Swashbuckle.AspNetCore SwaggerOperation attribute not found

Another option is to set Name property for your HttpGet filter like this:

[HttpGet(Name = "GetAllAdresses")]
[Produces("application/json")]
[ProducesResponseType((int)HttpStatusCode.NotFound)]
[ProducesResponseType(typeof(List<AddressDto>), (int)HttpStatusCode.OK)]
[SwaggerOperation("GetAllAdresses")]
public async Task<IActionResult> GetAllAsync()
{
   ....
}

I ran across this today. I needed to add the following nuget package that was just added for V3.0.0:

Swashbuckle.AspNetCore.Annotations

Breaking changes are described here

Please also note that you need to add the following to Startup.cs or your Swagger extension:

AddSwaggerGen(c => { ... c.EnableAnnotations(); })