-- in.cue --
#S: {
	[string]: {a: int}
}
a: #S & {
	v: {b: int}
} @test(err, at=v.b, code=eval, contains="field not allowed", pos=[1:6])
-- out/errors.txt --
[eval] a.v.b: field not allowed:
    ./in.cue:5:6
-- out/eval/stats --
Leaks:  0
Freed:  6
Reused: 0
Allocs: 6
Retain: 0

Unifications: 6
Conjuncts:    9
Disjuncts:    0

NumCloseIDs: 1
-- out/diff-v2-v3.txt --
Missing positions: v3 reports fewer positions than v2 for the "field not allowed" error.
 a.v.b: field not allowed:
-    ./in.cue:2:12
-    ./in.cue:4:4
     ./in.cue:5:6
