diff --git a/Cargo.lock b/Cargo.lock
index cfdd873e80fab..79ffbaeb6d2bb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -737,6 +737,7 @@ dependencies = [
  "libc",
  "miow",
  "miropt-test-tools",
+ "rayon",
  "regex",
  "rustfix",
  "semver",
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 27f7f95f100e2..04c8118b6160c 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -594,6 +594,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     fn load(&mut self, ty: &'ll Type, ptr: &'ll Value, align: Align) -> &'ll Value {
         unsafe {
             let load = llvm::LLVMBuildLoad2(self.llbuilder, ty, ptr, UNNAMED);
+            let align = align.min(self.cx().tcx.sess.target.max_reliable_alignment());
             llvm::LLVMSetAlignment(load, align.bytes() as c_uint);
             load
         }
@@ -807,6 +808,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         assert_eq!(self.cx.type_kind(self.cx.val_ty(ptr)), TypeKind::Pointer);
         unsafe {
             let store = llvm::LLVMBuildStore(self.llbuilder, val, ptr);
+            let align = align.min(self.cx().tcx.sess.target.max_reliable_alignment());
             let align =
                 if flags.contains(MemFlags::UNALIGNED) { 1 } else { align.bytes() as c_uint };
             llvm::LLVMSetAlignment(store, align);
diff --git a/compiler/rustc_mir_transform/src/check_alignment.rs b/compiler/rustc_mir_transform/src/check_alignment.rs
index b70cca1484070..5115583f37c0f 100644
--- a/compiler/rustc_mir_transform/src/check_alignment.rs
+++ b/compiler/rustc_mir_transform/src/check_alignment.rs
@@ -1,3 +1,4 @@
+use rustc_abi::Align;
 use rustc_index::IndexVec;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::visit::PlaceContext;
@@ -11,10 +12,6 @@ pub(super) struct CheckAlignment;
 
 impl<'tcx> crate::MirPass<'tcx> for CheckAlignment {
     fn is_enabled(&self, sess: &Session) -> bool {
-        // FIXME(#112480) MSVC and rustc disagree on minimum stack alignment on x86 Windows
-        if sess.target.llvm_target == "i686-pc-windows-msvc" {
-            return false;
-        }
         sess.ub_checks()
     }
 
@@ -87,6 +84,33 @@ fn insert_alignment_check<'tcx>(
         ))),
     });
 
+    // If this target does not have reliable alignment, further limit the mask by anding it with
+    // the mask for the highest reliable alignment.
+    #[allow(irrefutable_let_patterns)]
+    if let max_align = tcx.sess.target.max_reliable_alignment()
+        && max_align < Align::MAX
+    {
+        let max_mask = max_align.bytes() - 1;
+        let max_mask = Operand::Constant(Box::new(ConstOperand {
+            span: source_info.span,
+            user_ty: None,
+            const_: Const::Val(
+                ConstValue::Scalar(Scalar::from_target_usize(max_mask, &tcx)),
+                tcx.types.usize,
+            ),
+        }));
+        stmts.push(Statement {
+            source_info,
+            kind: StatementKind::Assign(Box::new((
+                alignment_mask,
+                Rvalue::BinaryOp(
+                    BinOp::BitAnd,
+                    Box::new((Operand::Copy(alignment_mask), max_mask)),
+                ),
+            ))),
+        });
+    }
+
     // BitAnd the alignment mask with the pointer
     let alignment_bits =
         local_decls.push(LocalDecl::with_source_info(tcx.types.usize, source_info)).into();
diff --git a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
index 827853be280ed..3404c47bba2a3 100644
--- a/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/trait_goals.rs
@@ -1308,18 +1308,6 @@ where
                     return true;
                 }
 
-                // We don't consider a trait-bound global if it has a projection bound.
-                //
-                // See ui/traits/next-solver/normalization-shadowing/global-trait-with-project.rs
-                // for an example where this is necessary.
-                for p in goal.param_env.caller_bounds().iter() {
-                    if let ty::ClauseKind::Projection(proj) = p.kind().skip_binder() {
-                        if proj.projection_term.trait_ref(self.cx()) == trait_pred.trait_ref {
-                            return true;
-                        }
-                    }
-                }
-
                 false
             }
             _ => false,
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 39251f1ce2737..4be8a90368d29 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -2058,6 +2058,17 @@ impl<'a> Parser<'a> {
         }
         self.expect_field_ty_separator()?;
         let ty = self.parse_ty()?;
+        if self.token == token::Colon && self.look_ahead(1, |&t| t != token::Colon) {
+            self.dcx()
+                .struct_span_err(self.token.span, "found single colon in a struct field type path")
+                .with_span_suggestion_verbose(
+                    self.token.span,
+                    "write a path separator here",
+                    "::",
+                    Applicability::MaybeIncorrect,
+                )
+                .emit();
+        }
         let default = if self.token == token::Eq {
             self.bump();
             let const_expr = self.parse_expr_anon_const()?;
diff --git a/compiler/rustc_parse/src/parser/path.rs b/compiler/rustc_parse/src/parser/path.rs
index 1a02d45f0e3ce..1093e4f4af0a5 100644
--- a/compiler/rustc_parse/src/parser/path.rs
+++ b/compiler/rustc_parse/src/parser/path.rs
@@ -248,19 +248,13 @@ impl<'a> Parser<'a> {
             segments.push(segment);
 
             if self.is_import_coupler() || !self.eat_path_sep() {
-                let ok_for_recovery = self.may_recover()
-                    && match style {
-                        PathStyle::Expr => true,
-                        PathStyle::Type if let Some((ident, _)) = self.prev_token.ident() => {
-                            self.token == token::Colon
-                                && ident.as_str().chars().all(|c| c.is_lowercase())
-                                && self.token.span.lo() == self.prev_token.span.hi()
-                                && self
-                                    .look_ahead(1, |token| self.token.span.hi() == token.span.lo())
-                        }
-                        _ => false,
-                    };
-                if ok_for_recovery
+                // IMPORTANT: We can *only ever* treat single colons as typo'ed double colons in
+                // expression contexts (!) since only there paths cannot possibly be followed by
+                // a colon and still form a syntactically valid construct. In pattern contexts,
+                // a path may be followed by a type annotation. E.g., `let pat:ty`. In type
+                // contexts, a path may be followed by a list of bounds. E.g., `where ty:bound`.
+                if self.may_recover()
+                    && style == PathStyle::Expr // (!)
                     && self.token == token::Colon
                     && self.look_ahead(1, |token| token.is_ident() && !token.is_reserved_ident())
                 {
diff --git a/compiler/rustc_target/src/callconv/mod.rs b/compiler/rustc_target/src/callconv/mod.rs
index 7ecc46cc69db9..ae366e29e3232 100644
--- a/compiler/rustc_target/src/callconv/mod.rs
+++ b/compiler/rustc_target/src/callconv/mod.rs
@@ -144,6 +144,7 @@ pub struct ArgAttributes {
     /// (corresponding to LLVM's dereferenceable_or_null attributes, i.e., it is okay for this to be
     /// set on a null pointer, but all non-null pointers must be dereferenceable).
     pub pointee_size: Size,
+    /// The minimum alignment of the pointee, if any.
     pub pointee_align: Option<Align>,
 }
 
