static ExpressionSyntax GetDefaultValueExpression(SemanticModel semanticModel, MethodStatementSyntax methodStatement, TypeSyntax type)
{
var typeSymbol = semanticModel.GetTypeInfo(type).Type;
if (typeSymbol == null)
{
return(null);
}
if (typeSymbol.IsArrayType())
{
return(SyntaxFactory.ObjectCreationExpression(type));
}
if (typeSymbol.IsEnumType())
{
var members = type.GetMembers().OfType <EnumMemberDeclarationSyntax>();
if (!members.Any())
{
return(GetDefaultTypeExpression(type));
}
return(SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression, SyntaxFactory.Token(SyntaxKind.DotToken), SyntaxFactory.IdentifierName(members.First().Identifier)));
}
if (typeSymbol.IsKind(SymbolKind.DynamicType))
{
return(GetNothingExpression());
}
if (typeSymbol.IsReferenceType)
{
if (typeSymbol.GetTypeParameters().Any() && (methodStatement.TypeParameterList != null) && methodStatement.TypeParameterList.Parameters.Any())
{
return(GetDefaultTypeExpression(type));
}
return(GetNothingExpression());
}
switch (typeSymbol.SpecialType)
{
case SpecialType.System_Boolean:
return(SyntaxFactory.FalseLiteralExpression(SyntaxFactory.Token(SyntaxKind.FalseKeyword)));
case SpecialType.System_Char:
return(SyntaxFactory.LiteralExpression(SyntaxKind.CharacterLiteralExpression, SyntaxFactory.Literal('\0')));
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_Single:
case SpecialType.System_Double:
case SpecialType.System_Decimal:
return(SyntaxFactory.LiteralExpression(SyntaxKind.NumericLiteralExpression, SyntaxFactory.Literal(0)));
}
if (typeSymbol.IsNullableType())
{
return(GetNothingExpression());
}
if (typeSymbol.IsValueType)
{
return(SyntaxFactory.ObjectCreationExpression(type));
}
return(GetDefaultTypeExpression(type));
}