💅 lint/correctness/noUnusedVariables false positives

[mrazauskas]

Environment information

CLI:
  Version:                      1.8.0
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Platform:
  CPU Architecture:             aarch64
  OS:                           macos

Environment:
  BIOME_LOG_DIR:                unset
  NO_COLOR:                     unset
  TERM:                         "xterm-256color"
  JS_RUNTIME_VERSION:           "v20.14.0"
  JS_RUNTIME_NAME:              "node"
  NODE_PACKAGE_MANAGER:         "yarn/3.8.2"

Biome Configuration:
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Linter:
  JavaScript enabled:           true
  JSON enabled:                 true
  CSS enabled:                  false
  Recommended:                  true
  All:                          false
  Enabled rules:
  performance/noDelete
  suspicious/noCatchAssign
  suspicious/noUnsafeNegation
  style/noImplicitBoolean
  style/useImportType
  complexity/noMultipleSpacesInRegularExpressionLiterals
  a11y/useValidLang
  complexity/noUselessEmptyExport
  suspicious/useNamespaceKeyword
  suspicious/useValidTypeof
  suspicious/noAssignInExpressions
  a11y/useValidAriaRole
  correctness/noConstantCondition
  a11y/useAriaActivedescendantWithTabindex
  style/useDefaultParameterLast
  complexity/noEmptyTypeParameters
  correctness/noConstructorReturn
  style/useSelfClosingElements
  suspicious/noDuplicateParameters
  style/useTemplate
  correctness/noUnusedLabels
  complexity/noUselessTernary
  correctness/noUnreachableSuper
  suspicious/noCompareNegZero
  suspicious/noExplicitAny
  correctness/noSwitchDeclarations
  a11y/noAutofocus
  correctness/noUnsafeOptionalChaining
  correctness/noConstAssign
  suspicious/noControlCharactersInRegex
  complexity/noUselessTypeConstraint
  style/noVar
  suspicious/noDoubleEquals
  suspicious/noRedundantUseStrict
  style/useLiteralEnumMembers
  suspicious/noGlobalIsNan
  suspicious/noEmptyInterface
  suspicious/noSkippedTests
  suspicious/noMisleadingCharacterClass
  correctness/noPrecisionLoss
  suspicious/noRedeclare
  correctness/noStringCaseMismatch
  correctness/noSetterReturn
  correctness/noInvalidConstructorSuper
  suspicious/noImplicitAnyLet
  suspicious/noFallthroughSwitchClause
  suspicious/noUnsafeDeclarationMerging
  complexity/noUselessThisAlias
  correctness/noUnreachable
  a11y/useKeyWithClickEvents
  suspicious/noDuplicateObjectKeys
  complexity/noThisInStatic
  complexity/useOptionalChain
  correctness/noInnerDeclarations
  suspicious/noDuplicateCase
  a11y/useValidAnchor
  complexity/useRegexLiterals
  correctness/noSelfAssign
  style/noUselessElse
  style/useShorthandFunctionType
  style/useSingleCaseStatement
  suspicious/noShadowRestrictedNames
  a11y/useMediaCaption
  complexity/noUselessLabel
  complexity/noUselessCatch
  correctness/noUnsafeFinally
  a11y/useAriaPropsForRole
  style/useCollapsedElseIf
  correctness/noNonoctalDecimalEscape
  style/useEnumInitializers
  a11y/useHtmlLang
  suspicious/noDuplicateTestHooks
  style/useWhile
  complexity/useArrowFunction
  style/noInferrableTypes
  a11y/noNoninteractiveTabindex
  complexity/useSimpleNumberKeys
  correctness/useYield
  a11y/noInteractiveElementToNoninteractiveRole
  style/useNumericLiterals
  correctness/noUnnecessaryContinue
  suspicious/noApproximativeNumericConstant
  suspicious/noImportAssign
  suspicious/noLabelVar
  correctness/noGlobalObjectCalls
  style/noParameterProperties
  suspicious/useDefaultSwitchClauseLast
