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using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkSwitcher.FromAssembly(typeof(Tests).Assembly).Run(args);

[MemoryDiagnoser(false)]
public class Tests
{
    private List<object> _objects = Enumerable.Range(0, 100).Select(i => (object)i.ToString()).ToList();

    [Benchmark]
    public int Count() => _objects.Cast<string>().Count();

    [Benchmark]
    public bool Contains() => _objects.Cast<string>().Contains("99");

    [Benchmark]
    public int SkipTakeCount() => _objects.Cast<string>().Skip(90).Take(10).Count();

    [Benchmark]
    public string First() => _objects.Cast<string>().First();
    
    [Benchmark]
    public string Last() => _objects.Cast<string>().Last();

    [Benchmark]
    public string[] ToArray() => _objects.Cast<string>().ToArray();
    
    [Benchmark]
    public List<string> ToList() => _objects.Cast<string>().ToList();

    [Benchmark]
    public int[] SelectToArray() => _objects.Cast<string>().Select(s => s.Length).ToArray();
}

Will this still throw System.InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Int32'.?

Enumerable.Range(0, 100).Select(i => (object)i.ToString()).ToList().Cast<int>().Count()

Will this still throw System.InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Int32'.?

Enumerable.Range(0, 100).Select(i => (object)i.ToString()).ToList().Cast<int>().Count()

Not as written. These changes are always a balance with which side effects are actually necessary. Where/why are you relying on Cast.Count evaluating the full input?

Will this still throw System.InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Int32'.?

Enumerable.Range(0, 100).Select(i => (object)i.ToString()).ToList().Cast<int>().Count()

Not as written. These changes are always a balance with which side effects are actually necessary. Where/why are you relying on Cast.Count evaluating the full input?

It was just something I thought about while reviewing the code and wanted to check if the behaviour change was intended / known. I don't think I am relying on the exception and/or Cast.Count evaluating the full input.