ghc 6.10.4 infix declarations and '\' bug or not ?

in declaring fixity for an operator (\\) to get it to compile using ghc 6.10.4, I needed to use the following code infixl 9 \\\ (\\) a b = etc ... where I assume the first \ escapes the second \, using infixl 9 \\ generates a syntax error infixl 9 \\ used to compile no problems with ghc 6.8.2 what is going on here ? why do I now need to add an additional \ ?, where is this change documented ?, is this a bug?