Flags validation fails

In attachment is the test program for triggering the bug.

Compilation: gcc -o test test.c $(pkg-config --cflags --libs gobject-2.0)

Run: ./test

Set: 0x0
Got: 0x0

Set: 0x1
Got: 0x1


(process:25614): GLib-GObject-WARNING **: value "((TestFlags) HIGHEST_FLAG)" of type 'TestFlags' is invalid or out of range for property 'test-property' of type 'TestFlags'
Set: 0x80000000
Got: 0x0


(process:25614): GLib-GObject-WARNING **: value "((TestFlags) LOWEST_FLAG | HIGHEST_FLAG)" of type 'TestFlags' is invalid or out of range for property 'test-property' of type 'TestFlags'
Set: 0x80000001
Got: 0x0

test.c