Migrate InferenceTable into next-solver

crates/hir-ty/src/autoderef.rs

@@ -13,7 +13,7 @@ use triomphe::Arc;
 
 use crate::{
     Canonical, Goal, Interner, ProjectionTyExt, TraitEnvironment, Ty, TyBuilder, TyKind,
-    db::HirDatabase, infer::unify::InferenceTable,
+    db::HirDatabase, infer::unify::InferenceTable, next_solver::mapping::ChalkToNextSolver,
 };
 
 const AUTODEREF_RECURSION_LIMIT: usize = 20;
@@ -98,7 +98,7 @@ impl<'table, 'db> Autoderef<'table, 'db> {
         explicit: bool,
         use_receiver_trait: bool,
     ) -> Self {
-        let ty = table.resolve_ty_shallow(&ty);
+        let ty = table.structurally_resolve_type(&ty);
         Autoderef { table, ty, at_start: true, steps: Vec::new(), explicit, use_receiver_trait }
     }
 
@@ -114,7 +114,7 @@ impl<'table, 'db> Autoderef<'table, 'db, usize> {
         explicit: bool,
         use_receiver_trait: bool,
     ) -> Self {
-        let ty = table.resolve_ty_shallow(&ty);
+        let ty = table.structurally_resolve_type(&ty);
         Autoderef { table, ty, at_start: true, steps: 0, explicit, use_receiver_trait }
     }
 }
@@ -160,7 +160,7 @@ pub(crate) fn autoderef_step(
     use_receiver_trait: bool,
 ) -> Option<(AutoderefKind, Ty)> {
     if let Some(derefed) = builtin_deref(table.db, &ty, explicit) {
-        Some((AutoderefKind::Builtin, table.resolve_ty_shallow(derefed)))
+        Some((AutoderefKind::Builtin, table.structurally_resolve_type(derefed)))
     } else {
         Some((AutoderefKind::Overloaded, deref_by_trait(table, ty, use_receiver_trait)?))
     }
@@ -187,7 +187,7 @@ pub(crate) fn deref_by_trait(
     use_receiver_trait: bool,
 ) -> Option<Ty> {
     let _p = tracing::info_span!("deref_by_trait").entered();
-    if table.resolve_ty_shallow(&ty).inference_var(Interner).is_some() {
+    if table.structurally_resolve_type(&ty).inference_var(Interner).is_some() {
         // don't try to deref unknown variables
         return None;
     }
@@ -229,8 +229,8 @@ pub(crate) fn deref_by_trait(
         return None;
     }
 
-    table.register_obligation(implements_goal);
+    table.register_obligation(implements_goal.to_nextsolver(table.interner));
 
     let result = table.normalize_projection_ty(projection);
-    Some(table.resolve_ty_shallow(&result))
+    Some(table.structurally_resolve_type(&result))
 }

crates/hir-ty/src/chalk_ext.rs

@@ -245,26 +245,30 @@ impl TyExt for Ty {
     }
 
     fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>> {
+        let handle_async_block_type_impl_trait = |def: DefWithBodyId| {
+            let krate = def.module(db).krate();
+            if let Some(future_trait) = LangItem::Future.resolve_trait(db, krate) {
+                // This is only used by type walking.
+                // Parameters will be walked outside, and projection predicate is not used.
+                // So just provide the Future trait.
+                let impl_bound = Binders::empty(
+                    Interner,
+                    WhereClause::Implemented(TraitRef {
+                        trait_id: to_chalk_trait_id(future_trait),
+                        substitution: Substitution::empty(Interner),
+                    }),
+                );
+                Some(vec![impl_bound])
+            } else {
+                None
+            }
+        };
+
         match self.kind(Interner) {
             TyKind::OpaqueType(opaque_ty_id, subst) => {
                 match db.lookup_intern_impl_trait_id((*opaque_ty_id).into()) {
                     ImplTraitId::AsyncBlockTypeImplTrait(def, _expr) => {
-                        let krate = def.module(db).krate();
-                        if let Some(future_trait) = LangItem::Future.resolve_trait(db, krate) {
-                            // This is only used by type walking.
-                            // Parameters will be walked outside, and projection predicate is not used.
-                            // So just provide the Future trait.
-                            let impl_bound = Binders::empty(
-                                Interner,
-                                WhereClause::Implemented(TraitRef {
-                                    trait_id: to_chalk_trait_id(future_trait),
-                                    substitution: Substitution::empty(Interner),
-                                }),
-                            );
-                            Some(vec![impl_bound])
-                        } else {
-                            None
-                        }
+                        handle_async_block_type_impl_trait(def)
                     }
                     ImplTraitId::ReturnTypeImplTrait(func, idx) => {
                         db.return_type_impl_traits(func).map(|it| {
@@ -299,8 +303,9 @@ impl TyExt for Ty {
                             data.substitute(Interner, &opaque_ty.substitution)
                         })
                     }
-                    // It always has an parameter for Future::Output type.
-                    ImplTraitId::AsyncBlockTypeImplTrait(..) => unreachable!(),
+                    ImplTraitId::AsyncBlockTypeImplTrait(def, _) => {
+                        return handle_async_block_type_impl_trait(def);
+                    }
                 };
 
