Rollup of 8 pull requests

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -18,6 +18,7 @@ use rustc_middle::bug;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::middle::resolve_bound_vars::*;
 use rustc_middle::ty::{self, ir::TypeVisitor, DefIdTree, TyCtxt, TypeSuperVisitable};
+use rustc_session::lint;
 use rustc_span::def_id::DefId;
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
@@ -923,17 +924,16 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                         origin,
                         ..
                     }) => {
-
                         let (bound_vars, binders): (FxIndexMap<LocalDefId, ResolvedArg>, Vec<_>) =
                             bound_generic_params
-                            .iter()
-                            .enumerate()
-                            .map(|(late_bound_idx, param)| {
-                                let pair = ResolvedArg::late(late_bound_idx as u32, param);
-                                let r = late_arg_as_bound_arg(this.tcx, &pair.1, param);
-                                (pair, r)
-                            })
-                            .unzip();
+                                .iter()
+                                .enumerate()
+                                .map(|(late_bound_idx, param)| {
+                                    let pair = ResolvedArg::late(late_bound_idx as u32, param);
+                                    let r = late_arg_as_bound_arg(this.tcx, &pair.1, param);
+                                    (pair, r)
+                                })
+                                .unzip();
                         this.record_late_bound_vars(hir_id, binders.clone());
                         // Even if there are no lifetimes defined here, we still wrap it in a binder
                         // scope. If there happens to be a nested poly trait ref (an error), that
@@ -968,20 +968,22 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                                     continue;
                                 }
                                 this.insert_lifetime(lt, ResolvedArg::StaticLifetime);
-                                this.tcx
-                                    .sess
-                                    .struct_span_warn(
-                                        lifetime.ident.span,
-                                        &format!(
-                                            "unnecessary lifetime parameter `{}`",
+                                this.tcx.struct_span_lint_hir(
+                                    lint::builtin::UNUSED_LIFETIMES,
+                                    lifetime.hir_id,
+                                    lifetime.ident.span,
+                                    format!(
+                                        "unnecessary lifetime parameter `{}`",
+                                        lifetime.ident
+                                    ),
+                                    |lint| {
+                                        let help = &format!(
+                                            "you can use the `'static` lifetime directly, in place of `{}`",
                                             lifetime.ident,
-                                        ),
-                                    )
-                                    .help(&format!(
-                                        "you can use the `'static` lifetime directly, in place of `{}`",
-                                        lifetime.ident,
-                                    ))
-                                    .emit();
+                                        );
+                                        lint.help(help)
+                                    },
+                                );
                             }
                         }
                     }

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -932,25 +932,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     labels
                         .push((provided_span, format!("unexpected argument{}", provided_ty_name)));
                     let mut span = provided_span;
-                    if arg_idx.index() > 0
+                    if span.can_be_used_for_suggestions() {
+                        if arg_idx.index() > 0
                         && let Some((_, prev)) = provided_arg_tys
                             .get(ProvidedIdx::from_usize(arg_idx.index() - 1)
                     ) {
                         // Include previous comma
-                        span = span.with_lo(prev.hi());
-                    } else if let Some((_, next)) = provided_arg_tys.get(
-                        ProvidedIdx::from_usize(arg_idx.index() + 1),
-                    ) {
-                        // Include next comma
-                        span = span.until(*next);
+                        span = prev.shrink_to_hi().to(span);
                     }
-                    suggestions.push((span, String::new()));
+                        suggestions.push((span, String::new()));
 
-                    suggestion_text = match suggestion_text {
-                        SuggestionText::None => SuggestionText::Remove(false),
-                        SuggestionText::Remove(_) => SuggestionText::Remove(true),
-                        _ => SuggestionText::DidYouMean,
-                    };
+                        suggestion_text = match suggestion_text {
+                            SuggestionText::None => SuggestionText::Remove(false),
+                            SuggestionText::Remove(_) => SuggestionText::Remove(true),
+                            _ => SuggestionText::DidYouMean,
+                        };
+                    }
                 }
                 Error::Missing(expected_idx) => {
                     // If there are multiple missing arguments adjacent to each other,

compiler/rustc_middle/src/values.rs

@@ -2,7 +2,7 @@ use crate::dep_graph::DepKind;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{pluralize, struct_span_err, Applicability, MultiSpan};
 use rustc_hir as hir;
-use rustc_hir::def::DefKind;
+use rustc_hir::def::{DefKind, Res};
 use rustc_middle::ty::Representability;
 use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt};
 use rustc_query_system::query::QueryInfo;
@@ -199,7 +199,8 @@ fn find_item_ty_spans(
 ) {
     match ty.kind {
         hir::TyKind::Path(hir::QPath::Resolved(_, path)) => {
-            if let Some(def_id) = path.res.opt_def_id() {
+            if let Res::Def(kind, def_id) = path.res
+                && kind != DefKind::TyAlias {
                 let check_params = def_id.as_local().map_or(true, |def_id| {
                     if def_id == needle {
                         spans.push(ty.span);

