deconstructing witin LINQ comprehensions

[gafter]

It has been suggested that we support

from (a, b) in Pairs select a * b

from t in Pairs let (a, b) = t select a * b

[HaloFour]

Feels like a good first step towards #6877, starting with compiler-verified guaranteed to succeed tuple patterns.

[jamesqo]

Definitely seems like a good idea. +1

[ghost]

Ufff! for a moment I believed the asterisk (in the second example) represented an F-Sharpesque tuple style.

[atifaziz]

While we anxiously wait for this to appear in a future version of C#, one could deconstruct via a folding function for tuples, like this:

static class TupleExtensions
{
    public static TResult Fold<T1, T2, TResult>(this (T1, T2) tuple, Func<T1, T2, TResult> folder) =>
        folder(tuple.Item1, tuple.Item2);
}

and then use it in LINQ as follows:

from t in Pairs select t.Fold((a, b) => a * b);

[jcouv]

This language feature requests is tracked by dotnet/csharplang#189
I'll go ahead and close this Roslyn issue. Thanks