internal/core/adt: derive status from shared value

In some cases a shared value may not be fully
evaluated before a referencing node completes.
In these cases, the status of a node may not
reflect the actual status.
This can be mitigated by dereferencing the
value and taking its status instead.

Signed-off-by: Marcel van Lohuizen <[email protected]>
Change-Id: I6f2f5eb3dba035311e103c0500c010734e12891d
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1202214
Reviewed-by: Matthew Sackman <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

internal/core/adt/composite.go

@@ -536,6 +536,7 @@ const (
 )
 
 func (v *Vertex) Status() vertexStatus {
+	v = v.DerefValue()
 	return v.status
 }