Skip to content

Don't collect() when size_hint is useless #53019

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Aug 13, 2018
Merged

Don't collect() when size_hint is useless #53019

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 7 additions & 5 deletions src/librustc/infer/outlives/obligations.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -151,12 +151,14 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
debug!("process_registered_region_obligations()");

// pull out the region obligations with the given `body_id` (leaving the rest)
let my_region_obligations = {
let mut my_region_obligations = Vec::with_capacity(self.region_obligations.borrow().len());
{
let mut r_o = self.region_obligations.borrow_mut();
let my_r_o = r_o.drain_filter(|(ro_body_id, _)| *ro_body_id == body_id)
.map(|(_, obligation)| obligation).collect::<Vec<_>>();
my_r_o
};
my_region_obligations.extend(
r_o.drain_filter(|(ro_body_id, _)| *ro_body_id == body_id)
.map(|(_, obligation)| obligation)
);
}

let outlives = &mut TypeOutlives::new(
self,
Expand Down
7 changes: 6 additions & 1 deletion src/librustc_data_structures/small_vec.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -210,7 +210,12 @@ impl<A> Decodable for SmallVec<A>
A::Element: Decodable {
fn decode<D: Decoder>(d: &mut D) -> Result<SmallVec<A>, D::Error> {
d.read_seq(|d, len| {
(0..len).map(|i| d.read_seq_elt(i, |d| Decodable::decode(d))).collect()
let mut vec = SmallVec::with_capacity(len);
// FIXME(#48994) - could just be collected into a Result<SmallVec, D::Error>
for i in 0..len {
vec.push(d.read_seq_elt(i, |d| Decodable::decode(d))?);
}
Ok(vec)
})
}
}
Expand Down
6 changes: 5 additions & 1 deletion src/libsyntax/ast.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -501,7 +501,11 @@ impl Pat {
PatKind::Slice(pats, None, _) if pats.len() == 1 =>
pats[0].to_ty().map(TyKind::Slice)?,
PatKind::Tuple(pats, None) => {
let tys = pats.iter().map(|pat| pat.to_ty()).collect::<Option<Vec<_>>>()?;
let mut tys = Vec::with_capacity(pats.len());
// FIXME(#48994) - could just be collected into an Option<Vec>
for pat in pats {
tys.push(pat.to_ty()?);
}
TyKind::Tup(tys)
}
_ => return None,
Expand Down