Inconsistent constructor name causes a panic in signature files

If I declare a data constructor, and export it from a signature with a different name, I get a panic, as in the following .bkp file:

unit p where
  signature H(S(MkS)) where
    data S = NotMkS

ghc: panic! (the 'impossible' happened)
  (GHC version 9.0.1:
        nameModule
  internal MkS_02y
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler\GHC\Utils\Outputable.hs:1230:37 in ghc:GHC.Utils.Outputable
        pprPanic, called at compiler\GHC\Types\Name.hs:282:3 in ghc:GHC.Types.Name

This happens in general Backpack usage (i.e. isn't limited to .bkp files).

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