Design time build does not attempt to copy files to output (bin) directory.
Actual Behavior:
The caller appears to be target _CopyDevKitExtensionFiles in Microsoft.CodeAnalysis.LanguageServer.UnitTests.csproj. Design time build is broken, leading to lack of IDE features during development.
Since this is an error reported through the normal MSBuild mechanisms (as opposed to an uncaught exception or a missing target or something like that) it is reasonable to expect that it will be shown in the VS Error List.
Regardless of the error reporting you probably don't want _CopyDevKitExtensionFiles to run during a design-time build. The definition of the target should be updated to include Condition="'$(DesignTimeBuild)' != 'true'.
Version Used: ee863ed
Steps to Reproduce:
Open Roslyn.sln in Visual Studio.
Expected Behavior:
Design time build does not attempt to copy files to output (bin) directory.
Actual Behavior:
The caller appears to be target
_CopyDevKitExtensionFiles
in Microsoft.CodeAnalysis.LanguageServer.UnitTests.csproj. Design time build is broken, leading to lack of IDE features during development.