Auto merge of #128703 - compiler-errors:normalizing-tails, r=lcnr

Miscellaneous improvements to struct tail normalization

1. Make checks for foreign tails more accurate by normalizing the struct tail. I didn't write a test for this one.
2. Normalize when computing struct tail for `offset_of` for slice/str. This fixes the new solver only.
3. Normalizing when computing tails for disaligned reference check. This fixes both solvers.

r? lcnr

Author: bors

compiler/rustc_codegen_cranelift/src/common.rs

@@ -107,7 +107,7 @@ pub(crate) fn has_ptr_meta<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
         return false;
     }
 
-    let tail = tcx.struct_tail_erasing_lifetimes(ty, ParamEnv::reveal_all());
+    let tail = tcx.struct_tail_for_codegen(ty, ParamEnv::reveal_all());
     match tail.kind() {
         ty::Foreign(..) => false,
         ty::Str | ty::Slice(..) | ty::Dynamic(..) => true,

compiler/rustc_codegen_cranelift/src/unsize.rs

@@ -22,7 +22,7 @@ pub(crate) fn unsized_info<'tcx>(
     old_info: Option<Value>,
 ) -> Value {
     let (source, target) =
-        fx.tcx.struct_lockstep_tails_erasing_lifetimes(source, target, ParamEnv::reveal_all());
+        fx.tcx.struct_lockstep_tails_for_codegen(source, target, ParamEnv::reveal_all());
     match (&source.kind(), &target.kind()) {
         (&ty::Array(_, len), &ty::Slice(_)) => fx
             .bcx

compiler/rustc_codegen_llvm/src/builder.rs

@@ -12,7 +12,8 @@ use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_hir::def_id::DefId;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
 use rustc_middle::ty::layout::{
-    FnAbiError, FnAbiOfHelpers, FnAbiRequest, LayoutError, LayoutOfHelpers, TyAndLayout,
+    FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasParamEnv, LayoutError, LayoutOfHelpers,
+    TyAndLayout,
 };
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt};
 use rustc_sanitizers::{cfi, kcfi};
@@ -531,7 +532,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
     #[instrument(level = "trace", skip(self))]
     fn load_operand(&mut self, place: PlaceRef<'tcx, &'ll Value>) -> OperandRef<'tcx, &'ll Value> {
         if place.layout.is_unsized() {
-            let tail = self.tcx.struct_tail_with_normalize(place.layout.ty, |ty| ty, || {});
+            let tail = self.tcx.struct_tail_for_codegen(place.layout.ty, self.param_env());
             if matches!(tail.kind(), ty::Foreign(..)) {
                 // Unsized locals and, at least conceptually, even unsized arguments must be copied
                 // around, which requires dynamically determining their size. Therefore, we cannot

compiler/rustc_codegen_llvm/src/debuginfo/utils.rs

@@ -62,7 +62,7 @@ pub(crate) fn fat_pointer_kind<'ll, 'tcx>(
     cx: &CodegenCx<'ll, 'tcx>,
     pointee_ty: Ty<'tcx>,
 ) -> Option<FatPtrKind> {
-    let pointee_tail_ty = cx.tcx.struct_tail_erasing_lifetimes(pointee_ty, cx.param_env());
+    let pointee_tail_ty = cx.tcx.struct_tail_for_codegen(pointee_ty, cx.param_env());
     let layout = cx.layout_of(pointee_tail_ty);
     trace!(
         "fat_pointer_kind: {:?} has layout {:?} (is_unsized? {})",

compiler/rustc_codegen_ssa/src/base.rs

@@ -143,7 +143,7 @@ pub fn unsized_info<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 ) -> Bx::Value {
     let cx = bx.cx();
     let (source, target) =
-        cx.tcx().struct_lockstep_tails_erasing_lifetimes(source, target, bx.param_env());
+        cx.tcx().struct_lockstep_tails_for_codegen(source, target, bx.param_env());
     match (source.kind(), target.kind()) {
         (&ty::Array(_, len), &ty::Slice(_)) => {
             cx.const_usize(len.eval_target_usize(cx.tcx(), ty::ParamEnv::reveal_all()))

compiler/rustc_codegen_ssa/src/traits/type_.rs

@@ -91,7 +91,7 @@ pub trait DerivedTypeMethods<'tcx>: BaseTypeMethods<'tcx> + MiscMethods<'tcx> {
             return false;
         }
 
-        let tail = self.tcx().struct_tail_erasing_lifetimes(ty, param_env);
+        let tail = self.tcx().struct_tail_for_codegen(ty, param_env);
         match tail.kind() {
             ty::Foreign(..) => false,
             ty::Str | ty::Slice(..) | ty::Dynamic(..) => true,

compiler/rustc_const_eval/src/interpret/call.rs

@@ -678,9 +678,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                 } else {
                     // Doesn't have to be a `dyn Trait`, but the unsized tail must be `dyn Trait`.
                     // (For that reason we also cannot use `unpack_dyn_trait`.)
-                    let receiver_tail = self
-                        .tcx
-                        .struct_tail_erasing_lifetimes(receiver_place.layout.ty, self.param_env);
+                    let receiver_tail =
+                        self.tcx.struct_tail_for_codegen(receiver_place.layout.ty, self.param_env);
                     let ty::Dynamic(receiver_trait, _, ty::Dyn) = receiver_tail.kind() else {
                         span_bug!(
                             self.cur_span(),

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -386,7 +386,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     ) -> InterpResult<'tcx> {
         // A<Struct> -> A<Trait> conversion
         let (src_pointee_ty, dest_pointee_ty) =
-            self.tcx.struct_lockstep_tails_erasing_lifetimes(source_ty, cast_ty, self.param_env);
+            self.tcx.struct_lockstep_tails_for_codegen(source_ty, cast_ty, self.param_env);
 
         match (&src_pointee_ty.kind(), &dest_pointee_ty.kind()) {
             (&ty::Array(_, length), &ty::Slice(_)) => {

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -343,7 +343,7 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> {
         meta: MemPlaceMeta<M::Provenance>,
         pointee: TyAndLayout<'tcx>,
     ) -> InterpResult<'tcx> {
-        let tail = self.ecx.tcx.struct_tail_erasing_lifetimes(pointee.ty, self.ecx.param_env);
+        let tail = self.ecx.tcx.struct_tail_for_codegen(pointee.ty, self.ecx.param_env);
         match tail.kind() {
             ty::Dynamic(data, _, ty::Dyn) => {
                 let vtable = meta.unwrap_meta().to_pointer(self.ecx)?;

compiler/rustc_const_eval/src/util/alignment.rs

@@ -22,7 +22,7 @@ where
     };
 
     let ty = place.ty(local_decls, tcx).ty;
-    let unsized_tail = || tcx.struct_tail_with_normalize(ty, |ty| ty, || {});
+    let unsized_tail = || tcx.struct_tail_for_codegen(ty, param_env);
     match tcx.layout_of(param_env.and(ty)) {
         Ok(layout)
             if layout.align.abi <= pack