The attached file has 4 if statements similar to ...

    if (g1 = g2)

For all 4 if statements, the customer expects the compiler to issue a diagnostic about using = in an if statement, when == is probably intended. In 1 case, a diagnostic is issued. But in the other cases, no diagnostic is issued.

Build it ...

% cl2000 --verbose_diagnostics file.c
"file.c", line 14: warning: use of "=" where "==" may have been intended
      if (arg = 10)   // warning
          ^