COM010: Range Contract Cannot Be Satisfied by the Type


Severity	Error
Reported by	PostSharp.Patterns.Common
Message	`[<Attribute>] cannot be applied to "<Target>" because no value of the type <Type> is within its range.`

Cause

The range contracts, RangeAttribute and the attributes derived from it such as GreaterThanAttribute, LessThanAttribute or StrictlyGreaterThanAttribute, check at run time that a value is between a minimum and a maximum. At build time, PostSharp compares the bounds with the range of the type of the field, property or parameter, ignoring Nullable<T>. When the minimum is greater than the largest value of the type, or the maximum is smaller than its smallest value, every assignment would fail, so PostSharp reports COM010.

<Attribute> is the name of the contract class, <Target> the field, property or parameter, and <Type> the name of its type.

In the following example, the StockLevel property is a byte, which cannot be greater than 255.

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using System;
using PostSharp.Patterns.Contracts;

namespace Errors.COM010_Error;

public class Product
{
    // No byte value can be greater than 1000.
    [GreaterThan( 1000 )]
    public byte StockLevel { get; set; }
}

public static class Program
{
    public static void Main()
    {
        var product = new Product { StockLevel = 10 };
        Console.WriteLine( $"Stock level: {product.StockLevel}" );
    }
}

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error COM010: COM010_Error.cs(10,17): [GreaterThanAttribute] cannot be applied to "Errors.COM010_Error.Product.StockLevel" because no value of the type Byte is within its range.

Resolution

Change the type of the field, property or parameter to a type that can hold the values of the range, for example short or int instead of byte.
Otherwise, correct the bounds of the contract so that they fall within the range of the type.

In the following example, StockLevel is a short, so the contract accepts 1500 and rejects 10.

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using System;
using PostSharp.Patterns.Contracts;

namespace Errors.COM010_Fixed;

public class Product
{
    // A short can hold values greater than 1000.
    [GreaterThan( 1000 )]
    public short StockLevel { get; set; }
}

public static class Program
{
    public static void Main()
    {
        var product = new Product { StockLevel = 1500 };
        Console.WriteLine( $"Stock level: {product.StockLevel}" );

        try
        {
            product.StockLevel = 10;
        }
        catch ( ArgumentOutOfRangeException e )
        {
            Console.WriteLine( $"{e.GetType().Name}: {e.Message}" );
        }
    }
}

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Stock level: 1500
ArgumentOutOfRangeException: The property 'StockLevel' must be greater than 1000. (Parameter 'value')

Cause

Resolution

See Also