aalmada

public class RefEnumerationVariableAnalyzerTests : CodeFixVerifier
{
    protected override DiagnosticAnalyzer GetCSharpDiagnosticAnalyzer() 
        => new RefEnumerationVariableAnalyzer();

    protected override CodeFixProvider GetCSharpCodeFixProvider()
        => new RefEnumerationVariableCodeFixProvider();

    [Theory]
    [InlineData("TestData/HLQ004/NoDiagnostic/NoRef.cs")]

aalmada

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using System.Linq;

namespace NetFabric.Hyperlinq.Benchmarks
{
    [SimpleJob(RuntimeMoniker.Net472, baseline: true)]
    [SimpleJob(RuntimeMoniker.NetCoreApp50)]
    [MemoryDiagnoser]
    public class RangeContainsBenchmarks

aalmada

using BenchmarkDotNet.Attributes;
using System;
using System.Linq;

namespace ConsoleApp2
{
    [MemoryDiagnoser]
    [DisassemblyDiagnoser(printSource: true)]
    public class ArrayBenchmarks
    {

aalmada

Array.Int32.ArrayInt32WhereCount

References:

• JM.LinqFaster: 1.1.2
• LinqAF: 3.0.0.0
• StructLinq.BCL: 0.19.1
• NetFabric.Hyperlinq: 3.0.0-beta26

Results:

aalmada

public static Expression Using(ParameterExpression variable, Expression content)
{
    return variable.Type switch
    {
        {IsValueType: true} => ValueTypeUsing(variable, content),

        _ => ReferenceTypeUsing(variable, content)
    };

    static Expression ValueTypeUsing(Expression variable, Expression content)

aalmada

namespace NetFabric.Hyperlinq
{
    public interface IValueEnumerable<out T, out TEnumerator>
        : IEnumerable<T>
        where TEnumerator : struct, IEnumerator<T>
    {
        new TEnumerator GetEnumerator();
    }

    public interface IValueReadOnlyCollection<out T, out TEnumerator>

aalmada

public static int Count<TEnumerable, TEnumerator, TSource>(this TEnumerable source)
    where TEnumerable : IValueEnumerable<TSource, TEnumerator>
    where TEnumerator : struct, IEnumerator<TSource>
{
    using var enumerator = source.GetEnumerator();
    var count = 0;
    while (enumerator.MoveNext())
        count++;
    return count;
} 

aalmada

public class Enumerable<T>
{
    public Enumerable<T> GetEnumerator() 
        => this;

    public T Current 
        => default;

    public bool MoveNext() 
        => default;

aalmada

public static int Count<TEnumerable, TEnumerator, TSource>(this TEnumerable source)
    where TEnumerable : IValueEnumerable<TSource, TEnumerator>
    where TEnumerator : struct, IEnumerator<TSource>
{
    var counter = 0;
    using var enumerator = source.GetEnumerator();
    checked
    {
        while (enumerator.MoveNext())
            counter++;

aalmada

public static async ValueTask<int> CountAsync<TEnumerable, TEnumerator, TSource>(this TEnumerable source, CancellationToken cancellationToken = default)
    where TEnumerable : IAsyncValueEnumerable<TSource, TEnumerator>
    where TEnumerator : struct, IAsyncEnumerator<TSource>
{
    var counter = 0;
    var enumerator = source.GetAsyncEnumerator(cancellationToken);
    try
    {
        checked
        {