prefer-const not work with mutiple functions

Tell us about your environment

Node version: v10.16.3 npm version: v6.12.0 Local ESLint version: v6.6.0 Global ESLint version: v6.6.0

What did you expect to happen?

rule of prefer-const mess up in multiple function. the config is:

"prefer-const": [
      "warn",
      {
        "destructuring": "all",
        "ignoreReadBeforeAssign": true
      }
    ],

file a.js

function a (){
  let foo =0;
  foo = 1;
}
function b (){
  let foo =0;
  foo = 1;
}
function c (){
  let foo =0;
  foo = 1;
}

will eslint --fix output as

function a (){
  let foo =0;
  foo = 1;
}
function b (){
  const foo =0;
  foo = 1;
}
function c (){
  const foo =0;
  foo = 1;
}

Are you willing to submit a pull request to fix this bug?

Can’t help with resolution.

[g-plane]

Feel free to do this!

[kaicataldo]

Oh, I see - yes, that does look like a bug.