Auto merge of #131495 - matthiaskrgr:rollup-lwf2u4i, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #130625 (Fix a few relative paths in rustc doc)
 - #131397 (fix/update teach_note from 'escaping mutable ref/ptr' const-check)
 - #131479 (Apple: Avoid redundant `-Wl,-dylib` flag when linking)
 - #131480 (Fix hardcoded strip path when cross-compiling from Linux to Darwin)
 - #131482 (structurally resolve adts and tuples expectations too)
 - #131484 (Add myself back to review rotation)
 - #131491 (impossible obligations fast path)

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

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1087,7 +1087,9 @@ fn link_natively(
     let strip = sess.opts.cg.strip;
 
     if sess.target.is_like_osx {
-        let stripcmd = "/usr/bin/strip";
+        // Use system `strip` when running on host macOS.
+        // <https://github.com/rust-lang/rust/pull/130781>
+        let stripcmd = if cfg!(target_os = "macos") { "/usr/bin/strip" } else { "strip" };
         match (strip, crate_type) {
             (Strip::Debuginfo, _) => {
                 strip_symbols_with_external_utility(sess, stripcmd, out_filename, Some("-S"))

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -404,12 +404,14 @@ impl<'a> GccLinker<'a> {
     fn build_dylib(&mut self, crate_type: CrateType, out_filename: &Path) {
         // On mac we need to tell the linker to let this library be rpathed
         if self.sess.target.is_like_osx {
-            if !self.is_ld {
+            if self.is_cc() {
+                // `-dynamiclib` makes `cc` pass `-dylib` to the linker.
                 self.cc_arg("-dynamiclib");
+            } else {
+                self.link_arg("-dylib");
+                // Clang also sets `-dynamic`, but that's implied by `-dylib`, so unnecessary.
             }
 
-            self.link_arg("-dylib");
-
             // Note that the `osx_rpath_install_name` option here is a hack
             // purely to support bootstrap right now, we should get a more
             // principled solution at some point to force the compiler to pass

compiler/rustc_const_eval/messages.ftl

@@ -134,14 +134,16 @@ const_eval_incompatible_return_types =
 const_eval_incompatible_types =
     calling a function with argument of type {$callee_ty} passing data of type {$caller_ty}
 
-const_eval_interior_mutable_data_refer =
+const_eval_interior_mutable_ref_escaping =
     {const_eval_const_context}s cannot refer to interior mutable data
     .label = this borrow of an interior mutable value may end up in the final value
     .help = to fix this, the value can be extracted to a separate `static` item and then referenced
     .teach_note =
-        A constant containing interior mutable data behind a reference can allow you to modify that data.
-        This would make multiple uses of a constant to be able to see different values and allow circumventing
-        the `Send` and `Sync` requirements for shared mutable data, which is unsound.
+        References that escape into the final value of a constant or static must be immutable.
+        This is to avoid accidentally creating shared mutable state.
+
+
+        If you really want global mutable state, try using an interior mutable `static` or a `static mut`.
 
 const_eval_intern_kind = {$kind ->
     [static] static
@@ -229,6 +231,24 @@ const_eval_modified_global =
 
 const_eval_mutable_ptr_in_final = encountered mutable pointer in final value of {const_eval_intern_kind}
 
