What version of CUE are you using (cue version)?

8a6ed2c44ebc23549793d3fdd71523b88523b542

Does this issue reproduce with the latest stable release?

N/A

What did you do?

exec cue vet x.cue 
-- x.cue --
_x1: matchN(2, [_x1, _x1])
x: 3 & _x1

What did you expect to see?

Passing test. The recursive matchN should be equivalent to:

_x1: _x1 & _x1

which is fine.

What did you see instead?

The process uses all available memory before crashing.

This only applies to the old evaluator, not evalv3.