Fix a bug where void returns on upcalls crash the JVM

CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file. This change
 
 ## [Unreleased]
 ### Fixed
+- Void return types on upcalls crash the JVM
 - Invalid implementation of serialize-into for primitive types
 
 ## [0.1.192] - 2021-09-30

src/clj/coffi/mem.clj

@@ -315,7 +315,8 @@
 (defmethod serialize* :default
   [obj type _scope]
   (if-let [prim (primitive-type type)]
-    ((primitive-cast prim) obj)
+    (when-not (= ::void prim)
+      ((primitive-cast prim) obj))
     (throw (ex-info "Attempted to serialize a non-primitive type with primitive methods"
                     {:type type
                      :object obj}))))