[Git][ghc/ghc][wip/T23070] Wibbles

[Simon Peyton Jones (@simonpj)]

Simon Peyton Jones pushed to branch wip/T23070 at Glasgow Haskell Compiler / GHC


Commits:
8357a7db by Simon Peyton Jones at 2023-03-04T10:22:12+00:00
Wibbles

- - - - -


2 changed files:

- compiler/GHC/Tc/Solver/Dict.hs
- compiler/GHC/Tc/Solver/Equality.hs


Changes:

=====================================
compiler/GHC/Tc/Solver/Dict.hs
=====================================
@@ -39,7 +39,6 @@ import GHC.Driver.Session
 
 import qualified GHC.LanguageExtensions as LangExt
 
-import Data.List( deleteFirstsBy )
 import Data.Maybe ( listToMaybe, mapMaybe )
 
 


=====================================
compiler/GHC/Tc/Solver/Equality.hs
=====================================
@@ -244,7 +244,7 @@ can_eq_nc' False rdr_env envs ev eq_rel _ ps_ty1 _ ps_ty2
        ; can_eq_nc' True rdr_env envs new_ev eq_rel xi1 xi1 xi2 xi2 }
 
 ----------------------------
--- Look for a canonical LHS. See Note [Canonical LHS].
+-- Look for a canonical LHS.
 -- Only rewritten types end up below here.
 ----------------------------
 
@@ -2497,10 +2497,6 @@ We avoid this problem by orienting the resulting given so that the unification
 variable is on the left (note that alternatively we could attempt to
 enforce this at canonicalization).
 
-See also Note [No touchables as FunEq RHS] in GHC.Tc.Solver.Monad; avoiding
-double unifications is the main reason we disallow touchable
-unification variables as RHS of type family equations: F xis ~ alpha.
-
 Note [Do not unify representational equalities]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Consider   [W] alpha ~R# b



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8357a7db55ced7e9f8f42c7ab77bc1408b0599a1

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8357a7db55ced7e9f8f42c7ab77bc1408b0599a1
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