Made some FFI related code evaluate things more.

- Previously some foreign values were wrapped up as thunks, which moved
  around where runtime errors occured a bit.

parser-typechecker/src/Unison/Runtime/Foreign.hs

@@ -33,7 +33,7 @@ import qualified Crypto.Hash as Hash
 import Unsafe.Coerce
 
 data Foreign where
-  Wrap :: Reference -> e -> Foreign
+  Wrap :: Reference -> !e -> Foreign
 
 promote :: (a -> a -> r) -> b -> c -> r
 promote (~~) x y = unsafeCoerce x ~~ unsafeCoerce y

parser-typechecker/src/Unison/Runtime/Foreign/Function.hs

@@ -16,6 +16,7 @@ import GHC.IO.Exception (IOException(..), IOErrorType(..))
 import Control.Concurrent (ThreadId)
 import Control.Concurrent.MVar (MVar)
 import Control.Concurrent.STM (TVar)
+import Control.Exception (evaluate)
 import qualified Data.Char as Char
 import Data.Foldable (toList)
 import Data.Text (Text, pack, unpack)
@@ -95,7 +96,7 @@ instance ForeignConvention Closure where
   readForeign _  [    ] _ _    = foreignCCError "Closure"
   writeForeign ustk bstk c = do
     bstk <- bump bstk
-    (ustk, bstk) <$ poke bstk c
+    (ustk, bstk) <$ (poke bstk =<< evaluate c)
 
 instance ForeignConvention Text where
   readForeign = readForeignBuiltin