Regression in .NET 9 RC2: IDE0052 reports false positive with source-generated method

[bart-vmware]

Version Used:
.NET 9 RC2

Steps to Reproduce:
After updating from .NET 8 to .NET 9 RC2, we're getting a false positive on this line:

internal sealed partial class DecryptionConfigurationProvider(
    IList<IConfigurationProvider> providers, ITextDecryptor? textDecryptor, ILoggerFactory loggerFactory)
    : CompositeConfigurationProvider(providers, loggerFactory)
{
#pragma warning disable IDE0052 // Remove unread private members
    private readonly ILogger<DecryptionConfigurationProvider> _logger = loggerFactory.CreateLogger<DecryptionConfigurationProvider>();
#pragma warning restore IDE0052 // Remove unread private members

    // ...

    [LoggerMessage(Level = LogLevel.Trace, Message = "Decrypted value '{CipherValue}' at key '{Key}' to '{PlainTextValue}'.")]
    private partial void LogDecrypt(string key, string? cipherValue, string? plainTextValue);
}

The private field is used by the source-generated LogDecrypt logger method, so the warning should not appear.

To reproduce, clone the repo at https://github.com/SteeltoeOSS/Steeltoe, check out branch try-net90, open src/Steeltoe.All.sln in Visual Studio 2022 v17.12 (latest preview) and build.

Diagnostic Id:
IDE0052

Expected Behavior:
No warning, which is the behavior in .NET 8.

Actual Behavior:
A warning appears during build.