#15760: Preserve parens in TH -------------------------------------+------------------------------------- Reporter: goldfire | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Template | Version: 8.6.1 Haskell | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Template Haskell supports parentheses in its AST. So does GHC. Yet GHC casually discards parentheses when desugaring TH quotes. We should preserve them. I was originally thinking that this could get rid of `Note [Adding parens for splices]` in Convert, but that processing would still be necessary if we are converting TH AST that did not come from a quote. Actually, it gets worse with this change, because we don't want to add ''redundant'' parens. Still, I think preserving parens is the right thing to do here. It also makes it possible for a client to give special meaning to, say, nested parens: Perhaps `process [| f x |]` and `process [| f ((x)) |]` will behave differently. (Idiom brackets, anyone?) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15760 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler