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# Class Method Types
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**[Ticket(s)](/search?q="ClassMethodTypes"&ticket=on)**
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## Brief Explanation
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In [ Haskell 98, s4.3.1](http://www.haskell.org/onlinereport/decls.html#class-decls), the signatures of methods in a class may contain constraints, but these constraints must not mention the argument of the type class. The following is illegal:
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However this restriction is not implemented by Hugs, following a suggestion of Mark Jones in
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[ Typing Haskell in Haskell](http://www.cse.ogi.edu/~mpj/thih/), and can be turned off in GHC with `-fglasgow-exts`.
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## Tickets
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<table><tr><th>[\#17](https://gitlab.haskell.org//haskell/prime/issues/17)</th>
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<td>relax restriction on signatures of class methods</td></tr></table> |
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\ No newline at end of file |
