-- want --
valid:
valid.cue
other/valid.cue
cue.mod/module.cue
cue.mod/pkg_other/x
cue.mod/pkg/x
cue.mod/usr/x
cue.mod/gen/x
GO.MOD
vendor/x/y
valid.go

omitted:
sub1/cue.mod/module.cue: file is in another module
sub1/something.cue: file is in another module
sub2/CUE.MOD/module.cue: file is in another module
.hg_archival.txt: file is inserted by 'hg archive' and is always omitted

invalid:
cue.mod/Module.cue: cue.mod/module.cue files must have lowercase names
not/../clean: file path is not clean
CUE.MOD/module.cue: cue.mod directories must have lowercase names
invalid.go': malformed file path "invalid.go'": invalid char '\''
valid.go: multiple entries for file "valid.go"
-- valid.cue --
-- other/valid.cue --
-- cue.mod/module.cue --
-- cue.mod/Module.cue --
-- cue.mod/pkg_other/x --
-- cue.mod/pkg/x --
-- cue.mod/usr/x --
-- cue.mod/gen/x --
-- not/../clean --
-- GO.MOD --
-- CUE.MOD/module.cue --
-- invalid.go' --
-- vendor/x/y --
-- sub1/cue.mod/module.cue --
-- sub1/something.cue --
-- sub2/CUE.MOD/module.cue --
-- .hg_archival.txt --
-- valid.go --
duplicate
-- valid.go --
another duplicate