Remove unnecessary discard (IDE0110)

Overview

This rule flags unnecessary discard patterns. A discard pattern is unnecessary when used in a context where it has no effect.

Options

This rule has no associated code-style options.

Example

// Code with violations
switch (o)
{
    case int _:
        Console.WriteLine("Value was an int");
        break;
    case string _:
        Console.WriteLine("Value was a string");
        break;
}

// Fixed code
switch (o)
{
    case int:
        Console.WriteLine("Value was an int");
        break;
    case string:
        Console.WriteLine("Value was a string");
        break;
}

Suppress a warning

If you want to suppress only a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable IDE0110
// The code that's violating the rule is on this line.
#pragma warning restore IDE0110

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.IDE0110.severity = none

To disable all of the code-style rules, set the severity for the category Style to none in the configuration file.

[*.{cs,vb}]
dotnet_analyzer_diagnostic.category-Style.severity = none

For more information, see How to suppress code analysis warnings.

See also

• Language rules
• Code style rules reference