message: Add explicit param onto operator bool() to not accidentally cast to int
diff: @@ -60,7 +60,7 @@ public:
  return *this;
  }
  // utility functions
  - operator bool() const { return words != NULL && offset < words->size(); }
  + explicit operator bool() const { return words != NULL && offset < words->size(); }
  uint32_t &operator*() { return cur(); }
  const uint32_t &operator*() const { return cur(); }
  spv::Op opcode() { return spv::Op(cur() & spv::OpCodeMask); }
  