# Compiler Error CS0151

A value of an integral type expected

A variable was used in a situation where an integral data type was required. For more information, see Types.

## Example of ambiguous conversion

This error can occur when there is no conversion or if the available implicit conversions result in an ambiguous situation. The following example generates CS0151:

public class MyClass
{
public static implicit operator int (MyClass aa)
{
return 0;
}

public static implicit operator long (MyClass aa)
{
return 0;
}

public static void Main()
{
MyClass a = new MyClass();

// Compiler cannot choose between int and long.
switch (a)   // CS0151
// try the following line instead
// switch ((int)a)
{
case 1:
break;
}
}
}


## Example of void method

A void method invocation in a switch match expression generates CS0151. You can fix the error by calling a method that returns an integral type such as int or long instead.

class C
{
static void Main()
{
switch (M()) // CS0151
{
default:
break;
}
}

static void M()
{
}
}