uncrustify is not a compiler.

Let have a look on:

# if A
   int abc( int a, int b, int c)
   {
      // do something
# else
   int abc( int a, int b)
   {
      // do something else
# endif
   }

It will produce an error, because uncrustify doesn't evaluate the value of A.
uncrustify will read all the lines, a compiler only a part of it, depending on A.

uncrustify encounter two opening braces but only one closing brace.