C# nullable reference types and TreatWarningsAsErrors across the solution

[indcoder]

Enable C# nullable reference types and treat warnings as errors across the solution to improve null-safety and catch issues earlier in development.

Why

• Nullable enables C#'s null-reference static analysis:
  • Warns about potential null reference issues
  • Forces explicit handling of nullable types
  • Makes null safety visible in your code
• TreatWarningsAsErrors turns warnings into build failures:
  • Code won't compile until null issues (and other warnings) are fixed
  • Catches problems during development rather than production

Proposal
Add these settings to a Directory.Build.props file placed next to the solution (.sln) so they apply to all projects:

Suggested Directory.Build.props


enable
true

Suggested rollout checklist

• Add Directory.Build.props (near solution file) with above settings
• Run solution build to collect warnings
• Fix null-related and other warnings or suppress justified ones
• Create PR with changes and request reviews
• Optionally: add a CI job to ensure builds fail on warnings