Auto merge of rust-lang#112702 - Dylan-DPC:rollup-12d6qay, r=Dylan-DPC

Rollup of 7 pull requests

Successful merges:

 - rust-lang#112163 (fix: inline `predicate_may_hold_fatal` and remove expect call in it)
 - rust-lang#112399 (Instantiate closure synthetic substs in root universe)
 - rust-lang#112443 (Opportunistically resolve regions in new solver)
 - rust-lang#112535 (reorder attributes to make miri-test-libstd work again)
 - rust-lang#112579 (Fix building libstd documentation on FreeBSD.)
 - rust-lang#112639 (Fix `dead_code_cgu` computation)
 - rust-lang#112642 (Handle interpolated literal errors)

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

Author: bors

compiler/rustc_hir_typeck/src/closure.rs

@@ -98,7 +98,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             self.tcx.typeck_root_def_id(expr_def_id.to_def_id()),
         );
 
-        let tupled_upvars_ty = self.next_ty_var(TypeVariableOrigin {
+        let tupled_upvars_ty = self.next_root_ty_var(TypeVariableOrigin {
             kind: TypeVariableOriginKind::ClosureSynthetic,
             span: self.tcx.def_span(expr_def_id),
         });
@@ -143,7 +143,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
             // Create a type variable (for now) to represent the closure kind.
             // It will be unified during the upvar inference phase (`upvar.rs`)
-            None => self.next_ty_var(TypeVariableOrigin {
+            None => self.next_root_ty_var(TypeVariableOrigin {
                 // FIXME(eddyb) distinguish closure kind inference variables from the rest.
                 kind: TypeVariableOriginKind::ClosureSynthetic,
                 span: expr_span,

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -189,6 +189,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub fn errors_reported_since_creation(&self) -> bool {
         self.tcx.sess.err_count() > self.err_count_on_creation
     }
+
+    pub fn next_root_ty_var(&self, origin: TypeVariableOrigin) -> Ty<'tcx> {
+        self.tcx.mk_ty_var(self.next_ty_var_id_in_universe(origin, ty::UniverseIndex::ROOT))
+    }
 }
 
 impl<'a, 'tcx> Deref for FnCtxt<'a, 'tcx> {

compiler/rustc_middle/src/infer/canonical.rs

@@ -82,15 +82,40 @@ impl CanonicalVarValues<'_> {
     }
 
     pub fn is_identity_modulo_regions(&self) -> bool {
-        self.var_values.iter().enumerate().all(|(bv, arg)| match arg.unpack() {
-            ty::GenericArgKind::Lifetime(_) => true,
-            ty::GenericArgKind::Type(ty) => {
-                matches!(*ty.kind(), ty::Bound(ty::INNERMOST, bt) if bt.var.as_usize() == bv)
-            }
-            ty::GenericArgKind::Const(ct) => {
-                matches!(ct.kind(), ty::ConstKind::Bound(ty::INNERMOST, bc) if bc.as_usize() == bv)
+        let mut var = ty::BoundVar::from_u32(0);
+        for arg in self.var_values {
+            match arg.unpack() {
+                ty::GenericArgKind::Lifetime(r) => {
+                    if let ty::ReLateBound(ty::INNERMOST, br) = *r
+                        && var == br.var
+                    {
+                        var = var + 1;
+                    } else {
+                        // It's ok if this region var isn't unique
+                    }
+                },
+                ty::GenericArgKind::Type(ty) => {
+                    if let ty::Bound(ty::INNERMOST, bt) = *ty.kind()
+                        && var == bt.var
+                    {
+                        var = var + 1;
+                    } else {
+                        return false;
+                    }
+                }
+                ty::GenericArgKind::Const(ct) => {
+                    if let ty::ConstKind::Bound(ty::INNERMOST, bc) = ct.kind()
+                        && var == bc
+                    {
+                        var = var + 1;
+                    } else {
+                        return false;
+                    }
+                }
             }
-        })
+        }
+
+        true
     }
 }
 

compiler/rustc_monomorphize/src/partitioning.rs

@@ -155,14 +155,16 @@ where
     // functions and statics defined in the local crate.
     let PlacedRootMonoItems { mut codegen_units, internalization_candidates, unique_inlined_stats } = {
         let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_place_roots");
-        place_root_mono_items(cx, mono_items)
-    };
+        let mut placed = place_root_mono_items(cx, mono_items);
 
-    for cgu in &mut codegen_units {
-        cgu.create_size_estimate(tcx);
-    }
+        for cgu in &mut placed.codegen_units {
+            cgu.create_size_estimate(tcx);
+        }
 
-    debug_dump(tcx, "ROOTS", &codegen_units, unique_inlined_stats);
+        debug_dump(tcx, "ROOTS", &placed.codegen_units, placed.unique_inlined_stats);
+
+        placed
+    };
 
