the resolution of abbreviated commands in ghci is surprising.
GHCi, version 6.12.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading package ffi-1.0 ... linking ... done. Prelude> :i True data Bool = ... | True -- Defined in GHC.Bool Prelude> :def ifoo \_ -> putStrLn "ifoo" >> return "" Prelude> :i True ifoo
It seems that abbreviations are resolved to the command, that matches the prefix, which is defined last. I've found this behaviour very confusing in practice.
I'd expect rebinding :i to some command that's not :info to require an explicit declaration.