Bump chalk to 0.86

Two breaking changes:
- `TypeFolder` has been split into `TypeFolder` and `FallibleTypeFolder`
- `ProjectionTy::self_type_parameter()` has been removed

Author: lowr

Cargo.lock

@@ -27,6 +27,7 @@ debug = 0
 # chalk-solve = { path = "../chalk/chalk-solve" }
 # chalk-ir = { path = "../chalk/chalk-ir" }
 # chalk-recursive = { path = "../chalk/chalk-recursive" }
+# chalk-derive = { path = "../chalk/chalk-derive" }
 
 # ungrammar = { path = "../ungrammar" }
 

Cargo.toml

@@ -18,9 +18,10 @@ ena = "0.14.0"
 tracing = "0.1.35"
 rustc-hash = "1.1.0"
 scoped-tls = "1.0.0"
-chalk-solve = { version = "0.84.0", default-features = false }
-chalk-ir = "0.84.0"
-chalk-recursive = { version = "0.84.0", default-features = false }
+chalk-solve = { version = "0.86.0", default-features = false }
+chalk-ir = "0.86.0"
+chalk-recursive = { version = "0.86.0", default-features = false }
+chalk-derive = "0.86.0"
 la-arena = { version = "0.3.0", path = "../../lib/la-arena" }
 once_cell = "1.12.0"
 typed-arena = "2.0.1"

crates/hir-ty/Cargo.toml

@@ -823,10 +823,10 @@ pub(super) fn generic_predicate_to_inline_bound(
             Some(chalk_ir::Binders::new(binders, rust_ir::InlineBound::TraitBound(trait_bound)))
         }
         WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
-            if projection_ty.self_type_parameter(Interner) != self_ty_shifted_in {
+            let trait_ = projection_ty.trait_(db);
+            if projection_ty.self_type_parameter(db) != self_ty_shifted_in {
                 return None;
             }
-            let trait_ = projection_ty.trait_(db);
             let args_no_self = projection_ty.substitution.as_slice(Interner)[1..]
                 .iter()
                 .map(|ty| ty.clone().cast(Interner))

crates/hir-ty/src/chalk_db.rs

@@ -262,7 +262,7 @@ impl TyExt for Ty {
                                     WhereClause::AliasEq(AliasEq {
                                         alias: AliasTy::Projection(proj),
                                         ty: _,
-                                    }) => &proj.self_type_parameter(Interner) == self,
+                                    }) => &proj.self_type_parameter(db) == self,
                                     _ => false,
                                 })
                                 .collect::<Vec<_>>();
@@ -333,6 +333,7 @@ impl TyExt for Ty {
 pub trait ProjectionTyExt {
     fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef;
     fn trait_(&self, db: &dyn HirDatabase) -> TraitId;
+    fn self_type_parameter(&self, db: &dyn HirDatabase) -> Ty;
 }
 
 impl ProjectionTyExt for ProjectionTy {
@@ -349,6 +350,10 @@ impl ProjectionTyExt for ProjectionTy {
             _ => panic!("projection ty without parent trait"),
         }
     }
+
+    fn self_type_parameter(&self, db: &dyn HirDatabase) -> Ty {
+        self.trait_ref(db).self_type_parameter(Interner)
+    }
 }
 
 pub trait TraitRefExt {

crates/hir-ty/src/chalk_ext.rs

@@ -291,7 +291,7 @@ impl HirDisplay for ProjectionTy {
 
         let trait_ = f.db.trait_data(self.trait_(f.db));
         write!(f, "<")?;
-        self.self_type_parameter(Interner).hir_fmt(f)?;
+        self.self_type_parameter(f.db).hir_fmt(f)?;
         write!(f, " as {}", trait_.name)?;
         if self.substitution.len(Interner) > 1 {
             write!(f, "<")?;
@@ -731,7 +731,7 @@ impl HirDisplay for Ty {
                                         WhereClause::AliasEq(AliasEq {
                                             alias: AliasTy::Projection(proj),
                                             ty: _,
-                                        }) => &proj.self_type_parameter(Interner) == self,
+                                        }) => &proj.self_type_parameter(f.db) == self,
                                         _ => false,
                                     })
                                     .collect::<Vec<_>>();

