Use pattern matching (`not` operator) (IDE0083)

Overview

This style rule concerns the use of C# 9.0 not pattern, when possible.

Options specify the behavior that you want the rule to enforce. For information about configuring options, see Option format.

Property	Value	Description
Option name	csharp_style_prefer_not_pattern
Option values	`true`	Prefer to use the `not` pattern, when possible
	`false`	Prefer not to use the `not` pattern.
Default option value	`true`

The following examples show how code would be generated by code-generating features when the option is set to either true or false.

csharp

// csharp_style_prefer_not_pattern = true
var y = o is not C c;

// csharp_style_prefer_not_pattern = false
var y = !(o is C c);

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

csharp

#pragma warning disable IDE0083
// The code that's violating the rule is on this line.
#pragma warning restore IDE0083

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

ini

[*.{cs,vb}]
dotnet_diagnostic.IDE0083.severity = none

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

ini

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