CA1416 with guard attributes

[rolfbjarne]

Analyzer

Diagnostic ID: warning CA1416: This call site is reachable on: 'macOS/OSX', 'tvos' 12.2 and later. 'TestType.GpuRegistryId' is only supported on: 'tvos' 13.0 and later.

Analyzer source

SDK: Built-in CA analyzers in .NET 5 SDK or later

$ .dotnet/dotnet --version
10.0.100-preview.3.25167.3

Describe the bug

Incorrect CA1416 when trying to access API in code block protected using guard attributes.

Steps To Reproduce

Run this unit test: rolfbjarne@3c8fed4

Expected behavior

Unit test should pass

Actual behavior

Unit test fails:

Diagnostics:
// /0/Test0.cs(13,32): warning CA1416: This call site is reachable on: 'macOS/OSX', 'tvos' 12.2 and later. 'TestType.GpuRegistryId' is only supported on: 'tvos' 13.0 and later.

Additional context

This is not fixed by #7569 nor #7644.

[rolfbjarne]

CC @buyaa-n

[buyaa-n]

This is not fixed by #7569 nor #7644.

This is related to #7569

It is kind of an annotation issue, in the repro you shared GpuRegistryId attribute support list will have "tvos13.0" and "macos12.0". The [SupportedOSPlatform ("macos")] attribute on the property will be ignored because assembly has [SupportedOSPlatform ("macos12.0")] attribute and child (nested) API could not widen that support.

On the other side the Guard attributes will process [SupportedPlatformGuard ("macos")] and [SupportedOSPlatformGuard ("tvos13.0")] as is, because flow analysis doesn't evaluate parent (assembly) attributes.

That means the if (IsAtLeastXcode11) { } block is reachable on macos0.0 and tvos13.0 but the referenced API GpuRegistryId is only supported on "tvos13.0" and "macos12.0". If the guard had [SupportedOSPlatformGuard ("macos12.0")] or above instead of [SupportedOSPlatformGuard ("macos")] there should have been no issue

using System;
using System.Runtime.Versioning;

// removing the assembly: attributes make the test work
[assembly: SupportedOSPlatform ("tvos12.2")]
[assembly: SupportedOSPlatform ("macos12.0")]

partial class TestType {
    void DoSomething ()
    {
        if (IsAtLeastXcode11) {
            Console.WriteLine (GpuRegistryId); // warns here because guard allows `macos0.0` but API is supported from `macos12.0`
        }
    }

    [SupportedOSPlatform ("macos")]
    [SupportedOSPlatform ("tvos13.0")]
    public ulong? GpuRegistryId { get; private set; }

    [SupportedOSPlatformGuard ("macos")]
    [SupportedOSPlatformGuard ("tvos13.0")]
    internal static bool IsAtLeastXcode11 {
        get {
            return true;
        }
    }
}

Not sure if we want to tweak the analyzer for this or ask the user to add a proper guard, i.e [SupportedOSPlatformGuard ("macos12.0")]

[rolfbjarne]

ask the user to add a proper guard, i.e [SupportedOSPlatformGuard ("macos12.0")]

I can do that, thanks for the analysis!