[ ghc-Bugs-1234256 ] instance of synonym

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Bugs item #1234256, was opened at 2005-07-07 16:16
Message generated for change (Comment added) made by simonpj
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Category: Compiler (Type checker)
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Nobody/Anonymous (nobody)
Summary: instance of synonym

Initial Comment:
The following non-Haskell 98 instance is accepted even
without -fglasgow-exts:

type Foo = Double
instance Bounded Foo

The error message quotes the relevant part of the
Report (The instance type must be of form (T a b c)
where T is not a synonym, and a,b,c are distinct type
variables) and the code expresses this, but it seems
that type synonyms have already been expanded, so only
non-saturated ones are left at this stage.

ross at soi.city.ac.uk

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>Comment By: Simon Peyton Jones (simonpj)
Date: 2005-07-08 15:08

Message:
Logged In: YES 
user_id=50165

Good point. Now fixed, thank you

tcfail139 tests it.

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You can respond by visiting: 
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