Exception when evaluating `new('%(Identity)').Substring(23)`

[KirillOsenkov]

When MSBuild evaluates the Substring call on this line:

MonoDevelop.MSBuildEditor/MonoDevelop.MSBuild.Editor.Common/MonoDevelop.MSBuild.Editor.Common.csproj

Line 64 in c77880a

<Compile Update="@(Compile->WithMetadataValue('DefiningProjectName', '$(MSBuildProjectName)'))" Link="external/roslyn/$([System.String]::new('%(Identity)').Substring(23))" />

There's a first-chance exception because the literal string is %(Identity) (not expanded), so calling Substring(23) on it throws