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| author | Matthew Pickering <matthewtpickering@gmail.com> | 2021-04-09 15:12:49 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2021-04-10 05:33:38 -0400 |
| commit | 6974c9e478120f6c4eeb53ebfa935c30cafcdf8e (patch) | |
| tree | 60ad5e80d4221e004c1ca0c6ea1eab462cefc6f0 /compiler | |
| parent | d39a2b243b53b5c10895f8b56f1d7e2749c99a4b (diff) | |
| download | haskell-6974c9e478120f6c4eeb53ebfa935c30cafcdf8e.tar.gz | |
Fix magicDict in ghci (and in the presence of other ticks)
The problem was that ghci inserts some ticks around the crucial bit of
the expression. Just like in some of the other rules we now strip the
ticks so that the rule fires more reliably.
It was possible to defeat magicDict by using -fhpc as well, so not just an
issue in ghci.
Fixes #19667 and related to #19673
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/GHC/Core/Opt/ConstantFold.hs | 4 | ||||
| -rw-r--r-- | compiler/GHC/Types/Id/Make.hs | 5 |
2 files changed, 7 insertions, 2 deletions
diff --git a/compiler/GHC/Core/Opt/ConstantFold.hs b/compiler/GHC/Core/Opt/ConstantFold.hs index e7f834268d..88439edcc6 100644 --- a/compiler/GHC/Core/Opt/ConstantFold.hs +++ b/compiler/GHC/Core/Opt/ConstantFold.hs @@ -53,7 +53,7 @@ import GHC.Core.TyCon , tyConFamilySize ) import GHC.Core.DataCon ( dataConTagZ, dataConTyCon, dataConWrapId, dataConWorkId ) import GHC.Core.Utils ( eqExpr, cheapEqExpr, exprIsHNF, exprType - , stripTicksTop, stripTicksTopT, mkTicks ) + , stripTicksTop, stripTicksTopT, mkTicks, stripTicksE ) import GHC.Core.Multiplicity import GHC.Core.FVs import GHC.Core.Type @@ -2243,7 +2243,7 @@ match_inline _ = Nothing -- See Note [magicDictId magic] in "GHC.Types.Id.Make" -- for a description of what is going on here. match_magicDict :: [Expr CoreBndr] -> Maybe (Expr CoreBndr) -match_magicDict [Type _, Var wrap `App` Type a `App` Type _ `App` f, x, y ] +match_magicDict [Type _, (stripTicksE (const True) -> (Var wrap `App` Type a `App` Type _ `App` f)), x, y ] | Just (_, fieldTy, _) <- splitFunTy_maybe $ dropForAlls $ idType wrap , Just (_, dictTy, _) <- splitFunTy_maybe fieldTy , Just dictTc <- tyConAppTyCon_maybe dictTy diff --git a/compiler/GHC/Types/Id/Make.hs b/compiler/GHC/Types/Id/Make.hs index b2f9dc7adf..1fcdabc977 100644 --- a/compiler/GHC/Types/Id/Make.hs +++ b/compiler/GHC/Types/Id/Make.hs @@ -1843,6 +1843,11 @@ definition in Core. The rewrite rule works as follows: The `co` coercion is the newtype-coercion extracted from the type-class. The type class is obtained by looking at the type of wrap. +In the constant folding rule it's very import to make sure to strip all ticks +from the expression as if there's an occurence of +magicDict we *must* convert it for correctness. See #19667 for where this went +wrong in GHCi. + ------------------------------------------------------------- @realWorld#@ used to be a magic literal, \tr{void#}. If things get |