<<< native
[ EArray
    [ AlignRight , AlignRight ]
    [ [ [ EGrouped
            [ EPhantom (EText TextNormal "fail") , EIdentifier "H" ]
        ]
      , [ EIdentifier "A" ]
      ]
    , [ [ EGrouped
            [ EPhantom (EText TextNormal "fail") , EIdentifier "T" ]
        ]
      , [ EIdentifier "I" ]
      ]
    , [ [ EGrouped
            [ EPhantom (EText TextNormal "fail") , EIdentifier "U" ]
        ]
      , [ EIdentifier "Y" ]
      ]
    ]
, ESymbol Rel "="
, EArray
    [ AlignLeft , AlignLeft ]
    [ [ [ EIdentifier "A" ]
      , [ EGrouped
            [ EIdentifier "H" , EPhantom (EText TextNormal "fail") ]
        ]
      ]
    , [ [ EIdentifier "I" ]
      , [ EGrouped
            [ EIdentifier "T" , EPhantom (EText TextNormal "fail") ]
        ]
      ]
    , [ [ EIdentifier "Y" ]
      , [ EGrouped
            [ EIdentifier "U" , EPhantom (EText TextNormal "fail") ]
        ]
      ]
    ]
]
>>> tex
\begin{array}{rr}
{\phantom{\text{fail}}H} & A \\
{\phantom{\text{fail}}T} & I \\
{\phantom{\text{fail}}U} & Y
\end{array} = \begin{array}{ll}
A & {H\phantom{\text{fail}}} \\
I & {T\phantom{\text{fail}}} \\
Y & {U\phantom{\text{fail}}}
\end{array}