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Strange error when attempting to load file into hugs:

Hugs> :l test.hs
ERROR "test.hs":3 - Undefined data constructor "?"

Full content of file (yes, one line):

test :: [a] -> ([a],[a])

Can anyone enlighten me?


Note: Attempting to load the same file in ghci doesn't work either, but for reasons that make sense:

Prelude> :r
[1 of 1] Compiling Main             ( test.hs, interpreted )

test.hs:1:1:
The type signature for ‘test’ lacks an accompanying binding
Failed, modules loaded: none.
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