false positive no-unsafe-member-access when accessing same class fields inside $derived

[Theo-Steiner]

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?

@eslint/js@9.31.0

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

eslint-plugin-svelte@3.11.0

What did you do?

Configuration

import js from "@eslint/js";
import sveltePlugin from "eslint-plugin-svelte";
import tseslint from "typescript-eslint";
export default tseslint.config(
  js.configs.recommended,
  ...tseslint.configs.recommended,
  ...sveltePlugin.configs["flat/recommended"],
  {
    files: ['**/*.svelte.ts'],
    languageOptions: {
      parserOptions: {
        parser: tseslint.parser,
        extraFileExtensions: [".svelte"],
        projectService: true
      },
    }
  },
  {
  	rules: {
			'@typescript-eslint/no-unsafe-member-access': 'error',
		}
  }
);

export class Product {
  x = $state(1)
  y = $state(2)
  // broken
  result = $derived(this.x * this.y) // Unsafe member access .x on an `any` value. [@typescript-eslint/no-unsafe-member-access], Unsafe member access .y on an `any` value. [@typescript-eslint/no-unsafe-member-access]
}

What did you expect to happen?

accessing fields of the same class (this.x or this.y) from a call to $derived should infer the correct this of the surrounding class.

What actually happened?

a false positive no-unsafe-member-access error is triggered as this is inferred as any inside $derived

Link to GitHub Repo with Minimal Reproducible Example

eslint playground

Additional comments

Workaround

the error can be dodged by using $derived.by since the this type is inferred correctly inside the callback function