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Nullable directive is redundant (IDE0240)

  • Article
Property Value
Rule ID IDE0240
Title Nullable directive is redundant
Category Style
Subcategory Unnecessary code rules (expression-level preferences)
Applicable languages C#

Overview

This rule flags places where a #nullable directive is redundant. For example:

  • #nullable enable following another #nullable enable with no disablement in between.
  • #nullable enable in a project where nullable context is already enabled and hasn't been disabled.
  • #nullable restore following another #nullable restore with no nullability context change in between.
  • #nullable restore in a place that already matches the project context.

Options

This rule has no associated code-style options.

Example

// Code with violations (in a project with <Nullable>enable</Nullable>).
#nullable enable
Console.WriteLine("Hello world.");

// Fixed code.
Console.WriteLine("Hello world.");

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 IDE0240
// The code that's violating the rule is on this line.
#pragma warning restore IDE0240

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

[*.{cs,vb}]
dotnet_diagnostic.IDE0240.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