Package: gnat-4.1 Severity: important <built-in>:0: warning: 'const' attribute directive ignored <built-in>:0: warning: 'nothrow' attribute directive ignored <built-in>:0: warning: 'nothrow' attribute directive ignored <built-in>:0: warning: 'const' attribute directive ignored [...] The check tests for the error code _and_ for the compiler stderr output, and then assumes that the driver doesn't understand Ada.