Fix custom modifiers on Reflection (#4171)

- Make the guard check ModifiedType aware
  so it doesn't block custom modifiers
  on parameters.

- Sort modifiers in the same way the full
  framework does. Order matters in custom modifiers.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/MetadataReaderExtensions.cs b/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/MetadataReaderExtensions.cs
index b3705efff..772796ec9 100644
--- a/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/MetadataReaderExtensions.cs
+++ b/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/MetadataReaderExtensions.cs
@@ -77,6 +77,15 @@ namespace System.Reflection.Runtime.General
                 handleType == HandleType.TypeSpecification;
         }
 
+        public static bool IsTypeDefRefSpecOrModifiedTypeHandle(this Handle handle, MetadataReader reader)
+        {
+            HandleType handleType = handle.HandleType;
+            return handleType == HandleType.TypeDefinition ||
+                handleType == HandleType.TypeReference ||
+                handleType == HandleType.TypeSpecification ||
+                handleType == HandleType.ModifiedType;
+        }
+
         public static RuntimeAssemblyName ToRuntimeAssemblyName(this ScopeDefinitionHandle scopeDefinitionHandle, MetadataReader reader)
         {
             ScopeDefinition scopeDefinition = scopeDefinitionHandle.GetScopeDefinition(reader);