Don't ask the type loader to build instantiations over generic type definitions (#3478)

Found in CoreFX tests.

3 files changed, 13 insertions, 8 deletions

diff --git a/src/System.Private.Reflection.Execution/src/Internal/Reflection/Execution/ExecutionEnvironmentImplementation.MappingTables.cs b/src/System.Private.Reflection.Execution/src/Internal/Reflection/Execution/ExecutionEnvironmentImplementation.MappingTables.cs
index 9d058df01..895f7651b 100644
--- a/src/System.Private.Reflection.Execution/src/Internal/Reflection/Execution/ExecutionEnvironmentImplementation.MappingTables.cs
+++ b/src/System.Private.Reflection.Execution/src/Internal/Reflection/Execution/ExecutionEnvironmentImplementation.MappingTables.cs
@@ -227,7 +227,8 @@ namespace Internal.Reflection.Execution
         {
             if (RuntimeAugments.IsGenericTypeDefinition(elementTypeHandle))
             {
-                throw new NotSupportedException(SR.NotSupported_OpenType);
+                arrayTypeHandle = default(RuntimeTypeHandle);
+                return false;
             }
 
             // For non-dynamic arrays try to look up the array type in the ArrayMap blobs;
@@ -263,7 +264,8 @@ namespace Internal.Reflection.Execution
         {
             if (RuntimeAugments.IsGenericTypeDefinition(elementTypeHandle))
             {
-                throw new NotSupportedException(SR.NotSupported_OpenType);
+                arrayTypeHandle = default(RuntimeTypeHandle);
+                return false;
             }
             
             if ((rank < MDArray.MinRank) || (rank > MDArray.MaxRank))
@@ -343,7 +345,16 @@ namespace Internal.Reflection.Execution
 
             TypeInfo[] typeArguments = new TypeInfo[genericTypeArgumentHandles.Length];
             for (int i = 0; i < genericTypeArgumentHandles.Length; i++)
+            {
+                // Early out if one of the arguments is a generic definition.
+                // The reflection stack will use this to construct a Type that doesn't have a type handle.
+                // Note: this is different from the validation we do in EnsureSatisfiesClassConstraints because this
+                // should not throw.
+                if (RuntimeAugments.IsGenericTypeDefinition(genericTypeArgumentHandles[i]))
+                    return false;
+
                 typeArguments[i] = Type.GetTypeFromHandle(genericTypeArgumentHandles[i]).GetTypeInfo();
+            }
 
             ConstraintValidator.EnsureSatisfiesClassConstraints(typeDefinition, typeArguments);
 
diff --git a/src/System.Private.Reflection.Execution/src/Resources/Resources.resx b/src/System.Private.Reflection.Execution/src/Resources/Resources.resx
index ed51ff74b..6d4210f7e 100644
--- a/src/System.Private.Reflection.Execution/src/Resources/Resources.resx
+++ b/src/System.Private.Reflection.Execution/src/Resources/Resources.resx
@@ -201,9 +201,6 @@
   <data name="Argument_ConstraintFailed" xml:space="preserve">
     <value>'{0}', on '{1}' violates the constraint of type '{2}'.</value>
   </data>
-  <data name="NotSupported_OpenType" xml:space="preserve">
-    <value>Cannot create arrays of open type. </value>
-  </data>
   <data name="PlatformNotSupported_GetMethodInfoForStubDelegate" xml:space="preserve">
     <value>Obtaining a MethodInfo of a reflection-constructed delegate to a virtual method is not supported on this platform.</value>
   </data>
diff --git a/src/System.Private.Reflection.Execution/src/Resources/Strings.resx b/src/System.Private.Reflection.Execution/src/Resources/Strings.resx
index 028ba1076..905717d33 100644
--- a/src/System.Private.Reflection.Execution/src/Resources/Strings.resx
+++ b/src/System.Private.Reflection.Execution/src/Resources/Strings.resx
@@ -198,9 +198,6 @@
   <data name="Argument_ConstraintFailed" xml:space="preserve">
     <value>'{0}', on '{1}' violates the constraint of type '{2}'.</value>
   </data>
-  <data name="NotSupported_OpenType" xml:space="preserve">
-    <value>Cannot create arrays of open type. </value>
-  </data>
   <data name="PlatformNotSupported_GetMethodInfoForStubDelegate" xml:space="preserve">
     <value>Obtaining a MethodInfo of a reflection-constructed delegate to a virtual method is not supported on this platform.</value>
   </data>