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 3c769dad630a1..37ea0d6e7b58c 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -42,7 +42,9 @@ use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::{fmt, io};
 
-use rustc_abi::{Endian, ExternAbi, Integer, Size, TargetDataLayout, TargetDataLayoutErrors};
+use rustc_abi::{
+    Align, Endian, ExternAbi, Integer, Size, TargetDataLayout, TargetDataLayoutErrors,
+};
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_fs_util::try_canonicalize;
 use rustc_macros::{Decodable, Encodable, HashStable_Generic};
@@ -3599,6 +3601,25 @@ impl Target {
             _ => return None,
         })
     }
+
+    /// Returns whether this target is known to have unreliable alignment:
+    /// native C code for the target fails to align some data to the degree
+    /// required by the C standard. We can't *really* do anything about that
+    /// since unsafe Rust code may assume alignment any time, but we can at least
+    /// inhibit some optimizations, and we suppress the alignment checks that
+    /// would detect this unsoundness.
+    ///
+    /// Every target that returns less than `Align::MAX` here is still has a soundness bug.
+    pub fn max_reliable_alignment(&self) -> Align {
+        // FIXME(#112480) MSVC on x86-32 is unsound and fails to properly align many types with
+        // more-than-4-byte-alignment on the stack. This makes alignments larger than 4 generally
+        // unreliable on 32bit Windows.
+        if self.is_like_windows && self.arch == "x86" {
+            Align::from_bytes(4).unwrap()
+        } else {
+            Align::MAX
+        }
+    }
 }
 
 /// Either a target tuple string or a path to a JSON file.
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index cf6d2bc151fb0..00101010f14fa 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -240,8 +240,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             if !drcx.args_may_unify(obligation_args, bound_trait_ref.skip_binder().args) {
                 continue;
             }
-            // FIXME(oli-obk): it is suspicious that we are dropping the constness and
-            // polarity here.
             let wc = self.where_clause_may_apply(stack, bound_trait_ref)?;
             if wc.may_apply() {
                 candidates.vec.push(ParamCandidate(bound));
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index 54b6c22b2d821..cad7e42fd8212 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -1,3 +1,8 @@
+//! Core logic responsible for determining what it means for various type system
+//! primitives to be "well formed". Actually checking whether these primitives are
+//! well formed is performed elsewhere (e.g. during type checking or item well formedness
+//! checking).
+
 use std::iter;
 
 use rustc_hir as hir;
@@ -15,12 +20,13 @@ use tracing::{debug, instrument, trace};
 
 use crate::infer::InferCtxt;
 use crate::traits;
+
 /// Returns the set of obligations needed to make `arg` well-formed.
 /// If `arg` contains unresolved inference variables, this may include
 /// further WF obligations. However, if `arg` IS an unresolved
 /// inference variable, returns `None`, because we are not able to
-/// make any progress at all. This is to prevent "livelock" where we
-/// say "$0 is WF if $0 is WF".
+/// make any progress at all. This is to prevent cycles where we
+/// say "?0 is WF if ?0 is WF".
 pub fn obligations<'tcx>(
     infcx: &InferCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
@@ -29,14 +35,14 @@ pub fn obligations<'tcx>(
     arg: GenericArg<'tcx>,
     span: Span,
 ) -> Option<PredicateObligations<'tcx>> {
-    // Handle the "livelock" case (see comment above) by bailing out if necessary.
+    // Handle the "cycle" case (see comment above) by bailing out if necessary.
     let arg = match arg.unpack() {
         GenericArgKind::Type(ty) => {
             match ty.kind() {
                 ty::Infer(ty::TyVar(_)) => {
                     let resolved_ty = infcx.shallow_resolve(ty);
                     if resolved_ty == ty {
-                        // No progress, bail out to prevent "livelock".
+                        // No progress, bail out to prevent cycles.
                         return None;
                     } else {
                         resolved_ty
@@ -51,7 +57,7 @@ pub fn obligations<'tcx>(
                 ty::ConstKind::Infer(_) => {
                     let resolved = infcx.shallow_resolve_const(ct);
                     if resolved == ct {
-                        // No progress.
+                        // No progress, bail out to prevent cycles.
                         return None;
                     } else {
                         resolved
@@ -74,7 +80,7 @@ pub fn obligations<'tcx>(
         recursion_depth,
         item: None,
     };
-    wf.compute(arg);
+    wf.add_wf_preds_for_generic_arg(arg);
     debug!("wf::obligations({:?}, body_id={:?}) = {:?}", arg, body_id, wf.out);
 
     let result = wf.normalize(infcx);
@@ -97,7 +103,7 @@ pub fn unnormalized_obligations<'tcx>(
 
     // However, if `arg` IS an unresolved inference variable, returns `None`,
     // because we are not able to make any progress at all. This is to prevent
-    // "livelock" where we say "$0 is WF if $0 is WF".
+    // cycles where we say "?0 is WF if ?0 is WF".
     if arg.is_non_region_infer() {
         return None;
     }
@@ -115,7 +121,7 @@ pub fn unnormalized_obligations<'tcx>(
         recursion_depth: 0,
         item: None,
     };
-    wf.compute(arg);
+    wf.add_wf_preds_for_generic_arg(arg);
     Some(wf.out)
 }
 
@@ -140,7 +146,7 @@ pub fn trait_obligations<'tcx>(
         recursion_depth: 0,
         item: Some(item),
     };
-    wf.compute_trait_pred(trait_pred, Elaborate::All);
+    wf.add_wf_preds_for_trait_pred(trait_pred, Elaborate::All);
     debug!(obligations = ?wf.out);
     wf.normalize(infcx)
 }
@@ -171,7 +177,7 @@ pub fn clause_obligations<'tcx>(
     // It's ok to skip the binder here because wf code is prepared for it
     match clause.kind().skip_binder() {
         ty::ClauseKind::Trait(t) => {
-            wf.compute_trait_pred(t, Elaborate::None);
+            wf.add_wf_preds_for_trait_pred(t, Elaborate::None);
         }
         ty::ClauseKind::HostEffect(..) => {
             // Technically the well-formedness of this predicate is implied by
@@ -179,22 +185,22 @@ pub fn clause_obligations<'tcx>(
         }
         ty::ClauseKind::RegionOutlives(..) => {}
         ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(ty, _reg)) => {
-            wf.compute(ty.into());
+            wf.add_wf_preds_for_generic_arg(ty.into());
         }
         ty::ClauseKind::Projection(t) => {
-            wf.compute_alias_term(t.projection_term);
-            wf.compute(t.term.into_arg());
+            wf.add_wf_preds_for_alias_term(t.projection_term);
+            wf.add_wf_preds_for_generic_arg(t.term.into_arg());
         }
         ty::ClauseKind::ConstArgHasType(ct, ty) => {
-            wf.compute(ct.into());
-            wf.compute(ty.into());
+            wf.add_wf_preds_for_generic_arg(ct.into());
+            wf.add_wf_preds_for_generic_arg(ty.into());
         }
         ty::ClauseKind::WellFormed(arg) => {
-            wf.compute(arg);
+            wf.add_wf_preds_for_generic_arg(arg);
         }
 
         ty::ClauseKind::ConstEvaluatable(ct) => {
-            wf.compute(ct.into());
+            wf.add_wf_preds_for_generic_arg(ct.into());
         }
     }
 
