Auto merge of rust-lang#16749 - Veykril:on-demand-validation-err, r=Veykril

internal: Some method resolution cleanups

Author: bors

Diff for: Cargo.toml

@@ -105,6 +105,10 @@ anyhow = "1.0.75"
 arrayvec = "0.7.4"
 bitflags = "2.4.1"
 cargo_metadata = "0.18.1"
+chalk-solve = { version = "0.96.0", default-features = false }
+chalk-ir = "0.96.0"
+chalk-recursive = { version = "0.96.0", default-features = false }
+chalk-derive = "0.96.0"
 command-group = "2.0.1"
 crossbeam-channel = "0.5.8"
 dissimilar = "1.0.7"

Diff for: crates/hir-ty/Cargo.toml

@@ -23,10 +23,10 @@ oorandom = "11.1.3"
 tracing.workspace = true
 rustc-hash.workspace = true
 scoped-tls = "1.0.0"
-chalk-solve = { version = "0.96.0", default-features = false }
-chalk-ir = "0.96.0"
-chalk-recursive = { version = "0.96.0", default-features = false }
-chalk-derive = "0.96.0"
+chalk-solve.workspace = true
+chalk-ir.workspace = true
+chalk-recursive.workspace = true
+chalk-derive.workspace = true
 la-arena.workspace = true
 once_cell = "1.17.0"
 triomphe.workspace = true

Diff for: crates/hir-ty/src/autoderef.rs

@@ -113,23 +113,23 @@ pub(crate) fn autoderef_step(
     ty: Ty,
     explicit: bool,
 ) -> Option<(AutoderefKind, Ty)> {
-    if let Some(derefed) = builtin_deref(table, &ty, explicit) {
+    if let Some(derefed) = builtin_deref(table.db, &ty, explicit) {
         Some((AutoderefKind::Builtin, table.resolve_ty_shallow(derefed)))
     } else {
         Some((AutoderefKind::Overloaded, deref_by_trait(table, ty)?))
     }
 }
 
 pub(crate) fn builtin_deref<'ty>(
-    table: &mut InferenceTable<'_>,
+    db: &dyn HirDatabase,
     ty: &'ty Ty,
     explicit: bool,
 ) -> Option<&'ty Ty> {
     match ty.kind(Interner) {
         TyKind::Ref(.., ty) => Some(ty),
         TyKind::Raw(.., ty) if explicit => Some(ty),
         &TyKind::Adt(chalk_ir::AdtId(adt), ref substs) => {
-            if crate::lang_items::is_box(table.db, adt) {
+            if crate::lang_items::is_box(db, adt) {
                 substs.at(Interner, 0).ty(Interner)
             } else {
                 None

Diff for: crates/hir-ty/src/infer/coerce.rs

@@ -647,7 +647,7 @@ impl InferenceTable<'_> {
         let goal: InEnvironment<DomainGoal> =
             InEnvironment::new(&self.trait_env.env, coerce_unsized_tref.cast(Interner));
 
-        let canonicalized = self.canonicalize(goal);
+        let canonicalized = self.canonicalize_with_free_vars(goal);
 
         // FIXME: rustc's coerce_unsized is more specialized -- it only tries to
         // solve `CoerceUnsized` and `Unsize` goals at this point and leaves the

