user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Auto merge of #75595 - davidtwco:polymorphization-predicate-simplification-correction, r=eddyb

Browse source 
polymorphize: if any param in a predicate is used, then all are used

Addresses [review](https://github.com/rust-lang/rust/pull/75518#discussion_r470907646) [comments](https://github.com/rust-lang/rust/pull/75518#discussion_r470907865) [from](https://github.com/rust-lang/rust/pull/75518#discussion_r470908188) @eddyb in #75518 that I didn't get to resolve before bors merged.

This PR modifies polymorphization's handling of predicates so that if any generic parameter is used in a predicate then all parameters in that predicate are used.

r? @eddyb
This commit is contained in:
bors 2020-08-20 05:06:55 +00:00
commit 1a22a0ff93
2 changed files with 28 additions and 74 deletions
Download patch file Download diff file Expand all files Collapse all files

17
src/test/ui/polymorphization/predicates.rs
View file

@ -60,6 +60,21 @@ where
std::mem::size_of::<C>()
}
// Finally, check that `F` is considered used because `G` is used when neither are in the self-ty
// of the predicate.
trait Foobar<F, G> {}
impl Foobar<u32, u32> for () {}
#[rustc_polymorphize_error]
fn foobar<F, G>() -> usize
where
(): Foobar<F, G>,
{
std::mem::size_of::<G>()
}
fn main() {
let x = &[2u32];
foo(x.iter());
@ -69,4 +84,6 @@ fn main() {
let _ = a.next();
let _ = quux::<u8, u16, u32>();
let _ = foobar::<u32, u32>();
}