nothing-comparison

Flag x == nothing / x != nothing, which compares against nothing by value. nothing is the singleton instance of Nothing, so an identity test (=== / !==, or isnothing) is meant: it is faster and cannot be overloaded. The rule reports a safe fix rewriting == to === and != to !==.

Comparing against nothing by value:

if x == nothing
    1
end

warning: nothing-comparison
 --> example.jl:1:4
  |
1 | if x == nothing
  |    ^^^^^^^^^^^^ comparison against `nothing` by value; use `===` or `isnothing`
  = help: Replace `==` with `===`

After applying the fix:

if x === nothing
    1
end