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Require Debug for Pointee::Metadata

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Useful for debugging
This commit is contained in:
Stepan Koltsov 2024-03-29 03:44:16 +00:00
parent db2f9759f4
commit b110cb3dc6
2 changed files with 10 additions and 2 deletions
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2
library/core/src/ptr/metadata.rs
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@ -57,7 +57,7 @@ pub trait Pointee {
// NOTE: Keep trait bounds in `static_assert_expected_bounds_for_metadata` // NOTE: Keep trait bounds in `static_assert_expected_bounds_for_metadata`
// in `library/core/src/ptr/metadata.rs` // in `library/core/src/ptr/metadata.rs`
// in sync with those here: // in sync with those here:
type Metadata: Copy + Send + Sync + Ord + Hash + Unpin; type Metadata: fmt::Debug + Copy + Send + Sync + Ord + Hash + Unpin;
} }
/// Pointers to types implementing this trait alias are “thin”. /// Pointers to types implementing this trait alias are “thin”.

10
library/core/tests/ptr.rs
View file

@ -841,11 +841,19 @@ fn ptr_metadata_bounds() {
fn static_assert_expected_bounds_for_metadata<Meta>() fn static_assert_expected_bounds_for_metadata<Meta>()
where where
// Keep this in sync with the associated type in `library/core/src/ptr/metadata.rs` // Keep this in sync with the associated type in `library/core/src/ptr/metadata.rs`
Meta: Copy + Send + Sync + Ord + std::hash::Hash + Unpin, Meta: Debug + Copy + Send + Sync + Ord + std::hash::Hash + Unpin,
{ {
} }
} }
#[test]
fn pointee_metadata_debug() {
assert_eq!("()", format!("{:?}", metadata::<u32>(&17)));
assert_eq!("2", format!("{:?}", metadata::<[u32]>(&[19, 23])));
let for_dyn = format!("{:?}", metadata::<dyn Debug>(&29));
assert!(for_dyn.starts_with("DynMetadata(0x"), "{:?}", for_dyn);
}
#[test] #[test]
fn dyn_metadata() { fn dyn_metadata() {
#[derive(Debug)] #[derive(Debug)]