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Get rid of Substitution::suffix

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This commit is contained in:
Florian Diebold 2021-04-05 21:49:27 +02:00
parent b443e5304e
commit 2a83645e1b
2 changed files with 6 additions and 10 deletions
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6
crates/hir_ty/src/lib.rs
View file

@ -79,12 +79,6 @@ impl Substitution {
pub fn prefix(&self, n: usize) -> Substitution {
Substitution::intern(self.interned()[..std::cmp::min(self.len(&Interner), n)].into())
}
pub fn suffix(&self, n: usize) -> Substitution {
Substitution::intern(
self.interned()[self.len(&Interner) - std::cmp::min(self.len(&Interner), n)..].into(),
)
}
}
/// Return an index of a parameter in the generic type parameter list by it's id.

10
crates/hir_ty/src/method_resolution.rs
View file

@ -709,8 +709,9 @@ pub(crate) fn inherent_impl_substs(
) -> Option<Substitution> {
// we create a var for each type parameter of the impl; we need to keep in
// mind here that `self_ty` might have vars of its own
let self_ty_vars = self_ty.binders.len(&Interner);
let vars = TyBuilder::subst_for_def(db, impl_id)
.fill_with_bound_vars(DebruijnIndex::INNERMOST, self_ty.binders.len(&Interner))
.fill_with_bound_vars(DebruijnIndex::INNERMOST, self_ty_vars)
.build();
let self_ty_with_vars = db.impl_self_ty(impl_id).substitute(&Interner, &vars);
let mut kinds = self_ty.binders.interned().to_vec();
@ -725,14 +726,15 @@ pub(crate) fn inherent_impl_substs(
binders: CanonicalVarKinds::from_iter(&Interner, kinds),
value: (self_ty_with_vars, self_ty.value.clone()),
};
let substs = super::infer::unify(&tys);
let substs = super::infer::unify(&tys)?;
// We only want the substs for the vars we added, not the ones from self_ty.
// Also, if any of the vars we added are still in there, we replace them by
// Unknown. I think this can only really happen if self_ty contained
// Unknown, and in that case we want the result to contain Unknown in those
// places again.
substs
.map(|s| fallback_bound_vars(s.suffix(vars.len(&Interner)), self_ty.binders.len(&Interner)))
let suffix =
Substitution::from_iter(&Interner, substs.iter(&Interner).cloned().skip(self_ty_vars));
Some(fallback_bound_vars(suffix, self_ty_vars))
}
/// This replaces any 'free' Bound vars in `s` (i.e. those with indices past