@@ -372,14 +378,18 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
     }
 
     /// Pushes the obligations required for `trait_ref` to be WF into `self.out`.
-    fn compute_trait_pred(&mut self, trait_pred: ty::TraitPredicate<'tcx>, elaborate: Elaborate) {
+    fn add_wf_preds_for_trait_pred(
+        &mut self,
+        trait_pred: ty::TraitPredicate<'tcx>,
+        elaborate: Elaborate,
+    ) {
         let tcx = self.tcx();
         let trait_ref = trait_pred.trait_ref;
 
         // Negative trait predicates don't require supertraits to hold, just
         // that their args are WF.
         if trait_pred.polarity == ty::PredicatePolarity::Negative {
-            self.compute_negative_trait_pred(trait_ref);
+            self.add_wf_preds_for_negative_trait_pred(trait_ref);
             return;
         }
 
@@ -445,15 +455,15 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
 
     // Compute the obligations that are required for `trait_ref` to be WF,
     // given that it is a *negative* trait predicate.
-    fn compute_negative_trait_pred(&mut self, trait_ref: ty::TraitRef<'tcx>) {
+    fn add_wf_preds_for_negative_trait_pred(&mut self, trait_ref: ty::TraitRef<'tcx>) {
         for arg in trait_ref.args {
-            self.compute(arg);
+            self.add_wf_preds_for_generic_arg(arg);
         }
     }
 
     /// Pushes the obligations required for an alias (except inherent) to be WF
     /// into `self.out`.
-    fn compute_alias_term(&mut self, data: ty::AliasTerm<'tcx>) {
+    fn add_wf_preds_for_alias_term(&mut self, data: ty::AliasTerm<'tcx>) {
         // A projection is well-formed if
         //
         // (a) its predicates hold (*)
@@ -478,13 +488,13 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
         let obligations = self.nominal_obligations(data.def_id, data.args);
         self.out.extend(obligations);
 
-        self.compute_projection_args(data.args);
+        self.add_wf_preds_for_projection_args(data.args);
     }
 
     /// Pushes the obligations required for an inherent alias to be WF
     /// into `self.out`.
     // FIXME(inherent_associated_types): Merge this function with `fn compute_alias`.
-    fn compute_inherent_projection(&mut self, data: ty::AliasTy<'tcx>) {
+    fn add_wf_preds_for_inherent_projection(&mut self, data: ty::AliasTy<'tcx>) {
         // An inherent projection is well-formed if
         //
         // (a) its predicates hold (*)
@@ -511,7 +521,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
         data.args.visit_with(self);
     }
 
-    fn compute_projection_args(&mut self, args: GenericArgsRef<'tcx>) {
+    fn add_wf_preds_for_projection_args(&mut self, args: GenericArgsRef<'tcx>) {
         let tcx = self.tcx();
         let cause = self.cause(ObligationCauseCode::WellFormed(None));
         let param_env = self.param_env;
@@ -557,7 +567,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
 
     /// Pushes all the predicates needed to validate that `ty` is WF into `out`.
     #[instrument(level = "debug", skip(self))]
-    fn compute(&mut self, arg: GenericArg<'tcx>) {
+    fn add_wf_preds_for_generic_arg(&mut self, arg: GenericArg<'tcx>) {
         arg.visit_with(self);
         debug!(?self.out);
     }
@@ -596,7 +606,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
             .collect()
     }
 
-    fn from_object_ty(
+    fn add_wf_preds_for_dyn_ty(
         &mut self,
         ty: Ty<'tcx>,
         data: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
@@ -651,6 +661,13 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                     outlives,
                 ));
             }
+
+            // We don't add any wf predicates corresponding to the trait ref's generic arguments
+            // which allows code like this to compile:
+            // ```rust
+            // trait Trait<T: Sized> {}
+            // fn foo(_: &dyn Trait<[u32]>) {}
+            // ```
         }
     }
 }
@@ -761,7 +778,7 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
                 self.out.extend(obligations);
             }
             ty::Alias(ty::Inherent, data) => {
-                self.compute_inherent_projection(data);
+                self.add_wf_preds_for_inherent_projection(data);
                 return; // Subtree handled by compute_inherent_projection.
             }
 
@@ -895,7 +912,7 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
                 //
                 // Here, we defer WF checking due to higher-ranked
                 // regions. This is perhaps not ideal.
-                self.from_object_ty(t, data, r);
+                self.add_wf_preds_for_dyn_ty(t, data, r);
 
                 // FIXME(#27579) RFC also considers adding trait
                 // obligations that don't refer to Self and
@@ -917,11 +934,11 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
             // 1. Check if they have been resolved, and if so proceed with
             //    THAT type.
             // 2. If not, we've at least simplified things (e.g., we went
-            //    from `Vec<$0>: WF` to `$0: WF`), so we can
+            //    from `Vec?0>: WF` to `?0: WF`), so we can
             //    register a pending obligation and keep
             //    moving. (Goal is that an "inductive hypothesis"
             //    is satisfied to ensure termination.)
-            // See also the comment on `fn obligations`, describing "livelock"
+            // See also the comment on `fn obligations`, describing cycle
             // prevention, which happens before this can be reached.
             ty::Infer(_) => {
                 let cause = self.cause(ObligationCauseCode::WellFormed(None));
diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs
index 3d4ab33240af2..63ea035bd0e8e 100644
--- a/compiler/rustc_ty_utils/src/abi.rs
+++ b/compiler/rustc_ty_utils/src/abi.rs
@@ -347,7 +347,8 @@ fn adjust_for_rust_scalar<'tcx>(
             None
         };
         if let Some(kind) = kind {
-            attrs.pointee_align = Some(pointee.align);
+            attrs.pointee_align =
+                Some(pointee.align.min(cx.tcx().sess.target.max_reliable_alignment()));
 
             // `Box` are not necessarily dereferenceable for the entire duration of the function as
             // they can be deallocated at any time. Same for non-frozen shared references (see
diff --git a/library/core/src/num/f128.rs b/library/core/src/num/f128.rs
index 2ee25969289fc..e25f7091c933c 100644
--- a/library/core/src/num/f128.rs
+++ b/library/core/src/num/f128.rs
@@ -804,7 +804,7 @@ impl f128 {
         }
     }
 
-    /// Calculates the middle point of `self` and `rhs`.
+    /// Calculates the midpoint (average) between `self` and `rhs`.
     ///
     /// This returns NaN when *either* argument is NaN or if a combination of
     /// +inf and -inf is provided as arguments.
@@ -821,6 +821,7 @@ impl f128 {
     /// # }
     /// ```
     #[inline]
+    #[doc(alias = "average")]
     #[unstable(feature = "f128", issue = "116909")]
     #[rustc_const_unstable(feature = "f128", issue = "116909")]
     pub const fn midpoint(self, other: f128) -> f128 {
diff --git a/library/core/src/num/f16.rs b/library/core/src/num/f16.rs
index 69882d13c177f..bd00ed0f4ede0 100644
--- a/library/core/src/num/f16.rs
+++ b/library/core/src/num/f16.rs
@@ -792,7 +792,7 @@ impl f16 {
         }
     }
 
