/// <summary>
/// Return the default value constant for the given type,
/// or null if the default value is not a constant.
/// </summary>
public static ConstantValue GetDefaultValue(this TypeSymbol type)
{
// SPEC: A default-value-expression is a constant expression (§7.19) if the type
// SPEC: is a reference type or a type parameter that is known to be a reference type (§10.1.5).
// SPEC: In addition, a default-value-expression is a constant expression if the type is
// SPEC: one of the following value types:
// SPEC: sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, bool, or any enumeration type.
Debug.Assert((object)type != null);
if (type.IsErrorType())
{
return(null);
}
if (type.IsReferenceType)
{
return(ConstantValue.Null);
}
if (type.IsValueType)
{
if (type.IsEnumType())
{
throw new NotImplementedException();
//type = type.GetEnumUnderlyingType();
}
switch (type.SpecialType)
{
case SpecialType.System_SByte:
case SpecialType.System_Byte:
case SpecialType.System_Int16:
case SpecialType.System_UInt16:
case SpecialType.System_Int32:
case SpecialType.System_UInt32:
case SpecialType.System_Int64:
case SpecialType.System_UInt64:
case SpecialType.System_Char:
case SpecialType.System_Boolean:
case SpecialType.System_Single:
case SpecialType.System_Double:
case SpecialType.System_Decimal:
return(ConstantValue.Default(type.SpecialType));
}
}
return(null);
}
private static bool IsPossiblyByRefTypeParameter(TypeSymbol type)
{
if (type.IsTypeParameter())
{
return(true);
}
if (type.IsErrorType())
{
//var byRefReturnType = type as ByRefReturnErrorTypeSymbol;
//return ((object)byRefReturnType != null) && byRefReturnType.ReferencedType.IsTypeParameter();
throw new NotImplementedException();
}
return(false);
}