PVS-Studio warning V547 for TinyCAD

void CBOMGenerator::GenerateBomForDesign(
  int level, size_t parentPos, ....)
{
  ....
  if (parentPos >= 0) cmrParent = cmrDefaultParent;
  ....
}

This suspicious code was found in TinyCAD project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression 'parentPos >= 0' is always true. Unsigned type value is always >= 0. bomgenerator.cpp 77

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