Auto merge of rust-lang#126332 - GuillaumeGomez:rollup-bu1q4pz, r=GuillaumeGomez

Rollup of 9 pull requests

Successful merges:

 - rust-lang#126039 (Promote `arm64ec-pc-windows-msvc` to tier 2)
 - rust-lang#126075 (Remove `DebugWithInfcx` machinery)
 - rust-lang#126228 (Provide correct parent for nested anon const)
 - rust-lang#126232 (interpret: dyn trait metadata check: equate traits in a proper way)
 - rust-lang#126242 (Simplify provider api to improve llvm ir)
 - rust-lang#126294 (coverage: Replace the old span refiner with a single function)
 - rust-lang#126295 (No uninitalized report in a pre-returned match arm)
 - rust-lang#126312 (Update `rustc-perf` submodule)
 - rust-lang#126322 (Follow up to splitting core's PanicInfo and std's PanicInfo)

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

Author: bors

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -557,8 +557,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         // for the branching codepaths that aren't covered, to point at them.
         let map = self.infcx.tcx.hir();
         let body = map.body_owned_by(self.mir_def_id());
-
-        let mut visitor = ConditionVisitor { spans: &spans, name: &name, errors: vec![] };
+        let mut visitor =
+            ConditionVisitor { tcx: self.infcx.tcx, spans: &spans, name: &name, errors: vec![] };
         visitor.visit_body(&body);
 
         let mut show_assign_sugg = false;
@@ -4372,13 +4372,14 @@ impl<'hir> Visitor<'hir> for BreakFinder {
 
 /// Given a set of spans representing statements initializing the relevant binding, visit all the
 /// function expressions looking for branching code paths that *do not* initialize the binding.
-struct ConditionVisitor<'b> {
+struct ConditionVisitor<'b, 'tcx> {
+    tcx: TyCtxt<'tcx>,
     spans: &'b [Span],
     name: &'b str,
     errors: Vec<(Span, String)>,
 }
 
-impl<'b, 'v> Visitor<'v> for ConditionVisitor<'b> {
+impl<'b, 'v, 'tcx> Visitor<'v> for ConditionVisitor<'b, 'tcx> {
     fn visit_expr(&mut self, ex: &'v hir::Expr<'v>) {
         match ex.kind {
             hir::ExprKind::If(cond, body, None) => {
@@ -4464,6 +4465,12 @@ impl<'b, 'v> Visitor<'v> for ConditionVisitor<'b> {
                                     ),
                                 ));
                             } else if let Some(guard) = &arm.guard {
+                                if matches!(
+                                    self.tcx.hir_node(arm.body.hir_id),
+                                    hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Ret(_), .. })
+                                ) {
+                                    continue;
+                                }
                                 self.errors.push((
                                     arm.pat.span.to(guard.span),
                                     format!(
@@ -4473,6 +4480,12 @@ impl<'b, 'v> Visitor<'v> for ConditionVisitor<'b> {
                                     ),
                                 ));
                             } else {
+                                if matches!(
+                                    self.tcx.hir_node(arm.body.hir_id),
+                                    hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Ret(_), .. })
+                                ) {
+                                    continue;
+                                }
                                 self.errors.push((
                                     arm.pat.span,
                                     format!(

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -387,7 +387,6 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         match (&src_pointee_ty.kind(), &dest_pointee_ty.kind()) {
             (&ty::Array(_, length), &ty::Slice(_)) => {
                 let ptr = self.read_pointer(src)?;
-                // u64 cast is from usize to u64, which is always good
                 let val = Immediate::new_slice(
                     ptr,
                     length.eval_target_usize(*self.tcx, self.param_env),
@@ -405,13 +404,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 let (old_data, old_vptr) = val.to_scalar_pair();
                 let old_data = old_data.to_pointer(self)?;
                 let old_vptr = old_vptr.to_pointer(self)?;
-                let (ty, old_trait) = self.get_ptr_vtable(old_vptr)?;
-                if old_trait != data_a.principal() {
-                    throw_ub!(InvalidVTableTrait {
-                        expected_trait: data_a,
-                        vtable_trait: old_trait,
-                    });
-                }
+                let ty = self.get_ptr_vtable_ty(old_vptr, Some(data_a))?;
                 let new_vptr = self.get_vtable_ptr(ty, data_b.principal())?;
                 self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest)
             }