Diff for: crates/hir-ty/src/infer/expr.rs

@@ -312,15 +312,13 @@ impl InferenceContext<'_> {
             Expr::Call { callee, args, .. } => {
                 let callee_ty = self.infer_expr(*callee, &Expectation::none());
                 let mut derefs = Autoderef::new(&mut self.table, callee_ty.clone(), false);
-                let (res, derefed_callee) = 'b: {
-                    // manual loop to be able to access `derefs.table`
-                    while let Some((callee_deref_ty, _)) = derefs.next() {
-                        let res = derefs.table.callable_sig(&callee_deref_ty, args.len());
-                        if res.is_some() {
-                            break 'b (res, callee_deref_ty);
-                        }
+                let (res, derefed_callee) = loop {
+                    let Some((callee_deref_ty, _)) = derefs.next() else {
+                        break (None, callee_ty.clone());
+                    };
+                    if let Some(res) = derefs.table.callable_sig(&callee_deref_ty, args.len()) {
+                        break (Some(res), callee_deref_ty);
                     }
-                    (None, callee_ty.clone())
                 };
                 // if the function is unresolved, we use is_varargs=true to
                 // suppress the arg count diagnostic here
@@ -657,7 +655,7 @@ impl InferenceContext<'_> {
                                 );
                             }
                         }
-                        if let Some(derefed) = builtin_deref(&mut self.table, &inner_ty, true) {
+                        if let Some(derefed) = builtin_deref(self.table.db, &inner_ty, true) {
                             self.resolve_ty_shallow(derefed)
                         } else {
                             deref_by_trait(&mut self.table, inner_ty)
@@ -774,7 +772,7 @@ impl InferenceContext<'_> {
                     let receiver_adjustments = method_resolution::resolve_indexing_op(
                         self.db,
                         self.table.trait_env.clone(),
-                        canonicalized.value,
+                        canonicalized,
                         index_trait,
                     );
                     let (self_ty, mut adj) = receiver_adjustments
@@ -1559,7 +1557,7 @@ impl InferenceContext<'_> {
                 let canonicalized_receiver = self.canonicalize(receiver_ty.clone());
                 let resolved = method_resolution::lookup_method(
                     self.db,
-                    &canonicalized_receiver.value,
+                    &canonicalized_receiver,
                     self.table.trait_env.clone(),
                     self.get_traits_in_scope().as_ref().left_or_else(|&it| it),
                     VisibleFromModule::Filter(self.resolver.module()),
@@ -1608,7 +1606,7 @@ impl InferenceContext<'_> {
 
         let resolved = method_resolution::lookup_method(
             self.db,
-            &canonicalized_receiver.value,
+            &canonicalized_receiver,
             self.table.trait_env.clone(),
             self.get_traits_in_scope().as_ref().left_or_else(|&it| it),
             VisibleFromModule::Filter(self.resolver.module()),
@@ -1641,7 +1639,7 @@ impl InferenceContext<'_> {
                 };
 
                 let assoc_func_with_same_name = method_resolution::iterate_method_candidates(
-                    &canonicalized_receiver.value,
+                    &canonicalized_receiver,
                     self.db,
                     self.table.trait_env.clone(),
                     self.get_traits_in_scope().as_ref().left_or_else(|&it| it),

Diff for: crates/hir-ty/src/infer/path.rs

@@ -321,7 +321,7 @@ impl InferenceContext<'_> {
 
         let mut not_visible = None;
         let res = method_resolution::iterate_method_candidates(
-            &canonical_ty.value,
+            &canonical_ty,
             self.db,
             self.table.trait_env.clone(),
             self.get_traits_in_scope().as_ref().left_or_else(|&it| it),

Diff for: crates/hir-ty/src/infer/unify.rs

@@ -23,12 +23,9 @@ use crate::{
 };
 
 impl InferenceContext<'_> {
-    pub(super) fn canonicalize<T: TypeFoldable<Interner> + HasInterner<Interner = Interner>>(
-        &mut self,
-        t: T,
-    ) -> Canonicalized<T>
+    pub(super) fn canonicalize<T>(&mut self, t: T) -> Canonical<T>
     where
-        T: HasInterner<Interner = Interner>,
+        T: TypeFoldable<Interner> + HasInterner<Interner = Interner>,
     {
         self.table.canonicalize(t)
     }
@@ -128,14 +125,14 @@ impl<T: HasInterner<Interner = Interner>> Canonicalized<T> {
             }),
         );
         for (i, v) in solution.value.iter(Interner).enumerate() {
-            let var = self.free_vars[i].clone();
+            let var = &self.free_vars[i];
             if let Some(ty) = v.ty(Interner) {
                 // eagerly replace projections in the type; we may be getting types
                 // e.g. from where clauses where this hasn't happened yet
                 let ty = ctx.normalize_associated_types_in(new_vars.apply(ty.clone(), Interner));
                 ctx.unify(var.assert_ty_ref(Interner), &ty);
             } else {
-                let _ = ctx.try_unify(&var, &new_vars.apply(v.clone(), Interner));
+                let _ = ctx.try_unify(var, &new_vars.apply(v.clone(), Interner));
             }
         }
     }
@@ -243,7 +240,7 @@ pub(crate) struct InferenceTable<'a> {
     pub(crate) db: &'a dyn HirDatabase,
     pub(crate) trait_env: Arc<TraitEnvironment>,
     var_unification_table: ChalkInferenceTable,
-    type_variable_table: Vec<TypeVariableFlags>,
+    type_variable_table: SmallVec<[TypeVariableFlags; 16]>,
     pending_obligations: Vec<Canonicalized<InEnvironment<Goal>>>,
     /// Double buffer used in [`Self::resolve_obligations_as_possible`] to cut down on
     /// temporary allocations.
@@ -252,8 +249,8 @@ pub(crate) struct InferenceTable<'a> {
 
