#1401: otherwise ambiguous field names shouldn’t be treated as ambiguous when
the data constructor is known
-----------------------------------------+----------------------------------
Reporter: [EMAIL PROTECTED] | Owner:
Type: feature request | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.6.1
Severity: normal | Keywords:
Difficulty: Unknown | Os: Unknown
Testcase: | Architecture: Unknown
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Consider these three module definitions:
{{{
module A where
data A = A { label :: Char }
}}}
{{{
module B where
data B = B { label :: Char }
}}}
{{{
module X where
import A
import B
a = A { label = 'a' }
b = B { label = 'b' }
f (A { label = a }) (B { label = b }) = (a,b)
}}}
GHC currently treats all the occurences of {{{label}}} in module {{{C}}}
as ambiguous thereby conforming to the Haskell 98 standard. However, in
all these cases there is only one field to which {{{label}}} can refer
since the data constructor is known. So it should be possible to let GHC
treat the above code as legal by using a certain compiler option. This
would make the use of Haskell 98 records much more comfortable in certain
cases. Fields in different data types could be named equally if they
denote similar concepts without forcing the user of the data types to
qualify the field names over and over again.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1401>
GHC <http://www.haskell.org/ghc/>
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