-    /// Calculates the middle point of `self` and `rhs`.
+    /// Calculates the midpoint (average) between `self` and `rhs`.
     ///
     /// This returns NaN when *either* argument is NaN or if a combination of
     /// +inf and -inf is provided as arguments.
@@ -808,6 +808,7 @@ impl f16 {
     /// # }
     /// ```
     #[inline]
+    #[doc(alias = "average")]
     #[unstable(feature = "f16", issue = "116909")]
     #[rustc_const_unstable(feature = "f16", issue = "116909")]
     pub const fn midpoint(self, other: f16) -> f16 {
diff --git a/library/core/src/num/f32.rs b/library/core/src/num/f32.rs
index 7e056a6c1f3fa..c95ad2d0f35ad 100644
--- a/library/core/src/num/f32.rs
+++ b/library/core/src/num/f32.rs
@@ -986,7 +986,7 @@ impl f32 {
         }
     }
 
-    /// Calculates the middle point of `self` and `rhs`.
+    /// Calculates the midpoint (average) between `self` and `rhs`.
     ///
     /// This returns NaN when *either* argument is NaN or if a combination of
     /// +inf and -inf is provided as arguments.
@@ -998,6 +998,7 @@ impl f32 {
     /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
     /// ```
     #[inline]
+    #[doc(alias = "average")]
     #[stable(feature = "num_midpoint", since = "1.85.0")]
     #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
     pub const fn midpoint(self, other: f32) -> f32 {
diff --git a/library/core/src/num/f64.rs b/library/core/src/num/f64.rs
index b9ebbb1d76497..16b762ed6f0c9 100644
--- a/library/core/src/num/f64.rs
+++ b/library/core/src/num/f64.rs
@@ -1004,7 +1004,7 @@ impl f64 {
         }
     }
 
-    /// Calculates the middle point of `self` and `rhs`.
+    /// Calculates the midpoint (average) between `self` and `rhs`.
     ///
     /// This returns NaN when *either* argument is NaN or if a combination of
     /// +inf and -inf is provided as arguments.
@@ -1016,6 +1016,7 @@ impl f64 {
     /// assert_eq!((-5.5f64).midpoint(8.0), 1.25);
     /// ```
     #[inline]
+    #[doc(alias = "average")]
     #[stable(feature = "num_midpoint", since = "1.85.0")]
     #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
     pub const fn midpoint(self, other: f64) -> f64 {
diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
index 348457e2c00f6..ecc1c7bf9021d 100644
--- a/library/core/src/num/mod.rs
+++ b/library/core/src/num/mod.rs
@@ -130,7 +130,7 @@ depending on the target pointer size.
 
 macro_rules! midpoint_impl {
     ($SelfT:ty, unsigned) => {
-        /// Calculates the middle point of `self` and `rhs`.
+        /// Calculates the midpoint (average) between `self` and `rhs`.
         ///
         /// `midpoint(a, b)` is `(a + b) / 2` as if it were performed in a
         /// sufficiently-large unsigned integral type. This implies that the result is
@@ -146,6 +146,8 @@ macro_rules! midpoint_impl {
         #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
+        #[doc(alias = "average_floor")]
+        #[doc(alias = "average")]
         #[inline]
         pub const fn midpoint(self, rhs: $SelfT) -> $SelfT {
             // Use the well known branchless algorithm from Hacker's Delight to compute
@@ -154,7 +156,7 @@ macro_rules! midpoint_impl {
         }
     };
     ($SelfT:ty, signed) => {
-        /// Calculates the middle point of `self` and `rhs`.
+        /// Calculates the midpoint (average) between `self` and `rhs`.
         ///
         /// `midpoint(a, b)` is `(a + b) / 2` as if it were performed in a
         /// sufficiently-large signed integral type. This implies that the result is
@@ -173,6 +175,9 @@ macro_rules! midpoint_impl {
         #[rustc_const_stable(feature = "num_midpoint_signed", since = "1.87.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
+        #[doc(alias = "average_floor")]
+        #[doc(alias = "average_ceil")]
+        #[doc(alias = "average")]
         #[inline]
         pub const fn midpoint(self, rhs: Self) -> Self {
             // Use the well known branchless algorithm from Hacker's Delight to compute
@@ -184,7 +189,7 @@ macro_rules! midpoint_impl {
         }
     };
     ($SelfT:ty, $WideT:ty, unsigned) => {
-        /// Calculates the middle point of `self` and `rhs`.
+        /// Calculates the midpoint (average) between `self` and `rhs`.
         ///
         /// `midpoint(a, b)` is `(a + b) / 2` as if it were performed in a
         /// sufficiently-large unsigned integral type. This implies that the result is
@@ -200,13 +205,15 @@ macro_rules! midpoint_impl {
         #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
+        #[doc(alias = "average_floor")]
+        #[doc(alias = "average")]
         #[inline]
         pub const fn midpoint(self, rhs: $SelfT) -> $SelfT {
             ((self as $WideT + rhs as $WideT) / 2) as $SelfT
         }
     };
     ($SelfT:ty, $WideT:ty, signed) => {
-        /// Calculates the middle point of `self` and `rhs`.
+        /// Calculates the midpoint (average) between `self` and `rhs`.
         ///
         /// `midpoint(a, b)` is `(a + b) / 2` as if it were performed in a
         /// sufficiently-large signed integral type. This implies that the result is
@@ -225,6 +232,9 @@ macro_rules! midpoint_impl {
         #[rustc_const_stable(feature = "num_midpoint_signed", since = "1.87.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
+        #[doc(alias = "average_floor")]
+        #[doc(alias = "average_ceil")]
+        #[doc(alias = "average")]
         #[inline]
         pub const fn midpoint(self, rhs: $SelfT) -> $SelfT {
             ((self as $WideT + rhs as $WideT) / 2) as $SelfT
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 1b79112aec1fe..8a8b2733d5e88 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -1589,7 +1589,7 @@ macro_rules! nonzero_integer_signedness_dependent_methods {
             super::int_log10::$Int(self.get())
         }
 
-        /// Calculates the middle point of `self` and `rhs`.
+        /// Calculates the midpoint (average) between `self` and `rhs`.
         ///
         /// `midpoint(a, b)` is `(a + b) >> 1` as if it were performed in a
         /// sufficiently-large signed integral type. This implies that the result is
@@ -1615,6 +1615,8 @@ macro_rules! nonzero_integer_signedness_dependent_methods {
         #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
+        #[doc(alias = "average_floor")]
+        #[doc(alias = "average")]
         #[inline]
         pub const fn midpoint(self, rhs: Self) -> Self {
             // SAFETY: The only way to get `0` with midpoint is to have two opposite or
diff --git a/src/doc/rustc-dev-guide/src/tests/minicore.md b/src/doc/rustc-dev-guide/src/tests/minicore.md
index e4853b6d40e35..507b259e0275d 100644
--- a/src/doc/rustc-dev-guide/src/tests/minicore.md
+++ b/src/doc/rustc-dev-guide/src/tests/minicore.md
@@ -6,25 +6,37 @@
 ui/codegen/assembly test suites. It provides `core` stubs for tests that need to
 build for cross-compiled targets but do not need/want to run.
 
