Rollup of 6 pull requests

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -623,7 +623,7 @@ pub fn create_compressed_metadata_file_for_xcoff(
 /// that contains a custom section of the name `section_name` with contents
 /// `data`.
 ///
-/// NB: the `object` crate does not yet have support for writing the the wasm
+/// NB: the `object` crate does not yet have support for writing the wasm
 /// object file format. The format is simple enough that for now an extra crate
 /// from crates.io (such as `wasm-encoder`). The file format is:
 ///

compiler/rustc_feature/src/unstable.rs

@@ -518,7 +518,7 @@ declare_features! (
     (unstable, marker_trait_attr, "1.30.0", Some(29864)),
     /// Allows exhaustive pattern matching on types that contain uninhabited types in cases that are
     /// unambiguously sound.
-    (incomplete, min_exhaustive_patterns, "1.77.0", Some(119612)),
+    (unstable, min_exhaustive_patterns, "1.77.0", Some(119612)),
     /// A minimal, sound subset of specialization intended to be used by the
     /// standard library until the soundness issues with specialization
     /// are fixed.

compiler/rustc_hir/src/hir.rs

@@ -3004,6 +3004,11 @@ impl<'hir> Item<'hir> {
         matches!(self.kind, ItemKind::Enum(..) | ItemKind::Struct(..) | ItemKind::Union(..))
     }
 
+    /// Check if this is an [`ItemKind::Struct`] or [`ItemKind::Union`].
+    pub fn is_struct_or_union(&self) -> bool {
+        matches!(self.kind, ItemKind::Struct(..) | ItemKind::Union(..))
+    }
+
     expect_methods_self_kind! {
         expect_extern_crate, Option<Symbol>, ItemKind::ExternCrate(s), *s;
 

compiler/rustc_hir_analysis/src/collect.rs

@@ -1025,7 +1025,15 @@ fn adt_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::AdtDef<'_> {
 
     let is_anonymous = item.ident.name == kw::Empty;
     let repr = if is_anonymous {
-        tcx.adt_def(tcx.local_parent(def_id)).repr()
+        let parent = tcx.local_parent(def_id);
+        if let Node::Item(item) = tcx.hir_node_by_def_id(parent)
+            && item.is_struct_or_union()
+        {
+            tcx.adt_def(parent).repr()
+        } else {
+            tcx.dcx().span_delayed_bug(item.span, "anonymous field inside non struct/union");
+            ty::ReprOptions::default()
+        }
     } else {
         tcx.repr_options_of_def(def_id)
     };

compiler/rustc_middle/src/lib.rs

@@ -24,6 +24,8 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
+#![cfg_attr(bootstrap, feature(exhaustive_patterns))]
+#![cfg_attr(not(bootstrap), feature(min_exhaustive_patterns))]
 #![feature(rustdoc_internals)]
 #![feature(allocator_api)]
 #![feature(array_windows)]
@@ -32,7 +34,6 @@
 #![feature(core_intrinsics)]
 #![feature(const_type_name)]
 #![feature(discriminant_kind)]
-#![feature(exhaustive_patterns)]
 #![feature(coroutines)]
 #![feature(generic_nonzero)]
 #![feature(if_let_guard)]

compiler/rustc_middle/src/traits/select.rs

@@ -139,7 +139,7 @@ pub enum SelectionCandidate<'tcx> {
     /// generated for an `async ||` expression.
     AsyncClosureCandidate,
 
-    /// Implementation of the the `AsyncFnKindHelper` helper trait, which
+    /// Implementation of the `AsyncFnKindHelper` helper trait, which
     /// is used internally to delay computation for async closures until after
     /// upvar analysis is performed in HIR typeck.
     AsyncFnKindHelperCandidate,

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -90,23 +90,23 @@ pub(super) fn generate_coverage_spans(
 struct CurrCovspan {
     span: Span,
     bcb: BasicCoverageBlock,
-    is_closure: bool,
+    is_hole: bool,
 }
 
 impl CurrCovspan {
-    fn new(span: Span, bcb: BasicCoverageBlock, is_closure: bool) -> Self {
-        Self { span, bcb, is_closure }
+    fn new(span: Span, bcb: BasicCoverageBlock, is_hole: bool) -> Self {
+        Self { span, bcb, is_hole }
     }
 
