Throw NotSupportedException when using SetErrorStatusOnException in Mono Runtime and Native AOT environment.

src/OpenTelemetry/CHANGELOG.md

@@ -2,12 +2,17 @@
 
 ## Unreleased
 
+* Throw NotSupportedException when using `ExceptionProcessor` for Tracing in
+  Mono Runtime and Native AOT environment because the the dependent
+  `Marshal.GetExceptionPointers()` API is not supported in these platforms.
+  ([#5347](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5347))
+
 * Fixed an issue where `LogRecord.Attributes` (or `LogRecord.StateValues` alias)
   could become out of sync with `LogRecord.State` if either is set directly via
   the public setters. This was done to further mitigate issues introduced in
   1.5.0 causing attributes added using custom processor(s) to be missing after
   upgrading. For details see:
-  [#5169](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5169)
+  ([#5169](https://github.com/open-telemetry/opentelemetry-dotnet/pull/5169))
 
 * Fixed an issue where `SimpleExemplarReservoir` was not resetting internal
   state for cumulative temporality.

src/OpenTelemetry/Trace/ExceptionProcessor.cs

@@ -19,22 +19,16 @@ internal sealed class ExceptionProcessor : BaseProcessor<Activity>
     public ExceptionProcessor()
     {
 #if NET6_0_OR_GREATER || NETFRAMEWORK
+        Marshal.GetExceptionPointers(); // attempt to access pointers to test for platform support
         this.fnGetExceptionPointers = Marshal.GetExceptionPointers;
 #else
         // When running on netstandard or similar the Marshal class is not a part of the netstandard API
         // but it would still most likely be available in the underlying framework, so use reflection to retrieve it.
-        try
-        {
-            var flags = BindingFlags.Static | BindingFlags.Public;
-            var method = typeof(Marshal).GetMethod("GetExceptionPointers", flags, null, Type.EmptyTypes, null)
-                ?? throw new InvalidOperationException("Marshal.GetExceptionPointers method could not be resolved reflectively.");
-            var lambda = Expression.Lambda<Func<IntPtr>>(Expression.Call(method));
-            this.fnGetExceptionPointers = lambda.Compile();
-        }
-        catch (Exception ex)
-        {
-            throw new NotSupportedException($"'{typeof(Marshal).FullName}.GetExceptionPointers' is not supported", ex);
-        }
+        var flags = BindingFlags.Static | BindingFlags.Public;
+        var method = typeof(Marshal).GetMethod("GetExceptionPointers", flags, null, Type.EmptyTypes, null)
+            ?? throw new InvalidOperationException("Marshal.GetExceptionPointers method could not be resolved reflectively.");
+        var lambda = Expression.Lambda<Func<IntPtr>>(Expression.Call(method));
+        this.fnGetExceptionPointers = lambda.Compile();
 #endif
     }