     // Merge until we have at most `max_cgu_count` codegen units.
     // `merge_codegen_units` is responsible for updating the CGU size
@@ -179,59 +181,34 @@ where
     // local functions the definition of which is marked with `#[inline]`.
     {
         let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_place_inline_items");
-        place_inlined_mono_items(cx, &mut codegen_units)
-    };
+        place_inlined_mono_items(cx, &mut codegen_units);
 
-    for cgu in &mut codegen_units {
-        cgu.create_size_estimate(tcx);
-    }
+        for cgu in &mut codegen_units {
+            cgu.create_size_estimate(tcx);
+        }
 
-    debug_dump(tcx, "INLINE", &codegen_units, unique_inlined_stats);
+        debug_dump(tcx, "INLINE", &codegen_units, unique_inlined_stats);
+    }
 
     // Next we try to make as many symbols "internal" as possible, so LLVM has
     // more freedom to optimize.
     if !tcx.sess.link_dead_code() {
         let _prof_timer = tcx.prof.generic_activity("cgu_partitioning_internalize_symbols");
         internalize_symbols(cx, &mut codegen_units, internalization_candidates);
+
+        debug_dump(tcx, "INTERNALIZE", &codegen_units, unique_inlined_stats);
     }
 
+    // Mark one CGU for dead code, if necessary.
     let instrument_dead_code =
         tcx.sess.instrument_coverage() && !tcx.sess.instrument_coverage_except_unused_functions();
-
     if instrument_dead_code {
-        assert!(
-            codegen_units.len() > 0,
-            "There must be at least one CGU that code coverage data can be generated in."
-        );
-
-        // Find the smallest CGU that has exported symbols and put the dead
-        // function stubs in that CGU. We look for exported symbols to increase
-        // the likelihood the linker won't throw away the dead functions.
-        // FIXME(#92165): In order to truly resolve this, we need to make sure
-        // the object file (CGU) containing the dead function stubs is included
-        // in the final binary. This will probably require forcing these
-        // function symbols to be included via `-u` or `/include` linker args.
-        let mut cgus: Vec<_> = codegen_units.iter_mut().collect();
-        cgus.sort_by_key(|cgu| cgu.size_estimate());
-
-        let dead_code_cgu =
-            if let Some(cgu) = cgus.into_iter().rev().find(|cgu| {
-                cgu.items().iter().any(|(_, (linkage, _))| *linkage == Linkage::External)
-            }) {
-                cgu
-            } else {
-                // If there are no CGUs that have externally linked items,
-                // then we just pick the first CGU as a fallback.
-                &mut codegen_units[0]
-            };
-        dead_code_cgu.make_code_coverage_dead_code_cgu();
+        mark_code_coverage_dead_code_cgu(&mut codegen_units);
     }
 
     // Ensure CGUs are sorted by name, so that we get deterministic results.
     assert!(codegen_units.is_sorted_by(|a, b| Some(a.name().as_str().cmp(b.name().as_str()))));
 
-    debug_dump(tcx, "FINAL", &codegen_units, unique_inlined_stats);
-
     codegen_units
 }
 
@@ -363,9 +340,7 @@ fn merge_codegen_units<'tcx>(
 
         // Move the mono-items from `smallest` to `second_smallest`
         second_smallest.modify_size_estimate(smallest.size_estimate());
-        for (k, v) in smallest.items_mut().drain() {
-            second_smallest.items_mut().insert(k, v);
-        }
+        second_smallest.items_mut().extend(smallest.items_mut().drain());
 
         // Record that `second_smallest` now contains all the stuff that was
         // in `smallest` before.
@@ -545,6 +520,28 @@ fn internalize_symbols<'tcx>(
     }
 }
 
+fn mark_code_coverage_dead_code_cgu<'tcx>(codegen_units: &mut [CodegenUnit<'tcx>]) {
+    assert!(!codegen_units.is_empty());
+
+    // Find the smallest CGU that has exported symbols and put the dead
+    // function stubs in that CGU. We look for exported symbols to increase
+    // the likelihood the linker won't throw away the dead functions.
+    // FIXME(#92165): In order to truly resolve this, we need to make sure
+    // the object file (CGU) containing the dead function stubs is included
+    // in the final binary. This will probably require forcing these
+    // function symbols to be included via `-u` or `/include` linker args.
+    let dead_code_cgu = codegen_units
+        .iter_mut()
+        .filter(|cgu| cgu.items().iter().any(|(_, (linkage, _))| *linkage == Linkage::External))
+        .min_by_key(|cgu| cgu.size_estimate());
+
+    // If there are no CGUs that have externally linked items, then we just
+    // pick the first CGU as a fallback.
+    let dead_code_cgu = if let Some(cgu) = dead_code_cgu { cgu } else { &mut codegen_units[0] };
+
+    dead_code_cgu.make_code_coverage_dead_code_cgu();
+}
+
 fn characteristic_def_id_of_mono_item<'tcx>(
     tcx: TyCtxt<'tcx>,
     mono_item: MonoItem<'tcx>,

