diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs index e4407ff5051..497a1beb7dc 100644 --- a/crates/hir_ty/src/infer.rs +++ b/crates/hir_ty/src/infer.rs @@ -210,6 +210,7 @@ struct InferenceContext<'a> { table: unify::InferenceTable, trait_env: Arc, obligations: Vec, + last_obligations_check: Option, result: InferenceResult, /// The return type of the function being inferred, or the closure if we're /// currently within one. @@ -245,6 +246,7 @@ fn new(db: &'a dyn HirDatabase, owner: DefWithBodyId, resolver: Resolver) -> Sel result: InferenceResult::default(), table: unify::InferenceTable::new(), obligations: Vec::default(), + last_obligations_check: None, return_ty: TyKind::Unknown.intern(&Interner), // set in collect_fn_signature trait_env: owner .as_generic_def_id() @@ -334,6 +336,11 @@ fn insert_type_vars(&mut self, ty: Ty) -> Ty { } fn resolve_obligations_as_possible(&mut self) { + if self.last_obligations_check == Some(self.table.revision) { + // no change + return; + } + self.last_obligations_check = Some(self.table.revision); let obligations = mem::replace(&mut self.obligations, Vec::new()); for obligation in obligations { let in_env = InEnvironment::new(self.trait_env.env.clone(), obligation.clone()); @@ -360,6 +367,11 @@ fn resolve_obligations_as_possible(&mut self) { } } + fn push_obligation(&mut self, o: DomainGoal) { + self.obligations.push(o); + self.last_obligations_check = None; + } + fn unify(&mut self, ty1: &Ty, ty2: &Ty) -> bool { self.table.unify(ty1, ty2) } @@ -408,8 +420,8 @@ fn resolve_associated_type_with_params( }), ty: ty.clone(), }; - self.obligations.push(trait_ref.cast(&Interner)); - self.obligations.push(alias_eq.cast(&Interner)); + self.push_obligation(trait_ref.cast(&Interner)); + self.push_obligation(alias_eq.cast(&Interner)); self.resolve_ty_as_possible(ty) } None => self.err_ty(), @@ -436,7 +448,7 @@ fn normalize_projection_ty(&mut self, proj_ty: ProjectionTy) -> Ty { let var = self.table.new_type_var(); let alias_eq = AliasEq { alias: AliasTy::Projection(proj_ty), ty: var.clone() }; let obligation = alias_eq.cast(&Interner); - self.obligations.push(obligation); + self.push_obligation(obligation); var } diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs index 6279aa572c5..25ab3ea4c1a 100644 --- a/crates/hir_ty/src/infer/expr.rs +++ b/crates/hir_ty/src/infer/expr.rs @@ -99,7 +99,7 @@ fn callable_sig_from_fn_trait(&mut self, ty: &Ty, num_args: usize) -> Option<(Ve environment: trait_env, }); if self.db.trait_solve(krate, goal.value).is_some() { - self.obligations.push(implements_fn_trait); + self.push_obligation(implements_fn_trait); let output_proj_ty = crate::ProjectionTy { associated_ty_id: to_assoc_type_id(output_assoc_type), substitution: substs, @@ -964,7 +964,7 @@ fn register_obligations_for_call(&mut self, callable_ty: &Ty) { let (predicate, binders) = predicate.clone().subst(parameters).into_value_and_skipped_binders(); always!(binders == 0); // quantified where clauses not yet handled - self.obligations.push(predicate.cast(&Interner)); + self.push_obligation(predicate.cast(&Interner)); } // add obligation for trait implementation, if this is a trait method match def { @@ -974,7 +974,7 @@ fn register_obligations_for_call(&mut self, callable_ty: &Ty) { // construct a TraitRef let substs = parameters.prefix(generics(self.db.upcast(), trait_.into()).len()); - self.obligations.push( + self.push_obligation( TraitRef { trait_id: to_chalk_trait_id(trait_), substitution: substs } .cast(&Interner), ); diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs index cefa3850948..717738789b9 100644 --- a/crates/hir_ty/src/infer/path.rs +++ b/crates/hir_ty/src/infer/path.rs @@ -258,7 +258,7 @@ fn resolve_ty_assoc_item( .push(ty.clone()) .fill(std::iter::repeat_with(|| self.table.new_type_var())) .build(); - self.obligations.push( + self.push_obligation( TraitRef { trait_id: to_chalk_trait_id(trait_), substitution: trait_substs.clone(), diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs index 6e7b0f5a633..5ea4b7481ec 100644 --- a/crates/hir_ty/src/infer/unify.rs +++ b/crates/hir_ty/src/infer/unify.rs @@ -231,6 +231,7 @@ pub(crate) struct TypeVariableData { pub(crate) struct InferenceTable { pub(super) var_unification_table: InPlaceUnificationTable, pub(super) type_variable_table: TypeVariableTable, + pub(super) revision: u32, } impl InferenceTable { @@ -238,6 +239,7 @@ pub(crate) fn new() -> Self { InferenceTable { var_unification_table: InPlaceUnificationTable::new(), type_variable_table: TypeVariableTable { inner: Vec::new() }, + revision: 0, } } @@ -360,7 +362,10 @@ pub(super) fn unify_inner_trivial(&mut self, ty1: &Ty, ty2: &Ty, depth: usize) - == self.type_variable_table.is_diverging(*tv2) => { // both type vars are unknown since we tried to resolve them - self.var_unification_table.union(tv1.to_inner(), tv2.to_inner()); + if !self.var_unification_table.unioned(tv1.to_inner(), tv2.to_inner()) { + self.var_unification_table.union(tv1.to_inner(), tv2.to_inner()); + self.revision += 1; + } true } @@ -398,6 +403,7 @@ pub(super) fn unify_inner_trivial(&mut self, ty1: &Ty, ty2: &Ty, depth: usize) - tv.to_inner(), TypeVarValue::Known(other.clone().intern(&Interner)), ); + self.revision += 1; true }