microsoft / microsoft/TypeScript
unreachable code detected not work for if clause.
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Description
TypeScript Version: 3.9.2
Search Terms: unreachable
Code
const hel2 = (x: number) => {
switch (typeof x) {
case 'number': return 0
}
x // Unreachable code detected
}
const hel12 = (x: number) => {
if(typeof x === 'number'){
return 0;
}
x // expect same error here!
}
Expected behavior:
in commnet
Actual behavior:
in commnet
Related Issues:
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the TypeScript code sample and its Playground link, comparing unreachable-code diagnostics after the switch and if statements. Trace the compiler's unreachable-code analysis for these two control-flow forms and verify that equivalent cases produce the expected diagnostic before and after the change.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100