C# Error CS1942 – The type of the expression in the {0} clause is incorrect. Type inference failed in the call to ‘{1}’.

C# Error

CS1942 – The type of the expression in the {0} clause is incorrect. Type inference failed in the call to ‘{1}’.

Reason for the Error & Solution

The type of the expression in the ‘clause’ clause is incorrect. Type inference failed in the call to ‘method’.

This error is typically generated when the range variable has been given an incorrect explicit type.

To correct this error

1. If the range variable is explicitly typed, make sure that the type is either the same as, or implicitly convertible from, the type of the elements in the collection it iterates. If the range variable is preceded with the var keyword, remove var.

Example

The following code generates CS1942:

// cs1942.cs  
class Program  
    {  
        static void Main(string[] args)  
        {  
            var x = from var i in Enumerable.Range(1, 100) // CS1949  
                    select i; //CS1942  
        }  
    }  

CS1942 is related to CS1949 because the use of var with a range variable causes the underlying Cast<T> operation to fail because var is not a type.