Fix MA0071 false positive for else if chains with reachable prior branches

[Copilot]

MA0071 incorrectly flagged the final else in some else if chains, especially when conditions used method calls, leading to unsafe flattening suggestions. The rule now avoids diagnostics unless earlier branches in the same chain are proven to terminate unconditionally.

• Analyzer logic: constrain else if flattening

  • Updated AvoidUsingRedundantElseAnalyzer to require that every preceding branch in the enclosing else if chain has an unreachable endpoint before considering the current else redundant.
  • This prevents reporting when control flow can still continue past an earlier if branch.

• Regression coverage

  • Added a focused test reproducing the reported pattern:
    • first branch with method-call condition and reachable endpoint
    • second else if branch with continue
    • final else that must remain valid
  • Expected behavior: no MA0071 diagnostic.

• Rule documentation

  • Clarified MA0071 behavior for else if chains: simplification applies only when previous branches also jump unconditionally.

if (sc.Verify("first", cmp) is not null)
{
    Console.WriteLine("Handled"); // reachable endpoint
}
else if (sc.Verify("second", cmp) is not null)
{
    Console.WriteLine("Handled");
    continue;
}
else
{
    Console.WriteLine("Not handled"); // must not be flagged as redundant
}

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 1s1vsblobprodcus386.vsblob.vsassets.io
  • Triggering command: /usr/share/dotnet/dotnet dotnet restore --no-dependencies /home/REDACTED/work/Meziantou.Analyzer/Meziantou.Analyzer/Meziantou.Analyzer.slnx --packages /tmp/codeql-scratch-8ad8dc5536a632e8/dbs/csharp/working/packages /p:DisableImplicitNuGetFallbackFolder=true --verbosity normal /p:TargetFrameworkRootPath=/tmp/codeql-scratch-8ad8dc5536a632e8/dbs/csharp/working/emptyFakeDotnetRoot /p:NetCoreTargetingPackRoot=/tmp/codeql-scratch-8ad8dc5536a632e8/dbs/csharp/working/emptyFakeDotnetRoot /p:AllowMissingPrunePackageData=true -s REDACTED -s REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)