Where to submit examples for improving compiler error messages?

I seem to remember seeing here or on Twitter someone saying that "if a compileror borrowck error message is confusing or doesn't help resolve your problem, it's a bug and we should address it." But I lost where the right venue is to show examples.

I ran into a case today where I found a pair of suggested remedies that leads to a cycle of adding or removing references. (Basically, RangeInclusive doesn't implement Copy, leading to a move when that range is iterated upon in an inner loop. The suggestion is to borrow the iterator; but the &RangeInclusive doesn't implement Iterator, and the recommended change leads to a suggestion to remove the previously-suggested borrow.)

The proper answer appears to be here: rust - Why doesn't ops::Range<T> implement Copy, even if T is Copy? - Stack Overflow

While I hate the ergonomics and sloppiness, simply adding .clone() in the inner loop resolved the problem in one shot.

I suppose an error message that recognized the potential for this pair of conflicting recommendations and that pointed out the meta-issue would be better.

Related: the Vec API signature works fine in a similar method (which permits discontiguous values for iterating through an array), leading me to wonder what the most efficient way to specify a contiguous range that is not Copy-able? Is .clone() the best choice?

Here's a playground with some comments about the cycle:

Where to submit examples for improving compiler error messages?

1 Like

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.