Parsing of lambdas is not consistent with Haskell'98 report.

Consider the following expression:

(\x -> x :: Int . id)

GHC (without any -X flags) currently reports a parse error:

Illegal operator .' in type Int . id'[[br]] Use -XTypeOperators to allow operators in types

However, I think this expression is legal in Haskell'98 (and indeed still legal in Haskell 2010). The report gives an (ambiguous) expression grammar, which (unambiguously) parses the above as (\x -> (x :: Int)) . id. The report further says that lambdas extend as far as possible to the right, but the parse which GHC is using is not a possible parse according to the grammar, since infix operators (other than "->") are not allowed in the construction 'type'.

That said, I'd much rather see this fixed in the Haskell 2011 report than in GHC :)

Trac metadata

Trac field	Value
Version	6.10.4
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (Parser)
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