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Add method to get generic parameters in a type
| -rw-r--r-- | crates/hir-ty/src/lib.rs | 69 | ||||
| -rw-r--r-- | crates/hir/src/lib.rs | 8 |
2 files changed, 76 insertions, 1 deletions
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs index a1182445ed..cbeb61067d 100644 --- a/crates/hir-ty/src/lib.rs +++ b/crates/hir-ty/src/lib.rs @@ -39,11 +39,13 @@ use std::sync::Arc; use chalk_ir::{ fold::{Shift, TypeFoldable}, interner::HasInterner, - NoSolution, + visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor}, + NoSolution, TyData, }; use hir_def::{expr::ExprId, type_ref::Rawness, TypeOrConstParamId}; use hir_expand::name; use itertools::Either; +use rustc_hash::FxHashSet; use traits::FnTrait; use utils::Generics; @@ -562,3 +564,68 @@ pub fn callable_sig_from_fnonce( Some(CallableSig::from_params_and_return(params, ret_ty, false, Safety::Safe)) } + +struct PlaceholderCollector<'db> { + db: &'db dyn HirDatabase, + placeholders: FxHashSet<TypeOrConstParamId>, +} + +impl PlaceholderCollector<'_> { + fn collect(&mut self, idx: PlaceholderIndex) { + let id = from_placeholder_idx(self.db, idx); + self.placeholders.insert(id); + } +} + +impl TypeVisitor<Interner> for PlaceholderCollector<'_> { + type BreakTy = (); + + fn as_dyn(&mut self) -> &mut dyn TypeVisitor<Interner, BreakTy = Self::BreakTy> { + self + } + + fn interner(&self) -> Interner { + Interner + } + + fn visit_ty( + &mut self, + ty: &Ty, + outer_binder: DebruijnIndex, + ) -> std::ops::ControlFlow<Self::BreakTy> { + let has_placeholder_bits = TypeFlags::HAS_TY_PLACEHOLDER | TypeFlags::HAS_CT_PLACEHOLDER; + let TyData { kind, flags } = ty.data(Interner); + + if let TyKind::Placeholder(idx) = kind { + self.collect(*idx); + } else if flags.intersects(has_placeholder_bits) { + return ty.super_visit_with(self, outer_binder); + } else { + // Fast path: don't visit inner types (e.g. generic arguments) when `flags` indicate + // that there are no placeholders. + } + + std::ops::ControlFlow::Continue(()) + } + + fn visit_const( + &mut self, + constant: &chalk_ir::Const<Interner>, + _outer_binder: DebruijnIndex, + ) -> std::ops::ControlFlow<Self::BreakTy> { + if let chalk_ir::ConstValue::Placeholder(idx) = constant.data(Interner).value { + self.collect(idx); + } + std::ops::ControlFlow::Continue(()) + } +} + +/// Returns unique placeholders for types and consts contained in `value`. +pub fn collect_placeholders<T>(value: &T, db: &dyn HirDatabase) -> Vec<TypeOrConstParamId> +where + T: ?Sized + TypeVisitable<Interner>, +{ + let mut collector = PlaceholderCollector { db, placeholders: FxHashSet::default() }; + value.visit_with(&mut collector, DebruijnIndex::INNERMOST); + collector.placeholders.into_iter().collect() +} diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs index fc6a398ed3..24faa127e4 100644 --- a/crates/hir/src/lib.rs +++ b/crates/hir/src/lib.rs @@ -3599,6 +3599,14 @@ impl Type { _ => None, } } + + /// Returns unique `GenericParam`s contained in this type. + pub fn generic_params(&self, db: &dyn HirDatabase) -> FxHashSet<GenericParam> { + hir_ty::collect_placeholders(&self.ty, db) + .into_iter() + .map(|id| TypeOrConstParam { id }.split(db).either_into()) + .collect() + } } #[derive(Debug)] |