Bugs item #1300895, was opened at 2005-09-23 14:12
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Bjorn Bringert (bring)
Assigned to: Nobody/Anonymous (nobody)
Summary: Incomplete pattern warnings with GADTs
Initial Comment:
{-
With GADTs, -fwarn-incomplete-patterns complains
about missing
impossible cases.
-}
{-# OPTIONS_GHC -fglasgow-exts
-fwarn-incomplete-patterns #-}
data Var = Var
data Typ = Typ
data Tree a where
V :: String -> Tree Var
T_int :: Tree Typ
getId :: Tree Var -> String
getId (V x) = x
--getId T_int = "T_int"
{-
With the last line commented out:
gadt-pattern-warning.hs:11:0:
Warning: Pattern match(es) are non-exhaustive
In the definition of `getId': Patterns not
matched: T_int
Ok, modules loaded: Main.
With the last line not commented out:
gadt-pattern-warning.hs:12:6:
Inaccessible case alternative: Can't match types
`Typ' and `Var'
When checking the pattern: T_int
In the definition of `getId': getId T_int = "T_int"
Failed, modules loaded: none.
-}
----------------------------------------------------------------------
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=108032&aid=1300895&group_id=8032
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