Relax monad in conversion to ForeignPtr

lehins · Apr 2, 2020 · 16e2617 · 16e2617
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diff --git a/pvar/CHANGELOG.md b/pvar/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog for pvar
 
+## 0.2.x
+
+* Relax monad in conversion to ForeignPtr
+
 ## 0.2.0.0
 
 * Rename `modifyPVar` to `fetchModifyPVar` and `modifyPVarM` to `fetchModifyPVarM`. This

diff --git a/pvar/src/Data/Primitive/PVar.hs b/pvar/src/Data/Primitive/PVar.hs
@@ -132,7 +132,7 @@ withPtrPVar pvar f =
 -- | Convert `PVar` into a `ForeignPtr`, but only if it is backed by pinned memory.
 --
 -- @since 0.1.0
-toForeignPtrPVar :: PVar IO a -> Maybe (ForeignPtr a)
+toForeignPtrPVar :: PVar m a -> Maybe (ForeignPtr a)
 toForeignPtrPVar pvar
   | isPinnedPVar pvar = Just $ unsafeToForeignPtrPVar pvar
   | otherwise = Nothing

diff --git a/pvar/src/Data/Primitive/PVar/Unsafe.hs b/pvar/src/Data/Primitive/PVar/Unsafe.hs
@@ -61,10 +61,10 @@ import Data.Typeable
 -- | Convert `PVar` into a `ForeignPtr`, very unsafe if not backed by pinned memory.
 --
 -- @since 0.1.0
-unsafeToForeignPtrPVar :: PVar IO a -> ForeignPtr a
+unsafeToForeignPtrPVar :: PVar m a -> ForeignPtr a
 unsafeToForeignPtrPVar pvar@(PVar mba#) =
   case unsafeToPtrPVar pvar of
-    Ptr addr# -> ForeignPtr addr# (PlainPtr mba#)
+    Ptr addr# -> ForeignPtr addr# (PlainPtr (unsafeCoerce# mba#))
 {-# INLINE unsafeToForeignPtrPVar #-}