Wrong code suggestion when using "Mapped Types" as function parameter

[lNaymonl]

Type: Bug

Extension version: 5.3.20230827

Version: 1.81.1 (user setup)
Commit: 6c3e3dba23e8fadc360aed75ce363ba185c49794
Date: 2023-08-09T22:22:42.175Z
Electron: 22.3.18
ElectronBuildId: 22689846
Chromium: 108.0.5359.215
Node.js: 16.17.1
V8: 10.8.168.25-electron.0
OS: Windows_NT x64 10.0.19045

Problem:
The Codesuggestion shows "1", "2", "3", "4" event though a is "valA". When hovering it also shows that b has type "1" | "2". And when i select "3" or "4" it gives me the following error:
Argument of type '"3"' is not assignable to parameter of type '"1" | "2"'.

Expected:
The Codesuggestion should only display"1" and "2".

Source Code:

enum myEnum {
 valA = "valA",
 valB = "valB",
}

interface myEnumParamMapping {
 ["valA"]: "1" | "2";
 ["valB"]: "3" | "4";
}

function myFunction<K extends keyof typeof myEnum>(a: K, b: myEnumParamMapping[K]) {
 console.log({ a, b });
}

myFunction("valA", "2");

[13OnTheCode]

Elmo (@lNaymonl) My TypeScript version is 5.2.2, and when I tried to reproduce your issue, everything seems to be working fine, unless I missed something.

[andrewbranch]

I can reproduce this. Elmo (@lNaymonl) 拾叁 (@13OnTheCode) could you both post your tsconfig.json settings please?

[13OnTheCode]

Andrew Branch (@andrewbranch)

"compilerOptions": {
 "strict": true,
 "noEmit": true,
 "allowJs": true,
 "skipLibCheck": true,
 "isolatedModules": true,
 "esModuleInterop": true,
 "strictNullChecks": true,
 "resolveJsonModule": true,
 "useDefineForClassFields": true,
 "noUncheckedIndexedAccess": true,
 "allowImportingTsExtensions": true,
 "allowSyntheticDefaultImports": true,
 "forceConsistentCasingInFileNames": true
}

[andrewbranch]

Still repros for me with those settings 👀

[andrewbranch]

Mateusz Burzyński (@Andarist) does this look familiar to you?

[Andarist]

Yes, Im already investigating this and gonna likely put up a PR for this soon-ish

[andrewbranch]

Could have sworn either you or I have fixed this about 20 times already in the past

[lNaymonl]

I can reproduce this. Elmo (@lNaymonl) 拾叁 (@13OnTheCode) could you both post your tsconfig.json settings please?

{
 "compileOnSave": false,
 "compilerOptions": {
 "downlevelIteration": true,
 "module": "es2020",
 "outDir": "./dist/out-tsc",
 "sourceMap": true,
 "declaration": false,
 "moduleResolution": "node",
 "emitDecoratorMetadata": true,
 "experimentalDecorators": true,
 "target": "es2018",
 "resolveJsonModule": true,
 "allowSyntheticDefaultImports": true,
 "skipLibCheck": true,
 "typeRoots": [
 "node_modules/@types"
 ],
 "lib": [
 "es2017",
 "dom"
 ],
 "baseUrl": ".",
 "paths": {
 "globalize": [
 "../node_modules/globalize/dist/globalize"
 ],
 "globalize/*": [
 "../node_modules/globalize/dist/globalize/*"
 ],
 "cldr": [
 "../node_modules/cldrjs/dist/cldr"
 ],
 "cldr/*": [
 "../node_modules/cldrjs/dist/cldr/*"
 ]
 }
 }
}

[lNaymonl]

If i try it in VS, it works like a charm.
I also tried it without the vscode extension, which worked as well.

[Andarist]

I prepared a fix for this here: #55552