+const_eval_mutable_raw_escaping =
+    raw mutable pointers are not allowed in the final value of {const_eval_const_context}s
+    .teach_note =
+        Pointers that escape into the final value of a constant or static must be immutable.
+        This is to avoid accidentally creating shared mutable state.
+
+
+        If you really want global mutable state, try using an interior mutable `static` or a `static mut`.
+
+const_eval_mutable_ref_escaping =
+    mutable references are not allowed in the final value of {const_eval_const_context}s
+    .teach_note =
+        References that escape into the final value of a constant or static must be immutable.
+        This is to avoid accidentally creating shared mutable state.
+
+
+        If you really want global mutable state, try using an interior mutable `static` or a `static mut`.
+
 const_eval_nested_static_in_thread_local = #[thread_local] does not support implicit nested statics, please create explicit static items and refer to them instead
 const_eval_non_const_fmt_macro_call =
     cannot call non-const formatting macro in {const_eval_const_context}s
@@ -364,30 +384,11 @@ const_eval_unallowed_fn_pointer_call = function pointer calls are not allowed in
 const_eval_unallowed_heap_allocations =
     allocations are not allowed in {const_eval_const_context}s
     .label = allocation not allowed in {const_eval_const_context}s
-    .teach_note = The value of statics and constants must be known at compile time, and they live for the entire lifetime of a program. Creating a boxed value allocates memory on the heap at runtime, and therefore cannot be done at compile time.
+    .teach_note =
+        The runtime heap is not yet available at compile-time, so no runtime heap allocations can be created.
 
 const_eval_unallowed_inline_asm =
     inline assembly is not allowed in {const_eval_const_context}s
-const_eval_unallowed_mutable_raw =
-    raw mutable pointers are not allowed in the final value of {const_eval_const_context}s
-    .teach_note =
-        References in statics and constants may only refer to immutable values.
-
-
-        Statics are shared everywhere, and if they refer to mutable data one might violate memory
-        safety since holding multiple mutable references to shared data is not allowed.
-
-
-        If you really want global mutable state, try using static mut or a global UnsafeCell.
-
-const_eval_unallowed_mutable_refs =
-    mutable references are not allowed in the final value of {const_eval_const_context}s
-    .teach_note =
-        Statics are shared everywhere, and if they refer to mutable data one might violate memory
-        safety since holding multiple mutable references to shared data is not allowed.
-
-
-        If you really want global mutable state, try using static mut or a global UnsafeCell.
 
 const_eval_unallowed_op_in_const_context =
     {$msg}

compiler/rustc_const_eval/src/check_consts/check.rs

@@ -666,6 +666,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     }
                 }
 
+                // This can be called on stable via the `vec!` macro.
                 if tcx.is_lang_item(callee, LangItem::ExchangeMalloc) {
                     self.check_op(ops::HeapAllocation);
                     return;

compiler/rustc_const_eval/src/check_consts/ops.rs

@@ -402,7 +402,7 @@ impl<'tcx> NonConstOp<'tcx> for EscapingCellBorrow {
         DiagImportance::Secondary
     }
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx> {
-        ccx.dcx().create_err(errors::InteriorMutableDataRefer {
+        ccx.dcx().create_err(errors::InteriorMutableRefEscaping {
             span,
             opt_help: matches!(ccx.const_kind(), hir::ConstContext::Static(_)),
             kind: ccx.const_kind(),
@@ -430,12 +430,12 @@ impl<'tcx> NonConstOp<'tcx> for EscapingMutBorrow {
 
     fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx> {
         match self.0 {
-            hir::BorrowKind::Raw => ccx.tcx.dcx().create_err(errors::UnallowedMutableRaw {
+            hir::BorrowKind::Raw => ccx.tcx.dcx().create_err(errors::MutableRawEscaping {
                 span,
                 kind: ccx.const_kind(),
                 teach: ccx.tcx.sess.teach(E0764),
             }),
-            hir::BorrowKind::Ref => ccx.dcx().create_err(errors::UnallowedMutableRefs {
+            hir::BorrowKind::Ref => ccx.dcx().create_err(errors::MutableRefEscaping {
                 span,
                 kind: ccx.const_kind(),
                 teach: ccx.tcx.sess.teach(E0764),

compiler/rustc_const_eval/src/errors.rs

@@ -118,8 +118,8 @@ pub(crate) struct UnstableConstFn {
 }
 
 #[derive(Diagnostic)]
-#[diag(const_eval_unallowed_mutable_refs, code = E0764)]
-pub(crate) struct UnallowedMutableRefs {
+#[diag(const_eval_mutable_ref_escaping, code = E0764)]
+pub(crate) struct MutableRefEscaping {
     #[primary_span]
     pub span: Span,
     pub kind: ConstContext,
@@ -128,8 +128,8 @@ pub(crate) struct UnallowedMutableRefs {
 }
 
