Option to fail on warnings

I would like to propose an option that could make the compiler fail if at least one warning is encountered, regardless of errors and exit with a non-zero exit code.

This could be a simple flags such as --fail-on-warnings or a more sophisticated setting like --error-level that could introduce more granular control, i.e. still exit with 0 if compilation failed with errors.

Use case for this is either a purist approach when no warnings are tolerated or code quality control CI job that verifies new code with --checks-only.