compiler/rustc_mir_transform/src/instcombine.rs

@@ -30,6 +30,7 @@ impl<'tcx> MirPass<'tcx> for InstCombine {
                         ctx.combine_bool_cmp(&statement.source_info, rvalue);
                         ctx.combine_ref_deref(&statement.source_info, rvalue);
                         ctx.combine_len(&statement.source_info, rvalue);
+                        ctx.combine_cast(&statement.source_info, rvalue);
                     }
                     _ => {}
                 }
@@ -142,6 +143,14 @@ impl<'tcx> InstCombineContext<'tcx, '_> {
         }
     }
 
+    fn combine_cast(&self, _source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
+        if let Rvalue::Cast(_kind, operand, ty) = rvalue {
+            if operand.ty(self.local_decls, self.tcx) == *ty {
+                *rvalue = Rvalue::Use(operand.clone());
+            }
+        }
+    }
+
     fn combine_primitive_clone(
         &self,
         terminator: &mut Terminator<'tcx>,

compiler/rustc_trait_selection/src/solve/assembly.rs

@@ -1,6 +1,5 @@
 //! Code shared by trait and projection goals for candidate assembly.
 
-use super::infcx_ext::InferCtxtExt;
 #[cfg(doc)]
 use super::trait_goals::structural_traits::*;
 use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, MaybeCause, QueryResult};
@@ -206,7 +205,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         &mut self,
         goal: Goal<'tcx, G>,
     ) -> Vec<Candidate<'tcx>> {
-        debug_assert_eq!(goal, self.infcx.resolve_vars_if_possible(goal));
+        debug_assert_eq!(goal, self.resolve_vars_if_possible(goal));
 
         // HACK: `_: Trait` is ambiguous, because it may be satisfied via a builtin rule,
         // object bound, alias bound, etc. We are unable to determine this until we can at
@@ -250,25 +249,25 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         let &ty::Alias(ty::Projection, projection_ty) = goal.predicate.self_ty().kind() else {
             return
         };
-        self.infcx.probe(|_| {
-            let normalized_ty = self.infcx.next_ty_infer();
+        self.probe(|this| {
+            let normalized_ty = this.next_ty_infer();
             let normalizes_to_goal = goal.with(
                 tcx,
                 ty::Binder::dummy(ty::ProjectionPredicate {
                     projection_ty,
                     term: normalized_ty.into(),
                 }),
             );
-            let normalization_certainty = match self.evaluate_goal(normalizes_to_goal) {
+            let normalization_certainty = match this.evaluate_goal(normalizes_to_goal) {
                 Ok((_, certainty)) => certainty,
                 Err(NoSolution) => return,
             };
-            let normalized_ty = self.infcx.resolve_vars_if_possible(normalized_ty);
+            let normalized_ty = this.resolve_vars_if_possible(normalized_ty);
 
             // NOTE: Alternatively we could call `evaluate_goal` here and only have a `Normalized` candidate.
             // This doesn't work as long as we use `CandidateSource` in winnowing.
             let goal = goal.with(tcx, goal.predicate.with_self_ty(tcx, normalized_ty));
-            let normalized_candidates = self.assemble_and_evaluate_candidates(goal);
+            let normalized_candidates = this.assemble_and_evaluate_candidates(goal);
             for mut normalized_candidate in normalized_candidates {
                 normalized_candidate.result =
                     normalized_candidate.result.unchecked_map(|mut response| {