                 predicates.map(|it| it.into_value_and_skipped_binders().0)

crates/hir-ty/src/consteval_nextsolver.rs

@@ -27,7 +27,7 @@ use crate::{
     next_solver::{
         Const, ConstBytes, ConstKind, DbInterner, ErrorGuaranteed, GenericArg, GenericArgs,
         ParamConst, SolverDefId, Ty, ValueConst,
-        mapping::{ChalkToNextSolver, convert_args_for_result, convert_binder_to_early_binder},
+        mapping::{ChalkToNextSolver, NextSolverToChalk, convert_binder_to_early_binder},
     },
 };
 
@@ -145,7 +145,7 @@ pub fn try_const_usize<'db>(db: &'db dyn HirDatabase, c: Const<'db>) -> Option<u
                 SolverDefId::StaticId(id) => GeneralConstId::StaticId(id),
                 _ => unreachable!(),
             };
-            let subst = convert_args_for_result(interner, unevaluated_const.args.as_slice());
+            let subst = unevaluated_const.args.to_chalk(interner);
             let ec = db.const_eval(c, subst, None).ok()?.to_nextsolver(interner);
             try_const_usize(db, ec)
         }
@@ -168,7 +168,7 @@ pub fn try_const_isize<'db>(db: &'db dyn HirDatabase, c: &Const<'db>) -> Option<
                 SolverDefId::StaticId(id) => GeneralConstId::StaticId(id),
                 _ => unreachable!(),
             };
-            let subst = convert_args_for_result(interner, unevaluated_const.args.as_slice());
+            let subst = unevaluated_const.args.to_chalk(interner);
             let ec = db.const_eval(c, subst, None).ok()?.to_nextsolver(interner);
             try_const_isize(db, &ec)
         }

crates/hir-ty/src/infer.rs

@@ -55,10 +55,9 @@ use stdx::{always, never};
 use triomphe::Arc;
 
 use crate::{
-    AliasEq, AliasTy, Binders, ClosureId, Const, DomainGoal, GenericArg, Goal, ImplTraitId,
-    ImplTraitIdx, InEnvironment, IncorrectGenericsLenKind, Interner, Lifetime, OpaqueTyId,
-    ParamLoweringMode, PathLoweringDiagnostic, ProjectionTy, Substitution, TraitEnvironment, Ty,
-    TyBuilder, TyExt,
+    AliasEq, AliasTy, Binders, ClosureId, Const, DomainGoal, GenericArg, ImplTraitId, ImplTraitIdx,
+    IncorrectGenericsLenKind, Interner, Lifetime, OpaqueTyId, ParamLoweringMode,
+    PathLoweringDiagnostic, ProjectionTy, Substitution, TraitEnvironment, Ty, TyBuilder, TyExt,
     db::HirDatabase,
     fold_tys,
     generics::Generics,
@@ -70,6 +69,7 @@ use crate::{
     },
     lower::{ImplTraitLoweringMode, LifetimeElisionKind, diagnostics::TyLoweringDiagnostic},
     mir::MirSpan,
+    next_solver::{self, mapping::ChalkToNextSolver},
     static_lifetime, to_assoc_type_id,
     traits::FnTrait,
     utils::UnevaluatedConstEvaluatorFolder,
@@ -182,13 +182,13 @@ impl BindingMode {
 }
 
 #[derive(Debug)]
-pub(crate) struct InferOk<T> {
+pub(crate) struct InferOk<'db, T> {
     value: T,
-    goals: Vec<InEnvironment<Goal>>,
+    goals: Vec<next_solver::Goal<'db, next_solver::Predicate<'db>>>,
 }
 
