Auto merge of #96840 - cjgillot:query-feed, r=oli-obk

Allow to feed a value in another query's cache and remove `WithOptConstParam`

I used it to remove `WithOptConstParam` queries, as an example.

The idea is that a query (here `typeck(function)`) can write into another query's cache (here `type_of(anon const)`). The dependency node for `type_of` would depend on all the current dependencies of `typeck`.

There is still an issue with cycles: if `type_of(anon const)` is accessed before `typeck(function)`, we will still have the usual cycle.  The way around this issue is to `ensure` that `typeck(function)` is called before accessing `type_of(anon const)`.

When replayed, we may the following cases:
- `typeck` is green, in that case `type_of` is green too, and all is right;
- `type_of` is green, `typeck` may still be marked as red (it depends on strictly more things than `type_of`) -> we verify that the saved value and the re-computed value of `type_of` have the same hash;
- `type_of` is red, then `typeck` is red -> it's the caller responsibility to ensure `typeck` is recomputed *before* `type_of`.

As `anon consts` have their own `DefPathData`, it's not possible to have the def-id of the anon-const point to something outside the original function, but the general case may have to be resolved before using this device more broadly.

There is an open question about loading from the on-disk cache.  If `typeck` is loaded from the on-disk cache, the side-effect does not happen. The regular `type_of` implementation can go and fetch the correct value from the decoded `typeck` results, and the dep-graph will check that the hashes match, but I'm not sure we want to rely on this behaviour.

I specifically allowed to feed the value to `type_of` from inside a call to `type_of`.  In that case, the dep-graph will check that the fingerprints of both values match.

This implementation is still very sensitive to cycles, and requires that we call `typeck(function)` before `typeck(anon const)`.  The reason is that `typeck(anon const)` calls `type_of(anon const)`, which calls `typeck(function)`, which feeds `type_of(anon const)`, and needs to build the MIR so needs `typeck(anon const)`.  The latter call would not cycle, since `type_of(anon const)` has been set, but I'd rather not remove the cycle check.

Author: bors

compiler/rustc_borrowck/src/consumers.rs

@@ -6,7 +6,7 @@ use rustc_hir::def_id::LocalDefId;
 use rustc_index::vec::IndexSlice;
 use rustc_infer::infer::{DefiningAnchor, TyCtxtInferExt};
 use rustc_middle::mir::Body;
-use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::ty::TyCtxt;
 
 pub use super::{
     facts::{AllFacts as PoloniusInput, RustcFacts},
@@ -28,12 +28,9 @@ pub use super::{
 ///     that shows how to do this at `tests/run-make/obtain-borrowck/`.
 ///
 /// *   Polonius is highly unstable, so expect regular changes in its signature or other details.
-pub fn get_body_with_borrowck_facts(
-    tcx: TyCtxt<'_>,
-    def: ty::WithOptConstParam<LocalDefId>,
-) -> BodyWithBorrowckFacts<'_> {
+pub fn get_body_with_borrowck_facts(tcx: TyCtxt<'_>, def: LocalDefId) -> BodyWithBorrowckFacts<'_> {
     let (input_body, promoted) = tcx.mir_promoted(def);
-    let infcx = tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bind(def.did)).build();
+    let infcx = tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bind(def)).build();
     let input_body: &Body<'_> = &input_body.borrow();
     let promoted: &IndexSlice<_, _> = &promoted.borrow();
     *super::do_mir_borrowck(&infcx, input_body, promoted, true).1.unwrap()

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -19,7 +19,7 @@ use rustc_middle::mir::{
     FakeReadCause, LocalDecl, LocalInfo, LocalKind, Location, Operand, Place, PlaceRef,
     ProjectionElem, Rvalue, Statement, StatementKind, Terminator, TerminatorKind, VarBindingForm,
 };
-use rustc_middle::ty::{self, suggest_constraining_type_params, PredicateKind, Ty, TypeckResults};
+use rustc_middle::ty::{self, suggest_constraining_type_params, PredicateKind, Ty};
 use rustc_middle::util::CallKind;
 use rustc_mir_dataflow::move_paths::{InitKind, MoveOutIndex, MovePathIndex};
 use rustc_span::def_id::LocalDefId;
@@ -1350,8 +1350,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         finder.visit_expr(body_expr);
         let Some((closure_expr, closure)) = finder.res else { return };
 
