LuaLS / LuaLS/lua-language-server
Type narrowing in ternary operator not working correctly
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- Dominant language
- Lua
- Stars
- 4.4k
- Forks
- 442
- PR merge metrics
- No merged PRs in 30d
Description
How are you using the lua-language-server?
Visual Studio Code Extension (sumneko.lua)
Which OS are you using?
Windows
What is the issue affecting?
Type Checking
Expected Behaviour
In a ternary expression with type checking: "local a = type(x) == "something" and dosomething(x) or somethingelse(x)", the type should be narrowed for both cases
Actual Behaviour
The type is only narrowed for the first case (boolean here), in the second case it is still boolean or string
Reproduction steps
Copy the code
Additional Notes
No response
Log File
No response
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
Begin by reproducing the reported ternary expression in the Visual Studio Code extension on Windows and inspect the type-checking behavior for both branches. Confirm that the second branch narrows the value as expected rather than retaining the boolean-or-string type.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- lua
- Domain
- devtools
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100