cue.Value.Pos().Filename() returns unexpected path

[nxcc]

Hi all,
using the cue api I want to process some custom attributes in cue source files. This requires the path to the file where the attribute was found. The attached testscript.txtar shows a minimal example to reproduce the issue. This works for cm1, but fails for cm2. Instead of the expected path, the path to the k8s definition is returned. Is this behavior expected? The restult is the same for v0.4.3 and v0.5.0-beta.2.

import "k8s.io/api/core/v1"

cm1: {
    data: {} @myattr(foo)
}

cm2: v1.#ConfigMap & {
    data: {} @myattr(foo)
}

testscript output:

cm1 file: $WORK/test.cue
cm2 file: $WORK/cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue

Putting some dummy value into cm2.data

cm2: v1.#ConfigMap & {
    data: {
        _bar: true
    } @myattr(foo)
}

results in the expected path to be returned.

testscript.txtar