value == null returns false when value is null

[Galad]

Description

The operator override of a discriminated union returns fase when the 2 operands are null.

Repro steps

1. Create a discriminated union such as union Maybe<T>{ None | Some<T>}

2. Use the following code:

   Maybe value = null; var result = (value == null);

Expected behavior

result is true

Actual behavior

result is false

Known workarounds

Use ReferenceEquals(value, null) when checking for null values.

Or

Modify the operator override in generated code with this: public static bool operator ==(Maybe<T> left, Maybe<T> right) => left?.Equals(right) ?? ReferenceEquals(right, default(T));

Related information

• Release 1.0.1
• .NET Framework 4.5