Auto merge of #105348 - JohnTitor:rollup-q9bichr, r=JohnTitor

Rollup of 10 pull requests

Successful merges:

 - #104967 (Fix UI issues with Rustdoc scrape-examples feature.)
 - #105207 (interpret: clobber return place when calling function)
 - #105246 (Fix --pass in compiletest)
 - #105256 (Add small comment explaining what `method-margins.goml` test is about)
 - #105289 (Fix dupe word typos)
 - #105309 (rustdoc: remove no-op mobile CSS `.sidebar { margin: 0; padding: 0 }`)
 - #105313 (Update books)
 - #105315 (Normalize inherent associated types after substitution)
 - #105324 (Point at GAT `where` clause when an obligation is unsatisfied)
 - #105338 (Tweak "the following other types implement trait")

Failed merges:

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

Author: bors

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -240,7 +240,7 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
                     let align = ImmTy::from_uint(target_align, args[1].layout).into();
                     let fn_abi = self.fn_abi_of_instance(instance, ty::List::empty())?;
 
-                    // We replace the entire entire function call with a "tail call".
+                    // We replace the entire function call with a "tail call".
                     // Note that this happens before the frame of the original function
                     // is pushed on the stack.
                     self.eval_fn_call(

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -676,6 +676,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         return_to_block: StackPopCleanup,
     ) -> InterpResult<'tcx> {
         trace!("body: {:#?}", body);
+        // Clobber previous return place contents, nobody is supposed to be able to see them any more
+        // This also checks dereferenceable, but not align. We rely on all constructed places being
+        // sufficiently aligned (in particular we rely on `deref_operand` checking alignment).
+        self.write_uninit(return_place)?;
         // first push a stack frame so we have access to the local substs
         let pre_frame = Frame {
             body,

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1930,6 +1930,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     adt_substs,
                 );
                 let ty = tcx.bound_type_of(assoc_ty_did).subst(tcx, item_substs);
+                let ty = self.normalize_ty(span, ty);
                 return Ok((ty, DefKind::AssocTy, assoc_ty_did));
             }
         }

compiler/rustc_mir_dataflow/src/value_analysis.rs

@@ -406,7 +406,7 @@ impl<V: Clone> Clone for StateData<V> {
 /// The dataflow state for an instance of [`ValueAnalysis`].
 ///
 /// Every instance specifies a lattice that represents the possible values of a single tracked
-/// place. If we call this lattice `V` and set set of tracked places `P`, then a [`State`] is an
+/// place. If we call this lattice `V` and set of tracked places `P`, then a [`State`] is an
 /// element of `{unreachable} ∪ (P -> V)`. This again forms a lattice, where the bottom element is
 /// `unreachable` and the top element is the mapping `p ↦ ⊤`. Note that the mapping `p ↦ ⊥` is not
 /// the bottom element (because joining an unreachable and any other reachable state yields a

compiler/rustc_resolve/src/late.rs

@@ -1927,7 +1927,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                                 // We have a single lifetime => success.
                                 elision_lifetime = Elision::Param(res)
                             } else {
-                                // We have have multiple lifetimes => error.
+                                // We have multiple lifetimes => error.
                                 elision_lifetime = Elision::Err;
                             }
                         }

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

@@ -1810,7 +1810,8 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         &self,
         trait_pred: ty::PolyTraitPredicate<'tcx>,
     ) -> Vec<ImplCandidate<'tcx>> {
-        self.tcx
+        let mut candidates: Vec<_> = self
+            .tcx
             .all_impls(trait_pred.def_id())
             .filter_map(|def_id| {
                 if self.tcx.impl_polarity(def_id) == ty::ImplPolarity::Negative
@@ -1826,7 +1827,14 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 self.fuzzy_match_tys(trait_pred.skip_binder().self_ty(), imp.self_ty(), false)
                     .map(|similarity| ImplCandidate { trait_ref: imp, similarity })
             })
-            .collect()
+            .collect();
+        if candidates.iter().any(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. })) {
+            // If any of the candidates is a perfect match, we don't want to show all of them.
+            // This is particularly relevant for the case of numeric types (as they all have the
+            // same cathegory).
+            candidates.retain(|c| matches!(c.similarity, CandidateSimilarity::Exact { .. }));
+        }
+        candidates
     }
 
     fn report_similar_impl_candidates(

compiler/rustc_trait_selection/src/traits/project.rs

@@ -2321,11 +2321,10 @@ fn assoc_ty_own_obligations<'cx, 'tcx>(
     nested: &mut Vec<PredicateObligation<'tcx>>,
 ) {
     let tcx = selcx.tcx();
-    for predicate in tcx
+    let own = tcx
         .predicates_of(obligation.predicate.item_def_id)
-        .instantiate_own(tcx, obligation.predicate.substs)
-        .predicates
-    {
+        .instantiate_own(tcx, obligation.predicate.substs);
+    for (predicate, span) in std::iter::zip(own.predicates, own.spans) {
         let normalized = normalize_with_depth_to(
             selcx,
             obligation.param_env,
@@ -2334,9 +2333,30 @@ fn assoc_ty_own_obligations<'cx, 'tcx>(
             predicate,
             nested,
         );
+
+        let nested_cause = if matches!(
+            obligation.cause.code(),
+            super::CompareImplItemObligation { .. }
+                | super::CheckAssociatedTypeBounds { .. }
+                | super::AscribeUserTypeProvePredicate(..)
+        ) {
+            obligation.cause.clone()
+        } else if span.is_dummy() {
+            ObligationCause::new(
+                obligation.cause.span,
+                obligation.cause.body_id,
+                super::ItemObligation(obligation.predicate.item_def_id),
+            )
+        } else {
+            ObligationCause::new(
+                obligation.cause.span,
+                obligation.cause.body_id,
+                super::BindingObligation(obligation.predicate.item_def_id, span),
+            )
+        };
         nested.push(Obligation::with_depth(
             tcx,
-            obligation.cause.clone(),
+            nested_cause,
             obligation.recursion_depth + 1,
             obligation.param_env,
             normalized,

library/core/src/iter/sources/repeat_n.rs

@@ -20,7 +20,7 @@ use crate::mem::ManuallyDrop;
 /// #![feature(iter_repeat_n)]
 /// use std::iter;
 ///
-/// // four of the the number four:
+/// // four of the number four:
 /// let mut four_fours = iter::repeat_n(4, 4);
 ///
 /// assert_eq!(Some(4), four_fours.next());

library/core/src/str/pattern.rs

@@ -1894,7 +1894,7 @@ unsafe fn small_slice_eq(x: &[u8], y: &[u8]) -> bool {
     // Thus, derefencing both `px` and `py` in the loop below is safe.
     //
     // Moreover, we set `pxend` and `pyend` to be 4 bytes before the actual
-    // end of of `px` and `py`. Thus, the final dereference outside of the
+    // end of `px` and `py`. Thus, the final dereference outside of the
     // loop is guaranteed to be valid. (The final comparison will overlap with
     // the last comparison done in the loop for lengths that aren't multiples
     // of four.)

library/std/src/sync/mpmc/array.rs

@@ -225,7 +225,7 @@ impl<T> Channel<T> {
             let slot = unsafe { self.buffer.get_unchecked(index) };
             let stamp = slot.stamp.load(Ordering::Acquire);
 
-            // If the the stamp is ahead of the head by 1, we may attempt to pop.
+            // If the stamp is ahead of the head by 1, we may attempt to pop.
             if head + 1 == stamp {
                 let new = if index + 1 < self.cap {
                     // Same lap, incremented index.