Wide pointer metadata validity: check that the vtable is for the right trait

rust-lang / miri

An interpreter for Rust's mid-level intermediate representation

Apache License 2.0

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Wide pointer metadata validity: check that the vtable is for the right trait #3497

Closed RalfJung closed 2 months ago

RalfJung commented 2 months ago

With https://github.com/rust-lang/rust/pull/123572, rustc started assuming for UB purposes that a vtable pointer points to a vtabe that's sufficiently big for the given trait. Miri currently isn't able to check that UB.