Use Frozen collections instead of Immutable

OpenRewrite.Recipes.Net9.UseFrozenCollections

Replace ToImmutableDictionary() with ToFrozenDictionary() and ToImmutableHashSet() with ToFrozenSet(). Frozen collections (.NET 8+) provide better read performance for collections populated once and read many times.

Tags

• modernization
• csharp
• dotnet

Recipe source

This recipe is only available to users of Moderne.

This recipe is available under the Moderne Proprietary License.

Used by

This recipe is used as part of the following composite recipes:

• Migrate to .NET 9

Usage

In order to run C# recipes, you will need to use the Moderne CLI.

Once the CLI is installed, you can install this C# recipe package by running the following command:

Install the recipe package

mod config recipes nuget install OpenRewrite.MigrateDotNet

Then, you can run the recipe via:

Run the recipe

mod run . --recipe OpenRewrite.Recipes.Net9.UseFrozenCollections