 pub(crate) struct InferenceTableSnapshot {
     var_table_snapshot: chalk_solve::infer::InferenceSnapshot<Interner>,
+    type_variable_table: SmallVec<[TypeVariableFlags; 16]>,
     pending_obligations: Vec<Canonicalized<InEnvironment<Goal>>>,
-    type_variable_table_snapshot: Vec<TypeVariableFlags>,
 }
 
 impl<'a> InferenceTable<'a> {
@@ -262,7 +259,7 @@ impl<'a> InferenceTable<'a> {
             db,
             trait_env,
             var_unification_table: ChalkInferenceTable::new(),
-            type_variable_table: Vec::new(),
+            type_variable_table: SmallVec::new(),
             pending_obligations: Vec::new(),
             resolve_obligations_buffer: Vec::new(),
         }
@@ -292,27 +289,24 @@ impl<'a> InferenceTable<'a> {
     }
 
     fn fallback_value(&self, iv: InferenceVar, kind: TyVariableKind) -> Ty {
+        let is_diverging = self
+            .type_variable_table
+            .get(iv.index() as usize)
+            .map_or(false, |data| data.contains(TypeVariableFlags::DIVERGING));
+        if is_diverging {
+            return TyKind::Never.intern(Interner);
+        }
         match kind {
-            _ if self
-                .type_variable_table
-                .get(iv.index() as usize)
-                .map_or(false, |data| data.contains(TypeVariableFlags::DIVERGING)) =>
-            {
-                TyKind::Never
-            }
             TyVariableKind::General => TyKind::Error,
             TyVariableKind::Integer => TyKind::Scalar(Scalar::Int(IntTy::I32)),
             TyVariableKind::Float => TyKind::Scalar(Scalar::Float(FloatTy::F64)),
         }
         .intern(Interner)
     }
 
-    pub(crate) fn canonicalize<T: TypeFoldable<Interner> + HasInterner<Interner = Interner>>(
-        &mut self,
-        t: T,
-    ) -> Canonicalized<T>
+    pub(crate) fn canonicalize_with_free_vars<T>(&mut self, t: T) -> Canonicalized<T>
     where
-        T: HasInterner<Interner = Interner>,
+        T: TypeFoldable<Interner> + HasInterner<Interner = Interner>,
     {
         // try to resolve obligations before canonicalizing, since this might
         // result in new knowledge about variables
@@ -326,6 +320,16 @@ impl<'a> InferenceTable<'a> {
         Canonicalized { value: result.quantified, free_vars }
     }
 
+    pub(crate) fn canonicalize<T>(&mut self, t: T) -> Canonical<T>
+    where
+        T: TypeFoldable<Interner> + HasInterner<Interner = Interner>,
+    {
+        // try to resolve obligations before canonicalizing, since this might
+        // result in new knowledge about variables
+        self.resolve_obligations_as_possible();
+        self.var_unification_table.canonicalize(Interner, t).quantified
+    }
+
     /// Recurses through the given type, normalizing associated types mentioned
     /// in it by replacing them by type variables and registering obligations to
     /// resolve later. This should be done once for every type we get from some
@@ -434,6 +438,7 @@ impl<'a> InferenceTable<'a> {
     where
         T: HasInterner<Interner = Interner> + TypeFoldable<Interner>,
     {
+        // TODO check this vec here
         self.resolve_with_fallback_inner(&mut Vec::new(), t, &fallback)
     }
 
