Namespace mismatched compilation error to the generic type component event arguments

[ajithr]

Describe the bug

When using generic type to the Blazor component, the namespace is mismatched for EventCallback method arguments and throws compilation error.

MyGenComponent.razor:

@using GenericTypeBlazor.Shared.Models;

@typeparam T;

    <div>
        <ul>
            @ChildContent
        </ul>
    </div>


@code {
    [Parameter]
    protected RenderFragment ChildContent { get; set; }

    [Parameter]
    public IEnumerable<T> Data { get; set; }

    [Parameter]
    public EventCallback<EventArgsData<T>> EventOne { get; set; }

    [Parameter]
    public EventCallback<EventArguments> EventTwo { get; set; }
}

Models.cs

namespace GenericTypeBlazor.Shared.Models
{
    public class EventArgsData<T>
    {
        public bool IsRendered { get; set; }

        public T Data { get; set; }
    }

    public class EventArguments
    {
        public bool IsRendered { get; set; }

        public object Data { get; set; }
    }
}

Index.razor:

@page "/"
@using GenericTypeBlazor.Shared.Models;

<MyGenComponent Data="@MyData" EventTwo="@Event2"></MyGenComponent>

@code {
    public List<string> MyData = new List<string>() { "a", "b", "c", "d" };

    public void Event2(EventArguments args)
    {

    }
}

To Reproduce

Steps to reproduce the behavior:

1. Clone the below Github repository.

https://github.com/ajithr/BlazorGenericType

2. Run this application and it will throws the below error

1>obj\Debug\netcoreapp3.0\Razor\Pages\Index.razor.g.cs(103,295,103,301): error CS0234: The type or namespace name 'Shared' does not exist in the namespace '__Blazor.GenericTypeBlazor' (are you missing an assembly reference?)

Expected behavior

The EventCallback should be work with both generic type and non generic type arguments when using @typeparam in the Blazor component.

Screenshots

Additional context

.NET Core SDK (reflecting any global.json):
 Version:   3.0.100-preview6-012264
 Commit:    be3f0c1a03

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.17763
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.0.100-preview6-012264\

Host (useful for support):
  Version: 3.0.0-preview6-27804-01
  Commit:  fdf81c6faf

.NET Core SDKs installed:
  1.1.13 [C:\Program Files\dotnet\sdk]
  2.1.202 [C:\Program Files\dotnet\sdk]
  2.1.505 [C:\Program Files\dotnet\sdk]
  2.1.602 [C:\Program Files\dotnet\sdk]
  2.1.700-preview-009618 [C:\Program Files\dotnet\sdk]
  2.1.800-preview-009696 [C:\Program Files\dotnet\sdk]
  3.0.100-preview6-012264 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0-preview6.19307.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 1.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 1.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0-preview6-27804-01 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.0.0-preview6-27804-01 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

[Faolan-dimplex]

@ajithr Thanks, was having trouble reproducing exactly what caused the error

[mkArtakMSFT]

Thanks for all the details, @ajithr.
We'll try to repro this and update this issue accordingly.

[MajdajkD]

Possibly somewhat related to #13220 ?