Commit 3354c68e authored by Committed by Marge Bot
Pretty-printing of the * kind
Before this patch, GHC always printed the * kind unparenthesized. This led to two issues: 1. Sometimes GHC printed invalid or incorrect code. For example, GHC would print: type F @* x = x when it meant to print: type F @(*) x = x In the former case, instead of a kind application we were getting a type operator (@*). 2. Sometimes GHC printed kinds that were correct but hard to read. Should Either * Int be read as Either (*) Int or as (*) Either Int ? This depends on whether -XStarIsType is enabled, but it would be easier if we didn't have to check for the flag when reading the code. We can solve both problems by assigning (*) a different precedence. Note that Haskell98 kinds are not affected: ((* -> *) -> *) -> * does NOT become (((*) -> (*)) -> (*)) -> (*) The parentheses are added when (*) is used in a function argument position: F * * * becomes F (*) (*) (*) F A * B becomes F A (*) B Proxy * becomes Proxy (*) a * -> * becomes a (*) -> *
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