private static ReadOnlyCollection <PrimitiveType> GetPrimitiveCommonSuperTypes( PrimitiveType primitiveType1, PrimitiveType primitiveType2) { TypeSemantics.ComputeCommonTypeClosure(); return(TypeSemantics._commonTypeClosure[(int)primitiveType1.PrimitiveTypeKind, (int)primitiveType2.PrimitiveTypeKind]); }