tree 75701a34b15aedb9c2146fd105df25eabf982956
parent 267379b61aa69cf01e665261b10ce341ae19ff65
author Marcel van Lohuizen <mpvl@golang.org> 1612769637 +0100
committer Marcel van Lohuizen <mpvl@golang.org> 1612794591 +0000

internal/core/compile: make `>10 <20` a compile error

Or in general, fail on any expression that must be concrete,
but can never evaluate to a concrete value.

Although technically correct CUE, it can never resolve to
a valid value and allowing it gives too much confusion to
the user.

At evaluation time expressions of the form `int + 1` were
already flagged. Now it also flags `>a + 1`, as `>a` will
never be concrete, even if `a` resolves fine.

Note that `(>10 & <a) + 1` is fine, though, as the bounds
can still resolve to concrete value when unified.

Making it a compile error, instead of a evaluation error,
ensures that this error doesn't go unnoticed and give
unexpected results.

Fixes #742
Fixes #405

Change-Id: Ib2032778ca5dcb6ef1681b4e03498ff039d37c7f
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8665
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Paul Jolly <paul@myitcv.org.uk>