crates/hir-ty/src/display.rs

@@ -4,7 +4,7 @@ use std::{fmt, mem, sync::Arc};
 
 use chalk_ir::{
     cast::Cast, fold::TypeFoldable, interner::HasInterner, zip::Zip, CanonicalVarKind, FloatTy,
-    IntTy, NoSolution, TyVariableKind, UniverseIndex,
+    IntTy, TyVariableKind, UniverseIndex,
 };
 use chalk_solve::infer::ParameterEnaVariableExt;
 use ena::unify::UnifyKey;
@@ -331,7 +331,6 @@ impl<'a> InferenceTable<'a> {
             &mut resolve::Resolver { table: self, var_stack, fallback },
             DebruijnIndex::INNERMOST,
         )
-        .expect("fold failed unexpectedly")
     }
 
     pub(crate) fn resolve_completely<T>(&mut self, t: T) -> T
@@ -452,13 +451,14 @@ impl<'a> InferenceTable<'a> {
         f: impl FnOnce(&mut Self) -> T,
     ) -> T {
         use chalk_ir::fold::TypeFolder;
+
+        #[derive(chalk_derive::FallibleTypeFolder)]
+        #[has_interner(Interner)]
         struct VarFudger<'a, 'b> {
             table: &'a mut InferenceTable<'b>,
             highest_known_var: InferenceVar,
         }
         impl<'a, 'b> TypeFolder<Interner> for VarFudger<'a, 'b> {
-            type Error = NoSolution;
-
             fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
                 self
             }
@@ -472,37 +472,37 @@ impl<'a> InferenceTable<'a> {
                 var: chalk_ir::InferenceVar,
                 kind: TyVariableKind,
                 _outer_binder: chalk_ir::DebruijnIndex,
-            ) -> chalk_ir::Fallible<chalk_ir::Ty<Interner>> {
-                Ok(if var < self.highest_known_var {
+            ) -> chalk_ir::Ty<Interner> {
+                if var < self.highest_known_var {
                     var.to_ty(Interner, kind)
                 } else {
                     self.table.new_type_var()
-                })
+                }
             }
 
             fn fold_inference_lifetime(
                 &mut self,
                 var: chalk_ir::InferenceVar,
                 _outer_binder: chalk_ir::DebruijnIndex,
-            ) -> chalk_ir::Fallible<chalk_ir::Lifetime<Interner>> {
-                Ok(if var < self.highest_known_var {
+            ) -> chalk_ir::Lifetime<Interner> {
+                if var < self.highest_known_var {
                     var.to_lifetime(Interner)
                 } else {
                     self.table.new_lifetime_var()
-                })
+                }
             }
 
             fn fold_inference_const(
                 &mut self,
                 ty: chalk_ir::Ty<Interner>,
                 var: chalk_ir::InferenceVar,
                 _outer_binder: chalk_ir::DebruijnIndex,
-            ) -> chalk_ir::Fallible<chalk_ir::Const<Interner>> {
-                Ok(if var < self.highest_known_var {
+            ) -> chalk_ir::Const<Interner> {
+                if var < self.highest_known_var {
                     var.to_const(Interner, ty)
                 } else {
                     self.table.new_const_var(ty)
-                })
+                }
             }
         }
 
@@ -512,7 +512,6 @@ impl<'a> InferenceTable<'a> {
         self.rollback_to(snapshot);
         result
             .fold_with(&mut VarFudger { table: self, highest_known_var }, DebruijnIndex::INNERMOST)
-            .expect("fold_with with VarFudger")
     }
 
     /// This checks whether any of the free variables in the `canonicalized`
@@ -639,21 +638,24 @@ mod resolve {
     use chalk_ir::{
         cast::Cast,
         fold::{TypeFoldable, TypeFolder},
-        Fallible, NoSolution,
     };
     use hir_def::type_ref::ConstScalar;
 
