Created attachment 232100 [details]
Testcase

I stumbled on it while trying to generate docs for Firefox, here's a minimized testcase:

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[a.cpp]
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#include "a.h"

#define N(f)

enum e {
  #define M N
  #include "a.h"
};

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[a.h]
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#define M

M(
    A |
    //'
    B
)

#undef M

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With MACRO_EXPANSION enabled (all other settings are default), this example causes Doxygen 1.8.2 to stall on preprocessing a.cpp (100% core usage, runs infinitely).

OS: Windows 7 SP1