-        let typeck_results: &TypeckResults<'_> =
-            tcx.typeck_opt_const_arg(self.body.source.with_opt_param().as_local().unwrap());
+        let typeck_results = tcx.typeck(self.mir_def_id());
 
         // Check that the parent of the closure is a method call,
         // with receiver matching with local's type (modulo refs)

compiler/rustc_borrowck/src/lib.rs

@@ -119,24 +119,12 @@ impl<'tcx> TyCtxtConsts<'tcx> {
 }
 
 pub fn provide(providers: &mut Providers) {
-    *providers = Providers {
-        mir_borrowck: |tcx, did| {
-            if let Some(def) = ty::WithOptConstParam::try_lookup(did, tcx) {
-                tcx.mir_borrowck_const_arg(def)
-            } else {
-                mir_borrowck(tcx, ty::WithOptConstParam::unknown(did))
-            }
-        },
-        mir_borrowck_const_arg: |tcx, (did, param_did)| {
-            mir_borrowck(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
-        },
-        ..*providers
-    };
+    *providers = Providers { mir_borrowck, ..*providers };
 }
 
-fn mir_borrowck(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> &BorrowCheckResult<'_> {
+fn mir_borrowck(tcx: TyCtxt<'_>, def: LocalDefId) -> &BorrowCheckResult<'_> {
     let (input_body, promoted) = tcx.mir_promoted(def);
-    debug!("run query mir_borrowck: {}", tcx.def_path_str(def.did.to_def_id()));
+    debug!("run query mir_borrowck: {}", tcx.def_path_str(def.to_def_id()));
 
     if input_body.borrow().should_skip() {
         debug!("Skipping borrowck because of injected body");
@@ -150,7 +138,7 @@ fn mir_borrowck(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> &Bor
         return tcx.arena.alloc(result);
     }
 
-    let hir_owner = tcx.hir().local_def_id_to_hir_id(def.did).owner;
+    let hir_owner = tcx.hir().local_def_id_to_hir_id(def).owner;
 
     let infcx =
         tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bind(hir_owner.def_id)).build();
@@ -167,19 +155,19 @@ fn mir_borrowck(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> &Bor
 /// If `return_body_with_facts` is true, then return the body with non-erased
 /// region ids on which the borrow checking was performed together with Polonius
 /// facts.
-#[instrument(skip(infcx, input_body, input_promoted), fields(id=?input_body.source.with_opt_param().as_local().unwrap()), level = "debug")]
+#[instrument(skip(infcx, input_body, input_promoted), fields(id=?input_body.source.def_id()), level = "debug")]
 fn do_mir_borrowck<'tcx>(
     infcx: &InferCtxt<'tcx>,
     input_body: &Body<'tcx>,
     input_promoted: &IndexSlice<Promoted, Body<'tcx>>,
     return_body_with_facts: bool,
 ) -> (BorrowCheckResult<'tcx>, Option<Box<BodyWithBorrowckFacts<'tcx>>>) {
-    let def = input_body.source.with_opt_param().as_local().unwrap();
+    let def = input_body.source.def_id().expect_local();
     debug!(?def);
 
     let tcx = infcx.tcx;
     let infcx = BorrowckInferCtxt::new(infcx);
-    let param_env = tcx.param_env(def.did);
+    let param_env = tcx.param_env(def);
 
     let mut local_names = IndexVec::from_elem(None, &input_body.local_decls);
     for var_debug_info in &input_body.var_debug_info {
@@ -207,7 +195,7 @@ fn do_mir_borrowck<'tcx>(
         errors.set_tainted_by_errors(e);
     }
     let upvars: Vec<_> = tcx
-        .closure_captures(def.did)
+        .closure_captures(def)
         .iter()
         .map(|&captured_place| {
             let capture = captured_place.info.capture_kind;
@@ -249,7 +237,7 @@ fn do_mir_borrowck<'tcx>(
         .iterate_to_fixpoint()
         .into_results_cursor(&body);
 
