internal: Migrate inference to next solver

crates/hir-def/src/expr_store/path.rs

@@ -88,7 +88,7 @@ pub struct AssociatedTypeBinding {
 }
 
 /// A single generic argument.
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum GenericArg {
     Type(TypeRefId),
     Lifetime(LifetimeRefId),

crates/hir-ty/src/autoderef.rs

@@ -5,12 +5,15 @@
 
 use std::fmt;
 
+use hir_def::TraitId;
 use hir_def::{TypeAliasId, lang_item::LangItem};
 use rustc_type_ir::inherent::{IntoKind, Ty as _};
 use tracing::debug;
 use triomphe::Arc;
 
+use crate::next_solver::TraitRef;
 use crate::next_solver::infer::InferOk;
+use crate::next_solver::infer::traits::Obligation;
 use crate::{
     TraitEnvironment,
     db::HirDatabase,
@@ -38,14 +41,14 @@ pub fn autoderef<'db>(
     ty: crate::Canonical<crate::Ty>,
 ) -> impl Iterator<Item = crate::Ty> + use<> {
     let mut table = InferenceTable::new(db, env);
-    let interner = table.interner;
-    let ty = table.instantiate_canonical(ty);
-    let mut autoderef = Autoderef::new_no_tracking(&mut table, ty.to_nextsolver(interner));
+    let interner = table.interner();
+    let ty = table.instantiate_canonical(ty.to_nextsolver(interner));
+    let mut autoderef = Autoderef::new_no_tracking(&mut table, ty);
     let mut v = Vec::new();
     while let Some((ty, _steps)) = autoderef.next() {
         // `ty` may contain unresolved inference variables. Since there's no chance they would be
         // resolved, just replace with fallback type.
-        let resolved = autoderef.table.resolve_completely(ty.to_chalk(interner));
+        let resolved = autoderef.table.resolve_completely(ty).to_chalk(interner);
 
         // If the deref chain contains a cycle (e.g. `A` derefs to `B` and `B` derefs to `A`), we
         // would revisit some already visited types. Stop here to avoid duplication.
@@ -101,6 +104,7 @@ struct AutoderefSnapshot<'db, Steps> {
 
 #[derive(Clone, Copy)]
 struct AutoderefTraits {
+    trait_: TraitId,
     trait_target: TypeAliasId,
 }
 
@@ -215,16 +219,26 @@ impl<'a, 'db, Steps: TrackAutoderefSteps<'db>> Autoderef<'a, 'db, Steps> {
             Some(it) => Some(*it),
             None => {
                 let traits = if self.use_receiver_trait {
-                    AutoderefTraits {
-                        trait_target: LangItem::ReceiverTarget
-                            .resolve_type_alias(self.table.db, self.table.trait_env.krate)
-                            .or_else(|| {
-                                LangItem::DerefTarget
-                                    .resolve_type_alias(self.table.db, self.table.trait_env.krate)
-                            })?,
-                    }
+                    (|| {
+                        Some(AutoderefTraits {
+                            trait_: LangItem::Receiver
+                                .resolve_trait(self.table.db, self.table.trait_env.krate)?,
+                            trait_target: LangItem::ReceiverTarget
+                                .resolve_type_alias(self.table.db, self.table.trait_env.krate)?,
+                        })
+                    })()
+                    .or_else(|| {
+                        Some(AutoderefTraits {
+                            trait_: LangItem::Deref
+                                .resolve_trait(self.table.db, self.table.trait_env.krate)?,
+                            trait_target: LangItem::DerefTarget
+                                .resolve_type_alias(self.table.db, self.table.trait_env.krate)?,
+                        })
+                    })?
                 } else {
                     AutoderefTraits {
+                        trait_: LangItem::Deref
+                            .resolve_trait(self.table.db, self.table.trait_env.krate)?,
                         trait_target: LangItem::DerefTarget
                             .resolve_type_alias(self.table.db, self.table.trait_env.krate)?,
                     }
@@ -236,10 +250,22 @@ impl<'a, 'db, Steps: TrackAutoderefSteps<'db>> Autoderef<'a, 'db, Steps> {
 
     fn overloaded_deref_ty(&mut self, ty: Ty<'db>) -> Option<Ty<'db>> {
         debug!("overloaded_deref_ty({:?})", ty);
-        let interner = self.table.interner;
+        let interner = self.table.interner();
 
