[Git][ghc/ghc][wip/spj-reinstallable-base2] unsafeCoercePrimName

6 May 2026

Rodrigo Mesquita pushed to branch wip/spj-reinstallable-base2 at Glasgow Haskell Compiler / GHC


Commits:
25497cb4 by Rodrigo Mesquita at 2026-05-06T17:51:42+01:00
unsafeCoercePrimName

- - - - -


5 changed files:

- compiler/GHC/Builtin/KnownKeys.hs
- compiler/GHC/HsToCore.hs
- compiler/GHC/Tc/Module.hs
- compiler/GHC/Tc/Utils/Concrete.hs
- libraries/base/src/GHC/Essentials.hs


Changes:

=====================================
compiler/GHC/Builtin/KnownKeys.hs
=====================================
@@ -271,6 +271,9 @@ knownKeyTable
     , (mkDataOcc ":$$:",      typeErrorVAppendDataConKey)
     , (mkDataOcc "ShowType",  typeErrorShowTypeDataConKey)
 
+    -- Unsafe coercion proofs
+    , (mkVarOcc "unsafeCoerce#", unsafeCoercePrimIdKey)
+
     -- Plugins
     , (mkTcOcc "Plugin", pluginTyConKey)
     , (mkTcOcc "FrontendPlugin", frontendPluginTyConKey)
@@ -372,10 +375,7 @@ basicKnownKeyNames
         starKindRepName,
         starArrStarKindRepName,
         starArrStarArrStarKindRepName,
-        constraintKindRepName,
-
-        -- Unsafe coercion proofs
-        unsafeCoercePrimName
+        constraintKindRepName
     ]
 
 
@@ -437,10 +437,6 @@ constraintKindRepName  = varQual gHC_TYPES         (fsLit "krep$Constraint") con
 withDictClassName :: Name
 withDictClassName = clsQual gHC_MAGIC_DICT (fsLit "WithDict") withDictClassKey

--- Unsafe coercion proofs
-unsafeCoercePrimName:: Name
-unsafeCoercePrimName    = varQual gHC_INTERNAL_UNSAFE_COERCE (fsLit "unsafeCoerce#") unsafeCoercePrimIdKey
-
 genericClassKeys :: [KnownKey]
 genericClassKeys = [genClassKey, gen1ClassKey]
 


=====================================
compiler/GHC/HsToCore.hs
=====================================
@@ -86,7 +86,6 @@ import GHC.Types.SourceFile
 import GHC.Types.TypeEnv
 import GHC.Types.Name
 import GHC.Types.Name.Set
-import GHC.Types.Name.Env
 import GHC.Types.Name.Ppr
 import GHC.Types.HpcInfo
 
@@ -99,6 +98,7 @@ import Data.List (partition)
 import Data.IORef
 import GHC.Iface.Make (mkRecompUsageInfo)
 import GHC.Runtime.Interpreter (interpreterProfiled)
+import GHC.Types.Unique.FM
 
 {-
 ************************************************************************
@@ -684,13 +684,14 @@ patchMagicDefns pairs
   -- optimization: check whether we're in a magic module before looking
   -- at all the ids
   = do { this_mod <- getModule
+       ; magicDefnModules <- mkMagicDefnModules
        ; if this_mod `elemModuleSet` magicDefnModules
          then traverse patchMagicDefn pairs
          else return pairs }
 
 patchMagicDefn :: (Id, CoreExpr) -> DsM (Id, CoreExpr)
 patchMagicDefn orig_pair@(orig_id, orig_rhs)
-  | Just mk_magic_pair <- lookupNameEnv magicDefnsEnv (getName orig_id)
+  | Just mk_magic_pair <- lookupUFM magicDefnsEnv (getUnique orig_id)
   = do { magic_pair@(magic_id, _) <- mk_magic_pair orig_id orig_rhs
 
        -- Patching should not change the Name or the type of the Id
@@ -701,22 +702,25 @@ patchMagicDefn orig_pair@(orig_id, orig_rhs)
   | otherwise
   = return orig_pair
 
-magicDefns :: [(Name,    Id -> CoreExpr     -- old Id and RHS
+magicDefns :: [(KnownKey,    Id -> CoreExpr     -- old Id and RHS
                       -> DsM (Id, CoreExpr) -- new Id and RHS
                )]
-magicDefns = [ (unsafeCoercePrimName, mkUnsafeCoercePrimPair) ]
+magicDefns = [ (unsafeCoercePrimIdKey, mkUnsafeCoercePrimPair) ]
 
