Flow type spread appears unsupported as of 6.25.0

[rsolomon]

Given the following code:

export type Test1 = {
  a: number,
};

export type Test2 = {
  ...Test1,
  b: string,
};

And running eslint@3.19.0 with babel-core@6.25.0 yields the following error:

Cannot read property '1' of undefined
TypeError: Cannot read property '1' of undefined
    at scope.references.forEach.reference (node_modules/eslint/lib/rules/no-use-before-define.js:206:83)

Note that disabling the no-use-before-define rule does fix the problem, but it suggests that there's still something underlying that is unsupported.

[rosskevin]

This might be due to earlier dependencies in your transitive dependency tree. What is your output of yarn list babel-core babel-types?

If you can't get your dependencies updated, you can force up these with yarn --flat.

[soda0289]

Sounds like a duplicate of this: #485
I'm working on a solution should be posted soon.

[rsolomon]

Aye I did see that one, but the error being reported is different. I wasn't 100% sure if it was the same root cause. Happy to close this one if so.

[soda0289]

The problem is with the scope analysis tool. We currently monkey patch it to handle type definitions but it needs to be updated to handle spread.

[kmiyashiro]

Edit: Sorry, this is probably a bug in eslint-plugin-flowtype. (gajus/eslint-plugin-flowtype#207)

I also get an error, although it's a different one. I'm using babel-core@6.25 and babel-eslint@7.2.3. Is this just an error in eslint-plugin-flowtype?

type Props = {
  foo: string
}

type OtherProps = {
  ...Props
}

output of eslint

Cannot read property 'type' of undefined
TypeError: Cannot read property 'type' of undefined
    at /Users/kelly/src/product-store/node_modules/eslint-plugin-flowtype/dist/rules/noDupeKeys.js:76:31
    at arrayEach (/Users/kelly/src/product-store/node_modules/lodash/lodash.js:537:11)
    at Function.forEach (/Users/kelly/src/product-store/node_modules/lodash/lodash.js:9359:14)
    at EventEmitter.checkForDuplicates (/Users/kelly/src/product-store/node_modules/eslint-plugin-flowtype/dist/rules/noDupeKeys.js:71:22)
    at emitOne (events.js:96:13)
    at EventEmitter.emit (events.js:188:7)
    at NodeEventGenerator.applySelector (/Users/kelly/src/product-store/node_modules/eslint/lib/util/node-event-generator.js:265:26)
    at NodeEventGenerator.applySelectors (/Users/kelly/src/product-store/node_modules/eslint/lib/util/node-event-generator.js:294:22)
    at NodeEventGenerator.enterNode (/Users/kelly/src/product-store/node_modules/eslint/lib/util/node-event-generator.js:308:14)
    at CodePathAnalyzer.enterNode (/Users/kelly/src/product-store/node_modules/eslint/lib/code-path-analysis/code-path-analyzer.js:602:23)
    at CommentEventGenerator.enterNode (/Users/kelly/src/product-store/node_modules/eslint/lib/util/comment-event-generator.js:98:23)

I tried opening this in chrome dev tools and I see that there is indeed no value

[hzoo]

Just FYI babel-core is unrelated to eslint/babel-eslint. The only thing babel-eslint uses is the parser (babylon) and some utils like babel-types.

And yes it probably doesn't handle it given the rule that is erroring is no-undef/no-use-before-define

[irnc]

The issue seems to be because of missing range property on GenericTypeAnnotation and Identifier nodes stored under argument of ObjectTypeSpreadProperty.

Issue could be reproduced in ASP Explorer using babel-eslint-7.2.3, i.e. there is no range, while start and end are in place.

Using babylon7-7.0.0-beta.12 with ranges option gives the range property on all nodes.

babel-eslint@7.2.2 uses babylon@^6.16.1, so issue should be fixed somewhere between 6.16.1 and 7.0.0-beta.12.

[hzoo]

Clsoing for inactivity, I believe updating the package version should work

[niieani]

@hzoo I'm using the latest version of babel-eslint (8.0.2) and still get the same error from eslint.

[sibelius]

"eslint": "^4.19.1",
"babel-eslint": "^8.2.3",

fixed the issue for me