No error in the error list for incompatible netcoreapp1.1 and netcoreapp2.0 apps

[abpiskunov]

Repro:

1. Create a core web app targeting 1.1, and then create a core class lib targeting 2.0.
2. Try to add core class lib dependency to web app.
3. wait for restore is complete (it should fail) and build solution

Actual output:

Restoring NuGet packages...
To prevent NuGet from restoring packages during build, open the Visual Studio Options dialog, click on the Package Manager node and uncheck 'Allow NuGet to download missing packages during build.'
NuGet package restore failed.
1>------ Build started: Project: ClassLibrary1, Configuration: Debug Any CPU ------
1>ClassLibrary1 -> C:\Users\antonpis\source\repos\WebApplication2\ClassLibrary1\bin\Debug\netcoreapp2.0\ClassLibrary1.dll
2>------ Build started: Project: WebApplication2, Configuration: Debug Any CPU ------
2>C:\Users\antonpis\source\repos\WebApplication2\WebApplication2\WebApplication2.csproj : error NU1201: Project ClassLibrary1 is not compatible with netcoreapp1.1 (.NETCoreApp,Version=v1.1). Project ClassLibrary1 supports: netcoreapp2.0 (.NETCoreApp,Version=v2.0)
2>C:\Program Files\dotnet\sdk\2.0.0-preview3-006815\Sdks\Microsoft.NET.Sdk\build\Microsoft.NET.Sdk.Common.targets(87,5): error : Project 'C:\Users\antonpis\source\repos\WebApplication2\ClassLibrary1\ClassLibrary1.csproj' targets '.NETCoreApp,Version=v2.0'. It cannot be referenced by a project that targets '.NETCoreApp,Version=v1.1'.
2>Done building project "ClassLibrary1.csproj" -- FAILED.
2>Done building project "WebApplication2.csproj" -- FAILED.
========== Build: 1 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

And no error : Project 'C:\Users\antonpis\source\repos\WebApplication2\ClassLibrary1\ClassLibrary1.csproj' targets '.NETCoreApp,Version=v2.0'. It cannot be referenced by a project that targets '.NETCoreApp,Version=v1.1'. in the error list.

Expected:

error to be present in the error list since it is in the output.

[davkean]

This is will inadvertently fixed by dotnet/msbuild#1276 - which will pull the error message into the consuming project and hence will show in the Error List.

[Pilchie]

Confirmed the error does show in the errrorlist in 15.6 Preview 1 (and presumably 15.5, though I didn't check there).