Downgrade MT2255 warning to a log message Fixes #25670 by rolfbjarne · Pull Request #25696 · dotnet/macios

rolfbjarne · 2026-06-16T08:31:47Z

The MT2255 warning ("Unknown or unsupported Dlfcn pattern") fires when the linker encounters a Dlfcn call pattern it cannot inline. This is not actionable for developers using third-party libraries (like Avalonia) that call Dlfcn directly -- the call still works correctly at runtime, it just won't be inlined for a minor performance optimization.

Since there's nothing the developer can do about it, downgrade from a build warning to a verbose log message (level 3) so it doesn't pollute build output.

Fixes #25670

🤖 Pull request created by Copilot

The MT2255 warning fires for any Dlfcn call pattern we don't support inlining. This is not actionable for developers using third-party libraries (like Avalonia) that call Dlfcn directly in patterns we don't handle. The call still works correctly at runtime - it just won't be inlined. Downgrade from a build warning to a verbose log message (level 3) so it doesn't pollute build output. Fixes #25670 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

rolfbjarne · 2026-06-16T12:32:11Z

/azp run

azure-pipelines · 2026-06-16T12:32:41Z

Azure Pipelines successfully started running 3 pipeline(s).

Copilot

Pull request overview

This PR updates the .NET linker step that inlines ObjCRuntime.Dlfcn patterns to stop emitting MT2255 as a build warning, and instead emit it as a verbosity-level log message, since the pattern is non-actionable for many third-party libraries and does not affect runtime correctness.

Changes:

Replaced MT2255 warning reporting with App.Log (3, ...) messages for unsupported/unrecognized Dlfcn inlining patterns.
Kept additional diagnostic details (e.g., unexpected IL sequences / opcode mismatches) in the verbose logs where applicable.

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rolfbjarne · 2026-06-17T10:59:51Z

/azp run

azure-pipelines · 2026-06-17T11:00:26Z

Azure Pipelines successfully started running 3 pipeline(s).

…2255-to

vs-mobiletools-engineering-service2 · 2026-06-18T10:03:47Z

✅ [CI Build #f5adf5d] Build passed (Build packages) ✅

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Hash: f5adf5d3f53ff743634c516b12b9a9491334c87c [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T10:06:29Z

✅ [CI Build #f5adf5d] Build passed (Detect API changes) ✅

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Hash: f5adf5d3f53ff743634c516b12b9a9491334c87c [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T10:22:24Z

✅ API diff for current PR / commit

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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: f5adf5d3f53ff743634c516b12b9a9491334c87c [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T13:11:39Z

🔥 [CI Build #f5adf5d] Build failed (Build macOS tests) 🔥

Build failed for the job 'Build macOS tests' (with job status 'Canceled')

Pipeline on Agent
Hash: f5adf5d3f53ff743634c516b12b9a9491334c87c [PR build]

vs-mobiletools-engineering-service2 · 2026-06-18T17:01:10Z

🚀 [CI Build #f5adf5d] Test results 🚀

Test results

✅ All tests passed on VSTS: test results.

🎉 All 220 tests passed 🎉

Tests counts

✅ assembly-processing: All 1 tests passed. Html Report (VSDrops) Download
✅ 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. [attempt 4] 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 (iOS): All 15 tests passed. [attempt 2] Html Report (VSDrops) Download
✅ linker (MacCatalyst): All 15 tests passed. Html Report (VSDrops) Download
✅ linker (macOS): All 21 tests passed. Html Report (VSDrops) Download
✅ linker (tvOS): All 15 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 21 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 24 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 24 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 21 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. [attempt 2] Html Report (VSDrops) Download
✅ Tests on macOS Tahoe (26): All 5 tests passed. Html Report (VSDrops) Download

Linux Build Verification

✅ Linux build succeeded

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Hash: f5adf5d3f53ff743634c516b12b9a9491334c87c [PR build]

rolfbjarne added the copilot label Jun 16, 2026

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