         // <ty as Deref>, or whatever the equivalent trait is that we've been asked to walk.
-        let AutoderefTraits { trait_target } = self.autoderef_traits()?;
+        let AutoderefTraits { trait_, trait_target } = self.autoderef_traits()?;
+
+        let trait_ref = TraitRef::new(interner, trait_.into(), [ty]);
+        let obligation =
+            Obligation::new(interner, ObligationCause::new(), self.table.trait_env.env, trait_ref);
+        // We detect whether the self type implements `Deref` before trying to
+        // structurally normalize. We use `predicate_may_hold_opaque_types_jank`
+        // to support not-yet-defined opaque types. It will succeed for `impl Deref`
+        // but fail for `impl OtherTrait`.
+        if !self.table.infer_ctxt.predicate_may_hold_opaque_types_jank(&obligation) {
+            debug!("overloaded_deref_ty: cannot match obligation");
+            return None;
+        }
 
         let (normalized_ty, obligations) = structurally_normalize_ty(
             self.table,
@@ -316,7 +342,7 @@ pub(crate) fn overloaded_deref_ty<'db>(
     table: &InferenceTable<'db>,
     ty: Ty<'db>,
 ) -> Option<InferOk<'db, Ty<'db>>> {
-    let interner = table.interner;
+    let interner = table.interner();
 
     let trait_target = LangItem::DerefTarget.resolve_type_alias(table.db, table.trait_env.krate)?;
 

crates/hir-ty/src/builder.rs

@@ -15,7 +15,10 @@ use crate::{
     error_lifetime,
     generics::generics,
     infer::unify::InferenceTable,
-    next_solver::{DbInterner, EarlyBinder, mapping::ChalkToNextSolver},
+    next_solver::{
+        DbInterner, EarlyBinder,
+        mapping::{ChalkToNextSolver, NextSolverToChalk},
+    },
     primitive, to_assoc_type_id, to_chalk_trait_id,
 };
 
@@ -141,10 +144,13 @@ impl<D> TyBuilder<D> {
 
     #[tracing::instrument(skip_all)]
     pub(crate) fn fill_with_inference_vars(self, table: &mut InferenceTable<'_>) -> Self {
-        self.fill(|x| match x {
-            ParamKind::Type => table.new_type_var().cast(Interner),
-            ParamKind::Const(ty) => table.new_const_var(ty.clone()).cast(Interner),
-            ParamKind::Lifetime => table.new_lifetime_var().cast(Interner),
+        self.fill(|x| {
+            match x {
+                ParamKind::Type => crate::next_solver::GenericArg::Ty(table.next_ty_var()),
+                ParamKind::Const(_) => table.next_const_var().into(),
+                ParamKind::Lifetime => table.next_region_var().into(),
+            }
+            .to_chalk(table.interner())
         })
     }
 

crates/hir-ty/src/chalk_db.rs

@@ -2,7 +2,7 @@
 //! about the code that Chalk needs.
 use hir_def::{CallableDefId, GenericDefId};
 
-use crate::{Interner, Substitution, db::HirDatabase, mapping::from_chalk};
+use crate::{Interner, db::HirDatabase, mapping::from_chalk};
 
 pub(crate) type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
 pub(crate) type TraitId = chalk_ir::TraitId<Interner>;
@@ -53,16 +53,3 @@ pub(crate) fn adt_variance_query(db: &dyn HirDatabase, adt_id: hir_def::AdtId) -
         }),
     )
 }
-
-/// Returns instantiated predicates.
-pub(super) fn convert_where_clauses(
-    db: &dyn HirDatabase,
-    def: GenericDefId,
-    substs: &Substitution,
-) -> Vec<chalk_ir::QuantifiedWhereClause<Interner>> {
-    db.generic_predicates(def)
-        .iter()
-        .cloned()
-        .map(|pred| pred.substitute(Interner, substs))
-        .collect()
-}

