Revert "Merge CrateDisambiguator into StableCrateId"

This reverts commit d0ec85d3fb.

compiler/rustc_ty_utils/src/ty.rs

@@ -1,11 +1,12 @@
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
 use rustc_middle::hir::map as hir_map;
 use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{
     self, Binder, Predicate, PredicateKind, ToPredicate, Ty, TyCtxt, WithConstness,
 };
+use rustc_session::CrateDisambiguator;
 use rustc_span::Span;
 use rustc_trait_selection::traits;
 
@@ -387,6 +388,11 @@ fn param_env_reveal_all_normalized(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamE
     tcx.param_env(def_id).with_reveal_all_normalized(tcx)
 }
 
+fn crate_disambiguator(tcx: TyCtxt<'_>, crate_num: CrateNum) -> CrateDisambiguator {
+    assert_eq!(crate_num, LOCAL_CRATE);
+    tcx.sess.local_crate_disambiguator()
+}
+
 fn instance_def_size_estimate<'tcx>(
     tcx: TyCtxt<'tcx>,
     instance_def: ty::InstanceDef<'tcx>,
@@ -532,6 +538,7 @@ pub fn provide(providers: &mut ty::query::Providers) {
         param_env,
         param_env_reveal_all_normalized,
         trait_of_item,
+        crate_disambiguator,
         instance_def_size_estimate,
         issue33140_self_ty,
         impl_defaultness,