Rollup merge of #88709 - BoxyUwU:thir-abstract-const, r=lcnr

generic_const_exprs: use thir for abstract consts instead of mir

Changes `AbstractConst` building to use `thir` instead of `mir` so that there's less chance of consts unifying when they shouldn't because lowering to mir dropped information (see `abstract-consts-as-cast-5.rs` test)

r? `@lcnr`

1 files changed, 5 insertions, 4 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index cc4b7d08f45..2a0332a1124 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -26,6 +26,7 @@ use rustc_middle::middle::cstore::{ForeignModule, LinkagePreference, NativeLib};
 use rustc_middle::middle::exported_symbols::{ExportedSymbol, SymbolExportLevel};
 use rustc_middle::mir::interpret::{AllocDecodingSession, AllocDecodingState};
 use rustc_middle::mir::{self, Body, Promoted};
+use rustc_middle::thir;
 use rustc_middle::ty::codec::TyDecoder;
 use rustc_middle::ty::{self, Ty, TyCtxt, Visibility};
 use rustc_serialize::{opaque, Decodable, Decoder};
@@ -541,7 +542,7 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for Span {
     }
 }
 
-impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [mir::abstract_const::Node<'tcx>] {
+impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for &'tcx [thir::abstract_const::Node<'tcx>] {
     fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Result<Self, String> {
         ty::codec::RefDecodable::decode(d)
     }
@@ -1196,14 +1197,14 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
             .decode((self, tcx))
     }
 
-    fn get_mir_abstract_const(
+    fn get_thir_abstract_const(
         &self,
         tcx: TyCtxt<'tcx>,
         id: DefIndex,
-    ) -> Result<Option<&'tcx [mir::abstract_const::Node<'tcx>]>, ErrorReported> {
+    ) -> Result<Option<&'tcx [thir::abstract_const::Node<'tcx>]>, ErrorReported> {
         self.root
             .tables
-            .mir_abstract_consts
+            .thir_abstract_consts
             .get(self, id)
             .map_or(Ok(None), |v| Ok(Some(v.decode((self, tcx)))))
     }