Extension methods with EditorBrowsable(Never) defined in a referenced assembly show up in VS intellisense

[jnm2]

Version Used: VS 16.7.3

Steps to Reproduce:

1. Create a library project with a public extension method. Put [EditorBrowsable(EditorBrowsableState.Never)] on it.
2. Build the project.
3. Create a second library project and reference the bin/Debug assembly that was created by building the first project.
4. See the never-browsable extension method showing up in intellisense for the second library project where it offers to autocomplete extension methods that are in an unimported namespace.

Expected Behavior: The extension methods should stop polluting intellisense. They can't be removed without causing binary-breaking changes and they should remain extension methods so that code that used them gets the obsoletion message rather than a "method does not exist" compiler error.

Actual Behavior: The extension methods did not stop polluting intellisense.

[Youssef1313]

Related existing test:

roslyn/src/EditorFeatures/CSharpTest/Completion/CompletionProviders/SymbolCompletionProviderTests.cs

Lines 4282 to 4316 in 8949725

	[WorkItem(7336, "DevDiv_Projects/Roslyn")]
	[Fact, Trait(Traits.Feature, Traits.Features.Completion)]
	public async Task EditorBrowsable_ExtensionMethod_BrowsableNever()
	{
	var markup = @"
	class Program
	{
	void M()
	{
	new Goo().$$
	}
	}";
	var referencedCode = @"
	public class Goo
	{
	}
	public static class GooExtensions
	{
	[System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
	public static void Bar(this Goo goo, int x)
	{
	}
	}";
	await VerifyItemInEditorBrowsableContextsAsync(
	markup: markup,
	referencedCode: referencedCode,
	item: "Bar",
	expectedSymbolsSameSolution: 1,
	expectedSymbolsMetadataReference: 0,
	sourceLanguage: LanguageNames.CSharp,
	referencedLanguage: LanguageNames.CSharp);
	}

[jnm2]

Thanks, that was quite fast! Will the fixed version be 16.8.x?

[genlu]

Will the fixed version be 16.8.x?

Yes.