#15497: Coercion Quantification -------------------------------------+------------------------------------- Reporter: ningning | Owner: (none) Type: task | Status: closed Priority: normal | Milestone: Component: Compiler | Version: Resolution: fixed | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D5054 Wiki Page: | https://ghc.haskell.org/trac/ghc/wiki/DependentHaskell/Phase2| -------------------------------------+------------------------------------- Comment (by simonpj): On coercion quantification, I think it would be helpful to update [wiki:DependentHaskell/Phase2] * Under "Why homogeneous equality is good" explain how homogeneous equality can help the simplifier (in `exprIsConApp_maybe`). * On the same page, under "A small wrinkle: we need coercion quantification back", remove or rephrase the stuff about `(~~)`; perhaps use the ''data type'' `:~~:` rather than the ''class'' `(~~)`. * Promote "Another approach" for the class `(~~)` which appears lower down. It may be another approach but it is Our Plan for solving a Real Problem in introducing homogeneous equality at the moment, and as time goes on it is really helpful to know what The Plan is, with other approaches being discussed later. TL;DR: make the page reflect our current thinking as directly as possible. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15497#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler