Undecipherable error message from cabal haddock

[nrnrnr]

I tried to build Haddock documentation for a project I am working on, but I could not make progress:

nr@homedog ~/a/sandbox> cabal haddock
cabal: renderBuildTargetProblem: unexpected status (TargetDisabledByUser,Nothing)
CallStack (from HasCallStack):
  error, called at src/Distribution/Client/CmdErrorMessages.hs:356:14 in main:Distribution.Client.CmdErrorMessages

I don't know how to interpret the error message. Haskell experts where I work were also unable to interpret the error message.

I attach a couple of relevant files.
sandbox.cabal.txt
cabal.project.local.txt

[tomjaguarpaw]

Have you tried minimising the broken example? That might help narrow down the cause.

[nrnrnr]

Where would I start? Start removing .hs files from my cabal file one at a time?

[tomjaguarpaw]

Yes, and removing other configuration options from the cabal file.