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Add options to select GHCi prompt type errors

This SO post implicitly suggests some extra options for reporting type errors for expressions typed into GHCi. When GHCi reports a type error for an expression e typed at the prompt, it has effectively failed to check void e :: IO () and print e :: IO (). It always reports the error for the latter. There are three things a user may want, and I think options should control which ones are shown:

  1. Why didn't void e :: IO () check?
  2. Why didn't print e :: IO () check?
  3. If any type could be inferred for e, what was it?
Edited by David Feuer
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