Simplify new expression (IDE0090)

Property Value
Rule ID IDE0090
Title Simplify new expression
Category Style
Subcategory Language rules (expression-level preferences)
Applicable languages C# 9.0+
Options csharp_style_implicit_object_creation_when_type_is_apparent


This style rule concerns the use of C# 9.0 target-typed new expressions when the created type is apparent.


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_implicit_object_creation_when_type_is_apparent
Option values true Prefer target-typed new expressions when created type is apparent
false Do not prefer target-typed new expressions
Default option value true
// csharp_style_implicit_object_creation_when_type_is_apparent = true
C c = new();
C c2 = new() { Field = 0 };

// csharp_style_implicit_object_creation_when_type_is_apparent = false
C c = new C();
C c2 = new C() { Field = 0 };

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 IDE0090
// The code that's violating the rule is on this line.
#pragma warning restore IDE0090

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

dotnet_diagnostic.IDE0090.severity = none

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

dotnet_analyzer_diagnostic.category-Style.severity = none

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

See also