     fn into_prev(self) -> PrevCovspan {
-        let Self { span, bcb, is_closure } = self;
-        PrevCovspan { span, bcb, merged_spans: vec![span], is_closure }
+        let Self { span, bcb, is_hole } = self;
+        PrevCovspan { span, bcb, merged_spans: vec![span], is_hole }
     }
 
     fn into_refined(self) -> RefinedCovspan {
-        // This is only called in cases where `curr` is a closure span that has
+        // This is only called in cases where `curr` is a hole span that has
         // been carved out of `prev`.
-        debug_assert!(self.is_closure);
+        debug_assert!(self.is_hole);
         self.into_prev().into_refined()
     }
 }
@@ -118,12 +118,12 @@ struct PrevCovspan {
     /// List of all the original spans from MIR that have been merged into this
     /// span. Mainly used to precisely skip over gaps when truncating a span.
     merged_spans: Vec<Span>,
-    is_closure: bool,
+    is_hole: bool,
 }
 
 impl PrevCovspan {
     fn is_mergeable(&self, other: &CurrCovspan) -> bool {
-        self.bcb == other.bcb && !self.is_closure && !other.is_closure
+        self.bcb == other.bcb && !self.is_hole && !other.is_hole
     }
 
     fn merge_from(&mut self, other: &CurrCovspan) {
@@ -142,8 +142,8 @@ impl PrevCovspan {
     }
 
     fn refined_copy(&self) -> RefinedCovspan {
-        let &Self { span, bcb, merged_spans: _, is_closure } = self;
-        RefinedCovspan { span, bcb, is_closure }
+        let &Self { span, bcb, merged_spans: _, is_hole } = self;
+        RefinedCovspan { span, bcb, is_hole }
     }
 
     fn into_refined(self) -> RefinedCovspan {
@@ -156,12 +156,12 @@ impl PrevCovspan {
 struct RefinedCovspan {
     span: Span,
     bcb: BasicCoverageBlock,
-    is_closure: bool,
+    is_hole: bool,
 }
 
 impl RefinedCovspan {
     fn is_mergeable(&self, other: &Self) -> bool {
-        self.bcb == other.bcb && !self.is_closure && !other.is_closure
+        self.bcb == other.bcb && !self.is_hole && !other.is_hole
     }
 
     fn merge_from(&mut self, other: &Self) {
@@ -176,16 +176,16 @@ impl RefinedCovspan {
 ///  * Remove duplicate source code coverage regions
 ///  * Merge spans that represent continuous (both in source code and control flow), non-branching
 ///    execution
-///  * Carve out (leave uncovered) any span that will be counted by another MIR (notably, closures)
+///  * Carve out (leave uncovered) any "hole" spans that need to be left blank
+///    (e.g. closures that will be counted by their own MIR body)
 struct SpansRefiner {
     /// The initial set of coverage spans, sorted by `Span` (`lo` and `hi`) and by relative
     /// dominance between the `BasicCoverageBlock`s of equal `Span`s.
     sorted_spans_iter: std::vec::IntoIter<SpanFromMir>,
 
-    /// The current coverage span to compare to its `prev`, to possibly merge, discard, force the
-    /// discard of the `prev` (and or `pending_dups`), or keep both (with `prev` moved to
-    /// `pending_dups`). If `curr` is not discarded or merged, it becomes `prev` for the next
-    /// iteration.
+    /// The current coverage span to compare to its `prev`, to possibly merge, discard,
+    /// or cause `prev` to be modified or discarded.
+    /// If `curr` is not discarded or merged, it becomes `prev` for the next iteration.
     some_curr: Option<CurrCovspan>,
 
     /// The coverage span from a prior iteration; typically assigned from that iteration's `curr`.
@@ -229,7 +229,7 @@ impl SpansRefiner {
             let curr = self.curr();
 
             if prev.is_mergeable(curr) {
-                debug!("  same bcb (and neither is a closure), merge with prev={prev:?}");
+                debug!(?prev, "curr will be merged into prev");
                 let curr = self.take_curr();
                 self.prev_mut().merge_from(&curr);
             } else if prev.span.hi() <= curr.span.lo() {
@@ -238,15 +238,13 @@ impl SpansRefiner {
                 );
                 let prev = self.take_prev().into_refined();
                 self.refined_spans.push(prev);
-            } else if prev.is_closure {
+            } else if prev.is_hole {
                 // drop any equal or overlapping span (`curr`) and keep `prev` to test again in the
                 // next iter
-                debug!(
-                    "  curr overlaps a closure (prev). Drop curr and keep prev for next iter. prev={prev:?}",
-                );
+                debug!(?prev, "prev (a hole) overlaps curr, so discarding curr");
                 self.take_curr(); // Discards curr.
-            } else if curr.is_closure {
-                self.carve_out_span_for_closure();
+            } else if curr.is_hole {
+                self.carve_out_span_for_hole();
             } else {
                 self.cutoff_prev_at_overlapping_curr();
             }
@@ -270,10 +268,9 @@ impl SpansRefiner {
             }
         });
 