-magicDefnsEnv :: NameEnv (Id -> CoreExpr -> DsM (Id, CoreExpr))
-magicDefnsEnv = mkNameEnv magicDefns
+magicDefnsEnv :: UniqFM KnownKey (Id -> CoreExpr -> DsM (Id, CoreExpr))
+magicDefnsEnv = listToUFM magicDefns
 
-magicDefnModules :: ModuleSet
-magicDefnModules = mkModuleSet $ map (nameModule . getName . fst) magicDefns
+mkMagicDefnModules :: DsM ModuleSet
+mkMagicDefnModules = do
+  mods <- mapM (fmap nameModule . dsLookupKnownKeyName . fst) magicDefns
+  pure $ mkModuleSet mods
 
 mkUnsafeCoercePrimPair :: Id -> CoreExpr -> DsM (Id, CoreExpr)
 -- See Note [Wiring in unsafeCoerce#] for the defn we are creating here
 mkUnsafeCoercePrimPair _old_id old_expr
   = do { unsafe_equality_proof_id <- dsLookupKnownKeyId unsafeEqualityProofIdKey
        ; unsafe_equality_tc       <- dsLookupKnownKeyTyCon unsafeEqualityTyConKey
+       ; unsafeCoercePrimName     <- dsLookupKnownKeyName unsafeCoercePrimIdKey
 
        ; let [unsafe_refl_data_con] = tyConDataCons unsafe_equality_tc
 


=====================================
compiler/GHC/Tc/Module.hs
=====================================
@@ -2566,7 +2566,7 @@ tcGhciStmts stmts
       -- We use Any rather than a dummy type such as () because of
       -- the rules of unsafeCoerce#; see Unsafe/Coerce.hs for the details.
 
-      ; AnId unsafe_coerce_id <- tcLookupGlobal unsafeCoercePrimName
+      ; AnId unsafe_coerce_id <- tcLookupKnownKeyGlobal unsafeCoercePrimIdKey
            -- We use unsafeCoerce# here because of (U11) in
            -- Note [Implementing unsafeCoerce] in base:Unsafe.Coerce
 


=====================================
compiler/GHC/Tc/Utils/Concrete.hs
=====================================
@@ -18,7 +18,7 @@ module GHC.Tc.Utils.Concrete
 
 import GHC.Prelude
 
-import GHC.Builtin.KnownKeys       ( unsafeCoercePrimName )
+import GHC.Builtin.KnownKeys       ( unsafeCoercePrimIdKey )
 import GHC.Builtin.WiredIn.Types
 
 import GHC.Core.Coercion
@@ -45,6 +45,7 @@ import GHC.Utils.Outputable
 import GHC.Data.FastString     ( FastString, fsLit )
 
 import Control.Monad      ( void )
+import GHC.Types.Name (hasKnownKey)
 
 
 {- Note [Concrete overview]
@@ -857,7 +858,7 @@ idConcreteTvs id
   -- in the correct information in the desugarer).
   -- So, for the time being, we manually inspect the type of the original,
   -- unpatched Id to retrieve which of its outer forall-d tyvars should be concrete.
-  | idName id == unsafeCoercePrimName
+  | id `hasKnownKey`unsafeCoercePrimIdKey
   , (a_rep:_b_rep:a:_b:_, _) <- tcSplitForAllTyVars $ idType id
   -- NB: only check the argument representation, not the result representation.
   -- This is because the following is OK:
@@ -866,7 +867,7 @@ idConcreteTvs id
   --   unsafeCoerceWordRep = unsafeCoerce#
   = mkNameEnv
     [(tyVarName a_rep, ConcreteFRR $ FixedRuntimeRepOrigin (mkTyVarTy a)
-                                   $ FRRRepPolyId unsafeCoercePrimName RepPolyFunction
+                                   $ FRRRepPolyId (idName id) RepPolyFunction
                                    $ mkArgPos 1 Top)]
 
   | otherwise


=====================================
libraries/base/src/GHC/Essentials.hs
=====================================
@@ -161,7 +161,7 @@ module GHC.Essentials
     , CS.unpackAppendCStringUtf8#, CS.cstringLength#
     , eqString, inline
 
-    , UnsafeEquality( UnsafeRefl ), unsafeEqualityProof
+    , UnsafeEquality( UnsafeRefl ), unsafeEqualityProof, unsafeCoerce#
 
     -- Typeable and type representations
     , SomeTypeRep( SomeTypeRep ), TR.Module( Module )



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/25497cb478856fc82cdc5277f85eebb6...

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/25497cb478856fc82cdc5277f85eebb6...
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Rodrigo Mesquita (＠alt-romes)

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