There’s no point in having a public member in a non-public type because objects that can’t access the type will never
have the chance to access the member.
This rule raises an issue when a type has methods, fields, or inner types with higher visibility than the type itself has.
Noncompliant code example
internal class MyClass
{
public static decimal PI = 3.14m; // Noncompliant
public int GetOne() // Noncompliant
{
return 1;
}
protected record NestedType // Noncompliant: outer class is internal
{
public bool FlipCoin() // Noncompliant: outer class is internal
{
return false;
}
// ...
}
}
Compliant solution
public class MyClass // Class visibility upgrade makes members compliant
{
public static decimal PI = 3.14m;
public int GetOne()
{
return 1;
}
protected record NestedType
{
public bool FlipCoin() // Outer type is public
{
return false;
}
// ...
}
}
Exceptions
User defined operators need to be public:
public static implicit operator byte(MyClass a) => 1; // Compliant
public static explicit operator MyClass(byte a) => new MyClass(a); // Compliant
Nested types, even if private, can be used and inherited in the parent type. In this case, the visibility of the outer type is considered.
internal class MyClass
{
private class NestedClass
{
public int PublicProperty { get; } // Noncompliant: should be internal
protected internal int ProtectedInternalProperty { get; } // Compliant: can be used in `InternalsVisibleTo` assemblies
internal int InternalProperty { get; } // Compliant: can be used in `InternalsVisibleTo` assemblies
protected int ProtectedProperty { get; } // Compliant: can be used in derived type
private protected int PrivateProtectedProperty { get; } // Compliant: can be used in derived type
private int PrivateProperty { get; }
}
}
