PVS-Studio warning V519 for Clang

LangOptions() {
  ...
  SignedOverflowBehavior = SOB_Undefined;

  AssumeSaneOperatorNew = 1;
  AccessControl = 1;
  ElideConstructors = 1;

  SignedOverflowBehavior = 0;
  ...
}

This suspicious code was found in Clang project by PVS-Studio static code analyzer.
Warning message is:
V519 The 'SignedOverflowBehavior' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 207, 213. FrontendTests langoptions.h 213

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