+<div class="warning">
+Please note that [`minicore`] is only intended for `core` items, and explicitly
+**not** `std` or `alloc` items because `core` items are applicable to a wider
+range of tests.
+</div>
+
 A test can use [`minicore`] by specifying the `//@ add-core-stubs` directive.
 Then, mark the test with `#![feature(no_core)]` + `#![no_std]` + `#![no_core]`.
 Due to Edition 2015 extern prelude rules, you will probably need to declare
 `minicore` as an extern crate.
 
+## Implied compiler flags
+
 Due to the `no_std` + `no_core` nature of these tests, `//@ add-core-stubs`
 implies and requires that the test will be built with `-C panic=abort`.
-Unwinding panics are not supported.
+**Unwinding panics are not supported.**
+
+Tests will also be built with `-C force-unwind-tables=yes` to preserve CFI
+directives in assembly tests.
+
+TL;DR: `//@ add-core-stubs` implies two compiler flags:
+
+1. `-C panic=abort`
+2. `-C force-unwind-tables=yes`
+
+## Adding more `core` stubs
 
 If you find a `core` item to be missing from the [`minicore`] stub, consider
 adding it to the test auxiliary if it's likely to be used or is already needed
 by more than one test.
 
-<div class="warning">
-Please note that [`minicore`] is only intended for `core` items, and explicitly
-**not** `std` or `alloc` items because `core` items are applicable to a wider
-range of tests.
-</div>
-
 ## Example codegen test that uses `minicore`
 
 ```rust,no_run
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 9870e5011ebf6..50c7ae3ef8db2 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -34,7 +34,7 @@ target | notes
 -------|-------
 [`aarch64-apple-darwin`](platform-support/apple-darwin.md) | ARM64 macOS (11.0+, Big Sur+)
 `aarch64-unknown-linux-gnu` | ARM64 Linux (kernel 4.1, glibc 2.17+)
-`i686-pc-windows-msvc` | 32-bit MSVC (Windows 10+, Windows Server 2016+, Pentium 4) [^x86_32-floats-return-ABI]
+`i686-pc-windows-msvc` | 32-bit MSVC (Windows 10+, Windows Server 2016+, Pentium 4) [^x86_32-floats-return-ABI] [^win32-msvc-alignment]
 `i686-unknown-linux-gnu` | 32-bit Linux (kernel 3.2+, glibc 2.17+, Pentium 4) [^x86_32-floats-return-ABI]
 [`x86_64-apple-darwin`](platform-support/apple-darwin.md) | 64-bit macOS (10.12+, Sierra+)
 [`x86_64-pc-windows-gnu`](platform-support/windows-gnu.md) | 64-bit MinGW (Windows 10+, Windows Server 2016+)
@@ -43,6 +43,8 @@ target | notes
 
 [^x86_32-floats-return-ABI]: Due to limitations of the C ABI, floating-point support on `i686` targets is non-compliant: floating-point return values are passed via an x87 register, so NaN payload bits can be lost. Functions with the default Rust ABI are not affected. See [issue #115567][x86-32-float-return-issue].
 
+[^win32-msvc-alignment]: Due to non-standard behavior of MSVC, native C code on this target can cause types with an alignment of more than 4 bytes to be incorrectly aligned to only 4 bytes (this affects, e.g., `u64` and `i64`). Rust applies some mitigations to reduce the impact of this issue, but this can still cause unsoundness due to unsafe code that (correctly) assumes that references are always properly aligned. See [issue #112480](https://github.com/rust-lang/rust/issues/112480).
+
 [77071]: https://github.com/rust-lang/rust/issues/77071
 [x86-32-float-return-issue]: https://github.com/rust-lang/rust/issues/115567
 
@@ -95,7 +97,7 @@ target | notes
 [`armv7-unknown-linux-ohos`](platform-support/openharmony.md) | Armv7-A OpenHarmony
 [`loongarch64-unknown-linux-gnu`](platform-support/loongarch-linux.md) | LoongArch64 Linux, LP64D ABI (kernel 5.19, glibc 2.36)
 [`loongarch64-unknown-linux-musl`](platform-support/loongarch-linux.md) | LoongArch64 Linux, LP64D ABI (kernel 5.19, musl 1.2.5)
-[`i686-pc-windows-gnu`](platform-support/windows-gnu.md) | 32-bit MinGW (Windows 10+, Windows Server 2016+, Pentium 4) [^x86_32-floats-return-ABI]
+[`i686-pc-windows-gnu`](platform-support/windows-gnu.md) | 32-bit MinGW (Windows 10+, Windows Server 2016+, Pentium 4) [^x86_32-floats-return-ABI] [^win32-msvc-alignment]
 `powerpc-unknown-linux-gnu` | PowerPC Linux (kernel 3.2, glibc 2.17)
 `powerpc64-unknown-linux-gnu` | PPC64 Linux (kernel 3.2, glibc 2.17)
 [`powerpc64le-unknown-linux-gnu`](platform-support/powerpc64le-unknown-linux-gnu.md) | PPC64LE Linux (kernel 3.10, glibc 2.17)
@@ -169,7 +171,7 @@ target | std | notes
 [`i686-pc-windows-gnullvm`](platform-support/windows-gnullvm.md) | ✓ | 32-bit x86 MinGW (Windows 10+, Pentium 4), LLVM ABI [^x86_32-floats-return-ABI]
 [`i686-unknown-freebsd`](platform-support/freebsd.md) | ✓ | 32-bit x86 FreeBSD (Pentium 4) [^x86_32-floats-return-ABI]
 `i686-unknown-linux-musl` | ✓ | 32-bit Linux with musl 1.2.3 (Pentium 4) [^x86_32-floats-return-ABI]
-[`i686-unknown-uefi`](platform-support/unknown-uefi.md) | ? | 32-bit UEFI (Pentium 4, softfloat)
+[`i686-unknown-uefi`](platform-support/unknown-uefi.md) | ? | 32-bit UEFI (Pentium 4, softfloat) [^win32-msvc-alignment]
 [`loongarch64-unknown-none`](platform-support/loongarch-none.md) | * | LoongArch64 Bare-metal (LP64D ABI)
 [`loongarch64-unknown-none-softfloat`](platform-support/loongarch-none.md) | * | LoongArch64 Bare-metal (LP64S ABI)
 [`nvptx64-nvidia-cuda`](platform-support/nvptx64-nvidia-cuda.md) | * | --emit=asm generates PTX code that [runs on NVIDIA GPUs]
@@ -317,9 +319,9 @@ target | std | host | notes
 [`i686-unknown-netbsd`](platform-support/netbsd.md) | ✓ | ✓ | NetBSD/i386 (Pentium 4) [^x86_32-floats-return-ABI]
 [`i686-unknown-openbsd`](platform-support/openbsd.md) | ✓ | ✓ | 32-bit OpenBSD (Pentium 4) [^x86_32-floats-return-ABI]
 `i686-uwp-windows-gnu` | ✓ |  | [^x86_32-floats-return-ABI]
-[`i686-uwp-windows-msvc`](platform-support/uwp-windows-msvc.md) | ✓ |  | [^x86_32-floats-return-ABI]
+[`i686-uwp-windows-msvc`](platform-support/uwp-windows-msvc.md) | ✓ |  | [^x86_32-floats-return-ABI] [^win32-msvc-alignment]
 [`i686-win7-windows-gnu`](platform-support/win7-windows-gnu.md) | ✓ |   | 32-bit Windows 7 support [^x86_32-floats-return-ABI]
-[`i686-win7-windows-msvc`](platform-support/win7-windows-msvc.md) | ✓ |   | 32-bit Windows 7 support [^x86_32-floats-return-ABI]
+[`i686-win7-windows-msvc`](platform-support/win7-windows-msvc.md) | ✓ |   | 32-bit Windows 7 support [^x86_32-floats-return-ABI] [^win32-msvc-alignment]
 [`i686-wrs-vxworks`](platform-support/vxworks.md) | ✓ |  | [^x86_32-floats-return-ABI]
