[GHC] #597: Various error messages have inaccurate source locations

[GHC]

#597: Various error messages have inaccurate source locations
-------------------------------+--------------------------------------------
  Reporter:  simonmar          |          Owner:         
      Type:  task              |         Status:  new    
  Priority:  normal            |      Milestone:         
 Component:  Compiler          |        Version:  None   
  Severity:  normal            |     Resolution:  None   
  Keywords:                    |             Os:  Unknown
Difficulty:  Moderate (1 day)  |   Architecture:  Unknown
-------------------------------+--------------------------------------------
Changes (by simonmar):

  * architecture:  => Unknown
  * difficulty:  => Moderate (1 day)
  * os:  => Unknown

Old description:

> {{{
> Some error messages lack source location information, or have inaccurate
> locations.    Here are the ones we know about:
>
> * Should point to the import decl:
>   ShowFunctions.hs:1:0
>     Warning: Module `Text.Show.Functions' is imported, but nothing from
> it is used
>
> * Should point to the instance header:
>   mod41.hs:3:0:
>       Illegal instance declaration for `Eq (Either a a)'
>         (The instance type must be of form (T a b c)
>
> * Should point to 'deriving *Eq*', not the tycon:
>   tcfail046.hs:9:8:
>     No instance for `Eq (Pid -> Time -> Message a -> (MessList a,
> Continuation a
> ))'
>     When deriving the `Eq' instance for type `Continuation'
>
> * check_tau_type doesn't have location info?
>   tcfail100.hs:7:0:
>       Type synonym `A' should have 1 argument, but has been given 0
>       In the type synonym declaration for `B'
>
> * Location in LHsModule from the parser should really span the whole
>   file, rather than a point span at (1,0).
>
> * read016: should be the lhs only?
> * tcfail044: should be the instance head only.
>

> }}}

New description:

 {{{
 Some error messages lack source location information, or have inaccurate
 locations.    Here are the ones we know about:

 * Should point to the import decl:
   ShowFunctions.hs:1:0
     Warning: Module `Text.Show.Functions' is imported, but nothing from it
 is used

 * Should point to the instance header:
   mod41.hs:3:0:
       Illegal instance declaration for `Eq (Either a a)'
         (The instance type must be of form (T a b c)

 * Should point to 'deriving *Eq*', not the tycon:
   tcfail046.hs:9:8:
     No instance for `Eq (Pid -> Time -> Message a -> (MessList a,
 Continuation a
 ))'
     When deriving the `Eq' instance for type `Continuation'

 * check_tau_type doesn't have location info?
   tcfail100.hs:7:0:
       Type synonym `A' should have 1 argument, but has been given 0
       In the type synonym declaration for `B'

 * Location in LHsModule from the parser should really span the whole
   file, rather than a point span at (1,0).

 * read016: should be the lhs only?
 * tcfail044: should be the instance head only.


 }}}

-- 
Ticket URL: <http://cvs.haskell.org/trac/ghc/ticket/597>
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