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fix(33054): allow variables starting with an underscore in for/of statement (#36739)

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This commit is contained in:
Alexander T
2020-03-30 21:18:18 +03:00
committed by GitHub
parent 96f01227d4
commit d8170faee1
10 changed files with 230 additions and 2 deletions
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15
src/compiler/checker.ts
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@@ -31013,6 +31013,18 @@ namespace ts {
return tryCast(getRootDeclaration(node), isParameter);
}
function isValidUnusedLocalDeclaration(declaration: Declaration): boolean {
if (isBindingElement(declaration) && isIdentifierThatStartsWithUnderscore(declaration.name)) {
return !!findAncestor(declaration.parent, ancestor =>
isArrayBindingPattern(ancestor) || isVariableDeclaration(ancestor) || isVariableDeclarationList(ancestor) ? false :
isForOfStatement(ancestor) ? true : "quit"
);
}
return isAmbientModule(declaration) ||
(isVariableDeclaration(declaration) && isForInOrOfStatement(declaration.parent.parent) || isImportedDeclaration(declaration)) && isIdentifierThatStartsWithUnderscore(declaration.name!);
}
function checkUnusedLocalsAndParameters(nodeWithLocals: Node, addDiagnostic: AddUnusedDiagnostic): void {
// Ideally we could use the ImportClause directly as a key, but must wait until we have full ES6 maps. So must store key along with value.
const unusedImports = createMap<[ImportClause, ImportedDeclaration[]]>();
@@ -31026,8 +31038,7 @@ namespace ts {
}
for (const declaration of local.declarations) {
if (isAmbientModule(declaration) ||
(isVariableDeclaration(declaration) && isForInOrOfStatement(declaration.parent.parent) || isImportedDeclaration(declaration)) && isIdentifierThatStartsWithUnderscore(declaration.name!)) {
if (isValidUnusedLocalDeclaration(declaration)) {
continue;
}