Commit 5cb93af7 authored by Committed by Marge Bot
pretty-printer: Do not print ApplicativeDo join
* Do not print `join` in ApplictiveStmt, unless ppr-debug * Print parens around multiple parallel binds When ApplicativeDo is enabled, the renamer analyses the statements of a `do` block and in certain cases marks them as needing to be rewritten using `join`. For example, if you have: ``` foo = do a <- e1 b <- e2 doSomething a b ``` it will be desugared into: ``` foo = join (doSomething <$> e1 <*> e2) ``` After renaming but before desugaring the expression is stored essentially as: ``` foo = do [will need join] (a <- e1 | b <- e2) [no return] doSomething a b ``` Before this change, the pretty printer would print a call to `join`, even though it is not needed at this stage at all. The expression will be actually rewritten into one using join only at desugaring, at which point a literal call to join will be inserted.
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