 [`loongarch64-unknown-linux-ohos`](platform-support/openharmony.md) | ✓ |   | LoongArch64 OpenHarmony
 [`m68k-unknown-linux-gnu`](platform-support/m68k-unknown-linux-gnu.md) | ? |  | Motorola 680x0 Linux
diff --git a/src/doc/rustc/src/platform-support/x86_64-pc-cygwin.md b/src/doc/rustc/src/platform-support/x86_64-pc-cygwin.md
index 60aaa371bbc1f..e98aa996a6e5e 100644
--- a/src/doc/rustc/src/platform-support/x86_64-pc-cygwin.md
+++ b/src/doc/rustc/src/platform-support/x86_64-pc-cygwin.md
@@ -20,8 +20,9 @@ The `target_os` of the target is `cygwin`, and it is `unix`.
 
 ## Building the target
 
-For cross-compilation you want LLVM with [llvm/llvm-project#121439 (merged)](https://github.com/llvm/llvm-project/pull/121439) applied to fix the LLVM codegen on importing external global variables from DLLs.
-No native builds on Cygwin now. It should be possible theoretically though, but might need a lot of patches.
+For cross-compilation you want LLVM at least 20.1.0-rc1.
+No native builds on Cygwin now.
+The tracking issue for host tools on Cygwin is [#137819](https://github.com/rust-lang/rust/issues/137819).
 
 ## Building Rust programs
 
diff --git a/src/tools/compiletest/Cargo.toml b/src/tools/compiletest/Cargo.toml
index ba1b8f256586e..93f7b1cb7cf2c 100644
--- a/src/tools/compiletest/Cargo.toml
+++ b/src/tools/compiletest/Cargo.toml
@@ -18,6 +18,7 @@ glob = "0.3.0"
 home = "0.5.5"
 indexmap = "2.0.0"
 miropt-test-tools = { path = "../miropt-test-tools" }
+rayon = "1.10.0"
 regex = "1.0"
 rustfix = "0.8.1"
 semver = { version = "1.0.23", features = ["serde"] }
diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs
index 7948a273c1e86..ae4e44b94713f 100644
--- a/src/tools/compiletest/src/lib.rs
+++ b/src/tools/compiletest/src/lib.rs
@@ -33,6 +33,7 @@ use std::{env, fs, vec};
 use build_helper::git::{get_git_modified_files, get_git_untracked_files};
 use camino::{Utf8Path, Utf8PathBuf};
 use getopts::Options;
+use rayon::iter::{ParallelBridge, ParallelIterator};
 use tracing::*;
 use walkdir::WalkDir;
 
@@ -641,6 +642,18 @@ struct TestCollector {
     poisoned: bool,
 }
 
+impl TestCollector {
+    fn new() -> Self {
+        TestCollector { tests: vec![], found_path_stems: HashSet::new(), poisoned: false }
+    }
+
+    fn merge(&mut self, mut other: Self) {
+        self.tests.append(&mut other.tests);
+        self.found_path_stems.extend(other.found_path_stems);
+        self.poisoned |= other.poisoned;
+    }
+}
+
 /// Creates test structures for every test/revision in the test suite directory.
 ///
 /// This always inspects _all_ test files in the suite (e.g. all 17k+ ui tests),
@@ -659,10 +672,7 @@ pub(crate) fn collect_and_make_tests(config: Arc<Config>) -> Vec<CollectedTest>
     let cache = HeadersCache::load(&config);
 
     let cx = TestCollectorCx { config, cache, common_inputs_stamp, modified_tests };
-    let mut collector =
-        TestCollector { tests: vec![], found_path_stems: HashSet::new(), poisoned: false };
-
-    collect_tests_from_dir(&cx, &mut collector, &cx.config.src_test_suite_root, Utf8Path::new(""))
+    let collector = collect_tests_from_dir(&cx, &cx.config.src_test_suite_root, Utf8Path::new(""))
         .unwrap_or_else(|reason| {
             panic!("Could not read tests from {}: {reason}", cx.config.src_test_suite_root)
         });
@@ -768,25 +778,25 @@ fn modified_tests(config: &Config, dir: &Utf8Path) -> Result<Vec<Utf8PathBuf>, S
 /// that will be handed over to libtest.
 fn collect_tests_from_dir(
     cx: &TestCollectorCx,
-    collector: &mut TestCollector,
     dir: &Utf8Path,
     relative_dir_path: &Utf8Path,
-) -> io::Result<()> {
+) -> io::Result<TestCollector> {
     // Ignore directories that contain a file named `compiletest-ignore-dir`.
     if dir.join("compiletest-ignore-dir").exists() {
-        return Ok(());
+        return Ok(TestCollector::new());
     }
 
     // For run-make tests, a "test file" is actually a directory that contains an `rmake.rs`.
     if cx.config.mode == Mode::RunMake {
+        let mut collector = TestCollector::new();
         if dir.join("rmake.rs").exists() {
             let paths = TestPaths {
                 file: dir.to_path_buf(),
                 relative_dir: relative_dir_path.parent().unwrap().to_path_buf(),
             };
-            make_test(cx, collector, &paths);
+            make_test(cx, &mut collector, &paths);
             // This directory is a test, so don't try to find other tests inside it.
-            return Ok(());
+            return Ok(collector);
         }
     }
 
@@ -803,36 +813,47 @@ fn collect_tests_from_dir(
     // subdirectories we find, except for `auxiliary` directories.
     // FIXME: this walks full tests tree, even if we have something to ignore
     // use walkdir/ignore like in tidy?
-    for file in fs::read_dir(dir.as_std_path())? {
-        let file = file?;
-        let file_path = Utf8PathBuf::try_from(file.path()).unwrap();
-        let file_name = file_path.file_name().unwrap();
-
-        if is_test(file_name)
-            && (!cx.config.only_modified || cx.modified_tests.contains(&file_path))
-        {
-            // We found a test file, so create the corresponding libtest structures.
-            debug!(%file_path, "found test file");
-
-            // Record the stem of the test file, to check for overlaps later.
-            let rel_test_path = relative_dir_path.join(file_path.file_stem().unwrap());
-            collector.found_path_stems.insert(rel_test_path);
-
-            let paths =
-                TestPaths { file: file_path, relative_dir: relative_dir_path.to_path_buf() };
-            make_test(cx, collector, &paths);
-        } else if file_path.is_dir() {
-            // Recurse to find more tests in a subdirectory.
-            let relative_file_path = relative_dir_path.join(file_name);
-            if file_name != "auxiliary" {
-                debug!(%file_path, "found directory");
-                collect_tests_from_dir(cx, collector, &file_path, &relative_file_path)?;
+    fs::read_dir(dir.as_std_path())?
+        .par_bridge()
+        .map(|file| {
+            let mut collector = TestCollector::new();
+            let file = file?;
+            let file_path = Utf8PathBuf::try_from(file.path()).unwrap();
+            let file_name = file_path.file_name().unwrap();
+
+            if is_test(file_name)
+                && (!cx.config.only_modified || cx.modified_tests.contains(&file_path))
+            {
+                // We found a test file, so create the corresponding libtest structures.
+                debug!(%file_path, "found test file");
+
+                // Record the stem of the test file, to check for overlaps later.
+                let rel_test_path = relative_dir_path.join(file_path.file_stem().unwrap());
+                collector.found_path_stems.insert(rel_test_path);
+
+                let paths =
+                    TestPaths { file: file_path, relative_dir: relative_dir_path.to_path_buf() };
+                make_test(cx, &mut collector, &paths);
+            } else if file_path.is_dir() {
+                // Recurse to find more tests in a subdirectory.
+                let relative_file_path = relative_dir_path.join(file_name);
+                if file_name != "auxiliary" {
+                    debug!(%file_path, "found directory");
+                    collector.merge(collect_tests_from_dir(cx, &file_path, &relative_file_path)?);
+                }
+            } else {
+                debug!(%file_path, "found other file/directory");
             }
-        } else {
-            debug!(%file_path, "found other file/directory");
-        }
-    }
-    Ok(())
+            Ok(collector)
+        })
+        .reduce(
+            || Ok(TestCollector::new()),
+            |a, b| {
+                let mut a = a?;
+                a.merge(b?);
+                Ok(a)
+            },
+        )
 }
 
 /// Returns true if `file_name` looks like a proper test file name.
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index cc09463c358a7..fe23cce81e908 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1710,12 +1710,16 @@ impl<'test> TestCx<'test> {
         rustc.args(&self.props.compile_flags);
 
         // FIXME(jieyouxu): we should report a fatal error or warning if user wrote `-Cpanic=` with
-        // something that's not `abort`, however, by moving this last we should override previous
-        // `-Cpanic=`s
+        // something that's not `abort` and `-Cforce-unwind-tables` with a value that is not `yes`,
+        // however, by moving this last we should override previous `-Cpanic`s and
+        // `-Cforce-unwind-tables`s. Note that checking here is very fragile, because we'd have to
+        // account for all possible compile flag splittings (they have some... intricacies and are
+        // not yet normalized).
         //
         // `minicore` requires `#![no_std]` and `#![no_core]`, which means no unwinding panics.
         if self.props.add_core_stubs {
             rustc.arg("-Cpanic=abort");
+            rustc.arg("-Cforce-unwind-tables=yes");
         }
 
         rustc
diff --git a/tests/assembly/x86-return-float.rs b/tests/assembly/x86-return-float.rs
index 2c39c830684ec..165c11d228011 100644
--- a/tests/assembly/x86-return-float.rs
+++ b/tests/assembly/x86-return-float.rs
@@ -35,6 +35,7 @@ use minicore::*;
 pub fn return_f32(x: f32) -> f32 {
     // CHECK: movss {{.*}}(%ebp), %xmm0
     // CHECK-NEXT: popl %ebp
+    // linux-NEXT: .cfi_def_cfa
     // CHECK-NEXT: retl
     x
 }
@@ -44,6 +45,7 @@ pub fn return_f32(x: f32) -> f32 {
 pub fn return_f64(x: f64) -> f64 {
     // CHECK: movsd {{.*}}(%ebp), %xmm0
     // CHECK-NEXT: popl %ebp
+    // linux-NEXT: .cfi_def_cfa
     // CHECK-NEXT: retl
     x
 }
@@ -313,9 +315,13 @@ pub unsafe fn call_other_f64(x: &mut (usize, f64)) {
 #[no_mangle]
 pub fn return_f16(x: f16) -> f16 {
     // CHECK: pushl %ebp
+    // linux-NEXT: .cfi_def_cfa_offset
+    // linux-NEXT: .cfi_offset
     // CHECK-NEXT: movl %esp, %ebp
+    // linux-NEXT: .cfi_def_cfa_register
     // CHECK-NEXT: pinsrw $0, 8(%ebp), %xmm0
     // CHECK-NEXT: popl %ebp
+    // linux-NEXT: .cfi_def_cfa
     // CHECK-NEXT: retl
     x
 }
@@ -324,10 +330,14 @@ pub fn return_f16(x: f16) -> f16 {
 #[no_mangle]
 pub fn return_f128(x: f128) -> f128 {
     // CHECK: pushl %ebp
+    // linux-NEXT: .cfi_def_cfa_offset
+    // linux-NEXT: .cfi_offset
     // CHECK-NEXT: movl %esp, %ebp
+    // linux-NEXT: .cfi_def_cfa_register
     // linux-NEXT: movaps 8(%ebp), %xmm0
     // win-NEXT: movups 8(%ebp), %xmm0
     // CHECK-NEXT: popl %ebp
+    // linux-NEXT: .cfi_def_cfa
     // CHECK-NEXT: retl
     x
 }
diff --git a/tests/codegen/align-struct.rs b/tests/codegen/align-struct.rs
index cc65b08a9223c..402a184d4c07e 100644
--- a/tests/codegen/align-struct.rs
+++ b/tests/codegen/align-struct.rs
@@ -1,5 +1,7 @@
 //@ compile-flags: -C no-prepopulate-passes -Z mir-opt-level=0
-//
+// 32bit MSVC does not align things properly so we suppress high alignment annotations (#112480)
+//@ ignore-i686-pc-windows-msvc
+//@ ignore-i686-pc-windows-gnu
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen/issues/issue-56927.rs b/tests/codegen/issues/issue-56927.rs
index a40718689b3e0..415ef073e03ac 100644
--- a/tests/codegen/issues/issue-56927.rs
+++ b/tests/codegen/issues/issue-56927.rs
@@ -1,4 +1,7 @@
 //@ compile-flags: -C no-prepopulate-passes
+// 32bit MSVC does not align things properly so we suppress high alignment annotations (#112480)
+//@ ignore-i686-pc-windows-msvc
+//@ ignore-i686-pc-windows-gnu
 
 #![crate_type = "rlib"]
 
diff --git a/tests/ui/generics/single-colon-path-not-const-generics.stderr b/tests/ui/generics/single-colon-path-not-const-generics.stderr
index 9eb62de275614..163ea4bbda6cd 100644
--- a/tests/ui/generics/single-colon-path-not-const-generics.stderr
+++ b/tests/ui/generics/single-colon-path-not-const-generics.stderr
@@ -1,13 +1,15 @@
 error: path separator must be a double colon
   --> $DIR/single-colon-path-not-const-generics.rs:8:18
    |
+LL | pub struct Foo {
+   |            --- while parsing this struct
 LL |   a: Vec<foo::bar:A>,
    |                  ^
    |
 help: use a double colon instead
    |
 LL |   a: Vec<foo::bar::A>,
-   |                   +
+   |                  +
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/parser/ty-path-followed-by-single-colon.rs b/tests/ui/parser/ty-path-followed-by-single-colon.rs
new file mode 100644
index 0000000000000..a9082ea317a78
--- /dev/null
+++ b/tests/ui/parser/ty-path-followed-by-single-colon.rs
@@ -0,0 +1,22 @@
