Nullable Reference Types: CS8618 and/or CS8625 should be consistently reported for static fields/properties. #27014
Description
Version Used: 05/14/18 Nullable Reference Types Preview (csc reports 2.8.0.62830 (e595ee27)) with Visual Studio 15.7.1
Demonstration Code:
(For your convenience, here's all of the examples in this issue in one project: PathogenPlayground/InconsistentWarningsOnStaticFieldsAndProperties)
public class TestClass
{
public string TestProperty { get; }
public string testField;
public static string TestStaticProperty { get; }
public static string testStaticField;
}Expected Behavior:
A CS8618 warning is reported for all four fields/properties.
Actual Behavior:
CS8618 is only reported for the instance field/property:
warning CS8618: Non-nullable property 'TestProperty' is uninitialized.
warning CS8618: Non-nullable field 'testField' is uninitialized.
Variations
While reporting this issue, I ended up finding out that adding null initializers and a static constructor changed the behavior as observed in the examples below:
Adding a static constructor does not change anything:
// (No warnings for TestStaticProperty or testStaticField)
public class TestClass
{
public static string TestStaticProperty { get; }
public static string testStaticField;
static TestClass() { }
}Adding null initializers does not change anything:
// (No warnings for TestStaticProperty or testStaticField)
public class TestClass
{
public static string TestStaticProperty { get; } = null;
public static string testStaticField = null;
}Adding both null initializers and a static constructor does change things:
public class TestClass
{
public static string TestStaticProperty { get; } = null; // warning CS8625: Cannot convert null literal to non-nullable reference or unconstrained type parameter.
public static string testStaticField = null; // warning CS8625: Cannot convert null literal to non-nullable reference or unconstrained type parameter.
static TestClass() { }
}