[commit: ghc] master: Remove unused DerivInst constructor for DerivStuff (f4384ef)
Simon Peyton Jones
simonpj at microsoft.com
Tue Aug 30 21:12:00 UTC 2016
Ryan
I just wanted to thank you for all the work you are doing on 'deriving' and generics.
It's a very useful part of GHC, but it's sufficiently complicated that it's hard to dive in and make a quick fix. You are giving it sustained attention, and have become very familiar with the code, which is exactly what it needs.
Thank you! It's extremely valuable work.
I am conscious that I owe you a code review on D2280, but this week is bad and next week is worse. If I don't get to it, let's sit down at ICFP. I should not be standing in the way. Has anyone else given it a good review?
Simon
-----Original Message-----
From: ghc-commits [mailto:ghc-commits-bounces at haskell.org] On Behalf Of git at git.haskell.org
Sent: 29 August 2016 20:29
To: ghc-commits at haskell.org
Subject: [commit: ghc] master: Remove unused DerivInst constructor for DerivStuff (f4384ef)
Repository : ssh://git@git.haskell.org/ghc
On branch : master
Link : https://na01.safelinks.protection.outlook.com/?url=http%3a%2f%2fghc.haskell.org%2ftrac%2fghc%2fchangeset%2ff4384ef5b42bb64b55d6c930ed9850a021796f36%2fghc&data=01%7c01%7csimonpj%40microsoft.com%7cde5175bbe587432dbce208d3d042b188%7c72f988bf86f141af91ab2d7cd011db47%7c1&sdata=l7WnAtIxsN0brRXa5FKnFrEvk0pyxm48BIqyOiiiIx4%3d
>---------------------------------------------------------------
commit f4384ef5b42bb64b55d6c930ed9850a021796f36
Author: Ryan Scott <ryan.gl.scott at gmail.com>
Date: Mon Aug 29 15:26:53 2016 -0400
Remove unused DerivInst constructor for DerivStuff
Summary:
Back when derived `Generic` instances used to generate auxiliary datatypes,
they would also generate instances for those datatypes. Nowadays, GHC generics
uses a `DataKinds`-based encoding that requires neither auxiliary datatypes
(corresponding to the `DerivTyCon` constructor of `DerivStuff`) nor instances
for them (the `DerivInst` constructor of `DerivStuff`). It appears that
`DerivTyCon` constructor was removed at some point, but `DerivInst` never was.
No `DerivInst` values are ever constructed, so we can safely remove it.
Test Plan: It builds
Reviewers: austin, hvr, bgamari
Reviewed By: bgamari
Subscribers: thomie
Differential Revision: https://phabricator.haskell.org/D2481
>---------------------------------------------------------------
f4384ef5b42bb64b55d6c930ed9850a021796f36
compiler/typecheck/TcDeriv.hs | 5 ++---
compiler/typecheck/TcGenDeriv.hs | 22 +++++++++-------------
2 files changed, 11 insertions(+), 16 deletions(-)
diff --git a/compiler/typecheck/TcDeriv.hs b/compiler/typecheck/TcDeriv.hs index 70eaf5c..e38cfdc 100644
--- a/compiler/typecheck/TcDeriv.hs
+++ b/compiler/typecheck/TcDeriv.hs
@@ -387,13 +387,12 @@ tcDeriving deriv_infos deriv_decls
; let (inst_infos, deriv_stuff, maybe_fvs) = unzip3 (insts1 ++ insts2)
; loc <- getSrcSpanM
- ; let (binds, famInsts, extraInstances) =
- genAuxBinds loc (unionManyBags deriv_stuff)
+ ; let (binds, famInsts) = genAuxBinds loc (unionManyBags
+ deriv_stuff)
; dflags <- getDynFlags
; (inst_info, rn_binds, rn_dus) <-
- renameDeriv is_boot (inst_infos ++ (bagToList extraInstances)) binds
+ renameDeriv is_boot inst_infos binds
; unless (isEmptyBag inst_info) $
liftIO (dumpIfSet_dyn dflags Opt_D_dump_deriv "Derived instances"
diff --git a/compiler/typecheck/TcGenDeriv.hs b/compiler/typecheck/TcGenDeriv.hs
index 2eb8c07..dce0b16 100644
--- a/compiler/typecheck/TcGenDeriv.hs
+++ b/compiler/typecheck/TcGenDeriv.hs
@@ -70,7 +70,6 @@ import Lexeme
import FastString
import Pair
import Bag
-import TcEnv (InstInfo)
import StaticFlags( opt_PprStyle_Debug )
import ListSetOps ( assocMaybe )
@@ -90,12 +89,11 @@ data AuxBindSpec
data DerivStuff -- Please add this auxiliary stuff
= DerivAuxBind AuxBindSpec
- -- Generics
+ -- Generics and DeriveAnyClass
| DerivFamInst FamInst -- New type family instances
-- New top-level auxiliary bindings
| DerivHsBind (LHsBind RdrName, LSig RdrName) -- Also used for SYB
- | DerivInst (InstInfo RdrName) -- New, auxiliary instances
{-
************************************************************************
@@ -2346,11 +2344,11 @@ genAuxBindSpec loc (DerivMaxTag tycon)
max_tag = case (tyConDataCons tycon) of
data_cons -> toInteger ((length data_cons) - fIRST_TAG)
-type SeparateBagsDerivStuff = -- AuxBinds and SYB bindings
- ( Bag (LHsBind RdrName, LSig RdrName)
- -- Extra bindings (used by Generic only)
- , Bag (FamInst) -- Extra family instances
- , Bag (InstInfo RdrName)) -- Extra instances
+type SeparateBagsDerivStuff =
+ -- AuxBinds and SYB bindings
+ ( Bag (LHsBind RdrName, LSig RdrName)
+ -- Extra family instances (used by Generic and DeriveAnyClass)
+ , Bag (FamInst) )
genAuxBinds :: SrcSpan -> BagDerivStuff -> SeparateBagsDerivStuff genAuxBinds loc b = genAuxBinds' b2 where @@ -2363,16 +2361,14 @@ genAuxBinds loc b = genAuxBinds' b2 where
genAuxBinds' :: BagDerivStuff -> SeparateBagsDerivStuff
genAuxBinds' = foldrBag f ( mapBag (genAuxBindSpec loc) (rm_dups b1)
- , emptyBag, emptyBag)
+ , emptyBag )
f :: DerivStuff -> SeparateBagsDerivStuff -> SeparateBagsDerivStuff
f (DerivAuxBind _) = panic "genAuxBinds'" -- We have removed these before
f (DerivHsBind b) = add1 b
f (DerivFamInst t) = add2 t
- f (DerivInst i) = add3 i
- add1 x (a,b,c) = (x `consBag` a,b,c)
- add2 x (a,b,c) = (a,x `consBag` b,c)
- add3 x (a,b,c) = (a,b,x `consBag` c)
+ add1 x (a,b) = (x `consBag` a,b)
+ add2 x (a,b) = (a,x `consBag` b)
mkParentType :: TyCon -> Type
-- Turn the representation tycon of a family into
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