Invalid ExpressionStatement node when using a custom actions with parameters

[mcous]

Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.

What version of ESLint are you using?

8.49.0

What version of eslint-plugin-svelte are you using?

2.33.1

What did you do?

I encountered an interesting ESLint crash that appears to be an bad interaction between eslint-plugin-svelte, eslint-plugin-sonarjs, and @typescript-eslint/parser. Since the crash is primarily triggered by passing an argument to a Svelte action, I decided to file the issue here, though the actual cause may lie elsewhere!

With the sonarjs/no-unused-collection rule enabled, if the following conditions are met, ESLint will crash:

1. You have a Svelte component
2. Using lang="ts"
3. That import's a custom action
4. And attaches that action to an element
5. And passes an argument to that action

<script lang="ts">
  import { customAction } from "./action.js";
</script>

<p use:customAction={"hello"}>hello world</p>

The particular SonarJS rule above (to paraphrase) runs:

if (
  node.type === 'ExpressionStatement' &&
  node.expression.type === 'AssignmentExpression'
) {
  // ...
}

However, the following node gets passed to the rule:

Statement: {
  type: 'ExpressionStatement',
  directive: undefined,
  expression: null,
  range: [ 96, 145, [length]: 2 ],
  loc: { start: { line: 5, column: 20 }, end: { line: 6, column: 23 } },
  parent: {
    type: 'Program',
    // ...
  }
}

Since expression is null, expression.type crashes ESLint with TypeError: Cannot read properties of null (reading 'type'). I do not believe expression is allowed to be null, but I cannot figure out what exactly is producing this node.

What did you expect to happen?

Passing an argument to an imported custom Svelte action should not cause an ESLint crash, regardless of the plugins and rules I'm using.

What actually happened?

Oops! Something went wrong! :(

ESLint: 8.49.0

TypeError: Cannot read properties of null (reading 'type')
Occurred while linting /Users/mc/sandbox/no-empty-collection/component.svelte:1
Rule: "sonarjs/no-unused-collection"
    at isElementWrite (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:149:30)
    at isRead (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:118:18)
    at isUnusedCollection (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:84:18)
    at Array.filter (<anonymous>)
    at collectUnusedCollections (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:54:25)
    at /Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:59:9
    at Array.forEach (<anonymous>)
    at collectUnusedCollections (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:58:23)
    at Program:exit (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected][email protected]/node_modules/eslint-plugin-sonarjs/lib/rules/no-unused-collection.js:41:17)
    at ruleErrorHandler (/Users/mc/sandbox/no-empty-collection/node_modules/.pnpm/[email protected]/node_modules/eslint/lib/linter/linter.js:1051:28)

Link to GitHub Repo with Minimal Reproducible Example

https://github.com/mcous/eslint-svelte-null-expression-repro

Additional comments

I'd be interested in narrowing this reproduction down further if it was helpful (e.g. with svelte-eslint-parser directly), but I'm having trouble figuring out how the Svelte parser interacts with @typescript-eslint/parser

[ota-meshi]

Thanks for the bug report.
I think the parser is probably creating the variable scope incorrectly.
The parser tries to edit the scope manager generated by typescript-eslint to make it understand Svelte scopes, but I think something is probably wrong there.

[baseballyama]

I found that the issue occurs because retrieving the parent of a node obtained from the ScopeManager leads to a node that exists only in virtual code. However, I’m not sure what needs to be done to fundamentally fix this. Would it be better to create a custom ScopeManager?🤔