Nightly compiler fails with ICE if const parameter is used to define type of function input

[newpavlov]

Code:

fn foo<const N: usize>(val: &[u8; N]) { }

Error:

error: internal compiler error: array length could not be evaluated

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:356:17

[newpavlov]

Possibly duplicate of #60619?

[varkor]

This is one of the FIXMEs:

rust/src/librustc/ty/relate.rs

Lines 479 to 480 in b3207d5

	// FIXME(const_generics): this doesn't work right now,
	// because it tries to relate an `Infer` to a `Param`.

That said, it's useful to have a dedicated issue for this. It essentially means arrays with const generics are broken at the moment.

[varkor]

#60742 fixes this particular issue, though there are still remaining issues with arrays and const generics.

[harrysarson]

This is #60632?

[varkor]

This is #60632?

Fixed the link. I'm not doing very well at pasting links today 😄