Closed
Description
openedon Aug 19, 2021
This requires 2 different crates:
// crate-a
#![feature(const_fn_trait_bound)]
#![feature(const_trait_impl)]
#![feature(const_trait_bound_opt_out)]
#![allow(incomplete_features)]
pub trait A {
fn assoc() -> bool;
}
pub const fn foo<T: ?const A>() -> bool {
T::assoc()
}
// crate-b
#![feature(const_fn_trait_bound)]
#![feature(const_trait_impl)]
#![feature(const_trait_bound_opt_out)]
#![allow(incomplete_features)]
extern crate a;
struct Foo;
impl a::A for Foo {
fn assoc() -> bool {
println!("hey ho");
true
}
}
static F: bool = a::foo::<Foo>();
fn main() {
println!("{}", F);
}results in
error[E0080]: could not evaluate static initializer
--> /home/lcnr/wtf/a/src/lib.rs:11:5
|
11 | T::assoc()
| ^^^^^^^^^^
| |
| calling non-const function `<Foo as A>::assoc`
| inside `foo::<Foo>` at /home/lcnr/wtf/a/src/lib.rs:11:5
|
::: src/main.rs:15:19
|
15 | static F: bool = a::foo::<Foo>();
| --------------- inside `F` at src/main.rs:15:19
relevant code
rust/compiler/rustc_mir/src/transform/check_consts/check.rs
Lines 889 to 902 in 4968a8b
with #86986 we don't find any impl for PartialEq which might apply here which causes us to incorrectly accept https://github.com/rust-lang/rust/blob/master/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-fail.rs
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