False Positive Error with 'this' and object literal shorthand

[jbcpollak]

What version of ESLint are you using?

2.9.0

What parser (default, Babel-ESLint, etc.) are you using?

Node v5.7.1, server side code, not using Babel

Please show your full configuration:

// Based on the awesome config from walmart labs:
//https://github.com/walmartlabs/eslint-config-defaults
{
    "extends": "defaults/configurations/google",
    "rules": {
        "max-len": [2, 110, 2],
        "indent": [2, "tab"],
        "dot-location": [2, "property"],
        "no-mixed-spaces-and-tabs": [2, "smart-tabs"],
        "no-console": [2],
        "no-var": [2]
    },
    "env": {
        "node": true,
        "es6": true,
        "mocha": true
    },
    "ecmaFeatures": {
        "modules": true,
        "classes": true,
        "arrowFunctions": true,
        "blockBindings": true,
        "templateStrings": true
    }
}

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

    myFunc() {

        let that = 1;

        log.debug({
            that,
            this
        }, 'log message here');
    }

What did you expect to happen?

No error should be returned

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

  52:4  error  'this' is not defined  no-undef

This code works as expected:

    myFunc() {

        let that = 1;

        log.debug({
            that,
            this: this
        }, 'log message here');
    }

Probably a rare usecase, but in this case we wanted to log 'this' in our logger and have it appear as 'this'.

I think this is a regression, as I think this code has been in place for a while without throwing an error and with the same eslint config. We've just upgraded eslint.

[mysticatea]

Thank you for this issue.

let foo = {this};

This is a syntax error.
If you use shorthand properties, you cannot use keywords there.

https://tc39.github.io/ecma262/2016/#prod-ObjectLiteral

PropertyDefinition -> IdentifierReference -> Identifier -> IdentifierName but not ReserevedWord

I will open an issue on Acorn later.

[jbcpollak]

Interesting. I see it doesn't work in Chrome - either Node accepted it or I never hit that log condition, which seems unlikely. Thanks.

[mysticatea]

This has been fixed in Acorn.
I'm waiting for the next release.

[mysticatea]

Now Acorn v3.2.0 has been released: https://github.com/ternjs/acorn/releases/tag/3.2.0