This looks similar to JDK-8153870, but for arguments.

See the test:

    private static final VarHandle VH_LONG = MethodHandles.byteBufferViewVarHandle(
            long[].class, java.nio.ByteOrder.nativeOrder());

    ByteBuffer buffer;

    @Setup
    public void setup() {
        buffer = ByteBuffer.allocateDirect(3 * 1024).alignedSlice(8);
    }

    @Benchmark
    public void test_int() {
        for (int i = 0; i < 100; i++) {
            VH_LONG.set(buffer, i, i);
        }
    }

    @Benchmark
    public void test_long() {
        for (int i = 0; i < 100; i++) {
            VH_LONG.set(buffer, i, (long) i);
        }
    }

Benchmark                 Mode  Cnt     Score   Error  Units
VHLongMismatch.test_int   avgt    5  1370.022 ± 0.350  ns/op
VHLongMismatch.test_long  avgt    5    41.471 ± 0.537  ns/op

33x performance hit.

Tests:
  http://cr.openjdk.java.net/~shade/8160821/VHLongMismatch.java
  http://cr.openjdk.java.net/~shade/8160821/benchmarks.jar