Had a weird one - a C# recompilation caused the editor to CTD with the following error

(Filename: Packages/NoesisGUI/Runtime/NoesisUnity.cs Line: 360)

[NOESIS/E] Component 'Converter<NoesisApp.MediaState> ()' already registered
UnityEngine.StackTraceUtility:ExtractStackTrace ()
UnityEngine.DebugLogHandler:LogFormat (UnityEngine.LogType,UnityEngine.Object,string,object[])
UnityEngine.Logger:Log (UnityEngine.LogType,object,UnityEngine.Object)
UnityEngine.Debug:LogError (object,UnityEngine.Object)
NoesisUnity:UnityLog (int,string) (at Packages/NoesisGUI/Runtime/NoesisUnity.cs:360)
Noesis.Extend:RegisterNativeType (System.Type,bool) (at Packages/NoesisGUI/Runtime/API/Core/Extend.cs:1313)
Noesis.Extend:EnsureNativeType (System.Type,bool) (at Packages/NoesisGUI/Runtime/API/Core/Extend.cs:1823)
Noesis.Extend:EnsureNativeType (System.Type) (at Packages/NoesisGUI/Runtime/API/Core/Extend.cs:1815)
Noesis.Extend:Box (object) (at Packages/NoesisGUI/Runtime/API/Core/ExtendBoxing.cs:125)
Noesis.Extend:GetInstanceHandle (object) (at Packages/NoesisGUI/Runtime/API/Core/Extend.cs:6017)
Noesis.PropertyMetadata:SetDefaultValueHelper (object) (at Packages/NoesisGUI/Runtime/API/Proxies/PropertyMetadata.cs:53)
Noesis.PropertyMetadata:set_DefaultValue (object) (at Packages/NoesisGUI/Runtime/API/Proxies/PropertyMetadata.cs:36)
Noesis.FrameworkPropertyMetadata:.ctor (object) (at Packages/NoesisGUI/Runtime/API/Proxies/FrameworkPropertyMetadataExtend.cs:29)
NoesisApp.MediaElement:.cctor () (at Packages/NoesisGUI/Runtime/API/MediaElement/MediaElement.cs:116)
NoesisUnity:Init () (at Packages/NoesisGUI/Runtime/NoesisUnity.cs:71)
NoesisLangServer/<>c:<.cctor>b__0_0 () (at Packages/NoesisGUI/Editor/NoesisLangServer.cs:14)
UnityEditor.EditorApplication:Internal_CallUpdateFunctions ()

(Filename: Packages/NoesisGUI/Runtime/NoesisUnity.cs Line: 360)

=================================================================
    Native Crash Reporting
=================================================================
Got a UNKNOWN while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================

=================================================================
    Managed Stacktrace:
=================================================================
      at <unknown> <0xffffffff>
      at Noesis.NoesisGUI_PINVOKE:PropertyMetadata_SetDefaultValueHelper <0x0011b>
      at Noesis.PropertyMetadata:SetDefaultValueHelper <0x0011a>
      at Noesis.PropertyMetadata:set_DefaultValue <0x0008a>
      at Noesis.FrameworkPropertyMetadata:.ctor <0x000ca>
      at NoesisApp.MediaElement:.cctor <0x002b2>
      at System.Object:runtime_invoke_void <0x00184>
      at <unknown> <0xffffffff>
      at NoesisUnity:Init <0x007ca>
      at <>c:<.cctor>b__0_0 <0x000a2>
      at UnityEditor.EditorApplication:Internal_CallUpdateFunctions <0x00327>
      at System.Object:runtime_invoke_void <0x00184>
=================================================================
Received signal SIGSEGV
Obtained 2 stack frames
RtlLookupFunctionEntry returned NULL function. Aborting stack walk.
<Missing stacktrace information>

I've gotten used to editor CTDs while editing XAML using the VSCode extension, but C# is a new one. Haven't seen this one before and can't reproduce it, so don't have a good idea of what actually caused this.