Rollup of 7 pull requests

compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -1741,7 +1741,11 @@ impl<'tcx, Cx: TypeInformationCtxt<'tcx>, D: Delegate<'tcx>> ExprUseVisitor<'tcx
             }
 
             PatKind::Slice(before, ref slice, after) => {
-                let Some(element_ty) = place_with_id.place.ty().builtin_index() else {
+                let Some(element_ty) = self
+                    .cx
+                    .try_structurally_resolve_type(pat.span, place_with_id.place.ty())
+                    .builtin_index()
+                else {
                     debug!("explicit index of non-indexable type {:?}", place_with_id);
                     return Err(self
                         .cx

compiler/rustc_interface/src/tests.rs

@@ -799,10 +799,7 @@ fn test_unstable_options_tracking_hash() {
     tracked!(mir_opt_level, Some(4));
     tracked!(move_size_limit, Some(4096));
     tracked!(mutable_noalias, false);
-    tracked!(
-        next_solver,
-        Some(NextSolverConfig { coherence: true, globally: false, dump_tree: Default::default() })
-    );
+    tracked!(next_solver, Some(NextSolverConfig { coherence: true, globally: false }));
     tracked!(no_generate_arange_section, true);
     tracked!(no_jump_tables, true);
     tracked!(no_link, true);

compiler/rustc_lint/messages.ftl

@@ -233,6 +233,7 @@ lint_drop_trait_constraints =
 lint_dropping_copy_types = calls to `std::mem::drop` with a value that implements `Copy` does nothing
     .label = argument has type `{$arg_ty}`
     .note = use `let _ = ...` to ignore the expression or result
+    .suggestion = use `let _ = ...` to ignore the expression or result
 
 lint_dropping_references = calls to `std::mem::drop` with a reference instead of an owned value does nothing
     .label = argument has type `{$arg_ty}`

compiler/rustc_lint/src/drop_forget_useless.rs

@@ -1,12 +1,12 @@
-use rustc_hir::{Arm, Expr, ExprKind, Node};
+use rustc_hir::{Arm, Expr, ExprKind, Node, StmtKind};
 use rustc_middle::ty;
 use rustc_session::{declare_lint, declare_lint_pass};
 use rustc_span::sym;
 
 use crate::{
     lints::{
-        DropCopyDiag, DropRefDiag, ForgetCopyDiag, ForgetRefDiag, UndroppedManuallyDropsDiag,
-        UndroppedManuallyDropsSuggestion,
+        DropCopyDiag, DropCopySuggestion, DropRefDiag, ForgetCopyDiag, ForgetRefDiag,
+        UndroppedManuallyDropsDiag, UndroppedManuallyDropsSuggestion,
     },
     LateContext, LateLintPass, LintContext,
 };
@@ -164,10 +164,23 @@ impl<'tcx> LateLintPass<'tcx> for DropForgetUseless {
                     );
                 }
                 sym::mem_drop if is_copy && !drop_is_single_call_in_arm => {
+                    let sugg = if let Some((_, node)) = cx.tcx.hir().parent_iter(expr.hir_id).nth(0)
+                        && let Node::Stmt(stmt) = node
+                        && let StmtKind::Semi(e) = stmt.kind
+                        && e.hir_id == expr.hir_id
+                    {
+                        DropCopySuggestion::Suggestion {
+                            start_span: expr.span.shrink_to_lo().until(arg.span),
+                            end_span: arg.span.shrink_to_hi().until(expr.span.shrink_to_hi()),
+                        }
+                    } else {
+                        DropCopySuggestion::Note
+                    };
+
                     cx.emit_span_lint(
                         DROPPING_COPY_TYPES,
                         expr.span,
-                        DropCopyDiag { arg_ty, label: arg.span },
+                        DropCopyDiag { arg_ty, label: arg.span, sugg },
                     );
                 }
                 sym::mem_forget if is_copy => {

