97 lines
3.0 KiB
Rust
97 lines
3.0 KiB
Rust
// This test contains code with incorrect vtables in a const context:
|
|
// - from issue 86132: a trait object with invalid alignment caused an ICE in const eval, and now
|
|
// triggers an error
|
|
// - a similar test that triggers a previously-untested const UB error: emitted close to the above
|
|
// error, it checks the correctness of the size
|
|
//
|
|
// As is, this code will only hard error when the constants are used, and the errors are emitted via
|
|
// the `#[allow]`-able `const_err` lint. However, if the transparent wrapper technique to prevent
|
|
// reborrows is used -- from `ub-wide-ptr.rs` -- these two errors reach validation and would trigger
|
|
// ICEs as tracked by #86193. So we also use the transparent wrapper to verify proper validation
|
|
// errors are emitted instead of ICEs.
|
|
|
|
// stderr-per-bitwidth
|
|
// normalize-stderr-test "alloc\d+" -> "allocN"
|
|
|
|
trait Trait {}
|
|
|
|
const INVALID_VTABLE_ALIGNMENT: &dyn Trait =
|
|
unsafe { std::mem::transmute((&92u8, &[0usize, 1usize, 1000usize])) };
|
|
//~^ ERROR evaluation of constant value failed
|
|
//~| does not point to a vtable
|
|
|
|
const INVALID_VTABLE_SIZE: &dyn Trait =
|
|
unsafe { std::mem::transmute((&92u8, &[1usize, usize::MAX, 1usize])) };
|
|
//~^ ERROR evaluation of constant value failed
|
|
//~| does not point to a vtable
|
|
|
|
#[repr(transparent)]
|
|
struct W<T>(T);
|
|
|
|
fn drop_me(_: *mut usize) {}
|
|
|
|
const INVALID_VTABLE_ALIGNMENT_UB: W<&dyn Trait> =
|
|
unsafe { std::mem::transmute((&92u8, &(drop_me as fn(*mut usize), 1usize, 1000usize))) };
|
|
//~^^ ERROR it is undefined behavior to use this value
|
|
//~| expected a vtable pointer
|
|
|
|
const INVALID_VTABLE_SIZE_UB: W<&dyn Trait> =
|
|
unsafe { std::mem::transmute((&92u8, &(drop_me as fn(*mut usize), usize::MAX, 1usize))) };
|
|
//~^^ ERROR it is undefined behavior to use this value
|
|
//~| expected a vtable pointer
|
|
|
|
// Even if the vtable has a fn ptr and a reasonable size+align, it still does not work.
|
|
const INVALID_VTABLE_UB: W<&dyn Trait> =
|
|
unsafe { std::mem::transmute((&92u8, &(drop_me as fn(*mut usize), 1usize, 1usize))) };
|
|
//~^^ ERROR it is undefined behavior to use this value
|
|
//~| expected a vtable pointer
|
|
|
|
// Trying to access the data in a vtable does not work, either.
|
|
|
|
#[derive(Copy, Clone)]
|
|
struct Wide<'a>(&'a Foo, &'static VTable);
|
|
|
|
struct VTable {
|
|
drop: Option<for<'a> fn(&'a mut Foo)>,
|
|
size: usize,
|
|
align: usize,
|
|
bar: for<'a> fn(&'a Foo) -> u32,
|
|
}
|
|
|
|
trait Bar {
|
|
fn bar(&self) -> u32;
|
|
}
|
|
|
|
struct Foo {
|
|
foo: u32,
|
|
bar: bool,
|
|
}
|
|
|
|
impl Bar for Foo {
|
|
fn bar(&self) -> u32 {
|
|
self.foo
|
|
}
|
|
}
|
|
|
|
impl Drop for Foo {
|
|
fn drop(&mut self) {
|
|
assert!(!self.bar);
|
|
self.bar = true;
|
|
println!("dropping Foo");
|
|
}
|
|
}
|
|
|
|
#[repr(C)]
|
|
union Transmute<T: Copy, U: Copy> {
|
|
t: T,
|
|
u: U,
|
|
}
|
|
|
|
const FOO: &dyn Bar = &Foo { foo: 128, bar: false };
|
|
const G: Wide = unsafe { Transmute { t: FOO }.u };
|
|
//~^ ERROR it is undefined behavior to use this value
|
|
//~| encountered a dangling reference
|
|
// (it is dangling because vtables do not contain memory that can be dereferenced)
|
|
|
|
fn main() {}
|