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -0,0 +1,172 @@
+use rustc_hir::def_id::DefId;
+use rustc_infer::infer::at::ToTrace;
+use rustc_infer::infer::canonical::CanonicalVarValues;
+use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
+use rustc_infer::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
+use rustc_infer::traits::query::NoSolution;
+use rustc_infer::traits::ObligationCause;
+use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
+use rustc_middle::ty::{self, ir::TypeVisitor, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable};
+use rustc_span::DUMMY_SP;
+use std::ops::ControlFlow;
+
+use super::search_graph::SearchGraph;
+use super::Goal;
+
+pub struct EvalCtxt<'a, 'tcx> {
+    // FIXME: should be private.
+    pub(super) infcx: &'a InferCtxt<'tcx>,
+
+    pub(super) var_values: CanonicalVarValues<'tcx>,
+
+    pub(super) search_graph: &'a mut SearchGraph<'tcx>,
+
+    /// This field is used by a debug assertion in [`EvalCtxt::evaluate_goal`],
+    /// see the comment in that method for more details.
+    pub in_projection_eq_hack: bool,
+}
+
+impl<'tcx> EvalCtxt<'_, 'tcx> {
+    pub(super) fn probe<T>(&mut self, f: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> T) -> T {
+        self.infcx.probe(|_| f(self))
+    }
+
+    pub(super) fn tcx(&self) -> TyCtxt<'tcx> {
+        self.infcx.tcx
+    }
+
+    pub(super) fn next_ty_infer(&self) -> Ty<'tcx> {
+        self.infcx.next_ty_var(TypeVariableOrigin {
+            kind: TypeVariableOriginKind::MiscVariable,
+            span: DUMMY_SP,
+        })
+    }
+
+    pub(super) fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx> {
+        self.infcx.next_const_var(
+            ty,
+            ConstVariableOrigin { kind: ConstVariableOriginKind::MiscVariable, span: DUMMY_SP },
+        )
+    }
+
+    /// Is the projection predicate is of the form `exists<T> <Ty as Trait>::Assoc = T`.
+    ///
+    /// This is the case if the `term` is an inference variable in the innermost universe
+    /// and does not occur in any other part of the predicate.
+    pub(super) fn term_is_fully_unconstrained(
+        &self,
+        goal: Goal<'tcx, ty::ProjectionPredicate<'tcx>>,
+    ) -> bool {
+        let term_is_infer = match goal.predicate.term.unpack() {
+            ty::TermKind::Ty(ty) => {
+                if let &ty::Infer(ty::TyVar(vid)) = ty.kind() {
+                    match self.infcx.probe_ty_var(vid) {
+                        Ok(value) => bug!("resolved var in query: {goal:?} {value:?}"),
+                        Err(universe) => universe == self.universe(),
+                    }
+                } else {
+                    false
+                }
+            }
+            ty::TermKind::Const(ct) => {
+                if let ty::ConstKind::Infer(ty::InferConst::Var(vid)) = ct.kind() {
+                    match self.infcx.probe_const_var(vid) {
+                        Ok(value) => bug!("resolved var in query: {goal:?} {value:?}"),
+                        Err(universe) => universe == self.universe(),
+                    }
+                } else {
+                    false
+                }
+            }
+        };
+
+        // Guard against `<T as Trait<?0>>::Assoc = ?0>`.
+        struct ContainsTerm<'tcx> {
+            term: ty::Term<'tcx>,
+        }
+        impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsTerm<'tcx> {
+            type BreakTy = ();
+            fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+                if t.needs_infer() {
+                    if ty::Term::from(t) == self.term {
+                        ControlFlow::Break(())
+                    } else {
+                        t.super_visit_with(self)
+                    }
+                } else {
+                    ControlFlow::Continue(())
+                }
+            }
+
+            fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+                if c.needs_infer() {
+                    if ty::Term::from(c) == self.term {
+                        ControlFlow::Break(())
+                    } else {
+                        c.super_visit_with(self)
+                    }
+                } else {
+                    ControlFlow::Continue(())
+                }
+            }
+        }
+
+        let mut visitor = ContainsTerm { term: goal.predicate.term };
+
+        term_is_infer
+            && goal.predicate.projection_ty.visit_with(&mut visitor).is_continue()
+            && goal.param_env.visit_with(&mut visitor).is_continue()
+    }
+
+    #[instrument(level = "debug", skip(self, param_env), ret)]
+    pub(super) fn eq<T: ToTrace<'tcx>>(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
+        self.infcx
+            .at(&ObligationCause::dummy(), param_env)
+            .eq(lhs, rhs)
+            .map(|InferOk { value: (), obligations }| {
+                obligations.into_iter().map(|o| o.into()).collect()
+            })
+            .map_err(|e| {
+                debug!(?e, "failed to equate");
+                NoSolution
+            })
+    }
+
+    pub(super) fn instantiate_binder_with_infer<T: TypeFoldable<'tcx> + Copy>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+    ) -> T {
+        self.infcx.instantiate_binder_with_fresh_vars(
+            DUMMY_SP,
+            LateBoundRegionConversionTime::HigherRankedType,
+            value,
+        )
+    }
+
+    pub(super) fn instantiate_binder_with_placeholders<T: TypeFoldable<'tcx> + Copy>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+    ) -> T {
+        self.infcx.instantiate_binder_with_placeholders(value)
+    }
+
+    pub(super) fn resolve_vars_if_possible<T>(&self, value: T) -> T
+    where
+        T: TypeFoldable<'tcx>,
+    {
+        self.infcx.resolve_vars_if_possible(value)
+    }
+
+    pub(super) fn fresh_substs_for_item(&self, def_id: DefId) -> ty::SubstsRef<'tcx> {
+        self.infcx.fresh_substs_for_item(DUMMY_SP, def_id)
+    }
+
+    pub(super) fn universe(&self) -> ty::UniverseIndex {
+        self.infcx.universe()
+    }
+}