PVS-Studio warning V519 for ReactOS

#define SWAP(a,b,c)  c = a;\
                     a = b;\
                     a = c

BOOL FASTCALL
IntEngGradientFillTriangle(....)
{
  ...
  SWAP(v2,v3,t);
  ...
}

Masterpiece! This is what should have been written here: c = a; a = b; b = c;

This suspicious code was found in ReactOS project by PVS-Studio static code analyzer.
Warning message is:
V519 The 'v2' variable is assigned values twice successively. Perhaps this is a mistake. Check lines: 343, 343. win32k gradient.c 343

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/