Cannot read property 'superCalled' of undefined

[warent]

Tell us about your environment

• ESLint Version:
  ^3.8.1
• Node Version:
  7.6.0
• npm Version:
  4.1.2

What parser (default, Babel-ESLint, etc.) are you using?
"babel-eslint": "^7.0.0",
"eslint": "^3.8.1",
"eslint-config-react-app": "^0.6.2",
"eslint-plugin-flowtype": "^2.21.0",
"eslint-plugin-import": "^2.2.0",
"eslint-plugin-jsx-a11y": "^2.2.3",
"eslint-plugin-react": "^6.10.0"

Please show your full configuration:

{
  "extends": "react-app",
  "rules": {
    "semi": "warn",
    "no-mixed-spaces-and-tabs": "warn",
    "space-before-blocks": "warn",
    "space-unary-ops": "warn",
    "space-in-parens": "warn",
    "semi-spacing": "warn",
    "indent": ["warn", 2],
    "quotes": ["warn", "single"],
    "no-duplicate-imports": "warn",
    "jsx-quotes": ["warn", "prefer-double"],
    "react/jsx-curly-spacing": [2, "always"],
    "constructor-super": "warn",
    "prefer-spread": "warn",
    "no-var": "warn",
    "no-trailing-spaces": "warn",
    "object-curly-spacing": ["warn", "always"],
    "import/order": ["warn", { "groups": ["builtin", "external", "internal", "parent", "sibling", "index"], "newlines-between": "always" }],
    "no-multiple-empty-lines": ["warn", { "max": 1, "maxEOF": 1 }],
    "import/no-webpack-loader-syntax": "warn"
  },
  "globals": {
    "chrome": true
  }
}

What did you do? Please include the actual source code causing the issue.

class Extender {}
class BugProof extends Extender {

  constructor(props) {
    super(props);

    try {
      let arr = [];
      for (let a of arr) {

      }
    } catch (err) {

    }
  }
  
}

What did you expect to happen?
It shouldn't give any error

What actually happened? Please include the actual, raw output from ESLint.

file: 'bug.js'
severity: 'Error'
message: 'Parsing error: Unexpected token

  19 |   
  20 | 
> 21 | 
     | ^'
at: '21,1'
source: 'eslint'

The location of the "Parsing error: Unexpected token" will change depending on the last line edited.

[kaicataldo]

I haven't been able to reproduce, but whoever is looking into this should start with the no-this-before-super rule.

[warent]

Please note that the error goes away when the for loop is altered:

class Extender {}
class BugProof extends Extender {

  constructor(props) {
    super(props);

    try {
      for (let i = 0; i < 1; i++) {

      }
    } catch (err) {

    }
  }
}

If we keep the for..of loop, the error will also go away by one of the following:

• Removing the extends
• Removing the try..catch

[kaicataldo]

I can recreate this with the latest version of ESLint with the above code and this minimal config:

{
    "env": {
      "es6": true
    },
    "rules": {
      "no-this-before-super": "error"
    }
}

[aladdin-add]

@kaicataldo I find the error similar error seems occur in rule constructor-super: https://github.com/eslint/eslint/blob/master/lib/rules/constructor-super.js#L132

        function isCalledInSomePath(segment) {
            return segment.reachable && segInfoMap[segment.id].calledInSomePaths;
        }

segInfoMap[segment.id] sometimes can be undefined.

[not-an-aardvark]

It's possible that this is a bug in the core code path analysis logic.

[gyandeeps]

@mysticatea Any insight on this?

[mysticatea]

Oh, I'm sorry, I had overlooked this issue.
I will take a look.

[mysticatea]

It looks a bug in code path analysis. If ForInStatement#right is the first location which can throw a reference error in the outer try block, it has generated wrong code path. I need more investigation.