diff --git a/haskell/exe/Main.hs b/haskell/exe/Main.hs
index e4250fe..0b25177 100644
--- a/haskell/exe/Main.hs
+++ b/haskell/exe/Main.hs
@@ -1,22 +1,14 @@
 module Main (main) where
 
 import Data.ByteString
-import Foreign
 import Foreign.C
 import GarnetRs
 import GarnetRs.Safe
-import HsBindgen.Runtime.Marshal
 import HsBindgen.Runtime.PtrConst
 
 main :: IO ()
 main = do
     useAsCString "Haskell" $ hello . unsafeFromPtr
-    alloca \ptr -> do
-        writeRaw ptr T{a = CBool 1, b = 42}
-        hello_struct (unsafeFromPtr ptr)
-    alloca \ptr -> do
-        writeRaw ptr (Shape (Shape_Tag 0) (set_shape_body_circle (Circle_Body 3.14)))
-        hello_shape (unsafeFromPtr ptr)
-    alloca \ptr -> do
-        writeRaw ptr (Shape (Shape_Tag 1) (set_shape_body_rectangle (Rectangle_Body 10.0 5.0)))
-        hello_shape (unsafeFromPtr ptr)
+    hello_struct T{a = CBool 1, b = 42}
+    hello_shape $ Shape (Shape_Tag 0) $ set_shape_body_circle $ Circle_Body 3.14
+    hello_shape $ Shape (Shape_Tag 1) $ set_shape_body_rectangle $ Rectangle_Body 10.0 5.0
diff --git a/haskell/generated/GarnetRs/FunPtr.hs b/haskell/generated/GarnetRs/FunPtr.hs
index 432fe38..13f202f 100644
--- a/haskell/generated/GarnetRs/FunPtr.hs
+++ b/haskell/generated/GarnetRs/FunPtr.hs
@@ -28,7 +28,7 @@ $(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.un
   , "/* com_garnet_GarnetRs_get_hello_struct */"
   , "__attribute__ ((const))"
   , "void (*hs_bindgen_0f8c37ef19b17a6d (void)) ("
-  , "  struct T const *arg1"
+  , "  struct T arg1"
   , ")"
   , "{"
   , "  return &hello_struct;"
@@ -36,7 +36,7 @@ $(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.un
   , "/* com_garnet_GarnetRs_get_hello_shape */"
   , "__attribute__ ((const))"
   , "void (*hs_bindgen_287ff3ac660f333b (void)) ("
-  , "  struct Shape const *arg1"
+  , "  struct Shape arg1"
   , ")"
   , "{"
   , "  return &hello_shape;"
@@ -68,7 +68,7 @@ foreign import ccall unsafe "hs_bindgen_0f8c37ef19b17a6d" hs_bindgen_0f8c37ef19b
      IO (Ptr.FunPtr Void)
 
 -- __unique:__ @com_garnet_GarnetRs_get_hello_struct@
-hs_bindgen_0f8c37ef19b17a6d :: IO (Ptr.FunPtr ((HsBindgen.Runtime.PtrConst.PtrConst T) -> IO ()))
+hs_bindgen_0f8c37ef19b17a6d :: IO (Ptr.FunPtr (T -> IO ()))
 hs_bindgen_0f8c37ef19b17a6d =
   HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_0f8c37ef19b17a6d_base
 
@@ -79,7 +79,7 @@ hs_bindgen_0f8c37ef19b17a6d =
 
     __exported by:__ @garnet_rs.h@
 -}
-hello_struct :: Ptr.FunPtr ((HsBindgen.Runtime.PtrConst.PtrConst T) -> IO ())
+hello_struct :: Ptr.FunPtr (T -> IO ())
 hello_struct =
   GHC.IO.Unsafe.unsafePerformIO hs_bindgen_0f8c37ef19b17a6d
 
@@ -88,7 +88,7 @@ foreign import ccall unsafe "hs_bindgen_287ff3ac660f333b" hs_bindgen_287ff3ac660
      IO (Ptr.FunPtr Void)
 
 -- __unique:__ @com_garnet_GarnetRs_get_hello_shape@
-hs_bindgen_287ff3ac660f333b :: IO (Ptr.FunPtr ((HsBindgen.Runtime.PtrConst.PtrConst Shape) -> IO ()))
+hs_bindgen_287ff3ac660f333b :: IO (Ptr.FunPtr (Shape -> IO ()))
 hs_bindgen_287ff3ac660f333b =
   HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_287ff3ac660f333b_base
 
