Template Haskell splicing drops lots of type arguments

The conversion functions (in the Convert module) drop type arguments in various places.

Here are two examples:

data T a b c = Mk a b c

bar :: $( return $ AppT (InfixT (ConT ''Int) ''T (ConT ''Bool)) (ConT ''Double) )
bar = Mk 5 True 3.14

This correct code leads to an error

Expecting one more argument to ‘T Int Bool’

because the Double is forgotten.

Similarly,

baz :: $( return $ AppT (ParensT (ConT ''Maybe)) (ConT ''Int) )
baz = Just 5

fails because baz :: (Maybe) isn't valid.

On the other hand,

frob :: forall (a :: $( [t| * Int |] )). a -> a
frob x = x

is spuriously accepted, because GHC has forgotten about the Int argument.

Trac metadata

Trac field	Value
Version	8.4.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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