Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-ty/src/lib.rs')
| -rw-r--r-- | crates/hir-ty/src/lib.rs | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs index c4b700cbce..42c3b58d5a 100644 --- a/crates/hir-ty/src/lib.rs +++ b/crates/hir-ty/src/lib.rs @@ -81,7 +81,20 @@ pub type PlaceholderIndex = chalk_ir::PlaceholderIndex; pub type VariableKind = chalk_ir::VariableKind<Interner>; pub type VariableKinds = chalk_ir::VariableKinds<Interner>; pub type CanonicalVarKinds = chalk_ir::CanonicalVarKinds<Interner>; +/// Represents generic parameters and an item bound by them. When the item has parent, the binders +/// also contain the generic parameters for its parent. See chalk's documentation for details. +/// +/// One thing to keep in mind when working with `Binders` (and `Substitution`s, which represent +/// generic arguments) in rust-analyzer is that the ordering within *is* significant - the generic +/// parameters/arguments for an item MUST come before those for its parent. This is to facilitate +/// the integration with chalk-solve, which mildly puts constraints as such. See #13335 for its +/// motivation in detail. pub type Binders<T> = chalk_ir::Binders<T>; +/// Interned list of generic arguments for an item. When an item has parent, the `Substitution` for +/// it contains generic arguments for both its parent and itself. See chalk's documentation for +/// details. +/// +/// See `Binders` for the constraint on the ordering. pub type Substitution = chalk_ir::Substitution<Interner>; pub type GenericArg = chalk_ir::GenericArg<Interner>; pub type GenericArgData = chalk_ir::GenericArgData<Interner>; @@ -124,14 +137,6 @@ pub type ConstrainedSubst = chalk_ir::ConstrainedSubst<Interner>; pub type Guidance = chalk_solve::Guidance<Interner>; pub type WhereClause = chalk_ir::WhereClause<Interner>; -// FIXME: get rid of this -pub fn subst_prefix(s: &Substitution, n: usize) -> Substitution { - Substitution::from_iter( - Interner, - s.as_slice(Interner)[..std::cmp::min(s.len(Interner), n)].iter().cloned(), - ) -} - /// Return an index of a parameter in the generic type parameter list by it's id. pub fn param_idx(db: &dyn HirDatabase, id: TypeOrConstParamId) -> Option<usize> { generics(db.upcast(), id.parent).param_idx(id) @@ -382,7 +387,6 @@ pub(crate) fn fold_tys_and_consts<T: HasInterner<Interner = Interner> + TypeFold pub fn replace_errors_with_variables<T>(t: &T) -> Canonical<T> where T: HasInterner<Interner = Interner> + TypeFoldable<Interner> + Clone, - T: HasInterner<Interner = Interner>, { use chalk_ir::{ fold::{FallibleTypeFolder, TypeSuperFoldable}, |