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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Inconsistent tsc behavior on TS 5.4","articleBody":"### 🔎 Search Terms\r\n\r\n\"tsc inconsistent behavior\", \"tsc 0 errors\", \"ts 5.4 bug\", \"5.4.0-dev.20240219\"\r\n\r\n### 🕗 Version \u0026 Regression Information\r\n\r\nI wanted to update TS in our project from `v5.3.3` to `v5.4.3`. And I noticed several weird things:\r\n- When I was switching TS version in VS Code, it wasn't showing any errors. But `tsc --noEmit` was showing 2 errors. I thought that VS Code was just not ready to support `v5.4.3` yet. But the new version comes with `v5.4.3` and it still doesn't work correctly.\r\n- I run `tsc --noEmit`. It shows `2 errors`.  If I open a problematic file and put `// @ts-expect-error`, it shows only `1 error`. But if I remove that line, it instantly shows `0 errors`.\r\n\r\nThis changed between versions `5.4.0-dev.20240218` and `5.4.0-dev.20240219`.\r\n\r\n`5.4.0-dev.20240219` is the first version where I see this problem. I checked `@next` version which is `5.5.0-dev.20240412` and the error is still there.\r\n\r\nUnfortunately, I wasn't able to make a reproducible example due complexity of the code. But both errors are about `unknown` type where it should be detected just fine.\r\n\r\n### ⏯ Playground Link\r\n\r\n_No response_\r\n\r\n### 💻 Code\r\n\r\n_No response_\r\n\r\n### 🙁 Actual behavior\r\n\r\n- It doesn't show errors in VS Code\r\n- It shows errors in a console. But after applying `// @ts-expect-error` and removing that line, it shows `0 errors`.\r\n\r\n### 🙂 Expected behavior\r\n\r\n- Errors in VS Code are detected\r\n- It shows errors in a console. After applying `// @ts-expect-error` and removing that line, it shows all previous errors.\r\n\r\n### Additional information about the issue\r\n\r\n_No response_","author":{"url":"https://github.com/olegafx","@type":"Person","name":"olegafx"},"datePublished":"2024-04-12T22:47:27.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":6},"url":"https://github.com/58175/TypeScript/issues/58175"}