SafeUnion

import capstone.api;
import capstone.x86;

auto cs = new CapstoneX86(ModeFlags(Mode.bit32));
auto x86reg = new X86Register(cs, X86RegisterId.eip);

SafeUnion!X86OpValue safeVal;
assertThrown(safeVal.imm);    	   // Not initialised
safeVal.reg = x86reg;
assertThrown(safeVal.imm);    	   // cannot access the `long` since a `X86Register` is currently stored
safeVal.imm = 42;
assertNotThrown(safeVal.imm);      // can access the `long` now

// Corresponding operations on a regular union go unnoticed
X86OpValue unsafeVal;
unsafeVal.reg = x86reg;
assertNotThrown(unsafeVal.imm);