Intellisense not recognizes extension methods for generic classes from .NET Standard 2.0 references

_This issue has been moved from [a ticket on Developer Community](https://developercommunity.visualstudio.com/t/Intellisense-not-recognizes-extension-me/10648843)._

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\[severity:It’s more difficult to complete my work\]
I have a .NET Standard 2.0 Library in which I have defined this extension class.

```
public static class MyExtension
{
public static void ExtendEnumerable(this IEnumerable items) { }

public static void ExtendTObject(this T tObject) { }
}

```

There is a second .NET 8 project which references the .NET Standard 2.0 library. From whithin the .NET 8 project Intellisense doesn’t recognize `ExtendEnumerable<>` when the namespace is not already imported. It does tho recognizes `ExtendObject<>` and it also recognizes `MyExtension` class and imports the using properly.
Visual Studio option Text Editor > C# > Intellisense > Show items from unimported namespaces is enabled.

I provided a little sample project which contains the same extension class defined in 3 different frameworks. While `ExtendTObject<>` gets recognized correctly, `ExtendEnumerable<>` does so only for . NET6 and . NET8 libraries. See screenshot below:


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### Original Comments

#### Feedback Bot on 4/29/2024, 03:59 AM:

(private comment, text removed)

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### Original Solutions
(no solutions)