Good point. I've dramatically improved the error message to:
Foo.hs:8:
Couldn't match `Int' against `[(String, Int)]'
Expected type: Int
Inferred type: [(String, Int)]
When using functional dependencies to combine
?env :: Int, arising from a type signature at Foo.hs:7
?env :: [(String, Int)],
arising from use of implicit parameter `?env' at Foo.hs:8
When generalising the types for ident
Simon
| -----Original Message-----
| From: Alastair Reid [mailto:[EMAIL PROTECTED]]
| Sent: 26 April 2001 21:02
| To: [EMAIL PROTECTED]
| Subject: No line number in implicit parameter error message
|
|
|
| GHC 5.0 doesn't tell me which line the error is on in the
| attached program.
|
| $ rm -f T.o && ghc -c -fglasgow-exts T.hs
|
| Couldn't match `Int' against `[(String, Int)]'
| Expected type: Int
| Inferred type: [(String, Int)]
|
| The type error itself is correct: the type of ?env in the
| signature for ident should be Env not Int.
|
| --
| Alastair Reid [EMAIL PROTECTED]
| http://www.cs.utah.edu/~reid/
|
| module T where
|
| import Maybe
|
|
| type Env = [(String,Int)]
|
| ident :: (?env :: Int) => String -> Int
| ident x = fromJust (lookup x ?env)
|
| _______________________________________________
| Glasgow-haskell-bugs mailing list
| [EMAIL PROTECTED]
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|
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