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Fix skipiter not applicable in autoderef #21095

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Fix skipiter not applicable in autoderef #21095

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40 changes: 37 additions & 3 deletions crates/ide-completion/src/completions/dot.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -91,9 +91,9 @@ pub(crate) fn complete_dot(
// its return type, so we instead check for `<&Self as IntoIterator>::IntoIter`.
// Does <&receiver_ty as IntoIterator>::IntoIter` exist? Assume `iter` is valid
let iter = receiver_ty
.strip_references()
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@Veykril Veykril Nov 23, 2025

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Won't this break cases where we have a type T that derefs to U where T has interesting impls but U does not?

I think the proper fix here is to walk the autoderef chain and find the first candidate that impls IntoIterator instead

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@A4-Tacks A4-Tacks Nov 23, 2025

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I think the proper fix here is to walk the autoderef chain and find the first candidate that impls IntoIterator instead

Can't .find_map(|ty| ty.into_iterator_iter(ctx.db)) do it?

.add_reference(hir::Mutability::Shared)
.into_iterator_iter(ctx.db)
.autoderef(ctx.db)
.map(|ty| ty.strip_references().add_reference(hir::Mutability::Shared))
.find_map(|ty| ty.into_iterator_iter(ctx.db))
.map(|ty| (ty, SmolStr::new_static("iter()")));
// Does <receiver_ty as IntoIterator>::IntoIter` exist?
let into_iter = || {
Expand Down Expand Up @@ -1466,6 +1466,40 @@ fn foo() {
me into_iter().nth(…) (as Iterator) fn(&mut self, usize) -> Option<<Self as Iterator>::Item>
"#]],
);
check_no_kw(
r#"
//- minicore: iterator, deref
struct Foo;
impl Foo { fn iter(&self) -> Iter { Iter } }
impl IntoIterator for &Foo {
type Item = ();
type IntoIter = Iter;
fn into_iter(self) -> Self::IntoIter { Iter }
}
struct Ref;
impl core::ops::Deref for Ref {
type Target = Foo;
fn deref(&self) -> &Self::Target { &Foo }
}
struct Iter;
impl Iterator for Iter {
type Item = ();
fn next(&mut self) -> Option<Self::Item> { None }
}
fn foo() {
Ref.$0
}
"#,
expect![[r#"
me deref() (use core::ops::Deref) fn(&self) -> &<Self as Deref>::Target
me into_iter() (as IntoIterator) fn(self) -> <Self as IntoIterator>::IntoIter
me iter() fn(&self) -> Iter
me iter().by_ref() (as Iterator) fn(&mut self) -> &mut Self
me iter().into_iter() (as IntoIterator) fn(self) -> <Self as IntoIterator>::IntoIter
me iter().next() (as Iterator) fn(&mut self) -> Option<<Self as Iterator>::Item>
me iter().nth(…) (as Iterator) fn(&mut self, usize) -> Option<<Self as Iterator>::Item>
"#]],
);
}

#[test]
Expand Down