-    let locals_are_invalidated_at_exit = tcx.hir().body_owner_kind(def.did).is_fn_or_closure();
+    let locals_are_invalidated_at_exit = tcx.hir().body_owner_kind(def).is_fn_or_closure();
     let borrow_set =
         Rc::new(BorrowSet::build(tcx, body, locals_are_invalidated_at_exit, &mdpe.move_data));
 

compiler/rustc_borrowck/src/nll.rs

@@ -61,7 +61,7 @@ pub(crate) fn replace_regions_in_mir<'tcx>(
     body: &mut Body<'tcx>,
     promoted: &mut IndexSlice<Promoted, Body<'tcx>>,
 ) -> UniversalRegions<'tcx> {
-    let def = body.source.with_opt_param().as_local().unwrap();
+    let def = body.source.def_id().expect_local();
 
     debug!(?def);
 

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -394,7 +394,7 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
                     self.cx.ascribe_user_type(
                         constant.literal.ty(),
                         UserType::TypeOf(
-                            uv.def.did,
+                            uv.def,
                             UserSubsts { substs: uv.substs, user_self_ty: None },
                         ),
                         locations.span(&self.cx.body),
@@ -1766,7 +1766,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             if let Some(uv) = maybe_uneval {
                 if uv.promoted.is_none() {
                     let tcx = self.tcx();
-                    let def_id = uv.def.def_id_for_type_of();
+                    let def_id = uv.def;
                     if tcx.def_kind(def_id) == DefKind::InlineConst {
                         let def_id = def_id.expect_local();
                         let predicates =

compiler/rustc_borrowck/src/universal_regions.rs

@@ -226,7 +226,7 @@ impl<'tcx> UniversalRegions<'tcx> {
     /// known between those regions.
     pub fn new(
         infcx: &BorrowckInferCtxt<'_, 'tcx>,
-        mir_def: ty::WithOptConstParam<LocalDefId>,
+        mir_def: LocalDefId,
         param_env: ty::ParamEnv<'tcx>,
     ) -> Self {
         UniversalRegionsBuilder { infcx, mir_def, param_env }.build()
@@ -388,7 +388,7 @@ impl<'tcx> UniversalRegions<'tcx> {
 
 struct UniversalRegionsBuilder<'cx, 'tcx> {
     infcx: &'cx BorrowckInferCtxt<'cx, 'tcx>,
-    mir_def: ty::WithOptConstParam<LocalDefId>,
+    mir_def: LocalDefId,
     param_env: ty::ParamEnv<'tcx>,
 }
 
@@ -417,12 +417,12 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
         let mut indices = self.compute_indices(fr_static, defining_ty);
         debug!("build: indices={:?}", indices);
 
-        let typeck_root_def_id = self.infcx.tcx.typeck_root_def_id(self.mir_def.did.to_def_id());
+        let typeck_root_def_id = self.infcx.tcx.typeck_root_def_id(self.mir_def.to_def_id());
 
         // If this is a 'root' body (not a closure/generator/inline const), then
         // there are no extern regions, so the local regions start at the same
         // position as the (empty) sub-list of extern regions
-        let first_local_index = if self.mir_def.did.to_def_id() == typeck_root_def_id {
+        let first_local_index = if self.mir_def.to_def_id() == typeck_root_def_id {
             first_extern_index
         } else {
             // If this is a closure, generator, or inline-const, then the late-bound regions from the enclosing
@@ -433,7 +433,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             // }
             for_each_late_bound_region_in_recursive_scope(
                 self.infcx.tcx,
-                self.infcx.tcx.local_parent(self.mir_def.did),
+                self.infcx.tcx.local_parent(self.mir_def),
                 |r| {
                     debug!(?r);
                     if !indices.indices.contains_key(&r) {
@@ -462,13 +462,13 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
 
         let inputs_and_output = self.infcx.replace_bound_regions_with_nll_infer_vars(
             FR,
-            self.mir_def.did,
+            self.mir_def,
             bound_inputs_and_output,
             &mut indices,
         );
         // Converse of above, if this is a function/closure then the late-bound regions declared on its
         // signature are local.
-        for_each_late_bound_region_in_item(self.infcx.tcx, self.mir_def.did, |r| {
+        for_each_late_bound_region_in_item(self.infcx.tcx, self.mir_def, |r| {
             debug!(?r);
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
@@ -492,7 +492,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             if self.infcx.tcx.fn_sig(def_id).skip_binder().c_variadic() {
                 let va_list_did = self.infcx.tcx.require_lang_item(
                     LangItem::VaList,
-                    Some(self.infcx.tcx.def_span(self.mir_def.did)),
+                    Some(self.infcx.tcx.def_span(self.mir_def)),
                 );
 
                 let reg_vid = self
@@ -544,11 +544,11 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
     /// see `DefiningTy` for details.
     fn defining_ty(&self) -> DefiningTy<'tcx> {
         let tcx = self.infcx.tcx;
-        let typeck_root_def_id = tcx.typeck_root_def_id(self.mir_def.did.to_def_id());
+        let typeck_root_def_id = tcx.typeck_root_def_id(self.mir_def.to_def_id());
 