 #[derive(Diagnostic)]
-#[diag(const_eval_unallowed_mutable_raw, code = E0764)]
-pub(crate) struct UnallowedMutableRaw {
+#[diag(const_eval_mutable_raw_escaping, code = E0764)]
+pub(crate) struct MutableRawEscaping {
     #[primary_span]
     pub span: Span,
     pub kind: ConstContext,
@@ -181,8 +181,8 @@ pub(crate) struct UnallowedInlineAsm {
 }
 
 #[derive(Diagnostic)]
-#[diag(const_eval_interior_mutable_data_refer, code = E0492)]
-pub(crate) struct InteriorMutableDataRefer {
+#[diag(const_eval_interior_mutable_ref_escaping, code = E0492)]
+pub(crate) struct InteriorMutableRefEscaping {
     #[primary_span]
     #[label]
     pub span: Span,

compiler/rustc_hir/src/lib.rs

@@ -33,6 +33,7 @@ pub mod weak_lang_items;
 #[cfg(test)]
 mod tests;
 
+#[doc(no_inline)]
 pub use hir::*;
 pub use hir_id::*;
 pub use lang_items::{LangItem, LanguageItems};

compiler/rustc_hir_typeck/src/expr.rs

@@ -1783,7 +1783,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr: &'tcx hir::Expr<'tcx>,
     ) -> Ty<'tcx> {
         let flds = expected.only_has_type(self).and_then(|ty| {
-            let ty = self.resolve_vars_with_obligations(ty);
+            let ty = self.try_structurally_resolve_type(expr.span, ty);
             match ty.kind() {
                 ty::Tuple(flds) => Some(&flds[..]),
                 _ => None,
@@ -1861,7 +1861,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     ) {
         let tcx = self.tcx;
 
-        let adt_ty = self.resolve_vars_with_obligations(adt_ty);
+        let adt_ty = self.try_structurally_resolve_type(span, adt_ty);
         let adt_ty_hint = expected.only_has_type(self).and_then(|expected| {
             self.fudge_inference_if_ok(|| {
                 let ocx = ObligationCtxt::new(self);

compiler/rustc_index/src/lib.rs

@@ -17,6 +17,7 @@ mod vec;
 pub use idx::Idx;
 pub use rustc_index_macros::newtype_index;
 pub use slice::IndexSlice;
+#[doc(no_inline)]
 pub use vec::IndexVec;
 
 /// Type size assertion. The first argument is a type and the second argument is its expected size.

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

@@ -18,8 +18,8 @@ use crate::solve::inspect::{self, ProofTreeBuilder};
 use crate::solve::search_graph::SearchGraph;
 use crate::solve::{
     CanonicalInput, CanonicalResponse, Certainty, FIXPOINT_STEP_LIMIT, Goal, GoalEvaluationKind,
-    GoalSource, NestedNormalizationGoals, NoSolution, PredefinedOpaquesData, QueryResult,
-    SolverMode,
+    GoalSource, HasChanged, NestedNormalizationGoals, NoSolution, PredefinedOpaquesData,
+    QueryResult, SolverMode,
 };
 
