Erase type lifetime before writing type ID

Author: SpriteOvO

compiler/rustc_const_eval/src/const_eval/type_info.rs

@@ -273,7 +273,10 @@ impl<'tcx> InterpCx<'tcx, CompileTimeMachine<'tcx>> {
                     let ptr = self.mplace_to_ref(&name_place)?;
                     self.write_immediate(*ptr, &field_place)?
                 }
-                sym::ty => self.write_type_id(field_ty, &field_place)?,
+                sym::ty => {
+                    let field_ty = self.tcx.erase_and_anonymize_regions(field_ty);
+                    self.write_type_id(field_ty, &field_place)?
+                }
                 sym::offset => {
                     let offset = layout.fields.offset(idx as usize);
                     self.write_scalar(

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -13,7 +13,7 @@ use rustc_infer::infer::TyCtxtInferExt;
 use rustc_middle::mir::interpret::{CTFE_ALLOC_SALT, read_target_uint, write_target_uint};
 use rustc_middle::mir::{self, BinOp, ConstValue, NonDivergingIntrinsic};
 use rustc_middle::ty::layout::TyAndLayout;
-use rustc_middle::ty::{FloatTy, PolyExistentialPredicate, Ty, TyCtxt};
+use rustc_middle::ty::{FloatTy, PolyExistentialPredicate, Ty, TyCtxt, TypeVisitableExt};
 use rustc_middle::{bug, span_bug, ty};
 use rustc_span::{Symbol, sym};
 use rustc_trait_selection::traits::{Obligation, ObligationCause, ObligationCtxt};
@@ -73,6 +73,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         ty: Ty<'tcx>,
         dest: &impl Writeable<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx, ()> {
+        debug_assert!(
+            !ty.has_erasable_regions(),
+            "type {ty:?} has regions that need erasing before writing a TypeId",
+        );
+
         let tcx = self.tcx;
         let type_id_hash = tcx.type_id_hash(ty).as_u128();
         let op = self.const_val_to_op(

library/coretests/tests/mem/type_info.rs

@@ -91,7 +91,7 @@ fn test_structs() {
         assert!(ty.fields[1].ty == TypeId::of::<u16>());
         assert!(ty.fields[1].offset == offset_of!(TestStruct, second));
         assert!(ty.fields[2].name == "reference");
-        assert!(ty.fields[2].ty != TypeId::of::<&'static u16>()); // FIXME(type_info): should be ==
+        assert!(ty.fields[2].ty == TypeId::of::<&'static u16>());
         assert!(ty.fields[2].offset == offset_of!(TestStruct, reference));
     }