-impl<T> InferOk<T> {
-    fn map<U>(self, f: impl FnOnce(T) -> U) -> InferOk<U> {
+impl<'db, T> InferOk<'db, T> {
+    fn map<U>(self, f: impl FnOnce(T) -> U) -> InferOk<'db, U> {
         InferOk { value: f(self.value), goals: self.goals }
     }
 }
@@ -203,7 +203,7 @@ pub enum InferenceTyDiagnosticSource {
 
 #[derive(Debug)]
 pub(crate) struct TypeError;
-pub(crate) type InferResult<T> = Result<InferOk<T>, TypeError>;
+pub(crate) type InferResult<'db, T> = Result<InferOk<'db, T>, TypeError>;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum InferenceDiagnostic {
@@ -832,6 +832,7 @@ impl<'db> InferenceContext<'db> {
             coercion_casts,
             diagnostics: _,
         } = &mut result;
+        table.resolve_obligations_as_possible();
         table.fallback_if_possible();
 
         // Comment from rustc:
@@ -1480,7 +1481,8 @@ impl<'db> InferenceContext<'db> {
     }
 
     fn push_obligation(&mut self, o: DomainGoal) {
-        self.table.register_obligation(o.cast(Interner));
+        let goal: crate::Goal = o.cast(Interner);
+        self.table.register_obligation(goal.to_nextsolver(self.table.interner));
     }
 
     fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool {
@@ -1746,7 +1748,7 @@ impl<'db> InferenceContext<'db> {
 
                     ty = self.table.insert_type_vars(ty);
                     ty = self.table.normalize_associated_types_in(ty);
-                    ty = self.table.resolve_ty_shallow(&ty);
+                    ty = self.table.structurally_resolve_type(&ty);
                     if ty.is_unknown() {
                         return (self.err_ty(), None);
                     }
@@ -1817,7 +1819,7 @@ impl<'db> InferenceContext<'db> {
         let ty = match ty.kind(Interner) {
             TyKind::Alias(AliasTy::Projection(proj_ty)) => {
                 let ty = self.table.normalize_projection_ty(proj_ty.clone());
-                self.table.resolve_ty_shallow(&ty)
+                self.table.structurally_resolve_type(&ty)
             }
             _ => ty,
         };
@@ -2047,7 +2049,7 @@ impl Expectation {
     fn adjust_for_branches(&self, table: &mut unify::InferenceTable<'_>) -> Expectation {
         match self {
             Expectation::HasType(ety) => {
-                let ety = table.resolve_ty_shallow(ety);
+                let ety = table.structurally_resolve_type(ety);
                 if ety.is_ty_var() { Expectation::None } else { Expectation::HasType(ety) }
             }
             Expectation::RValueLikeUnsized(ety) => Expectation::RValueLikeUnsized(ety.clone()),

crates/hir-ty/src/infer/closure.rs

@@ -39,6 +39,7 @@ use crate::{
     infer::{BreakableKind, CoerceMany, Diverges, coerce::CoerceNever},
     make_binders,
     mir::{BorrowKind, MirSpan, MutBorrowKind, ProjectionElem},
+    next_solver::mapping::ChalkToNextSolver,
     to_assoc_type_id,
     traits::FnTrait,
     utils::{self, elaborate_clause_supertraits},
@@ -437,10 +438,10 @@ impl InferenceContext<'_> {
             associated_ty_id: to_assoc_type_id(future_output),
             substitution: Substitution::from1(Interner, ret_param_future.clone()),
         });
-        self.table.register_obligation(
+        let goal: crate::Goal =
             crate::AliasEq { alias: future_projection, ty: ret_param_future_output.clone() }
-                .cast(Interner),
-        );
+                .cast(Interner);
+        self.table.register_obligation(goal.to_nextsolver(self.table.interner));
 
         Some(FnSubst(Substitution::from_iter(
             Interner,
@@ -568,7 +569,10 @@ impl InferenceContext<'_> {
         let supplied_sig = self.supplied_sig_of_closure(body, ret_type, arg_types, closure_kind);
 
         let snapshot = self.table.snapshot();
-        if !self.table.unify(&expected_sig.substitution, &supplied_sig.expected_sig.substitution) {
+        if !self.table.unify::<_, crate::next_solver::GenericArgs<'_>>(
+            &expected_sig.substitution.0,
+            &supplied_sig.expected_sig.substitution.0,
+        ) {
             self.table.rollback_to(snapshot);
         }