OfType Followed by Some Operations Generates Non-compiling Code

[Java Roy]

I've only tested for Select and Where as delegates, but it may be more widespread. There are tests covering Skip and Take, and they seem to work fine. It will probably only affect operations that take a selector/predicate.

Here is some example user code that causes the problem:

TestData.ObjectStringArray.Gen().OfType<string>().Select(g => string.IsNullOrEmpty(g) ? '\0' : g[0])

TestData.ObjectStringArray.Gen().OfType<string>().Where(g => string.IsNullOrEmpty(g))

The Select generates (with most excluded for brevity)

internal struct Select_uF<TOut_p2> : IInternalStub<char>
    {
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal Select_uF(in OfType_p2<TOut_p2> source, global::System.Func<string, char> selector_uF) : this()
        {
            this.source_n2 = source.source_n2;
            this.selector_uF = selector_uF;
        }
        ...
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            public bool MoveNext()
            {
               ...
                while (true)
                {
                    ...
                    var current_p2 = (TOut_p2)(object)current_n2;
                    var current_uF = parent.selector_uF.Invoke(current_p2); // Error here
                    ...
                }

                return false;
            }

I think the constructor should take a Func<TOut_p2, char> instead of Func<string, char> as the error is Argument type 'TOut_p2' is not assignable to parameter type 'string'

Locally I inserted these two lines at https://github.com/cathei/LinqGen/blob/main/LinqGen.Tests/OperationTests.tt#L94 to generate failing tests:

("OfTypeSelect", "OfType<string>().Select(g => string.IsNullOrEmpty(g) ? '\0' : g[0])", "OfType<string>().Select(g => string.IsNullOrEmpty(g) ? '\0' : g[0])", castSources),
("OfTypeWhere", "OfType<string>().Where(g => string.IsNullOrEmpty(g))", "OfType<string>().Where(g => string.IsNullOrEmpty(g))", castSources),

[Maxwell Keonwoo Kang]

Thank you for reporting this issue! It was due to operations directly used the inferred type, not applying generic type arguments. It will be fixed in next release.

[Maxwell Keonwoo Kang]

Included in v0.2.2