// Any copyright is dedicated to the Public Domain. // http://creativecommons.org/licenses/publicdomain/ //----------------------------------------------------------------------------- var BUGNUMBER = 1146136; var summary = 'Parenthesized "destructuring patterns" are not usable as destructuring ' + 'patterns'; print(BUGNUMBER + ": " + summary); /************** * BEGIN TEST * **************/ // Don't pollute the top-level script with eval references. var savedEval = this[String.fromCharCode(101, 118, 97, 108)]; function checkError(code, nonstrictErr, strictErr) { function helper(exec, prefix, err) { var fullCode = prefix + code; try { var f = exec(fullCode); var error = "no early error, parsed code <" + fullCode + "> using " + exec.name; if (typeof f === "function") { try { f(); error += ", and the function can be called without error"; } catch (e) { error +=", and calling the function throws " + e; } } throw new Error(error); } catch (e) { assertEq(e instanceof err, true, "expected " + err.name + ", got " + e + " " + "for code <" + fullCode + "> when parsed using " + exec.name); } } helper(Function, "", nonstrictErr); helper(Function, "'use strict'; ", strictErr); helper(savedEval, "", nonstrictErr); helper(savedEval, "'use strict'; ", strictErr); } // Parenthesized destructuring patterns don't trigger grammar refinement, so we // get the usual SyntaxError for an invalid assignment target, per // 12.14.1 second bullet. checkError("var a, b; ([a, b]) = [1, 2];", SyntaxError, SyntaxError); checkError("var a, b; ({a, b}) = { a: 1, b: 2 };", SyntaxError, SyntaxError); // *Nested* parenthesized destructuring patterns, on the other hand, do trigger // grammar refinement. But subtargets in a destructuring pattern must be // either object/array literals that match the destructuring pattern refinement // *or* valid simple assignment targets (or such things with a default, with the // entire subtarget unparenthesized: |a = 3| is fine, |(a) = 3| is fine for // destructuring in an expression, |(a = 3)| is forbidden). Parenthesized // object/array patterns are neither. And so 12.14.5.1 third bullet requires an // early SyntaxError. checkError("var a, b; ({ a: ({ b: b }) } = { a: { b: 42 } });", SyntaxError, SyntaxError); checkError("var a, b; ({ a: { b: (b = 7) } } = { a: {} });", SyntaxError, SyntaxError); checkError("var a, b; ({ a: ([b]) } = { a: [42] });", SyntaxError, SyntaxError); checkError("var a, b; [(a = 5)] = [1];", SyntaxError, SyntaxError); checkError("var a, b; ({ a: (b = 7)} = { b: 1 });", SyntaxError, SyntaxError); Function("var a, b; [(a), b] = [1, 2];")(); Function("var a, b; [(a) = 5, b] = [1, 2];")(); Function("var a, b; [(arguments), b] = [1, 2];")(); Function("var a, b; [(arguments) = 5, b] = [1, 2];")(); Function("var a, b; [(eval), b] = [1, 2];")(); Function("var a, b; [(eval) = 5, b] = [1, 2];")(); var repair = {}, demolition = {}; Function("var a, b; [(repair.man), b] = [1, 2];")(); Function("var a, b; [(demolition['man']) = 'motel', b] = [1, 2];")(); Function("var a, b; [(demolition['man' + {}]) = 'motel', b] = [1, 2];")(); // evade constant-folding function classesEnabled() { try { new Function("class B { constructor() { } }; class D extends B { constructor() { super(); } }"); return true; } catch (e) { if (!(e instanceof SyntaxError)) throw e; return false; } } if (classesEnabled()) { Function("var a, b; var obj = { x() { [(super.man), b] = [1, 2]; } };")(); Function("var a, b; var obj = { x() { [(super[8]) = 'motel', b] = [1, 2]; } };")(); Function("var a, b; var obj = { x() { [(super[8 + {}]) = 'motel', b] = [1, 2]; } };")(); // evade constant-folding } // As noted above, when the assignment element has an initializer, the // assignment element must not be parenthesized. checkError("var a, b; [(repair.man = 17)] = [1];", SyntaxError, SyntaxError); checkError("var a, b; [(demolition['man'] = 'motel')] = [1, 2];", SyntaxError, SyntaxError); checkError("var a, b; [(demolition['man' + {}] = 'motel')] = [1];", SyntaxError, SyntaxError); // evade constant-folding if (classesEnabled()) { checkError("var a, b; var obj = { x() { [(super.man = 5)] = [1]; } };", SyntaxError, SyntaxError); checkError("var a, b; var obj = { x() { [(super[8] = 'motel')] = [1]; } };", SyntaxError, SyntaxError); checkError("var a, b; var obj = { x() { [(super[8 + {}] = 'motel')] = [1]; } };", SyntaxError, SyntaxError); // evade constant-folding } checkError("var a, b; [f() = 'ohai', b] = [1, 2];", SyntaxError, SyntaxError); checkError("var a, b; [(f()) = 'kthxbai', b] = [1, 2];", SyntaxError, SyntaxError); Function("var a, b; ({ a: (a), b} = { a: 1, b: 2 });")(); Function("var a, b; ({ a: (a) = 5, b} = { a: 1, b: 2 });")(); /******************************************************************************/ if (typeof reportCompare === "function") reportCompare(true, true); print("Tests complete");