@@ -99,6 +99,6 @@ hs_bindgen_287ff3ac660f333b =
 
     __exported by:__ @garnet_rs.h@
 -}
-hello_shape :: Ptr.FunPtr ((HsBindgen.Runtime.PtrConst.PtrConst Shape) -> IO ())
+hello_shape :: Ptr.FunPtr (Shape -> IO ())
 hello_shape =
   GHC.IO.Unsafe.unsafePerformIO hs_bindgen_287ff3ac660f333b
diff --git a/haskell/generated/GarnetRs/Safe.hs b/haskell/generated/GarnetRs/Safe.hs
index de1581a..202fdf0 100644
--- a/haskell/generated/GarnetRs/Safe.hs
+++ b/haskell/generated/GarnetRs/Safe.hs
@@ -5,6 +5,7 @@
 
 module GarnetRs.Safe where
 
+import qualified Foreign as F
 import qualified Foreign.C as FC
 import qualified GHC.Ptr as Ptr
 import qualified HsBindgen.Runtime.Internal.CAPI
@@ -23,16 +24,16 @@ $(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.un
   , "  hello(arg1);"
   , "}"
   , "void hs_bindgen_51157946af5519c9 ("
-  , "  struct T const *arg1"
+  , "  struct T *arg1"
   , ")"
   , "{"
-  , "  hello_struct(arg1);"
+  , "  hello_struct(*arg1);"
   , "}"
   , "void hs_bindgen_7de06f1fd827ca60 ("
-  , "  struct Shape const *arg1"
+  , "  struct Shape *arg1"
   , ")"
   , "{"
-  , "  hello_shape(arg1);"
+  , "  hello_shape(*arg1);"
   , "}"
   ]))
 
@@ -67,7 +68,7 @@ foreign import ccall safe "hs_bindgen_51157946af5519c9" hs_bindgen_51157946af551
 
 -- __unique:__ @com_garnet_GarnetRs_Safe_hello_struct@
 hs_bindgen_51157946af5519c9 ::
-     HsBindgen.Runtime.PtrConst.PtrConst T
+     Ptr.Ptr T
   -> IO ()
 hs_bindgen_51157946af5519c9 =
   HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_51157946af5519c9_base
@@ -79,10 +80,12 @@ hs_bindgen_51157946af5519c9 =
     __exported by:__ @garnet_rs.h@
 -}
 hello_struct ::
-     HsBindgen.Runtime.PtrConst.PtrConst T
+     T
      -- ^ __C declaration:__ @t@
   -> IO ()
-hello_struct = hs_bindgen_51157946af5519c9
+hello_struct =
+  \t0 ->
+    F.with t0 (\t1 -> hs_bindgen_51157946af5519c9 t1)
 
 -- __unique:__ @com_garnet_GarnetRs_Safe_hello_shape@
 foreign import ccall safe "hs_bindgen_7de06f1fd827ca60" hs_bindgen_7de06f1fd827ca60_base ::
@@ -91,7 +94,7 @@ foreign import ccall safe "hs_bindgen_7de06f1fd827ca60" hs_bindgen_7de06f1fd827c
 
 -- __unique:__ @com_garnet_GarnetRs_Safe_hello_shape@
 hs_bindgen_7de06f1fd827ca60 ::
-     HsBindgen.Runtime.PtrConst.PtrConst Shape
+     Ptr.Ptr Shape
   -> IO ()
 hs_bindgen_7de06f1fd827ca60 =
   HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_7de06f1fd827ca60_base
@@ -103,7 +106,9 @@ hs_bindgen_7de06f1fd827ca60 =
     __exported by:__ @garnet_rs.h@
 -}
 hello_shape ::
-     HsBindgen.Runtime.PtrConst.PtrConst Shape
+     Shape
      -- ^ __C declaration:__ @s@
   -> IO ()
-hello_shape = hs_bindgen_7de06f1fd827ca60
+hello_shape =
+  \s0 ->
+    F.with s0 (\s1 -> hs_bindgen_7de06f1fd827ca60 s1)
diff --git a/haskell/generated/GarnetRs/Unsafe.hs b/haskell/generated/GarnetRs/Unsafe.hs
index 2aec563..bc0034d 100644
--- a/haskell/generated/GarnetRs/Unsafe.hs
+++ b/haskell/generated/GarnetRs/Unsafe.hs
@@ -5,6 +5,7 @@
 
