Auto merge of #69247 - CAD97:remove-chalk, r=nikomatsakis

Remove experimental chalk option

As suggested by @nikomatsakis [here](#68807 (comment)).

The current version of chalk used by the experimental `-Zchalk` flag is [v0.9.0, which is over a year old](https://crates.io/crates/chalk-engine). Since v0.9.0, chalk has seen [a lot of further development](rust-lang/chalk@41dfe13...master), and the intent is to eventually upgrade rustc to use a more recent chalk.

However, it will take a decent chunk of effort to upgrade the current experimental chalk support, and it is currently [blocking at least some PRs](#68807) due to chalk:0.9.0's use of unstable features. So for the interim until the next chalk release and experimental rustc integration, we remove the chalk-specific code from rustc.

Author: bors

Diff for: Cargo.lock

@@ -419,25 +419,6 @@ dependencies = [
  "rustc-std-workspace-core",
 ]
 
-[[package]]
-name = "chalk-engine"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17ec698a6f053a23bfbe646d9f2fde4b02abc19125595270a99e6f44ae0bdd1a"
-dependencies = [
- "chalk-macros",
- "rustc-hash",
-]
-
-[[package]]
-name = "chalk-macros"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "295635afd6853aa9f20baeb7f0204862440c0fe994c5a253d5f479dac41d047e"
-dependencies = [
- "lazy_static 0.2.11",
-]
-
 [[package]]
 name = "chrono"
 version = "0.4.6"
@@ -3110,7 +3091,6 @@ dependencies = [
  "backtrace",
  "bitflags",
  "byteorder",
- "chalk-engine",
  "jobserver",
  "log",
  "measureme",
@@ -4144,7 +4124,6 @@ checksum = "b725dadae9fabc488df69a287f5a99c5eaf5d10853842a8a3dfac52476f544ee"
 name = "rustc_traits"
 version = "0.0.0"
 dependencies = [
- "chalk-engine",
  "log",
  "rustc",
  "rustc_ast",

Diff for: src/librustc/Cargo.toml

@@ -33,7 +33,6 @@ rustc_span = { path = "../librustc_span" }
 backtrace = "0.3.40"
 parking_lot = "0.9"
 byteorder = { version = "1.3" }
-chalk-engine = { version = "0.9.0", default-features=false }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 measureme = "0.7.1"
 rustc_session = { path = "../librustc_session" }

Diff for: src/librustc/query/mod.rs

@@ -1130,16 +1130,6 @@ rustc_queries! {
             desc { "evaluating trait selection obligation `{}`", goal.value.value }
         }
 
-        query evaluate_goal(
-            goal: traits::ChalkCanonicalGoal<'tcx>
-        ) -> Result<
-            &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, ()>>,
-            NoSolution
-        > {
-            no_force
-            desc { "evaluating trait selection obligation `{}`", goal.value.goal }
-        }
-
         /// Do not call this query directly: part of the `Eq` type-op
         query type_op_ascribe_user_type(
             goal: CanonicalTypeOpAscribeUserTypeGoal<'tcx>

Diff for: src/librustc/traits/mod.rs

@@ -7,9 +7,7 @@ pub mod select;
 pub mod specialization_graph;
 mod structural_impls;
 
-use crate::infer::canonical::Canonical;
 use crate::mir::interpret::ErrorHandled;
-use crate::ty::fold::{TypeFolder, TypeVisitor};
 use crate::ty::subst::SubstsRef;
 use crate::ty::{self, AdtKind, List, Ty, TyCtxt};
 
@@ -25,8 +23,6 @@ use std::rc::Rc;
 
 pub use self::select::{EvaluationCache, EvaluationResult, OverflowError, SelectionCache};
 
-pub type ChalkCanonicalGoal<'tcx> = Canonical<'tcx, InEnvironment<'tcx, ty::Predicate<'tcx>>>;
-
 pub use self::ObligationCauseCode::*;
 pub use self::SelectionError::*;
 pub use self::Vtable::*;
@@ -715,45 +711,6 @@ pub struct VtableTraitAliasData<'tcx, N> {
     pub nested: Vec<N>,
 }
 
-pub trait ExClauseFold<'tcx>
-where
-    Self: chalk_engine::context::Context + Clone,
-{
-    fn fold_ex_clause_with<F: TypeFolder<'tcx>>(
-        ex_clause: &chalk_engine::ExClause<Self>,
-        folder: &mut F,
-    ) -> chalk_engine::ExClause<Self>;
-
-    fn visit_ex_clause_with<V: TypeVisitor<'tcx>>(
-        ex_clause: &chalk_engine::ExClause<Self>,
-        visitor: &mut V,
-    ) -> bool;
-}
-
-pub trait ChalkContextLift<'tcx>
-where
-    Self: chalk_engine::context::Context + Clone,
-{
-    type LiftedExClause: Debug + 'tcx;
-    type LiftedDelayedLiteral: Debug + 'tcx;
-    type LiftedLiteral: Debug + 'tcx;
-
-    fn lift_ex_clause_to_tcx(
-        ex_clause: &chalk_engine::ExClause<Self>,
-        tcx: TyCtxt<'tcx>,
-    ) -> Option<Self::LiftedExClause>;
-
-    fn lift_delayed_literal_to_tcx(
-        ex_clause: &chalk_engine::DelayedLiteral<Self>,
-        tcx: TyCtxt<'tcx>,
-    ) -> Option<Self::LiftedDelayedLiteral>;
-
-    fn lift_literal_to_tcx(
-        ex_clause: &chalk_engine::Literal<Self>,
-        tcx: TyCtxt<'tcx>,
-    ) -> Option<Self::LiftedLiteral>;
-}
-
 #[derive(Clone, Debug, PartialEq, Eq, Hash, HashStable)]
 pub enum ObjectSafetyViolation {
     /// `Self: Sized` declared on the trait.

