//@ known-bug: #103507 #![feature(const_trait_impl, const_mut_refs)] struct Foo<'a> { bar: &'a mut Vec, } impl<'a> Foo<'a> { const fn spam(&mut self, baz: &mut Vec) { self.bar[0] = baz.len(); //FIXME ~^ ERROR: cannot call //FIXME ~| ERROR: cannot call //FIXME ~| ERROR: the trait bound } } fn main() {}