//@ revisions:rpass1 rpass2 // This test case makes sure re-order the methods in a vtable will // trigger recompilation of codegen units that instantiate it. // // See https://github.com/rust-lang/rust/issues/89598 trait Foo { #[cfg(rpass1)] fn method1(&self) -> u32; fn method2(&self) -> u32; #[cfg(rpass2)] fn method1(&self) -> u32; } impl Foo for u32 { fn method1(&self) -> u32 { 17 } fn method2(&self) -> u32 { 42 } } fn main() { // Before #89598 was fixed, the vtable allocation would be cached during // a MIR optimization pass and then the codegen pass for the main object // file would not register a dependency on it (because of the missing // dep-tracking). // // In the rpass2 session, the main object file would not be re-compiled, // thus the mod1::foo(x) call would pass in an outdated vtable, while the // mod1 object would expect the new, re-ordered vtable, resulting in a // call to the wrong method. let x: &dyn Foo = &0u32; assert_eq!(mod1::foo(x), 17); } mod mod1 { pub(super) fn foo(x: &dyn super::Foo) -> u32 { x.method1() } }