Diff for: src/librustc/traits/structural_impls.rs

@@ -595,42 +595,6 @@ impl<'a, 'tcx, G: Lift<'tcx>> Lift<'tcx> for traits::InEnvironment<'a, G> {
     }
 }
 
-impl<'tcx, C> Lift<'tcx> for chalk_engine::ExClause<C>
-where
-    C: chalk_engine::context::Context + Clone,
-    C: traits::ChalkContextLift<'tcx>,
-{
-    type Lifted = C::LiftedExClause;
-
-    fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        <C as traits::ChalkContextLift>::lift_ex_clause_to_tcx(self, tcx)
-    }
-}
-
-impl<'tcx, C> Lift<'tcx> for chalk_engine::DelayedLiteral<C>
-where
-    C: chalk_engine::context::Context + Clone,
-    C: traits::ChalkContextLift<'tcx>,
-{
-    type Lifted = C::LiftedDelayedLiteral;
-
-    fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        <C as traits::ChalkContextLift>::lift_delayed_literal_to_tcx(self, tcx)
-    }
-}
-
-impl<'tcx, C> Lift<'tcx> for chalk_engine::Literal<C>
-where
-    C: chalk_engine::context::Context + Clone,
-    C: traits::ChalkContextLift<'tcx>,
-{
-    type Lifted = C::LiftedLiteral;
-
-    fn lift_to_tcx(&self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        <C as traits::ChalkContextLift>::lift_literal_to_tcx(self, tcx)
-    }
-}
-
 ///////////////////////////////////////////////////////////////////////////
 // TypeFoldable implementations.
 
@@ -674,39 +638,3 @@ impl<'tcx> TypeFoldable<'tcx> for traits::Clauses<'tcx> {
         self.iter().any(|t| t.visit_with(visitor))
     }
 }
-
-impl<'tcx, C> TypeFoldable<'tcx> for chalk_engine::ExClause<C>
-where
-    C: traits::ExClauseFold<'tcx>,
-    C::Substitution: Clone,
-    C::RegionConstraint: Clone,
-{
-    fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
-        <C as traits::ExClauseFold>::fold_ex_clause_with(self, folder)
-    }
-
-    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
-        <C as traits::ExClauseFold>::visit_ex_clause_with(self, visitor)
-    }
-}
-
-EnumTypeFoldableImpl! {
-    impl<'tcx, C> TypeFoldable<'tcx> for chalk_engine::DelayedLiteral<C> {
-        (chalk_engine::DelayedLiteral::CannotProve)(a),
-        (chalk_engine::DelayedLiteral::Negative)(a),
-        (chalk_engine::DelayedLiteral::Positive)(a, b),
-    } where
-        C: chalk_engine::context::Context<CanonicalConstrainedSubst: TypeFoldable<'tcx>> + Clone,
-}
-
-EnumTypeFoldableImpl! {
-    impl<'tcx, C> TypeFoldable<'tcx> for chalk_engine::Literal<C> {
-        (chalk_engine::Literal::Negative)(a),
-        (chalk_engine::Literal::Positive)(a),
-    } where
-        C: chalk_engine::context::Context<GoalInEnvironment: Clone + TypeFoldable<'tcx>> + Clone,
-}
-
-CloneTypeFoldableAndLiftImpls! {
-    chalk_engine::TableIndex,
-}

Diff for: src/librustc_infer/infer/canonical/canonicalizer.rs

@@ -357,10 +357,8 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
                     // `TyVar(vid)` is unresolved, track its universe index in the canonicalized
                     // result.
                     Err(mut ui) => {
-                        if !self.infcx.unwrap().tcx.sess.opts.debugging_opts.chalk {
-                            // FIXME: perf problem described in #55921.
-                            ui = ty::UniverseIndex::ROOT;
-                        }
+                        // FIXME: perf problem described in #55921.
+                        ui = ty::UniverseIndex::ROOT;
                         self.canonicalize_ty_var(
                             CanonicalVarInfo {
                                 kind: CanonicalVarKind::Ty(CanonicalTyVarKind::General(ui)),
@@ -447,10 +445,8 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for Canonicalizer<'cx, 'tcx> {
                     // `ConstVar(vid)` is unresolved, track its universe index in the
                     // canonicalized result
                     Err(mut ui) => {
-                        if !self.infcx.unwrap().tcx.sess.opts.debugging_opts.chalk {
-                            // FIXME: perf problem described in #55921.
-                            ui = ty::UniverseIndex::ROOT;
-                        }
+                        // FIXME: perf problem described in #55921.
+                        ui = ty::UniverseIndex::ROOT;
                         return self.canonicalize_const_var(
                             CanonicalVarInfo { kind: CanonicalVarKind::Const(ui) },
                             ct,