Issue after updating from ASP.NET Core 1.0 to 1.1

Question

Following this Official ASP.NET Article I updated from ASP.NET Core 1.0 to 1.1. But when compiling my ASP.NET Core project I get the following error in AccountController.cs file:

Error:

The call is ambiguous between the following methods or properties: 'System.Security.Claims.PrincipalExtensions.FindFirstValue(System.Security.Claims.ClaimsPrincipal, string)' and 'System.Security.Claims.PrincipalExtensions.FindFirstValue(System.Security.Claims.ClaimsPrincipal, string)'

The error is at following at line var email = info.Principal.FindFirstValue(ClaimTypes.Email); at the end of following action method:

public async Task<IActionResult> ExternalLoginCallback(string returnUrl = null, string remoteError = null)
        {
            if (remoteError != null)
            {
                ModelState.AddModelError(string.Empty, $"Error from external provider: {remoteError}");
                return View(nameof(Login));
            }
            var info = await _signInManager.GetExternalLoginInfoAsync();
            if (info == null)
            {
                return RedirectToAction(nameof(Login));
            }

            // Sign in the user with this external login provider if the user already has a login.
            var result = await _signInManager.ExternalLoginSignInAsync(info.LoginProvider, info.ProviderKey, isPersistent: false);
            if (result.Succeeded)
            {
                _logger.LogInformation(5, "User logged in with {Name} provider.", info.LoginProvider);
                return RedirectToLocal(returnUrl);
            }
            if (result.RequiresTwoFactor)
            {
                return RedirectToAction(nameof(SendCode), new { ReturnUrl = returnUrl });
            }
            if (result.IsLockedOut)
            {
                return View("Lockout");
            }
            else
            {
                // If the user does not have an account, then ask the user to create an account.
                ViewData["ReturnUrl"] = returnUrl;
                ViewData["LoginProvider"] = info.LoginProvider;
                var email = info.Principal.FindFirstValue(ClaimTypes.Email);
                return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = email });
            }
        }

project.json:

{
  "userSecretsId": "aspnet-ABCTest-6af8ade3-87ff-4468-a9ce-8bb69c696ab8",

  "dependencies": {
    "Microsoft.NETCore.App": {
      "version": "1.1.0",
      "type": "platform"
    },
    "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-rc1-final",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.Mvc": "1.1.0",
    "Microsoft.AspNetCore.Mvc.Core": "1.1.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.1.0",
    "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
    "Microsoft.AspNetCore.Authentication.Cookies": "1.1.0",
    "Microsoft.AspNetCore.Diagnostics": "1.1.0",
    "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.1.0",
    "Microsoft.AspNetCore.Identity": "1.1.0",
    "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.1.0",
    "Microsoft.AspNetCore.Razor.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.1.0",
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.StaticFiles": "1.1.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.1.0",
    "Microsoft.Extensions.Configuration.Json": "1.1.0",
    "Microsoft.Extensions.Configuration.UserSecrets": "1.1.0",
    "Microsoft.Extensions.Logging": "1.1.0",
    "Microsoft.Extensions.Logging.Console": "1.1.0",
    "Microsoft.Extensions.Logging.Debug": "1.1.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.1.0",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.1.0",
    "Microsoft.VisualStudio.Web.CodeGeneration.Tools": "1.1.0-preview4-final",
    "Microsoft.VisualStudio.Web.CodeGenerators.Mvc": "1.1.0-preview4-final"  },

  "tools": {
    "BundlerMinifier.Core": "2.0.238"  },

  "frameworks": {
    "netcoreapp1.1": {
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  },

  "publishOptions": {
    "include": [
      "wwwroot",
      "Views",
      "Areas/**/Views",
      "appsettings.json",
      "web.config"
    ]
  },

  "scripts": {
    "prepublish": [ "bower install", "dotnet bundle" ],
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }
}

Answer 1

Try removing "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-rc1-final" from your dependencies. Mixing packages from different releases - in this case pre-RTM and 1.1.0 is usually the cause for such API ambiguity.