Poor error with dotnet run and multi-frameworks

Steps to reproduce

Create exe targeting multiple frameworks e.g.

<Project Sdk="Microsoft.NET.Sdk.Web">
  <PropertyGroup>
    <TargetFrameworks>netcoreapp1.1;net451</TargetFrameworks>
  </PropertyGroup>

then use dotnet run to run it

Expected behavior

Error message along lines of

You are trying to run an executable project that targets multiple frameworks. Please select a single framework to run with the -f flag.

Actual behavior

Poor error message

Unable to run your project Please ensure you have a runnable project type and ensure ‘dotnet run’ supports this project. The current OutputType is ‘Exe’

Environment data

dotnet --info output:

.NET Command Line Tools (2.0.0-preview1-005418)

Product Information: Version: 2.0.0-preview1-005418 Commit SHA-1 hash: 82c928e1ec

Runtime Environment: OS Name: Windows OS Version: 10.0.15061 OS Platform: Windows RID: win10-x64 Base Path: C:\Users\thund\AppData\Local\Microsoft\dotnet\sdk\2.0.0-preview1-005418\

[eerhardt]

@InsidiousForce - your issue is separate. Your TargetFramework is netstandard1.6.1, which is not a runnable framework. netstandard is for building libraries that can run on any of the .NET platforms: .NET Framework on Windows, Mono, .NET Core, UWP, Xamarin, etc.

If you want to run your project on .NET Core, please change your TargetFramework to netcoreapp1.1. After doing so, you can remove the PackageReferences to Microsoft.NETCore.Runtime.CoreCLR and Microsoft.NETCore.DotNetHostPolicy, since those will implicitly come through by targeting netcoreapp1.1.

[eerhardt]

@InsidiousForce - See https://github.com/dotnet/standard/blob/master/docs/faq.md, which is the de facto source in my opinion.

netcoreapp is not going away anytime soon, as far as I know. It is the target framework for .NET Core applications. We are currently working on netcoreapp2.0, the next version after 1.1.