(=) and (<>) operators handle left operand being null incorrectly - throwing a NullReferenceException.
This is particularly unexpected, and makes these operators non-reflexive.

Repro steps

type Foo = Foo
let nullFoo = Unchecked.defaultof<Foo>

Foo = nullFoo // false - as expected
nullFoo = Foo // throws a NullReferenceException

Foo <> nullFoo // true - as expected
nullFoo <> Foo // throws a NullReferenceException

Expected behavior

(=) and (<>) operators should be reflexive.

Actual behavior

When the left operand of / first argument to the operator is null, a NullReferenceException is thrown.

Known workarounds

System.Object.Equals has the expected behaviour as described above.

Related information

Provide any related information

• Windows 7
• .NET 4.6.1
• F# 4.0
• Severity : within F# this is a relatively minor issue as you are unlikely to encounter null instances, however in interop scenarios this is fairly painful and, I would argue, extremely unexpected behaviour.