💅 Consistent crash on malformed ternary

[fmajestic]

Environment information

CLI:
  Version:                      1.5.3
  Color support:                true

Platform:
  CPU Architecture:             x86_64
  OS:                           linux

Environment:
  BIOME_LOG_DIR:                unset
  NO_COLOR:                     unset
  TERM:                         "xterm-256color"
  JS_RUNTIME_VERSION:           "v21.5.0"
  JS_RUNTIME_NAME:              "node"
  NODE_PACKAGE_MANAGER:         "bun/1.0.25"

Biome Configuration:
  Status:                       Loaded successfully
  Formatter disabled:           false
  Linter disabled:              false
  Organize imports disabled:    false
  VCS disabled:                 true

Workspace:
  Open Documents:               0

Rule name

lint/correctness/noUnusedVariables

Playground link

https://biomejs.dev/playground/?lintRules=all&code=dAB5AHAAZQAgAFQAbwBQAGEAcwBjAGEAbABDAGEAcwBlADwAUwAgAGUAeAB0AGUAbgBkAHMAIABzAHQAcgBpAG4AZwA%2BACAAPQAgAFMAIABlAHgAdABlAG4AZABzACAAYAAkAHsAaQBuAGYAZQByACAAUAByAGUAZgBpAHgAfQBgACAAPwAgADoAIAA7AA%3D%3D

Expected result

I'm getting this crash message:

Source Location: /home/runner/work/biome/biome/crates/biome_js_semantic/src/semantic_model/model.rs:334:46
Thread Name: main
Message: no entry found for key

Just as the placeholder for this field says, "It should not throw an error." 😝

Code of Conduct

• I agree to follow Biome's Code of Conduct

[ematipico]

The code that you pasted is not valid. Look at the playground, and even Prettier throws an error. And TS too

I'm not sure why we don't throw any diagnostic though, that's weird.

[fmajestic]

Yeah, that's why I specifically said malformed ternary :D. const [xyy:?:""\n} = bar; is also invalid code but doesn't cause a hard crash.

I managed to narrow down the crash to that specific lint rule, but it happened while I was editing a file and typed in an "empty" ternary like that.

[ematipico]

Yeah, but the issue is not the linter. It's a parser issue :)

[togami2864]

I'll take a look:)

[togami2864]

The parser seems to be working fine, but the issue only reproduces in the production environment🤔

Screen.Recording.2024-02-04.at.16.43.37.mov

[ah-yu]

Hey @togami2864 , I took a look at this issue before and have some observations that I hope will be helpful:

• This issue only happens when the NoUnusedVariable rule is enabled.
• This issue disappears when the true branch of the condition type is not empty playground

I guess you can explore the issue more from here

biome/crates/biome_js_semantic/src/events.rs

Lines 484 to 487 in ee9b3ac

	// Delay the declaration of parameter types that are inferred.
	// Their scope corresponds to the true branch of the conditional type.
	self.infers
	.push(TsTypeParameterName::unwrap_cast(node.syntax().clone()));

[togami2864]

@ah-yu Awesome! Thank you!

[Conaclos]

@togami2864 Are you still working on it? If not, I could take a look :)

[togami2864]

How quickly did you fix it 🎉 Thank you!