Auto merge of #92805 - BoxyUwU:revert-lazy-anon-const-substs, r=lcnr

partially revertish `lazily "compute" anon const default substs`

reverts #87280 except for some of the changes around `ty::Unevaluated` having a visitor and a generic for promoted
why revert: <#92805 (comment)>

r? `@lcnr`

Author: bors

compiler/rustc_borrowck/src/type_check/liveness/trace.rs

@@ -171,7 +171,7 @@ impl<'me, 'typeck, 'flow, 'tcx> LivenessResults<'me, 'typeck, 'flow, 'tcx> {
         for (local, location) in drop_used {
             if !live_locals.contains(&local) {
                 let local_ty = self.cx.body.local_decls[local].ty;
-                if local_ty.has_free_regions(self.cx.typeck.tcx()) {
+                if local_ty.has_free_regions() {
                     self.cx.add_drop_live_facts_for(local, local_ty, &[location], &locations);
                 }
             }

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -426,7 +426,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                         self.cx.param_env.and(type_op::ascribe_user_type::AscribeUserType::new(
                             constant.literal.ty(),
                             uv.def.did,
-                            UserSubsts { substs: uv.substs(self.tcx()), user_self_ty: None },
+                            UserSubsts { substs: uv.substs, user_self_ty: None },
                         )),
                     ) {
                         span_mirbug!(
@@ -1970,7 +1970,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                         let predicates = self.prove_closure_bounds(
                             tcx,
                             def_id.expect_local(),
-                            uv.substs(tcx),
+                            uv.substs,
                             location,
                         );
                         self.normalize_and_prove_instantiated_predicates(

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -129,11 +129,13 @@ pub(crate) fn codegen_constant<'tcx>(
     };
     let const_val = match const_.val {
         ConstKind::Value(const_val) => const_val,
-        ConstKind::Unevaluated(uv) if fx.tcx.is_static(uv.def.did) => {
-            assert!(uv.substs(fx.tcx).is_empty());
-            assert!(uv.promoted.is_none());
+        ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
+            if fx.tcx.is_static(def.did) =>
+        {
+            assert!(substs.is_empty());
+            assert!(promoted.is_none());
 
-            return codegen_static_ref(fx, uv.def.did, fx.layout_of(const_.ty)).to_cvalue(fx);
+            return codegen_static_ref(fx, def.did, fx.layout_of(const_.ty)).to_cvalue(fx);
         }
         ConstKind::Unevaluated(unevaluated) => {
             match fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None) {

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -507,7 +507,7 @@ impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                         ty::Adt(def, ..) if !def.is_box() => {
                             // Again, only create type information if full debuginfo is enabled
                             if cx.sess().opts.debuginfo == DebugInfo::Full
-                                && !impl_self_ty.definitely_needs_subst(cx.tcx)
+                                && !impl_self_ty.needs_subst()
                             {
                                 Some(type_metadata(cx, impl_self_ty, rustc_span::DUMMY_SP))
                             } else {

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -1477,7 +1477,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 LocalRef::UnsizedPlace(_) => bug!("transmute must not involve unsized locals"),
                 LocalRef::Operand(None) => {
                     let dst_layout = bx.layout_of(self.monomorphized_place_ty(dst.as_ref()));
-                    assert!(!dst_layout.ty.has_erasable_regions(self.cx.tcx()));
+                    assert!(!dst_layout.ty.has_erasable_regions());
                     let place = PlaceRef::alloca(bx, dst_layout);
                     place.storage_live(bx);
                     self.codegen_transmute_into(bx, src, place);

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -209,7 +209,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         let mut allocate_local = |local| {
             let decl = &mir.local_decls[local];
             let layout = bx.layout_of(fx.monomorphize(decl.ty));
-            assert!(!layout.ty.has_erasable_regions(cx.tcx()));
+            assert!(!layout.ty.has_erasable_regions());
 
             if local == mir::RETURN_PLACE && fx.fn_abi.ret.is_indirect() {
                 debug!("alloc: {:?} (return place) -> place", local);

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -568,7 +568,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             ty::ConstKind::Param(_) | ty::ConstKind::Bound(..) => throw_inval!(TooGeneric),
             ty::ConstKind::Error(_) => throw_inval!(AlreadyReported(ErrorReported)),
             ty::ConstKind::Unevaluated(uv) => {
-                let instance = self.resolve(uv.def, uv.substs(*self.tcx))?;
+                let instance = self.resolve(uv.def, uv.substs)?;
                 Ok(self.eval_to_allocation(GlobalId { instance, promoted: uv.promoted })?.into())
             }
             ty::ConstKind::Infer(..) | ty::ConstKind::Placeholder(..) => {

compiler/rustc_const_eval/src/interpret/util.rs

@@ -9,7 +9,7 @@ where
     T: TypeFoldable<'tcx>,
 {
     debug!("ensure_monomorphic_enough: ty={:?}", ty);
-    if !ty.potentially_needs_subst() {
+    if !ty.needs_subst() {
         return Ok(());
     }
 
@@ -21,12 +21,8 @@ where
     impl<'tcx> TypeVisitor<'tcx> for UsedParamsNeedSubstVisitor<'tcx> {
         type BreakTy = FoundParam;
 
-        fn tcx_for_anon_const_substs(&self) -> Option<TyCtxt<'tcx>> {
-            Some(self.tcx)
-        }
-
         fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-            if !ty.potentially_needs_subst() {
+            if !ty.needs_subst() {
                 return ControlFlow::CONTINUE;
             }
 
@@ -44,7 +40,7 @@ where
                         let is_used = unused_params.contains(index).map_or(true, |unused| !unused);
                         // Only recurse when generic parameters in fns, closures and generators
                         // are used and require substitution.
-                        match (is_used, subst.definitely_needs_subst(self.tcx)) {
+                        match (is_used, subst.needs_subst()) {
                             // Just in case there are closures or generators within this subst,
                             // recurse.
                             (true, true) => return subst.super_visit_with(self),

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -347,7 +347,7 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
     fn check_local_or_return_ty(&mut self, ty: Ty<'tcx>, local: Local) {
         let kind = self.body.local_kind(local);
 
-        for ty in ty.walk(self.tcx) {
+        for ty in ty.walk() {
             let ty = match ty.unpack() {
                 GenericArgKind::Type(ty) => ty,
 

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

@@ -337,7 +337,7 @@ where
 
     // Check the qualifs of the value of `const` items.
     if let Some(ct) = constant.literal.const_for_ty() {
-        if let ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs_: _, promoted }) = ct.val {
+        if let ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) = ct.val {
             // Use qualifs of the type for the promoted. Promoteds in MIR body should be possible
             // only for `NeedsNonConstDrop` with precise drop checking. This is the only const
             // check performed after the promotion. Verify that with an assertion.