 module GarnetRs.Unsafe where
 
+import qualified Foreign as F
 import qualified Foreign.C as FC
 import qualified GHC.Ptr as Ptr
 import qualified HsBindgen.Runtime.Internal.CAPI
@@ -23,16 +24,16 @@ $(HsBindgen.Runtime.Internal.CAPI.addCSource (HsBindgen.Runtime.Internal.CAPI.un
   , "  hello(arg1);"
   , "}"
   , "void hs_bindgen_29d823ada2bc7302 ("
-  , "  struct T const *arg1"
+  , "  struct T *arg1"
   , ")"
   , "{"
-  , "  hello_struct(arg1);"
+  , "  hello_struct(*arg1);"
   , "}"
   , "void hs_bindgen_b3f40a03f07eaa85 ("
-  , "  struct Shape const *arg1"
+  , "  struct Shape *arg1"
   , ")"
   , "{"
-  , "  hello_shape(arg1);"
+  , "  hello_shape(*arg1);"
   , "}"
   ]))
 
@@ -67,7 +68,7 @@ foreign import ccall unsafe "hs_bindgen_29d823ada2bc7302" hs_bindgen_29d823ada2b
 
 -- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_struct@
 hs_bindgen_29d823ada2bc7302 ::
-     HsBindgen.Runtime.PtrConst.PtrConst T
+     Ptr.Ptr T
   -> IO ()
 hs_bindgen_29d823ada2bc7302 =
   HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_29d823ada2bc7302_base
@@ -79,10 +80,12 @@ hs_bindgen_29d823ada2bc7302 =
     __exported by:__ @garnet_rs.h@
 -}
 hello_struct ::
-     HsBindgen.Runtime.PtrConst.PtrConst T
+     T
      -- ^ __C declaration:__ @t@
   -> IO ()
-hello_struct = hs_bindgen_29d823ada2bc7302
+hello_struct =
+  \t0 ->
+    F.with t0 (\t1 -> hs_bindgen_29d823ada2bc7302 t1)
 
 -- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_shape@
 foreign import ccall unsafe "hs_bindgen_b3f40a03f07eaa85" hs_bindgen_b3f40a03f07eaa85_base ::
@@ -91,7 +94,7 @@ foreign import ccall unsafe "hs_bindgen_b3f40a03f07eaa85" hs_bindgen_b3f40a03f07
 
 -- __unique:__ @com_garnet_GarnetRs_Unsafe_hello_shape@
 hs_bindgen_b3f40a03f07eaa85 ::
-     HsBindgen.Runtime.PtrConst.PtrConst Shape
+     Ptr.Ptr Shape
   -> IO ()
 hs_bindgen_b3f40a03f07eaa85 =
   HsBindgen.Runtime.Internal.HasFFIType.fromFFIType hs_bindgen_b3f40a03f07eaa85_base
@@ -103,7 +106,9 @@ hs_bindgen_b3f40a03f07eaa85 =
     __exported by:__ @garnet_rs.h@
 -}
 hello_shape ::
-     HsBindgen.Runtime.PtrConst.PtrConst Shape
+     Shape
      -- ^ __C declaration:__ @s@
   -> IO ()
-hello_shape = hs_bindgen_b3f40a03f07eaa85
+hello_shape =
+  \s0 ->
+    F.with s0 (\s1 -> hs_bindgen_b3f40a03f07eaa85 s1)
diff --git a/rust/garnet_rs.h b/rust/garnet_rs.h
index 80da9bd..92cfeeb 100644
--- a/rust/garnet_rs.h
+++ b/rust/garnet_rs.h
@@ -31,6 +31,6 @@ typedef struct Shape {
 
 void hello(const char *c);
 
-void hello_struct(const struct T *t);
+void hello_struct(struct T t);
 
-void hello_shape(const struct Shape *s);
+void hello_shape(struct Shape s);
diff --git a/rust/lib.rs b/rust/lib.rs
index e84bdbc..533a443 100644
--- a/rust/lib.rs
+++ b/rust/lib.rs
@@ -16,7 +16,7 @@ struct T {
     b: u8,
 }
 #[unsafe(no_mangle)]
-extern "C" fn hello_struct(t: &T) -> () {
+extern "C" fn hello_struct(t: T) -> () {
     say_hello(&format!("{:?}", t))
 }
 
@@ -29,6 +29,6 @@ enum Shape {
 }
 
 #[unsafe(no_mangle)]
-extern "C" fn hello_shape(s: &Shape) -> () {
+extern "C" fn hello_shape(s: Shape) -> () {
     say_hello(&format!("{:?}", s))
 }