-        // Remove spans derived from closures, originally added to ensure the coverage
-        // regions for the current function leave room for the closure's own coverage regions
-        // (injected separately, from the closure's own MIR).
-        self.refined_spans.retain(|covspan| !covspan.is_closure);
+        // Discard hole spans, since their purpose was to carve out chunks from
+        // other spans, but we don't want the holes themselves in the final mappings.
+        self.refined_spans.retain(|covspan| !covspan.is_hole);
         self.refined_spans
     }
 
@@ -316,48 +313,43 @@ impl SpansRefiner {
             {
                 // Skip curr because prev has already advanced beyond the end of curr.
                 // This can only happen if a prior iteration updated `prev` to skip past
-                // a region of code, such as skipping past a closure.
-                debug!(
-                    "  prev.span starts after curr.span, so curr will be dropped (skipping past \
-                    closure?); prev={prev:?}",
-                );
+                // a region of code, such as skipping past a hole.
+                debug!(?prev, "prev.span starts after curr.span, so curr will be dropped");
             } else {
-                self.some_curr = Some(CurrCovspan::new(curr.span, curr.bcb, curr.is_closure));
+                self.some_curr = Some(CurrCovspan::new(curr.span, curr.bcb, curr.is_hole));
                 return true;
             }
         }
         false
     }
 
-    /// If `prev`s span extends left of the closure (`curr`), carve out the closure's span from
-    /// `prev`'s span. (The closure's coverage counters will be injected when processing the
-    /// closure's own MIR.) Add the portion of the span to the left of the closure; and if the span
-    /// extends to the right of the closure, update `prev` to that portion of the span. For any
-    /// `pending_dups`, repeat the same process.
-    fn carve_out_span_for_closure(&mut self) {
+    /// If `prev`s span extends left of the hole (`curr`), carve out the hole's span from
+    /// `prev`'s span. Add the portion of the span to the left of the hole; and if the span
+    /// extends to the right of the hole, update `prev` to that portion of the span.
+    fn carve_out_span_for_hole(&mut self) {
         let prev = self.prev();
         let curr = self.curr();
 
         let left_cutoff = curr.span.lo();
         let right_cutoff = curr.span.hi();
-        let has_pre_closure_span = prev.span.lo() < right_cutoff;
-        let has_post_closure_span = prev.span.hi() > right_cutoff;
-
-        if has_pre_closure_span {
-            let mut pre_closure = self.prev().refined_copy();
-            pre_closure.span = pre_closure.span.with_hi(left_cutoff);
-            debug!("  prev overlaps a closure. Adding span for pre_closure={:?}", pre_closure);
-            self.refined_spans.push(pre_closure);
+        let has_pre_hole_span = prev.span.lo() < right_cutoff;
+        let has_post_hole_span = prev.span.hi() > right_cutoff;
+
+        if has_pre_hole_span {
+            let mut pre_hole = prev.refined_copy();
+            pre_hole.span = pre_hole.span.with_hi(left_cutoff);
+            debug!(?pre_hole, "prev overlaps a hole; adding pre-hole span");
+            self.refined_spans.push(pre_hole);
         }
 
-        if has_post_closure_span {
-            // Mutate `prev.span` to start after the closure (and discard curr).
+        if has_post_hole_span {
+            // Mutate `prev.span` to start after the hole (and discard curr).
             self.prev_mut().span = self.prev().span.with_lo(right_cutoff);
-            debug!("  Mutated prev.span to start after the closure. prev={:?}", self.prev());
+            debug!(prev=?self.prev(), "mutated prev to start after the hole");
 
