Auto merge of rust-lang#101167 - matthiaskrgr:rollup-yt3jdmp, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#100898 (Do not report too many expr field candidates)
 - rust-lang#101056 (Add the syntax of references to their documentation summary.)
 - rust-lang#101106 (Rustdoc-Json: Retain Stripped Modules when they are imported, not when they have items)
 - rust-lang#101131 (CTFE: exposing pointers and calling extern fn is just impossible)
 - rust-lang#101141 (Simplify `get_trait_ref` fn used for `virtual_function_elimination`)
 - rust-lang#101146 (Various changes to logging of borrowck-related code)
 - rust-lang#101156 (Remove `Sync` requirement from lint pass objects)

Failed merges:

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

Author: bors

Diff for: compiler/rustc_borrowck/src/constraints/mod.rs

@@ -105,8 +105,8 @@ impl<'tcx> fmt::Debug for OutlivesConstraint<'tcx> {
     fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(
             formatter,
-            "({:?}: {:?}) due to {:?} ({:?})",
-            self.sup, self.sub, self.locations, self.variance_info
+            "({:?}: {:?}) due to {:?} ({:?}) ({:?})",
+            self.sup, self.sub, self.locations, self.variance_info, self.category,
         )
     }
 }

Diff for: compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -1119,20 +1119,14 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     /// short a lifetime. (But sometimes it is more useful to report
     /// it as a more direct conflict between the execution of a
     /// `Drop::drop` with an aliasing borrow.)
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn report_borrowed_value_does_not_live_long_enough(
         &mut self,
         location: Location,
         borrow: &BorrowData<'tcx>,
         place_span: (Place<'tcx>, Span),
         kind: Option<WriteKind>,
     ) {
-        debug!(
-            "report_borrowed_value_does_not_live_long_enough(\
-             {:?}, {:?}, {:?}, {:?}\
-             )",
-            location, borrow, place_span, kind
-        );
-
         let drop_span = place_span.1;
         let root_place =
             self.prefixes(borrow.borrowed_place.as_ref(), PrefixSet::All).last().unwrap();
@@ -1189,10 +1183,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let kind_place = kind.filter(|_| place_desc.is_some()).map(|k| (k, place_span.0));
         let explanation = self.explain_why_borrow_contains_point(location, &borrow, kind_place);
 
-        debug!(
-            "report_borrowed_value_does_not_live_long_enough(place_desc: {:?}, explanation: {:?})",
-            place_desc, explanation
-        );
+        debug!(?place_desc, ?explanation);
+
         let err = match (place_desc, explanation) {
             // If the outlives constraint comes from inside the closure,
             // for example:
@@ -1464,6 +1456,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         err
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn report_temporary_value_does_not_live_long_enough(
         &mut self,
         location: Location,
@@ -1473,13 +1466,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         proper_span: Span,
         explanation: BorrowExplanation<'tcx>,
     ) -> DiagnosticBuilder<'cx, ErrorGuaranteed> {
-        debug!(
-            "report_temporary_value_does_not_live_long_enough(\
-             {:?}, {:?}, {:?}, {:?}\
-             )",
-            location, borrow, drop_span, proper_span
-        );
-
         if let BorrowExplanation::MustBeValidFor { category, span, from_closure: false, .. } =
             explanation
         {

Diff for: compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -336,26 +336,22 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     ///   - second half is the place being accessed
     ///
     /// [d]: https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn explain_why_borrow_contains_point(
         &self,
         location: Location,
         borrow: &BorrowData<'tcx>,
         kind_place: Option<(WriteKind, Place<'tcx>)>,
     ) -> BorrowExplanation<'tcx> {
-        debug!(
-            "explain_why_borrow_contains_point(location={:?}, borrow={:?}, kind_place={:?})",
-            location, borrow, kind_place
-        );
-
         let regioncx = &self.regioncx;
         let body: &Body<'_> = &self.body;
         let tcx = self.infcx.tcx;
 
         let borrow_region_vid = borrow.region;
-        debug!("explain_why_borrow_contains_point: borrow_region_vid={:?}", borrow_region_vid);
+        debug!(?borrow_region_vid);
 
