SA1010 incorrectly reported on opening bracket in C# 11 list pattern

[jnm2]

// ⚠️ SA1010 Opening square brackets should not be preceded by a space
//                 ↓
if (new[] { 1 } is [1])
{
}

SDK 6.0.200 or newer required. Example csproj:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <LangVersion>preview</LangVersion>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.435">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
  </ItemGroup>

</Project>

[bjornhellander]

@jnm2, can you point to a large public repository that uses patterns extensively and also uses stylecop? Would be good for testing, to see that at least all existing problems in that repo gets fixed before releasing the next beta.

[jnm2]

@bjornhellander Sorry, not off the top of my head.

[alexrp]

FWIW, I use patterns a fair amount in some of my projects and have quite a few StyleCop rules disabled due to bugs (some relating to patterns, some not).

[bjornhellander]

@jnm2 No problem!
@alexrp Excellent. I will have a look. Thanks!

[AArnott]

It shows up in pattern matching within switch expressions as well:

    internal static TransparentAddress? TryParse(ReadOnlySpan<char> address)
    {
        if (address.Length < 2)
        {
            return null;
        }

        Span<byte> decoded = stackalloc byte[DecodedLength];
        Base58Check.Decode(address, decoded);
        return decoded[..2] switch
        {
            [0x1c, 0xb8] or [0x1d, 0x25] => new TransparentP2PKHAddress(address),
            [0x1c, 0xbd] or [0x1C, 0xBA] => new TransparentP2SHAddress(address),
            _ => null,
        };
    }

In the above snippet, SA1010 appears on the [ of [0x1d and [0x1C.

[bjornhellander]

Thanks for the example, @AArnott. The existing pull request should handle this case as well, if it gets merged.