crates/hir-ty/src/consteval.rs

@@ -4,8 +4,8 @@ use base_db::Crate;
 use chalk_ir::{BoundVar, DebruijnIndex, cast::Cast};
 use hir_def::{
     EnumVariantId, GeneralConstId, HasModule as _, StaticId,
-    expr_store::{Body, HygieneId, path::Path},
-    hir::{Expr, ExprId},
+    expr_store::{HygieneId, path::Path},
+    hir::Expr,
     resolver::{Resolver, ValueNs},
     type_ref::LiteralConstRef,
 };
@@ -19,13 +19,12 @@ use crate::{
     db::HirDatabase,
     display::DisplayTarget,
     generics::Generics,
-    infer::InferenceContext,
     lower::ParamLoweringMode,
     next_solver::{DbInterner, mapping::ChalkToNextSolver},
     to_placeholder_idx,
 };
 
-use super::mir::{MirEvalError, MirLowerError, interpret_mir, lower_to_mir, pad16};
+use super::mir::{MirEvalError, MirLowerError, interpret_mir, pad16};
 
 /// Extension trait for [`Const`]
 pub trait ConstExt {
@@ -56,12 +55,12 @@ impl ConstExt for Const {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum ConstEvalError {
-    MirLowerError(MirLowerError),
-    MirEvalError(MirEvalError),
+pub enum ConstEvalError<'db> {
+    MirLowerError(MirLowerError<'db>),
+    MirEvalError(MirEvalError<'db>),
 }
 
-impl ConstEvalError {
+impl ConstEvalError<'_> {
     pub fn pretty_print(
         &self,
         f: &mut String,
@@ -80,17 +79,17 @@ impl ConstEvalError {
     }
 }
 
-impl From<MirLowerError> for ConstEvalError {
-    fn from(value: MirLowerError) -> Self {
+impl<'db> From<MirLowerError<'db>> for ConstEvalError<'db> {
+    fn from(value: MirLowerError<'db>) -> Self {
         match value {
             MirLowerError::ConstEvalError(_, e) => *e,
             _ => ConstEvalError::MirLowerError(value),
         }
     }
 }
 
-impl From<MirEvalError> for ConstEvalError {
-    fn from(value: MirEvalError) -> Self {
+impl<'db> From<MirEvalError<'db>> for ConstEvalError<'db> {
+    fn from(value: MirEvalError<'db>) -> Self {
         ConstEvalError::MirEvalError(value)
     }
 }
@@ -225,35 +224,35 @@ pub fn try_const_isize(db: &dyn HirDatabase, c: &Const) -> Option<i128> {
     }
 }
 
-pub(crate) fn const_eval_cycle_result(
-    _: &dyn HirDatabase,
+pub(crate) fn const_eval_cycle_result<'db>(
+    _: &'db dyn HirDatabase,
     _: GeneralConstId,
     _: Substitution,
-    _: Option<Arc<TraitEnvironment<'_>>>,
-) -> Result<Const, ConstEvalError> {
+    _: Option<Arc<TraitEnvironment<'db>>>,
+) -> Result<Const, ConstEvalError<'db>> {
     Err(ConstEvalError::MirLowerError(MirLowerError::Loop))
 }
 
-pub(crate) fn const_eval_static_cycle_result(
-    _: &dyn HirDatabase,
+pub(crate) fn const_eval_static_cycle_result<'db>(
+    _: &'db dyn HirDatabase,
     _: StaticId,
-) -> Result<Const, ConstEvalError> {
+) -> Result<Const, ConstEvalError<'db>> {
     Err(ConstEvalError::MirLowerError(MirLowerError::Loop))
 }
 
