NetFabric.Hyperlinq.Analyzer

A Roslyn Analyzer that contains several rules to help improve enumeration performance when using C#.

Note: This analyzer is independent of NetFabric.Hyperlinq. The rules may be useful when you only use foreach, IEnumerable<T>, IAsyncEnumerable<T>, System.Linq or System.Linq.Async.

Rule ID	Category	Severity	Notes
HLQ001	Performance	Warning	Assigment to interface causes boxing of enumerator
HLQ002	Compiler	Error	Enumerable cannot be null.
HLQ003	Performance	Warning	Public methods should return highest admissible level interface.
HLQ004	Performance	Warning	The enumerator returns a reference to the item.
HLQ005	Performance	Warning	Avoid use of Single() and SingleOrDefault()
HLQ006	Performance	Warning	GetEnumerator() or GetAsyncEnumerator() should return a value type.
HLQ007	Performance	Warning	Consider returning a non-disposable enumerator.
HLQ008	Performance	Info	The enumerable is a value type. Consider making it readonly.
HLQ009	Performance	Info	Consider removing an empty optional enumerator method.
HLQ011	Compiler	Error	Mutable value-type enumerators cannot be stored in a readonly field.
HLQ012	Performance	Warning	Consider using CollectionsMarshal.AsSpan() when iterating a List<T>.
HLQ013	Performance	Warning	Consider using foreach when iterating an array or a Span<T>.

Usage

Visual Studio Marketplace

Install the NetFabric.Hyperlinq.Analyzer extension from the Visual Studio Marketplace.

Nuget package

Add the NetFabric.Hyperlinq.Analyzer package to your project using your favorite NuGet client.

If added manually to the .csproj, make sure to set PrivateAssets to all so that it's not added as a dependency. A floating version can be used to get the latest version.

<PackageReference Include="NetFabric.Hyperlinq.Analyzer" Version="2.*">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>

References

• Enumeration in .NET by Antão Almada
• NetFabric.Hyperlinq — Optimizing LINQ by Antão Almada
• Unit testing a Roslyn Analyzer by Antão Almada

Credits

The following open-source projects are used to build and test this project:

• .NET
• coveralls
• coverlet
• ILRepack
• ILRepack.MSBuild.Task
• NetFabric.CodeAnalysis
• xUnit.net