JSTests/test262/test/language/expressions/object/dstr/gen-meth-dflt-ary-ptrn-rest-ary-elision.js

// This file was procedurally generated from the following sources:
// - src/dstr-binding/ary-ptrn-rest-ary-elision.case
// - src/dstr-binding/default/gen-method-dflt.template
/*---
description: Rest element containing an elision (generator method (default parameter))
esid: sec-generator-function-definitions-runtime-semantics-propertydefinitionevaluation
features: [generators, destructuring-binding, default-parameters]
flags: [generated]
info: |
    GeneratorMethod :
        * PropertyName ( StrictFormalParameters ) { GeneratorBody }

    1. Let propKey be the result of evaluating PropertyName.
    2. ReturnIfAbrupt(propKey).
    3. If the function code for this GeneratorMethod is strict mode code,
       let strict be true. Otherwise let strict be false.
    4. Let scope be the running execution context's LexicalEnvironment.
    5. Let closure be GeneratorFunctionCreate(Method,
       StrictFormalParameters, GeneratorBody, scope, strict).
    [...]

    9.2.1 [[Call]] ( thisArgument, argumentsList)

    [...]
    7. Let result be OrdinaryCallEvaluateBody(F, argumentsList).
    [...]

    9.2.1.3 OrdinaryCallEvaluateBody ( F, argumentsList )

    1. Let status be FunctionDeclarationInstantiation(F, argumentsList).
    [...]

    9.2.12 FunctionDeclarationInstantiation(func, argumentsList)

    [...]
    23. Let iteratorRecord be Record {[[iterator]]:
        CreateListIterator(argumentsList), [[done]]: false}.
    24. If hasDuplicates is true, then
        [...]
    25. Else,
        b. Let formalStatus be IteratorBindingInitialization for formals with
           iteratorRecord and env as arguments.
    [...]

    13.3.3.6 Runtime Semantics: IteratorBindingInitialization

    BindingRestElement : ... BindingPattern

    1. Let A be ArrayCreate(0).
    [...]
    3. Repeat
       [...]
       b. If iteratorRecord.[[done]] is true, then
          i. Return the result of performing BindingInitialization of
             BindingPattern with A and environment as the arguments.
       [...]

    13.3.3.6 Runtime Semantics: IteratorBindingInitialization

    ArrayBindingPattern : [ Elision ]

    1. Return the result of performing
       IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord
       as the argument.

    12.14.5.3 Runtime Semantics: IteratorDestructuringAssignmentEvaluation

    Elision : ,

    1. If iteratorRecord.[[done]] is false, then
       a. Let next be IteratorStep(iteratorRecord.[[iterator]]).
       b. If next is an abrupt completion, set iteratorRecord.[[done]] to true.
       c. ReturnIfAbrupt(next).
       d. If next is false, set iteratorRecord.[[done]] to true.
    2. Return NormalCompletion(empty).

---*/
var first = 0;
var second = 0;
function* g() {
  first += 1;
  yield;
  second += 1;
};

var callCount = 0;
var obj = {
  *method([...[,]] = g()) {
    assert.sameValue(first, 1);
    assert.sameValue(second, 1);
    callCount = callCount + 1;
  }
};

obj.method().next();
assert.sameValue(callCount, 1, 'generator method invoked exactly once');