allow array references in areturn

c/execute.c

@@ -80,7 +80,7 @@ void op_anewarray(struct vm * vm, uint32_t index)
 
 void op_areturn(struct vm * vm)
 {
-  assert(vm->current_frame->return_type == 'L');
+  assert(vm->current_frame->return_type == 'L' || vm->current_frame->return_type == '[');
   vm_method_return(vm);
 }
 

c/frame.c

@@ -321,7 +321,8 @@ void vm_method_return(struct vm * vm)
   case 'I': [[fallthrough]];
   case 'L': [[fallthrough]];
   case 'S': [[fallthrough]];
-  case 'Z':
+  case 'Z': [[fallthrough]];
+  case '[':
     {
       uint32_t value = operand_stack_pop_u32(old_frame);
       operand_stack_push_u32(vm->current_frame, value);

p/TestArray.java

@@ -0,0 +1,17 @@
+package p;
+
+class TestArray {
+    static char[] test() {
+        char[] a = {'a', 'b', 'c', 'd'};
+        return a;
+    }
+
+    static char test2(char[] c) {
+        return (char)((int)(c[0]) * 2);
+    }
+
+    public static void main() {
+        char[] a = test();
+        test2(a);
+    }
+}