-    pub(super) struct Resolver<'a, 'b, F> {
+    #[derive(chalk_derive::FallibleTypeFolder)]
+    #[has_interner(Interner)]
+    pub(super) struct Resolver<
+        'a,
+        'b,
+        F: Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg,
+    > {
         pub(super) table: &'a mut InferenceTable<'b>,
         pub(super) var_stack: &'a mut Vec<InferenceVar>,
         pub(super) fallback: F,
     }
-    impl<'a, 'b, 'i, F> TypeFolder<Interner> for Resolver<'a, 'b, F>
+    impl<'a, 'b, F> TypeFolder<Interner> for Resolver<'a, 'b, F>
     where
-        F: Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg + 'i,
+        F: Fn(InferenceVar, VariableKind, GenericArg, DebruijnIndex) -> GenericArg,
     {
-        type Error = NoSolution;
-
         fn as_dyn(&mut self) -> &mut dyn TypeFolder<Interner, Error = Self::Error> {
             self
         }
@@ -667,20 +669,19 @@ mod resolve {
             var: InferenceVar,
             kind: TyVariableKind,
             outer_binder: DebruijnIndex,
-        ) -> Fallible<Ty> {
+        ) -> Ty {
             let var = self.table.var_unification_table.inference_var_root(var);
             if self.var_stack.contains(&var) {
                 // recursive type
                 let default = self.table.fallback_value(var, kind).cast(Interner);
-                return Ok((self.fallback)(var, VariableKind::Ty(kind), default, outer_binder)
+                return (self.fallback)(var, VariableKind::Ty(kind), default, outer_binder)
                     .assert_ty_ref(Interner)
-                    .clone());
+                    .clone();
             }
             let result = if let Some(known_ty) = self.table.var_unification_table.probe_var(var) {
                 // known_ty may contain other variables that are known by now
                 self.var_stack.push(var);
-                let result =
-                    known_ty.fold_with(self, outer_binder).expect("fold failed unexpectedly");
+                let result = known_ty.fold_with(self, outer_binder);
                 self.var_stack.pop();
                 result.assert_ty_ref(Interner).clone()
             } else {
@@ -689,15 +690,15 @@ mod resolve {
                     .assert_ty_ref(Interner)
                     .clone()
             };
-            Ok(result)
+            result
         }
 
         fn fold_inference_const(
             &mut self,
             ty: Ty,
             var: InferenceVar,
             outer_binder: DebruijnIndex,
-        ) -> Fallible<Const> {
+        ) -> Const {
             let var = self.table.var_unification_table.inference_var_root(var);
             let default = ConstData {
                 ty: ty.clone(),
@@ -707,35 +708,33 @@ mod resolve {
             .cast(Interner);
             if self.var_stack.contains(&var) {
                 // recursive
-                return Ok((self.fallback)(var, VariableKind::Const(ty), default, outer_binder)
+                return (self.fallback)(var, VariableKind::Const(ty), default, outer_binder)
                     .assert_const_ref(Interner)
-                    .clone());
+                    .clone();
             }
-            let result = if let Some(known_ty) = self.table.var_unification_table.probe_var(var) {
+            if let Some(known_ty) = self.table.var_unification_table.probe_var(var) {
                 // known_ty may contain other variables that are known by now
                 self.var_stack.push(var);
-                let result =
-                    known_ty.fold_with(self, outer_binder).expect("fold failed unexpectedly");
+                let result = known_ty.fold_with(self, outer_binder);
                 self.var_stack.pop();
                 result.assert_const_ref(Interner).clone()
             } else {
                 (self.fallback)(var, VariableKind::Const(ty), default, outer_binder)
                     .assert_const_ref(Interner)
                     .clone()
-            };
-            Ok(result)
+            }
         }
 
         fn fold_inference_lifetime(
             &mut self,
             _var: InferenceVar,
             _outer_binder: DebruijnIndex,
-        ) -> Fallible<Lifetime> {
+        ) -> Lifetime {
             // fall back all lifetimes to 'static -- currently we don't deal
             // with any lifetimes, but we can sometimes get some lifetime
             // variables through Chalk's unification, and this at least makes
             // sure we don't leak them outside of inference
-            Ok(crate::static_lifetime())
+            crate::static_lifetime()
         }
     }
 }