De-duplicate msbuild references

deduplicate_references.proj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <!-- For some reason, msbuild will sometimes duplicate all references in @(ReferencePath),
       which, given a particularly meaty nuget package (*cough*JetBrains.ReSharper.SDK*cough*),
       can overwhelm the command line. This little hack will de-duplicate references to
       reduce the pressure, but it's still going to hurt at some point...
       I'd really like to figure out why msbuild is duplicating. Given a simple test with
       just e.g. nunit, it works as expected. Perhaps it's something to do with the ReSharper
       SDK nuget, but I can't see it -->
  <PropertyGroup>
    <CoreCompileDependsOn>
      $(CoreCompileDependsOn);
      _RemoveDuplicateReferences
    </CoreCompileDependsOn>
  </PropertyGroup>
  <Target Name="_RemoveDuplicateReferences">
    <ItemGroup>
      <_DeduplicatedReferencePath />
    </ItemGroup>
    <RemoveDuplicates Inputs="@(ReferencePath)">
      <Output TaskParameter="Filtered"
              ItemName="_DeDuplicatedReferencePath"/>
    </RemoveDuplicates>
    <ItemGroup>
      <ReferencePath Remove="@(ReferencePath)" />
      <ReferencePath Include="@(_DeduplicatedReferencePath)" />
    </ItemGroup>
  </Target>
</Project>