  a11y/useAltText
  correctness/noEmptyCharacterClassInRegex
  suspicious/noSuspiciousSemicolonInJsx
  suspicious/noSparseArray
  a11y/useIframeTitle
  suspicious/noPrototypeBuiltins
  a11y/noSvgWithoutTitle
  correctness/noVoidElementsWithChildren
  style/useAsConstAssertion
  suspicious/noDebugger
  style/useExportType
  complexity/noUselessLoneBlockStatements
  style/noArguments
  a11y/useValidAriaValues
  suspicious/noMisleadingInstantiator
  suspicious/noThenProperty
  suspicious/noGlobalAssign
  suspicious/noCommentText
  suspicious/useGetterReturn
  suspicious/noDuplicateJsxProps
  a11y/noPositiveTabindex
  correctness/noEmptyPattern
  complexity/noExcessiveNestedTestSuites
  security/noDangerouslySetInnerHtmlWithChildren
  a11y/useKeyWithMouseEvents
  style/useNamingConvention
  suspicious/noExtraNonNullAssertion
  correctness/noRenderReturnValue
  correctness/useExhaustiveDependencies
  security/noGlobalEval
  style/noNonNullAssertion
  a11y/noRedundantRoles
  complexity/useFlatMap
  correctness/useIsNan
  correctness/noUnusedVariables
  style/useConst
  suspicious/noGlobalIsFinite
  suspicious/noSelfCompare
  suspicious/noAsyncPromiseExecutor
  security/noDangerouslySetInnerHtml
  style/useNodejsImportProtocol
  a11y/noDistractingElements
  style/useConsistentArrayType
  complexity/noWith
  suspicious/noArrayIndexKey
  style/useForOf
  suspicious/noDuplicateClassMembers
  complexity/noExtraBooleanCast
  performance/noAccumulatingSpread
  a11y/useValidAriaProps
  a11y/noRedundantAlt
  correctness/noChildrenProp
  suspicious/noConfusingLabels
  suspicious/noConfusingVoidType
  suspicious/noFocusedTests
  a11y/useButtonType
  a11y/noAriaUnsupportedElements
  correctness/noFlatMapIdentity
  style/useShorthandAssign
  a11y/noBlankTarget
  a11y/useHeadingContent
  correctness/useValidForDirection
  correctness/noUnusedPrivateClassMembers
  correctness/noVoidTypeReturn
  correctness/noInvalidUseBeforeDeclaration
  a11y/noAriaHiddenOnFocusable
  style/useBlockStatements
  a11y/useAnchorContent
  complexity/noUselessRename
  correctness/noInvalidNewBuiltin
  style/useNumberNamespace
  complexity/noUselessConstructor
  a11y/noAccessKey
  style/useExponentiationOperator
  style/noUnusedTemplateLiteral
  complexity/noUselessSwitchCase
  style/noNegationElse
  correctness/noUndeclaredVariables
  suspicious/useAwait
  style/useSingleVarDeclarator
  suspicious/noExportsInTest
  a11y/noNoninteractiveElementToInteractiveRole
  style/noCommaOperator
  suspicious/noConsoleLog
  suspicious/useIsArray
  a11y/noHeaderScope
  complexity/noUselessFragments
  suspicious/noMisrefactoredShorthandAssign
  complexity/noForEach
  suspicious/noClassAssign
  correctness/noUnusedImports
  suspicious/noFunctionAssign

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  Open Documents:               0

Rule name

noUnusedVariables

Playground link

https://biomejs.dev/playground/?lintRules=all&code=ZQB4AHAAbwByAHQAIAB0AHkAcABlACAAQwBsAGEAcwBzAGwAaQBrAGUAIAA9ACAAbgBlAHcAIAAoAGEAcgBnADoAIAB1AG4AawBuAG8AdwBuACkAIAA9AD4AIABzAHQAcgBpAG4AZwA7AAoACgBlAHgAcABvAHIAdAAgAHQAeQBwAGUAIABGAHUAbgBjAHQAaQBvAG4AbABpAGsAZQAgAD0AIAAoAGEAcgBnADoAIAB1AG4AawBuAG8AdwBuACkAIAA9AD4AIABzAHQAcgBpAG4AZwA7AAoA

Expected result

As you see in the playground, arg in type Classlike = new (arg: unknown) => string is reported as unused. Seems like this is a mistake, because arg in type Functionlike = (arg: unknown) => string is not reported as unused.

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