-- in.cue --
a: _
b: a @test(eq, {d: 1}) @test(shareID=ba)
a: {d: 1, d: _} @test(eq, {d: 1}) @test(shareID=ba)
b: _
-- out/eval/stats --
Leaks:  0
Freed:  4
Reused: 0
Allocs: 4
Retain: 0

Unifications: 4
Conjuncts:    7
Disjuncts:    0
-- out/todo.txt --
b: v2 evaluator expands b to a full struct; v3 shares the vertex with a.
