Seq(1, 2, 3).AsQueryable().Count() fails

[StanJav]

Seq(1, 2, 3).AsQueryable().Count() fails because MS uses Type.IsValueType to check parameters for linq methods (e.g. Count) and that doesn't work for struct.

See this: https://referencesource.microsoft.com/#system.core/Microsoft/Scripting/Ast/TypeUtils.cs,164)

Exception details:

System.ArgumentException : Expression of type 'LanguageExt.Seq`1[System.Int32]' cannot be used for parameter of type 'System.Collections.Generic.IEnumerable`1[System.Int32]' of method 'Int32 Count[Int32](System.Collections.Generic.IEnumerable`1[System.Int32])'
Parameter name: arg0

at System.Dynamic.Utils.ExpressionUtils.ValidateOneArgument(MethodBase method, ExpressionType nodeKind, Expression arguments, ParameterInfo pi, String methodParamName, String argumentParamName, Int32 index)
   at System.Linq.Expressions.Expression.Call(Expression instance, MethodInfo method, Expression arg0)
   at System.Linq.Expressions.Expression.Call(Expression instance, MethodInfo method, IEnumerable`1 arguments)
   at System.Linq.EnumerableRewriter.VisitMethodCall(MethodCallExpression m)
   at System.Linq.Expressions.MethodCallExpression.Accept(ExpressionVisitor visitor)
   at System.Linq.EnumerableExecutor`1.Execute()

[StanJav]

Sorry, closed for now. I am investigating one more very similar issue around IQueryable<T>.Freeze(). I will reopen later.

[StanJav]

@louthy I have added Enumerable & Queryable extensions for Lst, Set, Arr, Seq. It is ready for a review.

[louthy]

Thanks @StanJav - I'm still in London, but I'll probably head back this evening and be able to deploy to nu-get.