 pub(super) mod canonical;
@@ -126,11 +126,31 @@ pub enum GenerateProofTree {
 }
 
 pub trait SolverDelegateEvalExt: SolverDelegate {
+    /// Evaluates a goal from **outside** of the trait solver.
+    ///
+    /// Using this while inside of the solver is wrong as it uses a new
+    /// search graph which would break cycle detection.
     fn evaluate_root_goal(
         &self,
         goal: Goal<Self::Interner, <Self::Interner as Interner>::Predicate>,
         generate_proof_tree: GenerateProofTree,
-    ) -> (Result<(bool, Certainty), NoSolution>, Option<inspect::GoalEvaluation<Self::Interner>>);
+    ) -> (
+        Result<(HasChanged, Certainty), NoSolution>,
+        Option<inspect::GoalEvaluation<Self::Interner>>,
+    );
+
+    /// Check whether evaluating `goal` with a depth of `root_depth` may
+    /// succeed. This only returns `false` if the goal is guaranteed to
+    /// not hold. In case evaluation overflows and fails with ambiguity this
+    /// returns `true`.
+    ///
+    /// This is only intended to be used as a performance optimization
+    /// in coherence checking.
+    fn root_goal_may_hold_with_depth(
+        &self,
+        root_depth: usize,
+        goal: Goal<Self::Interner, <Self::Interner as Interner>::Predicate>,
+    ) -> bool;
 
     // FIXME: This is only exposed because we need to use it in `analyse.rs`
     // which is not yet uplifted. Once that's done, we should remove this.
@@ -139,7 +159,7 @@ pub trait SolverDelegateEvalExt: SolverDelegate {
         goal: Goal<Self::Interner, <Self::Interner as Interner>::Predicate>,
         generate_proof_tree: GenerateProofTree,
     ) -> (
-        Result<(NestedNormalizationGoals<Self::Interner>, bool, Certainty), NoSolution>,
+        Result<(NestedNormalizationGoals<Self::Interner>, HasChanged, Certainty), NoSolution>,
         Option<inspect::GoalEvaluation<Self::Interner>>,
     );
 }
@@ -149,31 +169,41 @@ where
     D: SolverDelegate<Interner = I>,
     I: Interner,
 {
-    /// Evaluates a goal from **outside** of the trait solver.
-    ///
-    /// Using this while inside of the solver is wrong as it uses a new
-    /// search graph which would break cycle detection.
     #[instrument(level = "debug", skip(self))]
     fn evaluate_root_goal(
         &self,
         goal: Goal<I, I::Predicate>,
         generate_proof_tree: GenerateProofTree,
-    ) -> (Result<(bool, Certainty), NoSolution>, Option<inspect::GoalEvaluation<I>>) {
-        EvalCtxt::enter_root(self, generate_proof_tree, |ecx| {
+    ) -> (Result<(HasChanged, Certainty), NoSolution>, Option<inspect::GoalEvaluation<I>>) {
+        EvalCtxt::enter_root(self, self.cx().recursion_limit(), generate_proof_tree, |ecx| {
             ecx.evaluate_goal(GoalEvaluationKind::Root, GoalSource::Misc, goal)
         })
     }
 
+    fn root_goal_may_hold_with_depth(
+        &self,
+        root_depth: usize,
+        goal: Goal<Self::Interner, <Self::Interner as Interner>::Predicate>,
+    ) -> bool {
+        self.probe(|| {
+            EvalCtxt::enter_root(self, root_depth, GenerateProofTree::No, |ecx| {
+                ecx.evaluate_goal(GoalEvaluationKind::Root, GoalSource::Misc, goal)
+            })
+            .0
+        })
+        .is_ok()
+    }
+
     #[instrument(level = "debug", skip(self))]
     fn evaluate_root_goal_raw(
         &self,
         goal: Goal<I, I::Predicate>,
         generate_proof_tree: GenerateProofTree,
     ) -> (
-        Result<(NestedNormalizationGoals<I>, bool, Certainty), NoSolution>,
+        Result<(NestedNormalizationGoals<I>, HasChanged, Certainty), NoSolution>,
         Option<inspect::GoalEvaluation<I>>,
     ) {
-        EvalCtxt::enter_root(self, generate_proof_tree, |ecx| {
+        EvalCtxt::enter_root(self, self.cx().recursion_limit(), generate_proof_tree, |ecx| {
             ecx.evaluate_goal_raw(GoalEvaluationKind::Root, GoalSource::Misc, goal)
         })
     }
@@ -197,10 +227,11 @@ where
     /// over using this manually (such as [`SolverDelegateEvalExt::evaluate_root_goal`]).
     pub(super) fn enter_root<R>(
         delegate: &D,
+        root_depth: usize,
         generate_proof_tree: GenerateProofTree,
         f: impl FnOnce(&mut EvalCtxt<'_, D>) -> R,
     ) -> (R, Option<inspect::GoalEvaluation<I>>) {
-        let mut search_graph = SearchGraph::new(delegate.solver_mode());
+        let mut search_graph = SearchGraph::new(delegate.solver_mode(), root_depth);
 
