Implement Type.IsTypeDefinition property on CoreCLR

src/mscorlib/shared/System/Reflection/TypeDelegator.cs

@@ -100,6 +100,7 @@ protected override PropertyInfo GetPropertyImpl(string name, BindingFlags bindin
 
         protected override TypeAttributes GetAttributeFlagsImpl() => typeImpl.Attributes;
 
+        public override bool IsTypeDefinition => typeImpl.IsTypeDefinition;
         public override bool IsSZArray => typeImpl.IsSZArray;
 
         protected override bool IsArrayImpl() => typeImpl.IsArray;

src/mscorlib/shared/System/Type.cs

@@ -32,6 +32,7 @@ protected Type() { }
         public override Type ReflectedType => null;
         public abstract Type UnderlyingSystemType { get; }
 
+        public virtual bool IsTypeDefinition { get { throw NotImplemented.ByDesign; } }
         public bool IsArray => IsArrayImpl();
         protected abstract bool IsArrayImpl();
         public bool IsByRef => IsByRefImpl();

src/mscorlib/src/System/Reflection/Emit/EnumBuilder.cs

@@ -242,6 +242,8 @@ protected override TypeAttributes GetAttributeFlagsImpl()
             return m_typeBuilder.Attributes;
         }
 
+        public override bool IsTypeDefinition => true;
+
         public override bool IsSZArray => false;
 
         protected override bool IsArrayImpl()

src/mscorlib/src/System/Reflection/Emit/GenericTypeParameterBuilder.cs

@@ -154,6 +154,8 @@ public override Type MakeArrayType(int rank)
 
         protected override TypeAttributes GetAttributeFlagsImpl() { return TypeAttributes.Public; }
 
+        public override bool IsTypeDefinition => false;
+
         public override bool IsSZArray => false;
 
         protected override bool IsArrayImpl() { return false; }

src/mscorlib/src/System/Reflection/Emit/SymbolType.cs

@@ -271,6 +271,9 @@ internal void SetFormat(string format, int curIndex, int length)
         #endregion
 
         #region Type Overrides
+
+        public override bool IsTypeDefinition => false;
+
         public override bool IsSZArray => m_cRank <= 1 && m_isSzArray;
 
         public override Type MakePointerType()

src/mscorlib/src/System/Reflection/Emit/TypeBuilder.cs

@@ -1109,6 +1109,8 @@ protected override TypeAttributes GetAttributeFlagsImpl()
             return m_iAttr;
         }
 
+        public override bool IsTypeDefinition => true;
+
         public override bool IsSZArray => false;
 
         protected override bool IsArrayImpl()

src/mscorlib/src/System/Reflection/Emit/TypeBuilderInstantiation.cs

@@ -189,6 +189,7 @@ public override Type BaseType
         public override MemberInfo[] GetMembers(BindingFlags bindingAttr) { throw new NotSupportedException(); }
         protected override TypeAttributes GetAttributeFlagsImpl() { return m_type.Attributes; }
 
+        public override bool IsTypeDefinition => false;
         public override bool IsSZArray => false;
 
         protected override bool IsArrayImpl() { return false; }

src/mscorlib/src/System/RtType.cs

@@ -3792,6 +3792,11 @@ public override Type[] GetGenericParameterConstraints()
         #endregion
 
         #region Misc
+        public override bool IsTypeDefinition
+        {
+            get { return RuntimeTypeHandle.IsTypeDefinition(this); }
+        }
+
         public override Type MakePointerType() { return new RuntimeTypeHandle(this).MakePointer(); }
         public override Type MakeByRefType() { return new RuntimeTypeHandle(this).MakeByRef(); }
         public override Type MakeArrayType() { return new RuntimeTypeHandle(this).MakeSZArray(); }

src/mscorlib/src/System/RuntimeHandles.cs

@@ -127,6 +127,24 @@ internal RuntimeTypeHandle(RuntimeType type)
             m_type = type;
         }
 
+        internal static bool IsTypeDefinition(RuntimeType type)
+        {
+            CorElementType corElemType = GetCorElementType(type);
+            if (!((corElemType >= CorElementType.Void && corElemType < CorElementType.Ptr) ||
+                    corElemType == CorElementType.ValueType ||
+                    corElemType == CorElementType.Class ||
+                    corElemType == CorElementType.TypedByRef ||
+                    corElemType == CorElementType.I ||
+                    corElemType == CorElementType.U ||
+                    corElemType == CorElementType.Object))
+                return false;
+
+            if (HasInstantiation(type) && !IsGenericTypeDefinition(type))
+                return false;
+
+            return true;
+        }
+
         internal static bool IsPrimitive(RuntimeType type)
         {
             CorElementType corElemType = GetCorElementType(type);