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| -rw-r--r-- | library/alloc/src/vec.rs | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/library/alloc/src/vec.rs b/library/alloc/src/vec.rs index ecc103fc98c..2e3f6ec60e5 100644 --- a/library/alloc/src/vec.rs +++ b/library/alloc/src/vec.rs @@ -2227,6 +2227,12 @@ fn write_in_place_with_drop<T>( #[rustc_unsafe_specialization_marker] trait SourceIterMarker: SourceIter<Source: AsIntoIter> {} +// The std-internal SourceIter/InPlaceIterable traits are only implemented by chains of +// Adapter<Adapter<Adapter<IntoIter>>> (all owned by core/std). Additional bounds +// on the adapter implementations (beyond `impl<I: Trait> Trait for Adapter<I>`) only depend on other +// traits already marked as specialization traits (Copy, TrustedRandomAccess, FusedIterator). +// I.e. the marker does not depend on lifetimes of user-supplied types. Modulo the Copy hole, which +// several other specializations already depend on. impl<T> SourceIterMarker for T where T: SourceIter<Source: AsIntoIter> + InPlaceIterable {} impl<T, I> SpecFrom<T, I> for Vec<T> |