src/test/ui/const-generics/const-expression-parameter.rs

#![feature(const_generics)]
//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash

fn i32_identity<const X: i32>() -> i32 {
    5
}

fn foo_a() {
    i32_identity::<-1>(); // ok
}

fn foo_b() {
    i32_identity::<1 + 2>(); //~ ERROR expected one of `,` or `>`, found `+`
}

fn foo_c() {
    i32_identity::< -1 >(); // ok
}

fn main() {
    i32_identity::<5>(); // ok
}