diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts index 778e31b9c5ba7..9512facfc5735 100644 --- a/src/compiler/checker.ts +++ b/src/compiler/checker.ts @@ -16702,6 +16702,14 @@ namespace ts { } } + function isRemovedPropertyFromObjectSpread(node: Node) { + if (isBindingElement(node) && isObjectBindingPattern(node.parent)) { + const lastElement = lastOrUndefined(node.parent.elements); + return lastElement !== node && !!lastElement.dotDotDotToken; + } + return false; + } + function errorUnusedLocal(node: Node, name: string) { if (isIdentifierThatStartsWithUnderScore(node)) { const declaration = getRootDeclaration(node.parent); @@ -16711,7 +16719,10 @@ namespace ts { return; } } - error(node, Diagnostics._0_is_declared_but_never_used, name); + + if (!isRemovedPropertyFromObjectSpread(node.kind === SyntaxKind.Identifier ? node.parent : node)) { + error(node, Diagnostics._0_is_declared_but_never_used, name); + } } function parameterNameStartsWithUnderscore(parameterName: DeclarationName) { diff --git a/tests/baselines/reference/unusedLocalsAndObjectSpread.errors.txt b/tests/baselines/reference/unusedLocalsAndObjectSpread.errors.txt new file mode 100644 index 0000000000000..56f2ba927fb70 --- /dev/null +++ b/tests/baselines/reference/unusedLocalsAndObjectSpread.errors.txt @@ -0,0 +1,40 @@ +tests/cases/compiler/unusedLocalsAndObjectSpread.ts(21,18): error TS6133: 'bar' is declared but never used. +tests/cases/compiler/unusedLocalsAndObjectSpread.ts(28,21): error TS6133: 'bar' is declared but never used. + + +==== tests/cases/compiler/unusedLocalsAndObjectSpread.ts (2 errors) ==== + + declare var console: { log(a: any): void }; + + function one() { + const foo = { a: 1, b: 2 }; + // 'a' is declared but never used + const {a, ...bar} = foo; + console.log(bar); + } + + function two() { + const foo = { a: 1, b: 2 }; + // '_' is declared but never used + const {a: _, ...bar} = foo; + console.log(bar); + } + + function three() { + const foo = { a: 1, b: 2 }; + // 'a' is declared but never used + const {a, ...bar} = foo; // bar should be unused + ~~~ +!!! error TS6133: 'bar' is declared but never used. + //console.log(bar); + } + + function four() { + const foo = { a: 1, b: 2 }; + // '_' is declared but never used + const {a: _, ...bar} = foo; // bar should be unused + ~~~ +!!! error TS6133: 'bar' is declared but never used. + //console.log(bar); + } + \ No newline at end of file diff --git a/tests/baselines/reference/unusedLocalsAndObjectSpread.js b/tests/baselines/reference/unusedLocalsAndObjectSpread.js new file mode 100644 index 0000000000000..2878f1b5c5c9b --- /dev/null +++ b/tests/baselines/reference/unusedLocalsAndObjectSpread.js @@ -0,0 +1,67 @@ +//// [unusedLocalsAndObjectSpread.ts] + +declare var console: { log(a: any): void }; + +function one() { + const foo = { a: 1, b: 2 }; + // 'a' is declared but never used + const {a, ...bar} = foo; + console.log(bar); +} + +function two() { + const foo = { a: 1, b: 2 }; + // '_' is declared but never used + const {a: _, ...bar} = foo; + console.log(bar); +} + +function three() { + const foo = { a: 1, b: 2 }; + // 'a' is declared but never used + const {a, ...bar} = foo; // bar should be unused + //console.log(bar); +} + +function four() { + const foo = { a: 1, b: 2 }; + // '_' is declared but never used + const {a: _, ...bar} = foo; // bar should be unused + //console.log(bar); +} + + +//// [unusedLocalsAndObjectSpread.js] +var __rest = (this && this.__rest) || function (s, e) { + var t = {}; + for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0) + t[p] = s[p]; + if (s != null && typeof Object.getOwnPropertySymbols === "function") + for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) if (e.indexOf(p[i]) < 0) + t[p[i]] = s[p[i]]; + return t; +}; +function one() { + var foo = { a: 1, b: 2 }; + // 'a' is declared but never used + var a = foo.a, bar = __rest(foo, ["a"]); + console.log(bar); +} +function two() { + var foo = { a: 1, b: 2 }; + // '_' is declared but never used + var _ = foo.a, bar = __rest(foo, ["a"]); + console.log(bar); +} +function three() { + var foo = { a: 1, b: 2 }; + // 'a' is declared but never used + var a = foo.a, bar = __rest(foo, ["a"]); // bar should be unused + //console.log(bar); +} +function four() { + var foo = { a: 1, b: 2 }; + // '_' is declared but never used + var _ = foo.a, bar = __rest(foo, ["a"]); // bar should be unused + //console.log(bar); +} diff --git a/tests/cases/compiler/unusedLocalsAndObjectSpread.ts b/tests/cases/compiler/unusedLocalsAndObjectSpread.ts new file mode 100644 index 0000000000000..b042b412c8e33 --- /dev/null +++ b/tests/cases/compiler/unusedLocalsAndObjectSpread.ts @@ -0,0 +1,31 @@ +//@noUnusedLocals:true + +declare var console: { log(a: any): void }; + +function one() { + const foo = { a: 1, b: 2 }; + // 'a' is declared but never used + const {a, ...bar} = foo; + console.log(bar); +} + +function two() { + const foo = { a: 1, b: 2 }; + // '_' is declared but never used + const {a: _, ...bar} = foo; + console.log(bar); +} + +function three() { + const foo = { a: 1, b: 2 }; + // 'a' is declared but never used + const {a, ...bar} = foo; // bar should be unused + //console.log(bar); +} + +function four() { + const foo = { a: 1, b: 2 }; + // '_' is declared but never used + const {a: _, ...bar} = foo; // bar should be unused + //console.log(bar); +}