Struct can be made 'readonly' (IDE0250)

Property	Value
Rule ID	IDE0250
Title	Struct can be made 'readonly'
Category	Style
Subcategory	Unnecessary code rules (modifier preferences)
Applicable languages	C#
Options	`csharp_style_prefer_readonly_struct`

Overview

This rule flags structs that aren't marked readonly when all their members are marked readonly.

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_readonly_struct
Option values	`true`	Prefer to make a struct `readonly` when all its fields are `readonly`.
	`false`	Disables the rule.
Default option value	`true`

// Code with violations.
struct S
{
    readonly int i;
}

// Fixed code.
readonly struct S
{
    readonly int i;
}

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 IDE0250
// The code that's violating the rule is on this line.
#pragma warning restore IDE0250

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

[*.{cs,vb}]
dotnet_diagnostic.IDE0250.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