@@ -541,7 +546,7 @@ impl<'a> InferenceTable<'a> {
             Err(_) => return false,
         };
         result.goals.iter().all(|goal| {
-            let canonicalized = self.canonicalize(goal.clone());
+            let canonicalized = self.canonicalize_with_free_vars(goal.clone());
             self.try_resolve_obligation(&canonicalized).is_some()
         })
     }
@@ -575,19 +580,15 @@ impl<'a> InferenceTable<'a> {
 
     pub(crate) fn snapshot(&mut self) -> InferenceTableSnapshot {
         let var_table_snapshot = self.var_unification_table.snapshot();
-        let type_variable_table_snapshot = self.type_variable_table.clone();
+        let type_variable_table = self.type_variable_table.clone();
         let pending_obligations = self.pending_obligations.clone();
-        InferenceTableSnapshot {
-            var_table_snapshot,
-            pending_obligations,
-            type_variable_table_snapshot,
-        }
+        InferenceTableSnapshot { var_table_snapshot, pending_obligations, type_variable_table }
     }
 
     #[tracing::instrument(skip_all)]
     pub(crate) fn rollback_to(&mut self, snapshot: InferenceTableSnapshot) {
         self.var_unification_table.rollback_to(snapshot.var_table_snapshot);
-        self.type_variable_table = snapshot.type_variable_table_snapshot;
+        self.type_variable_table = snapshot.type_variable_table;
         self.pending_obligations = snapshot.pending_obligations;
     }
 
@@ -606,7 +607,7 @@ impl<'a> InferenceTable<'a> {
         let in_env = InEnvironment::new(&self.trait_env.env, goal);
         let canonicalized = self.canonicalize(in_env);
 
-        self.db.trait_solve(self.trait_env.krate, self.trait_env.block, canonicalized.value)
+        self.db.trait_solve(self.trait_env.krate, self.trait_env.block, canonicalized)
     }
 
     pub(crate) fn register_obligation(&mut self, goal: Goal) {
@@ -615,7 +616,7 @@ impl<'a> InferenceTable<'a> {
     }
 
     fn register_obligation_in_env(&mut self, goal: InEnvironment<Goal>) {
-        let canonicalized = self.canonicalize(goal);
+        let canonicalized = self.canonicalize_with_free_vars(goal);
         let solution = self.try_resolve_obligation(&canonicalized);
         if matches!(solution, Some(Solution::Ambig(_))) {
             self.pending_obligations.push(canonicalized);
@@ -798,7 +799,7 @@ impl<'a> InferenceTable<'a> {
         let trait_data = self.db.trait_data(fn_once_trait);
         let output_assoc_type = trait_data.associated_type_by_name(&name![Output])?;
 
-        let mut arg_tys = vec![];
+        let mut arg_tys = Vec::with_capacity(num_args);
         let arg_ty = TyBuilder::tuple(num_args)
             .fill(|it| {
                 let arg = match it {
@@ -828,11 +829,7 @@ impl<'a> InferenceTable<'a> {
             environment: trait_env.clone(),
         };
         let canonical = self.canonicalize(obligation.clone());
-        if self
-            .db
-            .trait_solve(krate, self.trait_env.block, canonical.value.cast(Interner))
-            .is_some()
-        {
+        if self.db.trait_solve(krate, self.trait_env.block, canonical.cast(Interner)).is_some() {
             self.register_obligation(obligation.goal);
             let return_ty = self.normalize_projection_ty(projection);
             for fn_x in [FnTrait::Fn, FnTrait::FnMut, FnTrait::FnOnce] {
@@ -845,7 +842,7 @@ impl<'a> InferenceTable<'a> {
                 let canonical = self.canonicalize(obligation.clone());
                 if self
                     .db
-                    .trait_solve(krate, self.trait_env.block, canonical.value.cast(Interner))
+                    .trait_solve(krate, self.trait_env.block, canonical.cast(Interner))
                     .is_some()
                 {
                     return Some((fn_x, arg_tys, return_ty));