CA1845: Adds unnecessary using statement when implicit usings exist

[timheuer]

Version Used:
Microsoft Visual Studio Enterprise 2022 Int Preview (64-bit)
Version 17.0.0 Preview 5.0 [31808.319.d17.0]

Steps to Reproduce:

1. Create a new console app in .NET6 - default implicit usings
2. Add some code that triggers CA1845
3. Executing the code fix

Expected Behavior:
using System; is not added

Actual Behavior:
It is added

Not sure if this is expected with the ImplicitUsings feature, but I just always hate when tools add something immediately grayed out.

[Youssef1313]

Can someone move to dotnet/roslyn-analyzers?

Also tagging @NewellClark

[CyrusNajmabadi]

This is likely still in Roslyn. We have a mechanism to allow actions to add usings if missing. That likely needs to be updated to account for global usings.

[Youssef1313]

@CyrusNajmabadi Might need tweaks in both repos then? This is what the fixer in roslyn-analyzer does.

roslyn-analyzers/src/NetAnalyzers/CSharp/Microsoft.NetCore.Analyzers/Runtime/CSharpUseSpanBasedStringConcat.Fixer.cs

Lines 24 to 32 in 01f57af

	private protected override bool IsSystemNamespaceImported(Project project, IReadOnlyList<SyntaxNode> namespaceImports)
	{
	foreach (var import in namespaceImports)
	{
	if (import is UsingDirectiveSyntax { Name: IdentifierNameSyntax { Identifier: { ValueText: nameof(System) } } })
	return true;
	}
	return false;
	}

[CyrusNajmabadi]

Ah, in that cse, this is def on them. Moving. Thanks!