Patterns are treated differently between v2 and v3

[cuematthew]

What version of CUE are you using (cue version)?

master, commit 0cd0a0c05996db4f998e2b90b2a70e37fc7d209c

What did you do?

# -- evalv2 --
env CUE_EXPERIMENT=evalv3=0
exec cue eval --out cue ./in.cue
cmp stdout stdout.golden

# -- evalv3 --
env CUE_EXPERIMENT=evalv3=1
exec cue eval --out cue ./in.cue
cmp stdout stdout.golden

-- in.cue --
x: {[string]: _}
x: #d
#d: f: _

y: { x }
y: f: true
-- stdout.golden --
x: {
    f: _
}
#d: {
    f: _
}
y: {
    f: true
}

What did you expect to see?

both v2 and v3 should pass

What did you see instead?

# testscript  /tmp/testscript2.txtar
+ exec /home/matthew/go/bin/testscript -e GOPATH=/home/matthew/go -e CUEHOME=/home/matthew/cue/cue /tmp/testscript2.txtar
# -- evalv2 -- (0.103s)
# -- evalv3 -- (0.152s)
> env CUE_EXPERIMENT=evalv3=1
> exec cue eval --out cue ./in.cue
[stderr]
+ cd /home/matthew/cue/cue/cmd/cue
+ go build
+ exec /home/matthew/cue/cue/cmd/cue/cue eval --out cue ./in.cue
y.f: field not allowed:
    ./in.cue:2:4
    ./in.cue:1:5
    ./in.cue:3:5
    ./in.cue:6:4
[exit status 1]
FAIL: /tmp/testscript184019744/testscript2.txtar/script.txtar:8: unexpected command failure
error running /tmp/testscript2.txtar in /tmp/testscript184019744/testscript2.txtar

[cuematthew]

(Passes with new closedness).

[cuematthew]

Confirmed: with new closedness now landed, this passes.