         let region_sub = self.regioncx.find_sub_region_live_at(borrow_region_vid, location);
-        debug!("explain_why_borrow_contains_point: region_sub={:?}", region_sub);
+        debug!(?region_sub);
 
         match find_use::find(body, regioncx, tcx, region_sub, location) {
             Some(Cause::LiveVar(local, location)) => {
@@ -408,17 +404,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             opt_place_desc,
                         }
                     } else {
-                        debug!(
-                            "explain_why_borrow_contains_point: \
-                             Could not generate a region name"
-                        );
+                        debug!("Could not generate a region name");
                         BorrowExplanation::Unexplained
                     }
                 } else {
-                    debug!(
-                        "explain_why_borrow_contains_point: \
-                         Could not generate an error region vid"
-                    );
+                    debug!("Could not generate an error region vid");
                     BorrowExplanation::Unexplained
                 }
             }

Diff for: compiler/rustc_borrowck/src/lib.rs

@@ -975,6 +975,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         }
     }
 
+    #[instrument(level = "debug", skip(self, flow_state))]
     fn check_access_for_conflict(
         &mut self,
         location: Location,
@@ -983,11 +984,6 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         rw: ReadOrWrite,
         flow_state: &Flows<'cx, 'tcx>,
     ) -> bool {
-        debug!(
-            "check_access_for_conflict(location={:?}, place_span={:?}, sd={:?}, rw={:?})",
-            location, place_span, sd, rw,
-        );
-
         let mut error_reported = false;
         let tcx = self.infcx.tcx;
         let body = self.body;
@@ -1451,13 +1447,13 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
     /// Checks whether a borrow of this place is invalidated when the function
     /// exits
+    #[instrument(level = "debug", skip(self))]
     fn check_for_invalidation_at_exit(
         &mut self,
         location: Location,
         borrow: &BorrowData<'tcx>,
         span: Span,
     ) {
-        debug!("check_for_invalidation_at_exit({:?})", borrow);
         let place = borrow.borrowed_place;
         let mut root_place = PlaceRef { local: place.local, projection: &[] };
 

Diff for: compiler/rustc_borrowck/src/places_conflict.rs

@@ -44,6 +44,7 @@ pub(crate) fn places_conflict<'tcx>(
 /// access depth. The `bias` parameter is used to determine how the unknowable (comparing runtime
 /// array indices, for example) should be interpreted - this depends on what the caller wants in
 /// order to make the conservative choice and preserve soundness.
+#[instrument(level = "debug", skip(tcx, body))]
 pub(super) fn borrow_conflicts_with_place<'tcx>(
     tcx: TyCtxt<'tcx>,
     body: &Body<'tcx>,
@@ -53,11 +54,6 @@ pub(super) fn borrow_conflicts_with_place<'tcx>(
     access: AccessDepth,
     bias: PlaceConflictBias,
 ) -> bool {
-    debug!(
-        "borrow_conflicts_with_place({:?}, {:?}, {:?}, {:?})",
-        borrow_place, access_place, access, bias,
-    );
-
     // This Local/Local case is handled by the more general code below, but
     // it's so common that it's a speed win to check for it first.
     if let Some(l1) = borrow_place.as_local() && let Some(l2) = access_place.as_local() {
@@ -140,10 +136,9 @@ fn place_components_conflict<'tcx>(
     for (i, (borrow_c, &access_c)) in
         iter::zip(borrow_place.projection, access_place.projection).enumerate()
     {
-        debug!("borrow_conflicts_with_place: borrow_c = {:?}", borrow_c);
-        let borrow_proj_base = &borrow_place.projection[..i];
+        debug!(?borrow_c, ?access_c);
 
-        debug!("borrow_conflicts_with_place: access_c = {:?}", access_c);
+        let borrow_proj_base = &borrow_place.projection[..i];
 
