Add missing serializability checks for interfaces (#12483)

* Add missing serializability checks for interfaces The checks for argument & result type were missing before. I openey #12482 to do the same fix on the Scala side. fixes #12475 changelog_begin changelog_end * . changelog_begin changelog_end
digital-asset · Jan 19, 2022 · 681f8fc · 681f8fc
1 parent 7c59728
commit 681f8fc
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diff --git a/compiler/daml-lf-tools/src/DA/Daml/LF/TypeChecker/Serializability.hs b/compiler/daml-lf-tools/src/DA/Daml/LF/TypeChecker/Serializability.hs
@@ -161,6 +161,15 @@ checkTemplate mod0 tpl = do
   for_ (tplKey tpl) $ \key -> withContext (ContextTemplate mod0 tpl TPKey) $ do
     checkType SRKey (tplKeyType key)
 
+-- | Check whether a template satisfies all serializability constraints.
+checkInterface :: MonadGamma m => Module -> DefInterface -> m ()
+checkInterface _mod0 iface = do
+  -- TODO https://github.com/digital-asset/daml/issues/12051
+  -- Add per interface choice context.
+  for_ (intFixedChoices iface) $ \ch -> do
+      checkType SRChoiceArg (snd (chcArgBinder ch))
+      checkType SRChoiceRes (chcReturnType ch)
+
 -- | Check whether exception is serializable.
 checkException :: MonadGamma m => Module -> DefException -> m ()
 checkException mod0 exn = do
@@ -179,3 +188,6 @@ checkModule mod0 = do
   for_ (moduleExceptions mod0) $ \exn ->
     withContext (ContextDefException mod0 exn) $
       checkException mod0 exn
+  for_ (moduleInterfaces mod0) $ \iface ->
+    withContext (ContextDefInterface mod0 iface) $
+      checkInterface mod0 iface
diff --git a/compiler/damlc/tests/daml-test-files/InterfaceSerializabilityArgument.daml b/compiler/damlc/tests/daml-test-files/InterfaceSerializabilityArgument.daml
@@ -0,0 +1,21 @@
+-- @SINCE-LF-FEATURE DAML_INTERFACE
+-- @ERROR expected serializable type
+module InterfaceSerializabilityArgument where
+
+data NonSerializable = NonSerializable (() -> ())
+
+-- Dummy Eq and Show instances so we blow up in the serializability checker rather than
+-- the GHC typechecker.
+
+instance Eq NonSerializable where
+  (==) = error "undefined"
+instance Show NonSerializable where
+  show = error "undefined"
+
+interface I where
+   p : Party
+
+   choice NonSerializableArgument : ()
+     with f : NonSerializable
+     controller p this
+     do pure ()
diff --git a/compiler/damlc/tests/daml-test-files/InterfaceSerializabilityResult.daml b/compiler/damlc/tests/daml-test-files/InterfaceSerializabilityResult.daml
@@ -0,0 +1,20 @@
+-- @SINCE-LF-FEATURE DAML_INTERFACE
+-- @ERROR expected serializable type
+module InterfaceSerializabilityResult where
+
+data NonSerializable = NonSerializable (() -> ())
+
+-- Dummy Eq and Show instances so we blow up in the serializability checker rather than
+-- the GHC typechecker.
+
+instance Eq NonSerializable where
+  (==) = error "undefined"
+instance Show NonSerializable where
+  show = error "undefined"
+
+interface I where
+   p : Party
+
+   choice NonSerializableResult : NonSerializable
+     controller p this
+     do pure (NonSerializable identity)