+// Paths in type contexts may be followed by single colons.
+// This means we can't generally assume that the user typo'ed a double colon.
+// issue: <https://github.com/rust-lang/rust/issues/140227>
+//@ check-pass
+#![crate_type = "lib"]
+#![expect(non_camel_case_types)]
+
+#[rustfmt::skip]
+mod garden {
+
+    fn f<path>() where path:to::somewhere {} // OK!
+
+    fn g(_: impl Take<path:to::somewhere>) {} // OK!
+
+    #[cfg(any())] fn h() where a::path:to::nowhere {} // OK!
+
+    fn i(_: impl Take<path::<>:to::somewhere>) {} // OK!
+
+    mod to { pub(super) trait somewhere {} }
+    trait Take { type path; }
+
+}
diff --git a/tests/ui/suggestions/argument-list-from-path-sep-error-129273.fixed b/tests/ui/suggestions/argument-list-from-path-sep-error-129273.fixed
deleted file mode 100644
index f5dbf0c8b6f4e..0000000000000
--- a/tests/ui/suggestions/argument-list-from-path-sep-error-129273.fixed
+++ /dev/null
@@ -1,15 +0,0 @@
-//@ run-rustfix
-
-use std::fmt;
-
-struct Hello;
-
-impl fmt::Display for Hello {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { //~ ERROR path separator must be a double colon
-        write!(f, "hello")
-    }
-}
-
-fn main() {
-    let _ = Hello;
-}
diff --git a/tests/ui/suggestions/argument-list-from-path-sep-error-129273.rs b/tests/ui/suggestions/argument-list-from-path-sep-error-129273.rs
deleted file mode 100644
index c41880a26f6ec..0000000000000
--- a/tests/ui/suggestions/argument-list-from-path-sep-error-129273.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-//@ run-rustfix
-
-use std::fmt;
-
-struct Hello;
-
-impl fmt::Display for Hello {
-    fn fmt(&self, f: &mut fmt:Formatter) -> fmt::Result { //~ ERROR path separator must be a double colon
-        write!(f, "hello")
-    }
-}
-
-fn main() {
-    let _ = Hello;
-}
diff --git a/tests/ui/suggestions/argument-list-from-path-sep-error-129273.stderr b/tests/ui/suggestions/argument-list-from-path-sep-error-129273.stderr
deleted file mode 100644
index 713b071a625a0..0000000000000
--- a/tests/ui/suggestions/argument-list-from-path-sep-error-129273.stderr
+++ /dev/null
@@ -1,13 +0,0 @@
-error: path separator must be a double colon
-  --> $DIR/argument-list-from-path-sep-error-129273.rs:8:30
-   |
-LL |     fn fmt(&self, f: &mut fmt:Formatter) -> fmt::Result {
-   |                              ^
-   |
-help: use a double colon instead
-   |
-LL |     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-   |                               +
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/suggestions/struct-field-type-including-single-colon.rs b/tests/ui/suggestions/struct-field-type-including-single-colon.rs
index a3111028895dd..482641fc7cac9 100644
--- a/tests/ui/suggestions/struct-field-type-including-single-colon.rs
+++ b/tests/ui/suggestions/struct-field-type-including-single-colon.rs
@@ -7,14 +7,14 @@ mod foo {
 
 struct Foo {
     a: foo:A,
-    //~^ ERROR path separator must be a double colon
-    //~| ERROR struct `A` is private
+    //~^ ERROR found single colon in a struct field type path
+    //~| ERROR expected `,`, or `}`, found `:`
 }
 
 struct Bar {
     b: foo::bar:B,
-    //~^ ERROR path separator must be a double colon
-    //~| ERROR module `bar` is private
+    //~^ ERROR found single colon in a struct field type path
+    //~| ERROR expected `,`, or `}`, found `:`
 }
 
 fn main() {}
diff --git a/tests/ui/suggestions/struct-field-type-including-single-colon.stderr b/tests/ui/suggestions/struct-field-type-including-single-colon.stderr
index b9302b0453d5b..5ffc5b40849b6 100644
--- a/tests/ui/suggestions/struct-field-type-including-single-colon.stderr
+++ b/tests/ui/suggestions/struct-field-type-including-single-colon.stderr
@@ -1,51 +1,40 @@
-error: path separator must be a double colon
+error: found single colon in a struct field type path
   --> $DIR/struct-field-type-including-single-colon.rs:9:11
    |
 LL |     a: foo:A,
    |           ^
    |
-help: use a double colon instead
+help: write a path separator here
    |
 LL |     a: foo::A,
    |            +
 
-error: path separator must be a double colon
+error: expected `,`, or `}`, found `:`
+  --> $DIR/struct-field-type-including-single-colon.rs:9:11
+   |
+LL | struct Foo {
+   |        --- while parsing this struct
+LL |     a: foo:A,
+   |           ^
+
+error: found single colon in a struct field type path
   --> $DIR/struct-field-type-including-single-colon.rs:15:16
    |
 LL |     b: foo::bar:B,
    |                ^
    |
-help: use a double colon instead
+help: write a path separator here
    |
 LL |     b: foo::bar::B,
    |                 +
 
-error[E0603]: struct `A` is private
-  --> $DIR/struct-field-type-including-single-colon.rs:9:12
-   |
-LL |     a: foo:A,
-   |            ^ private struct
-   |
-note: the struct `A` is defined here
-  --> $DIR/struct-field-type-including-single-colon.rs:2:5
-   |
-LL |     struct A;
-   |     ^^^^^^^^^
-
-error[E0603]: module `bar` is private
-  --> $DIR/struct-field-type-including-single-colon.rs:15:13
+error: expected `,`, or `}`, found `:`
+  --> $DIR/struct-field-type-including-single-colon.rs:15:16
    |
+LL | struct Bar {
+   |        --- while parsing this struct
 LL |     b: foo::bar:B,
-   |             ^^^ - struct `B` is not publicly re-exported
-   |             |
-   |             private module
-   |
-note: the module `bar` is defined here
-  --> $DIR/struct-field-type-including-single-colon.rs:3:5
-   |
-LL |     mod bar {
-   |     ^^^^^^^
+   |                ^
 
 error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0603`.
diff --git a/triagebot.toml b/triagebot.toml
index 189223f2feba1..422996cb200dd 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -585,6 +585,11 @@ trigger_files = [
     "src/tools/compiletest"
 ]
 
+[autolabel."A-test-infra-minicore"]
+trigger_files = [
+    "tests/auxiliary/minicore.rs",
+]
+
 [autolabel."A-rustc-dev-guide"]
 trigger_files = [
     "src/doc/rustc-dev-guide",
@@ -869,6 +874,10 @@ cc = ["@GuillaumeGomez"]
 message = "This PR modifies `run-make` tests."
 cc = ["@jieyouxu"]
 
+[mentions."tests/auxiliary/minicore.rs"]
+message = "This PR modifies `tests/auxiliary/minicore.rs`."
+cc = ["@jieyouxu"]
+
 [mentions."src/rustdoc-json-types"]
 message = """
 rustdoc-json-types is a **public** (although nightly-only) API. \