diff --git a/wasm/wat.ml b/wasm/wat.ml
index 73183b0ed..db8fecdb6 100644
--- a/wasm/wat.ml
+++ b/wasm/wat.ml
@@ -311,12 +311,12 @@ module C = struct
     nodehv "loop" [ !$(Block_id.name id); results result ] body
 
   let br id args =
-    node "br" ([ !$(Block_id.name id) ] @ args)
+    node "br" [ !$(Block_id.name id); node "tuple.make" args ]
 
   let br' id = node "br" [ !$(Block_id.name id) ]
 
   let return args =
-    node "return" args
+    node "return" [ node "tuple.make" args ]
 
   let br_on_cast id typ arg =
     node "br_on_cast" [ !$(Block_id.name id); type_name typ; arg ]
@@ -347,7 +347,7 @@ module C = struct
     node "sub" [ type_name name; descr ]
 
   let opt_tuple fields =
-    fields
+    [ node "tuple.make" fields ]
 
   let tuple_make fields = node "tuple.make" fields