.net-core Understanding System.Runtime vs. mscorlib Popular Error: Accidently adding a mscorlib library as a dependencies to a netstandard/netcoreapp

Example

Another popular error is the referring of packages which does not satisfy all framework on the global scope when multiple frameworks are targeted.

{
    "version": "1.0.0-*",

    "dependencies": {
        "NETStandard.Library": "1.6.0",
        "Microsoft.AspNet.Identity.EntityFramework": "2.2.1"
    },

    "frameworks": {
        "netstandard1.3": { },
        "net451": { }
    }
}

The (meta) library NETStandard.Library works fine in this example, since it targets both netstandard1.3 and net451. However the library Microsoft.AspNet.Identity.EntityFramework does only target the .NET Framework net and mscorlib and therefore cannot be used for a netstandard output.

Either search for a library (version) which cover both frameworks or add the library in the conditional dependencies below the framework.

{
    "version": "1.0.0-*",

    "dependencies": {
        "NETStandard.Library": "1.6.0"
    },

    "frameworks": {
        "netstandard1.3": { },
        "net451": {
            "dependencies": {
                "Microsoft.AspNet.Identity.EntityFramework": "2.2.1",
            }
        }
    }
}

In this case, the library can only be used in conditional #ifdef blocks for the net451 build.