-        match tcx.hir().body_owner_kind(self.mir_def.did) {
+        match tcx.hir().body_owner_kind(self.mir_def) {
             BodyOwnerKind::Closure | BodyOwnerKind::Fn => {
-                let defining_ty = tcx.type_of(self.mir_def.def_id_for_type_of()).subst_identity();
+                let defining_ty = tcx.type_of(self.mir_def).subst_identity();
 
                 debug!("defining_ty (pre-replacement): {:?}", defining_ty);
 
@@ -562,20 +562,20 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
                     }
                     ty::FnDef(def_id, substs) => DefiningTy::FnDef(def_id, substs),
                     _ => span_bug!(
-                        tcx.def_span(self.mir_def.did),
+                        tcx.def_span(self.mir_def),
                         "expected defining type for `{:?}`: `{:?}`",
-                        self.mir_def.did,
+                        self.mir_def,
                         defining_ty
                     ),
                 }
             }
 
             BodyOwnerKind::Const | BodyOwnerKind::Static(..) => {
                 let identity_substs = InternalSubsts::identity_for_item(tcx, typeck_root_def_id);
-                if self.mir_def.did.to_def_id() == typeck_root_def_id {
+                if self.mir_def.to_def_id() == typeck_root_def_id {
                     let substs =
                         self.infcx.replace_free_regions_with_nll_infer_vars(FR, identity_substs);
-                    DefiningTy::Const(self.mir_def.did.to_def_id(), substs)
+                    DefiningTy::Const(self.mir_def.to_def_id(), substs)
                 } else {
                     // FIXME this line creates a dependency between borrowck and typeck.
                     //
@@ -587,15 +587,15 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
                     // below), so that `type_of(inline_const_def_id).substs(substs)` uses the
                     // proper type with NLL infer vars.
                     let ty = tcx
-                        .typeck(self.mir_def.did)
-                        .node_type(tcx.local_def_id_to_hir_id(self.mir_def.did));
+                        .typeck(self.mir_def)
+                        .node_type(tcx.local_def_id_to_hir_id(self.mir_def));
                     let substs = InlineConstSubsts::new(
                         tcx,
                         InlineConstSubstsParts { parent_substs: identity_substs, ty },
                     )
                     .substs;
                     let substs = self.infcx.replace_free_regions_with_nll_infer_vars(FR, substs);
-                    DefiningTy::InlineConst(self.mir_def.did.to_def_id(), substs)
+                    DefiningTy::InlineConst(self.mir_def.to_def_id(), substs)
                 }
             }
         }
@@ -611,7 +611,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
         defining_ty: DefiningTy<'tcx>,
     ) -> UniversalRegionIndices<'tcx> {
         let tcx = self.infcx.tcx;
-        let typeck_root_def_id = tcx.typeck_root_def_id(self.mir_def.did.to_def_id());
+        let typeck_root_def_id = tcx.typeck_root_def_id(self.mir_def.to_def_id());
         let identity_substs = InternalSubsts::identity_for_item(tcx, typeck_root_def_id);
         let fr_substs = match defining_ty {
             DefiningTy::Closure(_, substs)
@@ -647,7 +647,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
         let tcx = self.infcx.tcx;
         match defining_ty {
             DefiningTy::Closure(def_id, substs) => {
-                assert_eq!(self.mir_def.did.to_def_id(), def_id);
+                assert_eq!(self.mir_def.to_def_id(), def_id);
                 let closure_sig = substs.as_closure().sig();
                 let inputs_and_output = closure_sig.inputs_and_output();
                 let bound_vars = tcx.mk_bound_variable_kinds_from_iter(
@@ -682,7 +682,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             }
 