compiler/rustc_lint/src/lints.rs

@@ -677,11 +677,25 @@ pub struct DropRefDiag<'a> {
 
 #[derive(LintDiagnostic)]
 #[diag(lint_dropping_copy_types)]
-#[note]
 pub struct DropCopyDiag<'a> {
     pub arg_ty: Ty<'a>,
     #[label]
     pub label: Span,
+    #[subdiagnostic]
+    pub sugg: DropCopySuggestion,
+}
+
+#[derive(Subdiagnostic)]
+pub enum DropCopySuggestion {
+    #[note(lint_note)]
+    Note,
+    #[multipart_suggestion(lint_suggestion, style = "verbose", applicability = "maybe-incorrect")]
+    Suggestion {
+        #[suggestion_part(code = "let _ = ")]
+        start_span: Span,
+        #[suggestion_part(code = "")]
+        end_span: Span,
+    },
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_middle/src/arena.rs

@@ -61,7 +61,10 @@ macro_rules! arena_types {
             [] dtorck_constraint: rustc_middle::traits::query::DropckConstraint<'tcx>,
             [] candidate_step: rustc_middle::traits::query::CandidateStep<'tcx>,
             [] autoderef_bad_ty: rustc_middle::traits::query::MethodAutoderefBadTy<'tcx>,
-            [] canonical_goal_evaluation: rustc_next_trait_solver::solve::inspect::GoalEvaluationStep<rustc_middle::ty::TyCtxt<'tcx>>,
+            [] canonical_goal_evaluation:
+                rustc_next_trait_solver::solve::inspect::CanonicalGoalEvaluationStep<
+                    rustc_middle::ty::TyCtxt<'tcx>
+                >,
             [] query_region_constraints: rustc_middle::infer::canonical::QueryRegionConstraints<'tcx>,
             [] type_op_subtype:
                 rustc_middle::infer::canonical::Canonical<'tcx,

compiler/rustc_middle/src/traits/solve/cache.rs

@@ -17,7 +17,7 @@ pub struct EvaluationCache<'tcx> {
 #[derive(Debug, PartialEq, Eq)]
 pub struct CacheData<'tcx> {
     pub result: QueryResult<'tcx>,
-    pub proof_tree: Option<&'tcx [inspect::GoalEvaluationStep<TyCtxt<'tcx>>]>,
+    pub proof_tree: Option<&'tcx inspect::CanonicalGoalEvaluationStep<TyCtxt<'tcx>>>,
     pub additional_depth: usize,
     pub encountered_overflow: bool,
 }
@@ -28,7 +28,7 @@ impl<'tcx> EvaluationCache<'tcx> {
         &self,
         tcx: TyCtxt<'tcx>,
         key: CanonicalInput<'tcx>,
-        proof_tree: Option<&'tcx [inspect::GoalEvaluationStep<TyCtxt<'tcx>>]>,
+        proof_tree: Option<&'tcx inspect::CanonicalGoalEvaluationStep<TyCtxt<'tcx>>>,
         additional_depth: usize,
         encountered_overflow: bool,
         cycle_participants: FxHashSet<CanonicalInput<'tcx>>,
@@ -107,7 +107,7 @@ struct Success<'tcx> {
 #[derive(Clone, Copy)]
 pub struct QueryData<'tcx> {
     pub result: QueryResult<'tcx>,
-    pub proof_tree: Option<&'tcx [inspect::GoalEvaluationStep<TyCtxt<'tcx>>]>,
+    pub proof_tree: Option<&'tcx inspect::CanonicalGoalEvaluationStep<TyCtxt<'tcx>>>,
 }
 
 /// The cache entry for a goal `CanonicalInput`.

compiler/rustc_middle/src/ty/context.rs

@@ -103,7 +103,8 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
     type PredefinedOpaques = solve::PredefinedOpaques<'tcx>;
     type DefiningOpaqueTypes = &'tcx ty::List<LocalDefId>;
     type ExternalConstraints = ExternalConstraints<'tcx>;
-    type GoalEvaluationSteps = &'tcx [solve::inspect::GoalEvaluationStep<TyCtxt<'tcx>>];
+    type CanonicalGoalEvaluationStepRef =
+        &'tcx solve::inspect::CanonicalGoalEvaluationStep<TyCtxt<'tcx>>;
 
     type Ty = Ty<'tcx>;
     type Tys = &'tcx List<Ty<'tcx>>;

