With MACRO_EXPANSION=yes, in the following simplified example, the entries for VAR_MACRO1 expand, while the first entry for VAR_MACRO2 does not.  The C++ preprocessor considers all of them correct syntax, so the expected result is that each macro would expand.  (Thanks for taking a look.)

/// \file simpletest.h

#define VAR_MACRO1(...) void DemoFunction1(__VA_ARGS__) { }

VAR_MACRO1();
VAR_MACRO1(int x);
VAR_MACRO1(int x, float y);

#define VAR_MACRO2(T, ...) T DemoFunction2(__VA_ARGS__) { }

VAR_MACRO2(void);
VAR_MACRO2(void, int x);
VAR_MACRO2(void, int x, float y);

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The documentation generated looks like:

void 	DemoFunction1 ()
void 	DemoFunction1 (int x)
void 	DemoFunction1 (int x, float y)
 	VAR_MACRO2 (void)
void 	DemoFunction2 (int x)
void 	DemoFunction2 (int x, float y)