ppr of HsDo

The pretty printer turns foo = do let x = 1 Just 5 into foo = do { let x = 1; Just 5 } which does not parse, complaining about "parse error on input ‘Just’" Is this a parser error or a ppr problem? I am keen to fix the ppr to output foo = do let x = 1 Just 5 but I am not sure if there is a parser bug too. Alan