compiler/rustc_mir_build/src/build/expr/as_place.rs

@@ -4,7 +4,6 @@ use crate::build::expr::category::Category;
 use crate::build::ForGuard::{OutsideGuard, RefWithinGuard};
 use crate::build::{BlockAnd, BlockAndExtension, Builder, Capture, CaptureMap};
 use rustc_hir::def_id::LocalDefId;
-use rustc_middle::bug;
 use rustc_middle::hir::place::Projection as HirProjection;
 use rustc_middle::hir::place::ProjectionKind as HirProjectionKind;
 use rustc_middle::middle::region;
@@ -13,6 +12,7 @@ use rustc_middle::mir::*;
 use rustc_middle::thir::*;
 use rustc_middle::ty::AdtDef;
 use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty, Variance};
+use rustc_middle::{bug, span_bug};
 use rustc_span::Span;
 use rustc_target::abi::{FieldIdx, VariantIdx, FIRST_VARIANT};
 use tracing::{debug, instrument, trace};
@@ -252,7 +252,18 @@ fn strip_prefix<'a, 'tcx>(
 
 impl<'tcx> PlaceBuilder<'tcx> {
     pub(in crate::build) fn to_place(&self, cx: &Builder<'_, 'tcx>) -> Place<'tcx> {
-        self.try_to_place(cx).unwrap()
+        self.try_to_place(cx).unwrap_or_else(|| match self.base {
+            PlaceBase::Local(local) => span_bug!(
+                cx.local_decls[local].source_info.span,
+                "could not resolve local: {local:#?} + {:?}",
+                self.projection
+            ),
+            PlaceBase::Upvar { var_hir_id, closure_def_id: _ } => span_bug!(
+                cx.tcx.hir().span(var_hir_id.0),
+                "could not resolve upvar: {var_hir_id:?} + {:?}",
+                self.projection
+            ),
+        })
     }
 
     /// Creates a `Place` or returns `None` if an upvar cannot be resolved

compiler/rustc_monomorphize/src/collector.rs

@@ -1434,6 +1434,15 @@ impl<'v> RootCollector<'_, 'v> {
                 {
                     debug!("RootCollector: ADT drop-glue for `{id:?}`",);
 
+                    // This type is impossible to instantiate, so we should not try to
+                    // generate a `drop_in_place` instance for it.
+                    if self.tcx.instantiate_and_check_impossible_predicates((
+                        id.owner_id.to_def_id(),
+                        ty::List::empty(),
+                    )) {
+                        return;
+                    }
+
                     let ty = self.tcx.type_of(id.owner_id.to_def_id()).no_bound_vars().unwrap();
                     visit_drop_use(self.tcx, ty, true, DUMMY_SP, self.output);
                 }

compiler/rustc_session/src/config.rs

@@ -796,16 +796,6 @@ pub struct NextSolverConfig {
     /// Whether the new trait solver should be enabled everywhere.
     /// This is only `true` if `coherence` is also enabled.
     pub globally: bool,
-    /// Whether to dump proof trees after computing a proof tree.
-    pub dump_tree: DumpSolverProofTree,
-}
-
-#[derive(Default, Debug, Copy, Clone, Hash, PartialEq, Eq)]
-pub enum DumpSolverProofTree {
-    Always,
-    OnError,
-    #[default]
-    Never,
 }
 
 #[derive(Clone)]