         // Borrow and access path both have more components.
         //
@@ -180,7 +175,7 @@ fn place_components_conflict<'tcx>(
                 // idea, at least for now, so just give up and
                 // report a conflict. This is unsafe code anyway so
                 // the user could always use raw pointers.
-                debug!("borrow_conflicts_with_place: arbitrary -> conflict");
+                debug!("arbitrary -> conflict");
                 return true;
             }
             Overlap::EqualOrDisjoint => {
@@ -189,7 +184,7 @@ fn place_components_conflict<'tcx>(
             Overlap::Disjoint => {
                 // We have proven the borrow disjoint - further
                 // projections will remain disjoint.
-                debug!("borrow_conflicts_with_place: disjoint");
+                debug!("disjoint");
                 return false;
             }
         }

Diff for: compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -1167,8 +1167,9 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// Therefore, this method should only be used in diagnostic code,
     /// where displaying *some* named universal region is better than
     /// falling back to 'static.
+    #[instrument(level = "debug", skip(self))]
     pub(crate) fn approx_universal_upper_bound(&self, r: RegionVid) -> RegionVid {
-        debug!("approx_universal_upper_bound(r={:?}={})", r, self.region_value_str(r));
+        debug!("{}", self.region_value_str(r));
 
         // Find the smallest universal region that contains all other
         // universal regions within `region`.
@@ -1177,7 +1178,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let static_r = self.universal_regions.fr_static;
         for ur in self.scc_values.universal_regions_outlived_by(r_scc) {
             let new_lub = self.universal_region_relations.postdom_upper_bound(lub, ur);
-            debug!("approx_universal_upper_bound: ur={:?} lub={:?} new_lub={:?}", ur, lub, new_lub);
+            debug!(?ur, ?lub, ?new_lub);
             // The upper bound of two non-static regions is static: this
             // means we know nothing about the relationship between these
             // two regions. Pick a 'better' one to use when constructing
@@ -1201,7 +1202,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
             }
         }
 
-        debug!("approx_universal_upper_bound: r={:?} lub={:?}", r, lub);
+        debug!(?r, ?lub);
 
         lub
     }
@@ -2048,23 +2049,19 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// creating a constraint path that forces `R` to outlive
     /// `from_region`, and then finding the best choices within that
     /// path to blame.
+    #[instrument(level = "debug", skip(self, target_test))]
     pub(crate) fn best_blame_constraint(
         &self,
         body: &Body<'tcx>,
         from_region: RegionVid,
         from_region_origin: NllRegionVariableOrigin,
         target_test: impl Fn(RegionVid) -> bool,
     ) -> BlameConstraint<'tcx> {
-        debug!(
-            "best_blame_constraint(from_region={:?}, from_region_origin={:?})",
-            from_region, from_region_origin
-        );
-
         // Find all paths
         let (path, target_region) =
             self.find_constraint_paths_between_regions(from_region, target_test).unwrap();
         debug!(
-            "best_blame_constraint: path={:#?}",
+            "path={:#?}",
             path.iter()
                 .map(|c| format!(
                     "{:?} ({:?}: {:?})",
@@ -2116,7 +2113,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                 }
             })
             .collect();
-        debug!("best_blame_constraint: categorized_path={:#?}", categorized_path);
+        debug!("categorized_path={:#?}", categorized_path);
 
         // To find the best span to cite, we first try to look for the
         // final constraint that is interesting and where the `sup` is
@@ -2214,10 +2211,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         let best_choice =
             if blame_source { range.rev().find(find_region) } else { range.find(find_region) };
 
-        debug!(
-            "best_blame_constraint: best_choice={:?} blame_source={}",
-            best_choice, blame_source
-        );
+        debug!(?best_choice, ?blame_source);
 
         if let Some(i) = best_choice {
             if let Some(next) = categorized_path.get(i + 1) {
@@ -2254,7 +2248,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         // appears to be the most interesting point to report to the
         // user via an even more ad-hoc guess.
         categorized_path.sort_by(|p0, p1| p0.category.cmp(&p1.category));
-        debug!("best_blame_constraint: sorted_path={:#?}", categorized_path);
+        debug!("sorted_path={:#?}", categorized_path);
 
         categorized_path.remove(0)
     }

Diff for: compiler/rustc_borrowck/src/type_check/canonical.rs

@@ -24,7 +24,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
     /// **Any `rustc_infer::infer` operations that might generate region
     /// constraints should occur within this method so that those
     /// constraints can be properly localized!**
-    #[instrument(skip(self, category, op), level = "trace")]
+    #[instrument(skip(self, op), level = "trace")]
     pub(super) fn fully_perform_op<R, Op>(
         &mut self,
         locations: Locations,

