Defining a variable to itself that is undefined raises no errors

[pinn3]

Example:

var variable1 = variable1
let variable2 = variable2
const variable3 = variable3

[not-an-aardvark]

Relevant ESLint rule: no-use-before-define

[feross]

Good catch. We could try enabling the following rule:

    "no-use-before-define": [2, { "functions": false, "classes": false }]

Even with the most lax options to no-use-before-define, there are still way too many false positives (and this rule is not automatically fixable with standard --fix)

1..422
# tests 422
# pass  402
# fail  20

If eslint adds an option that doesn't flag the following as invalid, then we can do this. Otherwise, it's just too disruptive to valid code.

function myFn () {
  // Variable "a" is not necessarily used before it is defined
  console.log(a)
}
var a = 5

[feross]

I opened an issue on eslint to add the necessary option: eslint/eslint#7111

[feross]

Duplicate of #636

[feross]

(Btw, this will be part of standard v9.)