[wpiutil] Fix wpi::array for move-only types (#3917)

Fixes #3916.

wpiutil/src/test/native/cpp/ArrayTest.cpp

@@ -0,0 +1,30 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#include "gtest/gtest.h"
+#include "wpi/array.h"
+
+namespace {
+class MoveOnlyType {
+ public:
+  MoveOnlyType() = default;
+  MoveOnlyType(MoveOnlyType&&) = default;
+  MoveOnlyType& operator=(MoveOnlyType&&) = default;
+};
+}  // namespace
+
+TEST(ArrayTest, CopyableTypeCompiles) {
+  wpi::array<int, 3> arr1{1, 2, 3};
+
+  // Test deduction guide
+  wpi::array ar2{1, 2, 3};
+}
+
+TEST(ArrayTest, MoveOnlyTypeCompiles) {
+  wpi::array<MoveOnlyType, 3> arr1{MoveOnlyType{}, MoveOnlyType{},
+                                   MoveOnlyType{}};
+
+  // Test deduction guide
+  wpi::array arr2{MoveOnlyType{}, MoveOnlyType{}, MoveOnlyType{}};
+}