compiler/rustc_parse/src/parser/expr.rs

@@ -2023,17 +2023,14 @@ impl<'a> Parser<'a> {
         let recovered = self.recover_after_dot();
         let token = recovered.as_ref().unwrap_or(&self.token);
         match token::Lit::from_token(token) {
-            Some(token_lit) => {
-                match MetaItemLit::from_token_lit(token_lit, token.span) {
+            Some(lit) => {
+                match MetaItemLit::from_token_lit(lit, token.span) {
                     Ok(lit) => {
                         self.bump();
                         Some(lit)
                     }
                     Err(err) => {
-                        let span = token.span;
-                        let token::Literal(lit) = token.kind else {
-                            unreachable!();
-                        };
+                        let span = token.uninterpolated_span();
                         self.bump();
                         report_lit_error(&self.sess, err, lit, span);
                         // Pack possible quotes and prefixes from the original literal into

compiler/rustc_trait_selection/src/solve/canonicalize.rs

@@ -208,8 +208,25 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for Canonicalizer<'_, 'tcx> {
         t
     }
 
-    fn fold_region(&mut self, r: ty::Region<'tcx>) -> ty::Region<'tcx> {
-        let r = self.infcx.shallow_resolve(r);
+    fn fold_region(&mut self, mut r: ty::Region<'tcx>) -> ty::Region<'tcx> {
+        match self.canonicalize_mode {
+            CanonicalizeMode::Input => {
+                // Don't resolve infer vars in input, since it affects
+                // caching and may cause trait selection bugs which rely
+                // on regions to be equal.
+            }
+            CanonicalizeMode::Response { .. } => {
+                if let ty::ReVar(vid) = *r {
+                    r = self
+                        .infcx
+                        .inner
+                        .borrow_mut()
+                        .unwrap_region_constraints()
+                        .opportunistic_resolve_var(self.infcx.tcx, vid);
+                }
+            }
+        }
+
         let kind = match *r {
             ty::ReLateBound(..) => return r,
 

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -263,7 +263,10 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
             let (_orig_values, canonical_goal) = self.canonicalize_goal(goal);
             let new_canonical_response =
                 EvalCtxt::evaluate_canonical_goal(self.tcx(), self.search_graph, canonical_goal)?;
-            if !new_canonical_response.value.var_values.is_identity() {
+            // We only check for modulo regions as we convert all regions in
+            // the input to new existentials, even if they're expected to be
+            // `'static` or a placeholder region.
+            if !new_canonical_response.value.var_values.is_identity_modulo_regions() {
                 bug!(
                     "unstable result: re-canonicalized goal={canonical_goal:#?} \
                     first_response={canonical_response:#?} \

compiler/rustc_trait_selection/src/traits/coherence.rs

@@ -292,7 +292,12 @@ fn impl_intersection_has_impossible_obligation<'cx, 'tcx>(
             Obligation::new(infcx.tcx, ObligationCause::dummy(), param_env, predicate)
         })
         .chain(obligations)
-        .find(|o| !selcx.predicate_may_hold_fatal(o));
+        .find(|o| {
+            selcx.evaluate_root_obligation(o).map_or(
+                false, // Overflow has occurred, and treat the obligation as possibly holding.
+                |result| !result.may_apply(),
+            )
+        });
 
     if let Some(failing_obligation) = opt_failing_obligation {
         debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -518,19 +518,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
     // The result is "true" if the obligation *may* hold and "false" if
     // we can be sure it does not.
 
-    /// Evaluates whether the obligation `obligation` can be satisfied (by any means).
-    pub fn predicate_may_hold_fatal(&mut self, obligation: &PredicateObligation<'tcx>) -> bool {
-        debug!(?obligation, "predicate_may_hold_fatal");
-
-        // This fatal query is a stopgap that should only be used in standard mode,
-        // where we do not expect overflow to be propagated.
-        assert!(self.query_mode == TraitQueryMode::Standard);
-
-        self.evaluate_root_obligation(obligation)
-            .expect("Overflow should be caught earlier in standard query mode")
-            .may_apply()
-    }
-
     /// Evaluates whether the obligation `obligation` can be satisfied
     /// and returns an `EvaluationResult`. This is meant for the
     /// *initial* call.

library/alloc/src/lib.rs

@@ -56,6 +56,11 @@
 //! [`Rc`]: rc
 //! [`RefCell`]: core::cell
 
+// To run alloc tests without x.py without ending up with two copies of alloc, Miri needs to be
+// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
+// rustc itself never sets the feature, so this line has no affect there.
+#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
+//
 #![allow(unused_attributes)]
 #![stable(feature = "alloc", since = "1.36.0")]
 #![doc(
@@ -75,11 +80,6 @@
 ))]
 #![no_std]
 #![needs_allocator]
-// To run alloc tests without x.py without ending up with two copies of alloc, Miri needs to be
-// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
-// rustc itself never sets the feature, so this line has no affect there.
-#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
-//
 // Lints:
 #![deny(unsafe_op_in_unsafe_fn)]
 #![deny(fuzzy_provenance_casts)]