texmath-0.12.5: test/writer/eqn/msub-03.test
<<< native
[ ESub (EIdentifier "V") (ESymbol Bin "+")
, ESymbol Rel "="
, ESub
(EIdentifier "V")
(ESub (ESymbol Bin "+") (EPhantom (EIdentifier "fail")))
]
>>> eqn
V sub + = V sub {+ sub {hphantom fail}}