# Static rustc_lint_defs::builtin::CONST_EVALUATABLE_UNCHECKED

source ·

    pub static CONST_EVALUATABLE_UNCHECKED: &Lint

Expand description

The `const_evaluatable_unchecked` lint detects a generic constant used in a type.

#### §Example

    const fn foo<T>() -> usize {
        if std::mem::size_of::<*mut T>() < 8 { // size of *mut T does not depend on T
            4
        } else {
            8
        }
    }

    fn test<T>() {
        let _ = [0; foo::<T>()];
    }

{{produces}}

#### §Explanation

In the 1.43 release, some uses of generic parameters in array repeat expressions were accidentally allowed. This is a future-incompatible lint to transition this to a hard error in the future. See issue #76200 for a more detailed description and possible fixes.