         let mut ecx = EvalCtxt {
             delegate,
@@ -339,7 +370,7 @@ where
         goal_evaluation_kind: GoalEvaluationKind,
         source: GoalSource,
         goal: Goal<I, I::Predicate>,
-    ) -> Result<(bool, Certainty), NoSolution> {
+    ) -> Result<(HasChanged, Certainty), NoSolution> {
         let (normalization_nested_goals, has_changed, certainty) =
             self.evaluate_goal_raw(goal_evaluation_kind, source, goal)?;
         assert!(normalization_nested_goals.is_empty());
@@ -360,7 +391,7 @@ where
         goal_evaluation_kind: GoalEvaluationKind,
         _source: GoalSource,
         goal: Goal<I, I::Predicate>,
-    ) -> Result<(NestedNormalizationGoals<I>, bool, Certainty), NoSolution> {
+    ) -> Result<(NestedNormalizationGoals<I>, HasChanged, Certainty), NoSolution> {
         let (orig_values, canonical_goal) = self.canonicalize_goal(goal);
         let mut goal_evaluation =
             self.inspect.new_goal_evaluation(goal, &orig_values, goal_evaluation_kind);
@@ -378,8 +409,13 @@ where
             Ok(response) => response,
         };
 
-        let has_changed = !response.value.var_values.is_identity_modulo_regions()
-            || !response.value.external_constraints.opaque_types.is_empty();
+        let has_changed = if !response.value.var_values.is_identity_modulo_regions()
+            || !response.value.external_constraints.opaque_types.is_empty()
+        {
+            HasChanged::Yes
+        } else {
+            HasChanged::No
+        };
 
         let (normalization_nested_goals, certainty) =
             self.instantiate_and_apply_query_response(goal.param_env, orig_values, response);
@@ -552,7 +588,7 @@ where
         for (source, goal) in goals.goals {
             let (has_changed, certainty) =
                 self.evaluate_goal(GoalEvaluationKind::Nested, source, goal)?;
-            if has_changed {
+            if has_changed == HasChanged::Yes {
                 unchanged_certainty = None;
             }
 

compiler/rustc_next_trait_solver/src/solve/mod.rs

@@ -48,6 +48,14 @@ enum GoalEvaluationKind {
     Nested,
 }
 
+/// Whether evaluating this goal ended up changing the
+/// inference state.
+#[derive(PartialEq, Eq, Debug, Hash, Clone, Copy)]
+pub enum HasChanged {
+    Yes,
+    No,
+}
+
 // FIXME(trait-system-refactor-initiative#117): we don't detect whether a response
 // ended up pulling down any universes.
 fn has_no_inference_or_external_constraints<I: Interner>(

compiler/rustc_next_trait_solver/src/solve/search_graph.rs

@@ -40,9 +40,6 @@ where
     }
 
     const DIVIDE_AVAILABLE_DEPTH_ON_OVERFLOW: usize = 4;
-    fn recursion_limit(cx: I) -> usize {
-        cx.recursion_limit()
-    }
 
     fn initial_provisional_result(
         cx: I,

compiler/rustc_trait_selection/src/solve.rs

@@ -6,6 +6,7 @@ pub mod inspect;
 mod normalize;
 mod select;
 
+pub(crate) use delegate::SolverDelegate;
 pub use fulfill::{FulfillmentCtxt, NextSolverError};
 pub(crate) use normalize::deeply_normalize_for_diagnostics;
 pub use normalize::{deeply_normalize, deeply_normalize_with_skipped_universes};