non scalar sentinels allowed in array types

[xdBronch]

Zig Version

0.14.0-dev.2638+04c9f50ae

Steps to Reproduce and Observed Behavior

test {
    _ = [0:.{}]struct {};
}

non scalar sentinels were removed in #21509 but this still passes. its only when used on slices that it fails

test {
    _ = [:.{}]struct {};
}

a.zig:2:12: error: non-scalar sentinel type 'a.test_0__struct_377'
    _ = [:.{}]struct {};
          ~^~

Expected Behavior

compile error in both examples