compiler/rustc_session/src/options.rs

@@ -399,7 +399,8 @@ mod desc {
     pub const parse_instrument_xray: &str = "either a boolean (`yes`, `no`, `on`, `off`, etc), or a comma separated list of settings: `always` or `never` (mutually exclusive), `ignore-loops`, `instruction-threshold=N`, `skip-entry`, `skip-exit`";
     pub const parse_unpretty: &str = "`string` or `string=string`";
     pub const parse_treat_err_as_bug: &str = "either no value or a non-negative number";
-    pub const parse_next_solver_config: &str = "a comma separated list of solver configurations: `globally` (default), `coherence`, `dump-tree`, `dump-tree-on-error";
+    pub const parse_next_solver_config: &str =
+        "a comma separated list of solver configurations: `globally` (default), and `coherence`";
     pub const parse_lto: &str =
         "either a boolean (`yes`, `no`, `on`, `off`, etc), `thin`, `fat`, or omitted";
     pub const parse_linker_plugin_lto: &str =
@@ -1058,39 +1059,20 @@ mod parse {
         if let Some(config) = v {
             let mut coherence = false;
             let mut globally = true;
-            let mut dump_tree = None;
             for c in config.split(',') {
                 match c {
                     "globally" => globally = true,
                     "coherence" => {
                         globally = false;
                         coherence = true;
                     }
-                    "dump-tree" => {
-                        if dump_tree.replace(DumpSolverProofTree::Always).is_some() {
-                            return false;
-                        }
-                    }
-                    "dump-tree-on-error" => {
-                        if dump_tree.replace(DumpSolverProofTree::OnError).is_some() {
-                            return false;
-                        }
-                    }
                     _ => return false,
                 }
             }
 
-            *slot = Some(NextSolverConfig {
-                coherence: coherence || globally,
-                globally,
-                dump_tree: dump_tree.unwrap_or_default(),
-            });
+            *slot = Some(NextSolverConfig { coherence: coherence || globally, globally });
         } else {
-            *slot = Some(NextSolverConfig {
-                coherence: true,
-                globally: true,
-                dump_tree: Default::default(),
-            });
+            *slot = Some(NextSolverConfig { coherence: true, globally: true });
         }
 
         true

compiler/rustc_target/src/target_features.rs

@@ -199,11 +199,9 @@ const X86_ALLOWED_FEATURES: &[(&str, Stability)] = &[
     ("avx512bw", Unstable(sym::avx512_target_feature)),
     ("avx512cd", Unstable(sym::avx512_target_feature)),
     ("avx512dq", Unstable(sym::avx512_target_feature)),
-    ("avx512er", Unstable(sym::avx512_target_feature)),
     ("avx512f", Unstable(sym::avx512_target_feature)),
     ("avx512fp16", Unstable(sym::avx512_target_feature)),
     ("avx512ifma", Unstable(sym::avx512_target_feature)),
-    ("avx512pf", Unstable(sym::avx512_target_feature)),
     ("avx512vbmi", Unstable(sym::avx512_target_feature)),
     ("avx512vbmi2", Unstable(sym::avx512_target_feature)),
     ("avx512vl", Unstable(sym::avx512_target_feature)),

compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs

@@ -1,6 +1,3 @@
-use std::io::Write;
-use std::ops::ControlFlow;
-
 use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_hir::def_id::DefId;
 use rustc_infer::infer::at::ToTrace;
@@ -20,10 +17,10 @@ use rustc_middle::ty::{
     self, InferCtxtLike, OpaqueTypeKey, Ty, TyCtxt, TypeFoldable, TypeSuperVisitable,
     TypeVisitable, TypeVisitableExt, TypeVisitor,
 };
-use rustc_session::config::DumpSolverProofTree;
 use rustc_span::DUMMY_SP;
 use rustc_type_ir::{self as ir, CanonicalVarValues, Interner};
 use rustc_type_ir_macros::{Lift_Generic, TypeFoldable_Generic, TypeVisitable_Generic};
+use std::ops::ControlFlow;
 
 use crate::traits::coherence;
 use crate::traits::vtable::{count_own_vtable_entries, prepare_vtable_segments, VtblSegment};
@@ -135,8 +132,7 @@ impl<I: Interner> NestedGoals<I> {
 #[derive(PartialEq, Eq, Debug, Hash, HashStable, Clone, Copy)]
 pub enum GenerateProofTree {
     Yes,
-    IfEnabled,
-    Never,
+    No,
 }
 
 #[extension(pub trait InferCtxtEvalExt<'tcx>)]
@@ -182,7 +178,7 @@ impl<'a, 'tcx> EvalCtxt<'a, InferCtxt<'tcx>> {
             infcx,
             search_graph: &mut search_graph,
             nested_goals: NestedGoals::new(),
-            inspect: ProofTreeBuilder::new_maybe_root(infcx.tcx, generate_proof_tree),
+            inspect: ProofTreeBuilder::new_maybe_root(generate_proof_tree),
 
