public static void EmitConvertToType(this ILGenerator ilGenerator, Type typeFrom, Type typeTo, bool isChecked = true)
{
if (ilGenerator == null)
{
throw new ArgumentNullException(nameof(ilGenerator));
}
if (typeFrom == null)
{
throw new ArgumentNullException(nameof(typeFrom));
}
if (typeTo == null)
{
throw new ArgumentNullException(nameof(typeTo));
}
var nnExprType = typeFrom.Unwrap();
var nnType = typeTo.Unwrap();
if (nnType == nnExprType || nnType.IsEquivalentTo(nnExprType))
{
return;
}
if (typeFrom.IsInterface || // interface cast
typeTo.IsInterface ||
typeFrom == typeof(object) || // boxing cast
typeTo == typeof(object) ||
typeFrom == typeof(Enum) ||
typeFrom == typeof(ValueType) ||
TypeInfoUtils.IsLegalExplicitVariantDelegateConversion(typeFrom, typeTo))
{
ilGenerator.EmitCastToType(typeFrom, typeTo);
}
else if (typeFrom.IsNullableType() || typeTo.IsNullableType())
{
ilGenerator.EmitNullableConversion(typeFrom, typeTo, isChecked);
}
else if (!(typeFrom.IsConvertible() && typeTo.IsConvertible()) // primitive runtime conversion
&&
(nnExprType.GetTypeInfo().IsAssignableFrom(nnType) || // down cast
nnType.GetTypeInfo().IsAssignableFrom(nnExprType))) // up cast
{
ilGenerator.EmitCastToType(typeFrom, typeTo);
}
else if (typeFrom.IsArray && typeTo.IsArray)
{
// See DevDiv Bugs #94657.
ilGenerator.EmitCastToType(typeFrom, typeTo);
}
else
{
ilGenerator.EmitNumericConversion(typeFrom, typeTo, isChecked);
}
}
