 'tcx> {
+    tcx: TyCtxt<'tcx>,
+    predicates: &'a mut Vec<Predicate<'tcx>>,
+    fn_def_id: DefId,
+    bound_vars: &'tcx ty::List<ty::BoundVariableKind>,
+    seen: FxHashSet<DefId>,
+}
+
+impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> {
+    fn visit_ty(&mut self, ty: Ty<'tcx>) -> std::ops::ControlFlow<Self::BreakTy> {
+        if let ty::Alias(ty::Projection, alias_ty) = *ty.kind()
+            && self.tcx.def_kind(alias_ty.def_id) == DefKind::ImplTraitPlaceholder
+            && self.tcx.impl_trait_in_trait_parent(alias_ty.def_id) == self.fn_def_id
+            && self.seen.insert(alias_ty.def_id)
+        {
+            self.predicates.push(
+                ty::Binder::bind_with_vars(
+                    ty::ProjectionPredicate {
+                        projection_ty: alias_ty,
+                        term: self.tcx.mk_alias(ty::Opaque, alias_ty).into(),
+                    },
+                    self.bound_vars,
+                )
+                .to_predicate(self.tcx),
+            );
+
+            for bound in self.tcx.item_bounds(alias_ty.def_id).subst_iter(self.tcx, alias_ty.substs)
+            {
+                bound.visit_with(self);
+            }
+        }
+
+        ty.super_visit_with(self)
+    }
+}
+
 /// Elaborate the environment.
 ///
 /// Collect a list of `Predicate`'s used for building the `ParamEnv`. Adds `TypeWellFormedFromEnv`'s

src/bootstrap/config.rs

@@ -1315,15 +1315,6 @@ impl Config {
             } else {
                 RustfmtState::Unavailable
             };
-        } else {
-            // If using a system toolchain for bootstrapping, see if that has rustfmt available.
-            let host = config.build;
-            let rustfmt_path = config.initial_rustc.with_file_name(exe("rustfmt", host));
-            let bin_root = config.out.join(host.triple).join("stage0");
-            if !rustfmt_path.starts_with(&bin_root) {
-                // Using a system-provided toolchain; we shouldn't download rustfmt.
-                *config.initial_rustfmt.borrow_mut() = RustfmtState::SystemToolchain(rustfmt_path);
-            }
         }
 
         // Now that we've reached the end of our configuration, infer the

src/bootstrap/setup.rs

@@ -29,6 +29,7 @@ pub enum Profile {
 static SETTINGS_HASHES: &[&str] = &[
     "ea67e259dedf60d4429b6c349a564ffcd1563cf41c920a856d1f5b16b4701ac8",
     "56e7bf011c71c5d81e0bf42e84938111847a810eee69d906bba494ea90b51922",
+    "af1b5efe196aed007577899db9dae15d6dbc923d6fa42fa0934e68617ba9bbe0",
 ];
 static VSCODE_SETTINGS: &str = include_str!("../etc/vscode_settings.json");
 

src/etc/vscode_settings.json

@@ -1,7 +1,7 @@
 {
     "rust-analyzer.check.invocationLocation": "root",
     "rust-analyzer.check.invocationStrategy": "once",
-    "rust-analyzer.checkOnSave.overrideCommand": [
+    "rust-analyzer.check.overrideCommand": [
         "python3",
         "x.py",
         "check",
@@ -23,6 +23,6 @@
         "check",
         "--json-output"
     ],
-    "rust-analyzer.cargo.sysroot": "./build/host/stage0-sysroot",
+    "rust-analyzer.cargo.sysrootSrc": "./library",
     "rust-analyzer.rustc.source": "./Cargo.toml"
 }