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#![feature(generic_arg_infer)]
// Test that would start passing if we defer repeat expr copy checks to end of
// typechecking and they're checked after integer fallback occurs. We accomplish
// this by contriving a situation where integer fallback allows progress to be
// made on a trait goal that infers the length of a repeat expr.
use std::marker::PhantomData;
struct NotCopy;
trait Trait<const N: usize> {}
impl Trait<2> for u32 {}
impl Trait<1> for i32 {}
fn make_goal<T: Trait<N>, const N: usize>(_: &T, _: [NotCopy; N]) {}
fn main() {
let a = 1;
let b = [NotCopy; _];
//~^ ERROR: type annotations needed
// a is of type `?y`
// b is of type `[NotCopy; ?x]`
// there is a goal ?y: Trait<?x>` with two candidates:
// - `i32: Trait<1>`, ?y=i32 ?x=1 which doesnt require `NotCopy: Copy`
// - `u32: Trait<2>` ?y=u32 ?x=2 which requires `NotCopy: Copy`
make_goal(&a, b);
// final repeat expr checks:
//
// `NotCopy; ?x`
// - succeeds if fallback happens before repeat exprs as `i32: Trait<?x>` infers `?x=1`
// - fails if repeat expr checks happen first as `?x` is unconstrained so cannot be
// structurally resolved
}
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