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[no-use-before-define] False positive with optional chaining #1104

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jeroenvisser101 opened this issue Oct 18, 2019 · 4 comments · Fixed by #1169
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[no-use-before-define] False positive with optional chaining #1104

jeroenvisser101 opened this issue Oct 18, 2019 · 4 comments · Fixed by #1169
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bug Something isn't working has pr there is a PR raised to close this package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin scope analyser Issues that are caused by bugs/incomplete cases in the scope analyser
Milestone
scope analysis re...

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@jeroenvisser101
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Repro

{
  "rules": {
    "@typescript-eslint/no-use-before-define": ["error"]
  }
}
const updatedAt = data?.updatedAt;
//                      ^^^^^^^^^
// 'updatedAt' was used before it was defined. (@typescript-eslint/no-use-before-define)

Expected Result
Would not produce any errors.

Actual Result
Produces an error:

// 'updatedAt' was used before it was defined. (@typescript-eslint/no-use-before-define)

Additional Info
This issue seems to only happen when the variable name is the same as the property name. For instance, the code below does not show the warning:

const timestamp = data?.updatedAt;

Versions

package version
@typescript-eslint/parser 2.4.0
TypeScript 3.7.0-beta (15 Oct 2019)
ESLint 6.5.1
node 12.11.1
npm 6.11.3
yarn 1.19.1
@jeroenvisser101 jeroenvisser101 added package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin triage Waiting for team members to take a look labels Oct 18, 2019
@bradzacher bradzacher added bug Something isn't working and removed triage Waiting for team members to take a look labels Oct 19, 2019
This was referenced Oct 19, 2019
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Closed
@bradzacher bradzacher changed the title [no-use-before-define] Optional chaining confuses rule (TS 3.7) [no-use-before-define] False positive with optional chaining Oct 21, 2019
@bradzacher bradzacher added the scope analyser Issues that are caused by bugs/incomplete cases in the scope analyser label Oct 21, 2019
@bradzacher bradzacher mentioned this issue Oct 26, 2019
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@ghost
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ghost commented Oct 29, 2019

FWIW eslint(no-undef) also complains the same thing.

@bradzacher bradzacher mentioned this issue Oct 29, 2019
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@bradzacher
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This is known - #1116

@Nizarius Nizarius mentioned this issue Nov 4, 2019
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This was referenced Nov 5, 2019
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@bradzacher bradzacher added the has pr there is a PR raised to close this label Nov 8, 2019
@peoplenarthax
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This is known - #1116

Hej, in #1116 the do not ref to the same error, they refer to no-undef while here is "@typescript-eslint/no-use-before-define" what fails as well

@bradzacher
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That was in response to the the comment directly above, which said that no-undef has the error as well...

If you have an issue, please file a new one.

@typescript-eslint typescript-eslint locked as resolved and limited conversation to collaborators Nov 19, 2019
@bradzacher bradzacher added this to the scope analysis rewrite milestone Apr 6, 2020
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bug Something isn't working has pr there is a PR raised to close this package: eslint-plugin Issues related to @typescript-eslint/eslint-plugin scope analyser Issues that are caused by bugs/incomplete cases in the scope analyser
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Milestone
scope analysis rewrite
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feat(parser): handle optional chaining in scope analysis Nizarius/typescript-eslint
3 participants
@jeroenvisser101 @bradzacher @peoplenarthax