Diff for: compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1043,6 +1043,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             let CanonicalUserTypeAnnotation { span, ref user_ty, inferred_ty } = *user_annotation;
             let inferred_ty = self.normalize(inferred_ty, Locations::All(span));
             let annotation = self.instantiate_canonical_with_fresh_inference_vars(span, user_ty);
+            debug!(?annotation);
             match annotation {
                 UserType::Ty(mut ty) => {
                     ty = self.normalize(ty, Locations::All(span));

Diff for: compiler/rustc_codegen_ssa/src/meth.rs

@@ -1,6 +1,6 @@
 use crate::traits::*;
 
-use rustc_middle::ty::{self, subst::GenericArgKind, ExistentialPredicate, Ty, TyCtxt};
+use rustc_middle::ty::{self, subst::GenericArgKind, Ty};
 use rustc_session::config::Lto;
 use rustc_symbol_mangling::typeid_for_trait_ref;
 use rustc_target::abi::call::FnAbi;
@@ -29,7 +29,7 @@ impl<'a, 'tcx> VirtualIndex {
             && bx.cx().sess().lto() == Lto::Fat
         {
             let typeid =
-                bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), get_trait_ref(bx.tcx(), ty)));
+                bx.typeid_metadata(typeid_for_trait_ref(bx.tcx(), expect_dyn_trait_in_self(ty)));
             let vtable_byte_offset = self.0 * bx.data_layout().pointer_size.bytes();
             let type_checked_load = bx.type_checked_load(llvtable, vtable_byte_offset, typeid);
             let func = bx.extract_value(type_checked_load, 0);
@@ -64,17 +64,13 @@ impl<'a, 'tcx> VirtualIndex {
     }
 }
 
-fn get_trait_ref<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'tcx> {
+/// This takes a valid `self` receiver type and extracts the principal trait
+/// ref of the type.
+fn expect_dyn_trait_in_self<'tcx>(ty: Ty<'tcx>) -> ty::PolyExistentialTraitRef<'tcx> {
     for arg in ty.peel_refs().walk() {
         if let GenericArgKind::Type(ty) = arg.unpack() {
-            if let ty::Dynamic(trait_refs, _) = ty.kind() {
-                return trait_refs[0].map_bound(|trait_ref| match trait_ref {
-                    ExistentialPredicate::Trait(tr) => tr,
-                    ExistentialPredicate::Projection(proj) => proj.trait_ref(tcx),
-                    ExistentialPredicate::AutoTrait(_) => {
-                        bug!("auto traits don't have functions")
-                    }
-                });
+            if let ty::Dynamic(data, _) = ty.kind() {
+                return data.principal().expect("expected principal trait object");
             }
         }
     }

Diff for: compiler/rustc_const_eval/src/const_eval/error.rs

@@ -15,7 +15,6 @@ use crate::interpret::{
 /// The CTFE machine has some custom error kinds.
 #[derive(Clone, Debug)]
 pub enum ConstEvalErrKind {
-    NeedsRfc(String),
     ConstAccessesStatic,
     ModifiedGlobal,
     AssertFailure(AssertKind<ConstInt>),
@@ -42,9 +41,6 @@ impl fmt::Display for ConstEvalErrKind {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use self::ConstEvalErrKind::*;
         match *self {
-            NeedsRfc(ref msg) => {
-                write!(f, "\"{}\" needs an rfc before being allowed inside constants", msg)
-            }
             ConstAccessesStatic => write!(f, "constant accesses static"),
             ModifiedGlobal => {
                 write!(f, "modifying a static's initial value from another static's initializer")