Can't figure out how to specify System.DateTime.TryParse method in Trimmer descriptor XML file to have it retain this method overload

[rkeithhill-keysight]

We have a .NET library that dynamically loads a C++/CLI assembly from another app's install dir. I'm experimenting with using a Root descriptor XML file to tell the trimmer for my sample app, not to trim this a particular overload. The overload is:

System.MissingMethodException: Method not found: 'Boolean System.DateTime.TryParse(System.String, System.IFormatProvider, System.Globalization.DateTimeStyles, System.DateTime ByRef)'

I have tried variations specifying this method (or the entire DateTime type):

<linker>
  <assembly fullname="System.Private.CoreLib">
    <type fullname="System.Convert">
      <method signature="System.String ToString(System.Boolean,System.IFormatProvider)"/>
    </type>
    <!-- <type fullname="System.DateTime"/> -->
    <!-- public static bool TryParse([NotNullWhen(true)] string? s, IFormatProvider? provider, DateTimeStyles styles, out DateTime result) -->
      <!-- <method signature="System.Boolean TryParse(System.String,System.IFormatProvider,System.Globalization.DateTimeStyles,System.DateTime ByRef)"/> -->
      <!-- <method name="TryParse"/> -->
    <!-- </type> -->
  </assembly>
  <assembly fullname="System.Runtime">
    <type fullname="System.AppDomain">
      <method name="IsDefaultAppDomain"/>
    </type>
    <type fullname="System.DateTime"/>

I think DateTime is actually implemented/provided in System.Private.CoreLib.dll even though the API docs say System.Runtime.dll.

I've tried the simple <type fullname="System.DateTime"/> to keep all of DateTime. And I've tried specifying the signature. BTW it's not obvious in the docs how to specify a signature that has an out parameter. Also, the signature format does not seem to be forgiving RE extra spaces - so, no spaces between parameters.

The only way I've gotten my sample/test app to get past this missing method exception is to add a call to this DateTime.TryParse method overload in the app. That's fine for my testing, but not for folks who use my library. At the end of the day, I figure it won't be realistic to provide my library as "trim-enabled", but I'd like to get a bit further to see how big the problem is.

[huoyaoyuan]

Did you inspect the trimmed assemblies with ILSpy, to verify which are present/missing in System.Runtime and System.Private.CoreLib?

[rkeithhill-keysight]

I used dotPeek and found that System.Runtime.dll type forwards DateTime to System.Private.CoreLib.dll where the DateTime.TryParse overload is actually implemented:

The trimmed version does not have this particular overload. That's why I'm trying to figure out how to get the trimmer to not trim it. I can't seem to find an XML syntax/format that works.