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