unused variable is the warning that causes me the most pain
it happens so often that I want to test or debug something, disable some code, or replace some value by "5" or what not as a placeholder, and then get the unused variable warning
sure, it can be fixed with (void) casts, but sometimes there are multiple unused variables due to commenting out part of code, then you have to hunt all of them
and sure it can be fixed with a flag to disable this warning, but that may require a recompile of everything if the build system considers this a change of compiler flags
and sure you could disable it always, or only for certain modes, but the warning also has its merits
it happens so often that I want to test or debug something, disable some code, or replace some value by "5" or what not as a placeholder, and then get the unused variable warning
sure, it can be fixed with (void) casts, but sometimes there are multiple unused variables due to commenting out part of code, then you have to hunt all of them
and sure it can be fixed with a flag to disable this warning, but that may require a recompile of everything if the build system considers this a change of compiler flags
and sure you could disable it always, or only for certain modes, but the warning also has its merits