             // Only relevant when canonicalizing the response,
             // which we don't do within this evaluation context.
@@ -197,23 +193,14 @@ impl<'a, 'tcx> EvalCtxt<'a, InferCtxt<'tcx>> {
         };
         let result = f(&mut ecx);
 
-        let tree = ecx.inspect.finalize();
-        if let (Some(tree), DumpSolverProofTree::Always) = (
-            &tree,
-            infcx.tcx.sess.opts.unstable_opts.next_solver.map(|c| c.dump_tree).unwrap_or_default(),
-        ) {
-            let mut lock = std::io::stdout().lock();
-            let _ = lock.write_fmt(format_args!("{tree:?}\n"));
-            let _ = lock.flush();
-        }
-
+        let proof_tree = ecx.inspect.finalize();
         assert!(
             ecx.nested_goals.is_empty(),
             "root `EvalCtxt` should not have any goals added to it"
         );
 
         assert!(search_graph.is_empty());
-        (result, tree)
+        (result, proof_tree)
     }
 
     /// Creates a nested evaluation context that shares the same search graph as the
@@ -483,7 +470,6 @@ impl<'a, 'tcx> EvalCtxt<'a, InferCtxt<'tcx>> {
     // the certainty of all the goals.
     #[instrument(level = "trace", skip(self))]
     pub(super) fn try_evaluate_added_goals(&mut self) -> Result<Certainty, NoSolution> {
-        self.inspect.start_evaluate_added_goals();
         let mut response = Ok(Certainty::overflow(false));
         for _ in 0..FIXPOINT_STEP_LIMIT {
             // FIXME: This match is a bit ugly, it might be nice to change the inspect
@@ -501,8 +487,6 @@ impl<'a, 'tcx> EvalCtxt<'a, InferCtxt<'tcx>> {
             }
         }
 
-        self.inspect.evaluate_added_goals_result(response);
-
         if response.is_err() {
             self.tainted = Err(NoSolution);
         }
@@ -515,7 +499,6 @@ impl<'a, 'tcx> EvalCtxt<'a, InferCtxt<'tcx>> {
     /// Goals for the next step get directly added to the nested goals of the `EvalCtxt`.
     fn evaluate_added_goals_step(&mut self) -> Result<Option<Certainty>, NoSolution> {
         let tcx = self.tcx();
-        self.inspect.start_evaluate_added_goals_step();
         let mut goals = core::mem::take(&mut self.nested_goals);
 
         // If this loop did not result in any progress, what's our final certainty.

compiler/rustc_trait_selection/src/solve/fulfill.rs

@@ -79,7 +79,7 @@ impl<'tcx> ObligationStorage<'tcx> {
             // change.
             self.overflowed.extend(self.pending.extract_if(|o| {
                 let goal = o.clone().into();
-                let result = infcx.evaluate_root_goal(goal, GenerateProofTree::Never).0;
+                let result = infcx.evaluate_root_goal(goal, GenerateProofTree::No).0;
                 match result {
                     Ok((has_changed, _)) => has_changed,
                     _ => false,
@@ -159,7 +159,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
             let mut has_changed = false;
             for obligation in self.obligations.unstalled_for_select() {
                 let goal = obligation.clone().into();
-                let result = infcx.evaluate_root_goal(goal, GenerateProofTree::IfEnabled).0;
+                let result = infcx.evaluate_root_goal(goal, GenerateProofTree::No).0;
                 self.inspect_evaluated_obligation(infcx, &obligation, &result);
                 let (changed, certainty) = match result {
                     Ok(result) => result,
@@ -246,7 +246,7 @@ fn fulfillment_error_for_stalled<'tcx>(
     root_obligation: PredicateObligation<'tcx>,
 ) -> FulfillmentError<'tcx> {
     let (code, refine_obligation) = infcx.probe(|_| {
-        match infcx.evaluate_root_goal(root_obligation.clone().into(), GenerateProofTree::Never).0 {
+        match infcx.evaluate_root_goal(root_obligation.clone().into(), GenerateProofTree::No).0 {
             Ok((_, Certainty::Maybe(MaybeCause::Ambiguity))) => {
                 (FulfillmentErrorCode::Ambiguity { overflow: None }, true)
             }