             // Prevent this curr from becoming prev.
-            let closure_covspan = self.take_curr().into_refined();
-            self.refined_spans.push(closure_covspan); // since self.prev() was already updated
+            let hole_covspan = self.take_curr().into_refined();
+            self.refined_spans.push(hole_covspan); // since self.prev() was already updated
         }
     }
 

compiler/rustc_mir_transform/src/coverage/spans/from_mir.rs

@@ -52,14 +52,14 @@ pub(super) fn mir_to_initial_sorted_coverage_spans(
             // - Span A extends further left, or
             // - Both have the same start and span A extends further right
             .then_with(|| Ord::cmp(&a.span.hi(), &b.span.hi()).reverse())
-            // If two spans have the same lo & hi, put closure spans first,
-            // as they take precedence over non-closure spans.
-            .then_with(|| Ord::cmp(&a.is_closure, &b.is_closure).reverse())
+            // If two spans have the same lo & hi, put hole spans first,
+            // as they take precedence over non-hole spans.
+            .then_with(|| Ord::cmp(&a.is_hole, &b.is_hole).reverse())
             // After deduplication, we want to keep only the most-dominated BCB.
             .then_with(|| basic_coverage_blocks.cmp_in_dominator_order(a.bcb, b.bcb).reverse())
     });
 
-    // Among covspans with the same span, keep only one. Closure spans take
+    // Among covspans with the same span, keep only one. Hole spans take
     // precedence, otherwise keep the one with the most-dominated BCB.
     // (Ideally we should try to preserve _all_ non-dominating BCBs, but that
     // requires a lot more complexity in the span refiner, for little benefit.)
@@ -78,8 +78,8 @@ pub(super) fn mir_to_initial_sorted_coverage_spans(
 fn remove_unwanted_macro_spans(initial_spans: &mut Vec<SpanFromMir>) {
     let mut seen_macro_spans = FxHashSet::default();
     initial_spans.retain(|covspan| {
-        // Ignore (retain) closure spans and non-macro-expansion spans.
-        if covspan.is_closure || covspan.visible_macro.is_none() {
+        // Ignore (retain) hole spans and non-macro-expansion spans.
+        if covspan.is_hole || covspan.visible_macro.is_none() {
             return true;
         }
 
@@ -96,7 +96,7 @@ fn split_visible_macro_spans(initial_spans: &mut Vec<SpanFromMir>) {
     let mut extra_spans = vec![];
 
     initial_spans.retain(|covspan| {
-        if covspan.is_closure {
+        if covspan.is_hole {
             return true;
         }
 
@@ -112,7 +112,7 @@ fn split_visible_macro_spans(initial_spans: &mut Vec<SpanFromMir>) {
             return true;
         }
 
-        assert!(!covspan.is_closure);
+        assert!(!covspan.is_hole);
         extra_spans.push(SpanFromMir::new(before, covspan.visible_macro, covspan.bcb, false));
         extra_spans.push(SpanFromMir::new(after, covspan.visible_macro, covspan.bcb, false));
         false // Discard the original covspan that we just split.
@@ -148,6 +148,8 @@ fn bcb_to_initial_coverage_spans<'a, 'tcx>(
             let expn_span = filtered_statement_span(statement)?;
             let (span, visible_macro) = unexpand(expn_span)?;
 
+            // A statement that looks like the assignment of a closure expression
+            // is treated as a "hole" span, to be carved out of other spans.
             Some(SpanFromMir::new(span, visible_macro, bcb, is_closure_like(statement)))
         });
 
@@ -336,7 +338,10 @@ pub(super) struct SpanFromMir {
     pub(super) span: Span,
     visible_macro: Option<Symbol>,
     pub(super) bcb: BasicCoverageBlock,
-    pub(super) is_closure: bool,
+    /// If true, this covspan represents a "hole" that should be carved out
+    /// from other spans, e.g. because it represents a closure expression that
+    /// will be instrumented separately as its own function.
+    pub(super) is_hole: bool,
 }
 
 impl SpanFromMir {
@@ -348,8 +353,8 @@ impl SpanFromMir {
         span: Span,
         visible_macro: Option<Symbol>,
         bcb: BasicCoverageBlock,
-        is_closure: bool,
+        is_hole: bool,
     ) -> Self {
-        Self { span, visible_macro, bcb, is_closure }
+        Self { span, visible_macro, bcb, is_hole }
     }
 }

compiler/rustc_target/src/lib.rs

@@ -9,9 +9,10 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![doc(rust_logo)]
+#![cfg_attr(bootstrap, feature(exhaustive_patterns))]
+#![cfg_attr(not(bootstrap), feature(min_exhaustive_patterns))]
 #![feature(rustdoc_internals)]
 #![feature(assert_matches)]
-#![feature(exhaustive_patterns)]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]
 #![cfg_attr(bootstrap, feature(min_specialization))]