Minimal case for foreign allocate issue with wrenEnsureSlot

test.c

#include <stdio.h>
#include "wren.h"

void TEST_allocate(WrenVM* vm) {
  // HERE:
  // Changing the number of slots to be n + 2 where n is the number of arguments
  // for the foreign class constructor causes an error to occur.
  // It looks like Wren get's confused about what the return value
  // is supposed to be.
  wrenEnsureSlots(vm, 2);
  wrenSetSlotNewForeign(vm, 0, 0, sizeof(int*));
  wrenGetSlotHandle(vm, 0);
}

void error(
      WrenVM* vm,
      WrenErrorType type,
      const char* module,
      int line,
      const char* message) {

  printf("Err: %s", message);

}

void write(WrenVM* vm, const char* text)
{
  printf("%s", text);
}

WrenForeignClassMethods bindForeignClass(
   WrenVM* vm, const char* module, const char* className) {

   WrenForeignClassMethods methods;
   methods.allocate = TEST_allocate;
   methods.finalize = NULL;

   return methods;
}

int main() {

  WrenConfiguration config;
  wrenInitConfiguration(&config);
  config.writeFn = write;
  config.errorFn = error;
  config.bindForeignClassFn = bindForeignClass;

  WrenVM* vm = wrenNewVM(&config);

  WrenInterpretResult result = wrenInterpret(
    vm,
    "something",
    "foreign class Test { construct init() {} }\n"
    "System.print(\"Test\")\nTest.init()"
  );

  wrenFreeVM(vm);

  return 0;
}