@Test
	public void testNoCyclicDependencyProblemForTypedefPointer() {
		TypeDef typeDef = createTypeDef(union);
		Pointer typedefPointer = createPointer(typeDef, 4);
		try {
			union.add(typedefPointer);
		}
		catch (IllegalArgumentException e) {
			Assert.fail("Should be able to add a union typedef pointer to the pointer's union.");
		}
		try {
			union.insert(0, typedefPointer);
		}
		catch (IllegalArgumentException e) {
			Assert.fail(
				"Should be able to insert a union typedef pointer into the pointer's union.");
		}
	}
Test that a union can contain a pointer in it to a typedef of the same union.
Ghidra/Features/Base/src/test/java/ghidra/program/model/data/UnionDataTypeTest.java