hcs2hs failure

[Simon Peyton Jones]

Is anyone else seeing this in a GHC build

utils/hsc2hs/HSCParser.hs:170:14: error: [-Wunused-matches, -Werror=unused-matches]

    Defined but not used: 'd'

    |

170 |         '\'':d:'\'':_ -> do any3Chars_; text -- Case 2

    |              ^
Indeed, d looks unused.  But this line of code has been there since 28 Dec, so I can't understand why it has not bitten before.
With -Werror my build fails.  I could switch to -Wwarn, but I think -Werror is the default.
Simon
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