-pub(crate) fn const_eval_discriminant_cycle_result(
-    _: &dyn HirDatabase,
+pub(crate) fn const_eval_discriminant_cycle_result<'db>(
+    _: &'db dyn HirDatabase,
     _: EnumVariantId,
-) -> Result<i128, ConstEvalError> {
+) -> Result<i128, ConstEvalError<'db>> {
     Err(ConstEvalError::MirLowerError(MirLowerError::Loop))
 }
 
-pub(crate) fn const_eval_query(
-    db: &dyn HirDatabase,
+pub(crate) fn const_eval_query<'db>(
+    db: &'db dyn HirDatabase,
     def: GeneralConstId,
     subst: Substitution,
-    trait_env: Option<Arc<TraitEnvironment<'_>>>,
-) -> Result<Const, ConstEvalError> {
+    trait_env: Option<Arc<TraitEnvironment<'db>>>,
+) -> Result<Const, ConstEvalError<'db>> {
     let body = match def {
         GeneralConstId::ConstId(c) => {
             db.monomorphized_mir_body(c.into(), subst, db.trait_environment(c.into()))?
@@ -267,10 +266,10 @@ pub(crate) fn const_eval_query(
     Ok(c)
 }
 
-pub(crate) fn const_eval_static_query(
-    db: &dyn HirDatabase,
+pub(crate) fn const_eval_static_query<'db>(
+    db: &'db dyn HirDatabase,
     def: StaticId,
-) -> Result<Const, ConstEvalError> {
+) -> Result<Const, ConstEvalError<'db>> {
     let body = db.monomorphized_mir_body(
         def.into(),
         Substitution::empty(Interner),
@@ -280,10 +279,10 @@ pub(crate) fn const_eval_static_query(
     Ok(c)
 }
 
-pub(crate) fn const_eval_discriminant_variant(
-    db: &dyn HirDatabase,
+pub(crate) fn const_eval_discriminant_variant<'db>(
+    db: &'db dyn HirDatabase,
     variant_id: EnumVariantId,
-) -> Result<i128, ConstEvalError> {
+) -> Result<i128, ConstEvalError<'db>> {
     let def = variant_id.into();
     let body = db.body(def);
     let loc = variant_id.lookup(db);
@@ -317,44 +316,5 @@ pub(crate) fn const_eval_discriminant_variant(
     Ok(c)
 }
 
-// FIXME: Ideally constants in const eval should have separate body (issue #7434), and this function should
-// get an `InferenceResult` instead of an `InferenceContext`. And we should remove `ctx.clone().resolve_all()` here
-// and make this function private. See the fixme comment on `InferenceContext::resolve_all`.
-pub(crate) fn eval_to_const(
-    expr: ExprId,
-    mode: ParamLoweringMode,
-    ctx: &mut InferenceContext<'_>,
-    debruijn: DebruijnIndex,
-) -> Const {
-    let db = ctx.db;
-    let infer = ctx.fixme_resolve_all_clone();
-    fn has_closure(body: &Body, expr: ExprId) -> bool {
-        if matches!(body[expr], Expr::Closure { .. }) {
-            return true;
-        }
-        let mut r = false;
-        body.walk_child_exprs(expr, |idx| r |= has_closure(body, idx));
-        r
-    }
-    if has_closure(ctx.body, expr) {
-        // Type checking clousres need an isolated body (See the above FIXME). Bail out early to prevent panic.
-        return unknown_const(infer[expr].clone());
-    }
-    if let Expr::Path(p) = &ctx.body[expr] {
-        let resolver = &ctx.resolver;
-        if let Some(c) =
-            path_to_const(db, resolver, p, mode, || ctx.generics(), debruijn, infer[expr].clone())
-        {
-            return c;
-        }
-    }
-    if let Ok(mir_body) = lower_to_mir(ctx.db, ctx.owner, ctx.body, &infer, expr)
-        && let Ok((Ok(result), _)) = interpret_mir(db, Arc::new(mir_body), true, None)
-    {
-        return result;
-    }
-    unknown_const(infer[expr].clone())
-}
-
 #[cfg(test)]
 mod tests;