[msbuild] Ignore CS1685 in Xamarin.MacDev.Tasks tests.

[rolfbjarne]

Also treat all warnings as errors, since this project is now warning-free.

[Copilot]

Pull request overview

Updates the Xamarin.MacDev.Tasks MSBuild test project configuration to suppress a known compiler warning from ILMerged task assemblies and to enforce a warning-free build by promoting warnings to errors.

Changes:

• Add CS1685 to NoWarn to ignore the duplicate ImmutableArray<T> warning.
• Enable <TreatWarningsAsErrors>true</TreatWarningsAsErrors> (replacing the previous WarningsAsErrors=Nullable behavior).

[vs-mobiletools-engineering-service2]

✅ [CI Build #c5304fe] Build passed (Build packages) ✅

Pipeline on Agent
Hash: c5304fef4f0cbe99940f0b4069ef0defa5524f7f [PR build]

[vs-mobiletools-engineering-service2]

✅ [PR Build #c5304fe] Build passed (Detect API changes) ✅

Pipeline on Agent
Hash: c5304fef4f0cbe99940f0b4069ef0defa5524f7f [PR build]

[vs-mobiletools-engineering-service2]

✅ API diff for current PR / commit

NET (empty diffs)

• iOS: vsdrops gist ( No breaking changes )
• tvOS: vsdrops gist ( No breaking changes )
• MacCatalyst: vsdrops gist ( No breaking changes )
• macOS: vsdrops gist ( No breaking changes )

✅ API diff vs stable

NET (empty diffs)

• iOS: vsdrops gist ( No breaking changes )
• tvOS: vsdrops gist ( No breaking changes )
• MacCatalyst: vsdrops gist ( No breaking changes )
• macOS: vsdrops gist ( No breaking changes )

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

Pipeline on Agent
Hash: c5304fef4f0cbe99940f0b4069ef0defa5524f7f [PR build]

[vs-mobiletools-engineering-service2]

✅ [CI Build #c5304fe] Build passed (Build macOS tests) ✅

Pipeline on Agent
Hash: c5304fef4f0cbe99940f0b4069ef0defa5524f7f [PR build]

[vs-mobiletools-engineering-service2]

🚀 [CI Build #c5304fe] Test results 🚀

Test results

✅ All tests passed on VSTS: test results.

🎉 All 156 tests passed 🎉

Tests counts

✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (macOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 5 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ introspection: All 6 tests passed. Html Report (VSDrops) Download
✅ linker: All 44 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 11 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 15 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 12 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 11 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ sharpie: All 1 tests passed. Html Report (VSDrops) Download
✅ windows: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

macOS tests

✅ Tests on macOS Monterey (12): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Ventura (13): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Sonoma (14): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Sequoia (15): All 5 tests passed. Html Report (VSDrops) Download
✅ Tests on macOS Tahoe (26): All 5 tests passed. Html Report (VSDrops) Download

Linux Build Verification

✅ Linux build succeeded

Pipeline on Agent
Hash: c5304fef4f0cbe99940f0b4069ef0defa5524f7f [PR build]