| #![feature(trait_upcasting)] |
| //@ check-fail |
| // |
| // issue: <https://github.com/rust-lang/rust/pull/120222> |
| //! This would segfault at runtime. |
| |
| pub trait SupSupA { |
| fn method(&self) {} |
| } |
| pub trait SupSupB {} |
| impl<T> SupSupA for T {} |
| impl<T> SupSupB for T {} |
| |
| pub trait Super<T>: SupSupA + SupSupB {} |
| |
| pub trait Unimplemented {} |
| |
| pub trait Trait<T1, T2>: Super<T1> + Super<T2> { |
| fn missing_method(&self) |
| where |
| T1: Unimplemented, |
| { |
| } |
| } |
| |
| impl<S, T> Super<T> for S {} |
| |
| impl<S, T1, T2> Trait<T1, T2> for S {} |
| |
| #[inline(never)] |
| pub fn user1() -> &'static dyn Trait<u8, u8> { |
| &() |
| /* VTABLE: |
| .L__unnamed_2: |
| .quad core::ptr::drop_in_place<()> |
| .asciz "\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000" |
| .quad example::SupSupA::method |
| .quad .L__unnamed_4 // SupSupB vtable (pointer) |
| .zero 8 // null pointer for missing_method |
| */ |
| } |
| |
| #[inline(never)] |
| pub fn user2() -> &'static dyn Trait<u8, u16> { |
| &() |
| /* VTABLE: |
| .L__unnamed_3: |
| .quad core::ptr::drop_in_place<()> |
| .asciz "\000\000\000\000\000\000\000\000\001\000\000\000\000\000\000" |
| .quad example::SupSupA::method |
| .quad .L__unnamed_4 // SupSupB vtable (pointer) |
| .quad .L__unnamed_5 // Super<u16> vtable (pointer) |
| .zero 8 // null pointer for missing_method |
| */ |
| } |
| |
| fn main() { |
| let p: *const dyn Trait<u8, u8> = &(); |
| let p = p as *const dyn Trait<u8, u16>; // <- this is bad! |
| //~^ error: casting `*const dyn Trait<u8, u8>` as `*const dyn Trait<u8, u16>` is invalid |
| let p = p as *const dyn Super<u16>; // <- this upcast accesses improper vtable entry |
| // accessing from L__unnamed_2 the position for the 'Super<u16> vtable (pointer)', |
| // thus reading 'null pointer for missing_method' |
| |
| let p = p as *const dyn SupSupB; // <- this upcast dereferences (null) pointer from that entry |
| // to read the SupSupB vtable (pointer) |
| |
| // SEGFAULT |
| |
| println!("{:?}", p); |
| } |