             DefiningTy::Generator(def_id, substs, movability) => {
-                assert_eq!(self.mir_def.did.to_def_id(), def_id);
+                assert_eq!(self.mir_def.to_def_id(), def_id);
                 let resume_ty = substs.as_generator().resume_ty();
                 let output = substs.as_generator().return_ty();
                 let generator_ty = tcx.mk_generator(def_id, substs, movability);
@@ -700,14 +700,14 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             DefiningTy::Const(def_id, _) => {
                 // For a constant body, there are no inputs, and one
                 // "output" (the type of the constant).
-                assert_eq!(self.mir_def.did.to_def_id(), def_id);
-                let ty = tcx.type_of(self.mir_def.def_id_for_type_of()).subst_identity();
+                assert_eq!(self.mir_def.to_def_id(), def_id);
+                let ty = tcx.type_of(self.mir_def).subst_identity();
                 let ty = indices.fold_to_region_vids(tcx, ty);
                 ty::Binder::dummy(tcx.mk_type_list(&[ty]))
             }
 
             DefiningTy::InlineConst(def_id, substs) => {
-                assert_eq!(self.mir_def.did.to_def_id(), def_id);
+                assert_eq!(self.mir_def.to_def_id(), def_id);
                 let ty = substs.as_inline_const().ty();
                 ty::Binder::dummy(tcx.mk_type_list(&[ty]))
             }

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -91,7 +91,7 @@ pub(crate) fn eval_mir_constant<'tcx>(
             ),
         },
         ConstantKind::Unevaluated(mir::UnevaluatedConst { def, .. }, _)
-            if fx.tcx.is_static(def.did) =>
+            if fx.tcx.is_static(def) =>
         {
             span_bug!(constant.span, "MIR constant refers to static");
         }

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -333,7 +333,7 @@ fn exported_symbols_provider_local(
             match *mono_item {
                 MonoItem::Fn(Instance { def: InstanceDef::Item(def), substs }) => {
                     if substs.non_erasable_generics().next().is_some() {
-                        let symbol = ExportedSymbol::Generic(def.did, substs);
+                        let symbol = ExportedSymbol::Generic(def, substs);
                         symbols.push((
                             symbol,
                             SymbolExportInfo {

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -296,12 +296,12 @@ pub fn eval_to_allocation_raw_provider<'tcx>(
     }
 
     let cid = key.value;
-    let def = cid.instance.def.with_opt_param();
-    let is_static = tcx.is_static(def.did);
+    let def = cid.instance.def.def_id();
+    let is_static = tcx.is_static(def);
 
     let mut ecx = InterpCx::new(
         tcx,
-        tcx.def_span(def.did),
+        tcx.def_span(def),
         key.param_env,
         // Statics (and promoteds inside statics) may access other statics, because unlike consts
         // they do not have to behave "as if" they were evaluated at runtime.

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -375,9 +375,9 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
     ) -> InterpResult<'tcx, &'tcx mir::Body<'tcx>> {
         match instance {
             ty::InstanceDef::Item(def) => {
-                if ecx.tcx.is_ctfe_mir_available(def.did) {
-                    Ok(ecx.tcx.mir_for_ctfe_opt_const_arg(def))
-                } else if ecx.tcx.def_kind(def.did) == DefKind::AssocConst {
+                if ecx.tcx.is_ctfe_mir_available(def) {
+                    Ok(ecx.tcx.mir_for_ctfe(def))
+                } else if ecx.tcx.def_kind(def) == DefKind::AssocConst {
                     let guar = ecx.tcx.sess.delay_span_bug(
                         rustc_span::DUMMY_SP,
                         "This is likely a const item that is missing from its impl",
@@ -386,7 +386,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
                 } else {
                     // `find_mir_or_eval_fn` checks that this is a const fn before even calling us,
                     // so this should be unreachable.
-                    let path = ecx.tcx.def_path_str(def.did);
+                    let path = ecx.tcx.def_path_str(def);
                     bug!("trying to call extern function `{path}` at compile-time");
                 }
             }
@@ -410,9 +410,9 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
             // Execution might have wandered off into other crates, so we cannot do a stability-
             // sensitive check here. But we can at least rule out functions that are not const
             // at all.
-            if !ecx.tcx.is_const_fn_raw(def.did) {
+            if !ecx.tcx.is_const_fn_raw(def) {
                 // allow calling functions inside a trait marked with #[const_trait].
-                if !ecx.tcx.is_const_default_method(def.did) {
+                if !ecx.tcx.is_const_default_method(def) {
                     // We certainly do *not* want to actually call the fn
                     // though, so be sure we return here.
                     throw_unsup_format!("calling non-const function `{}`", instance)