args eval.md

Current

SuperCall : super Arguments

1. Let newTarget be GetNewTarget().
2. Assert: Type(newTarget) is Object.
3. Let func be ? GetSuperConstructor().
4. Let argList be ? ArgumentListEvaluation of Arguments.
5. Let result be ? Construct(func, argList, newTarget).
6. Let thisER be GetThisEnvironment().
7. Return ? thisER.BindThisValue(result). 

Possibly proposed in the PR

SuperCall : super Arguments

1. Let newTarget be GetNewTarget().
2. Assert: Type(newTarget) is Object.
3. Let func be GetSuperConstructor().
4. Let argList be ? ArgumentListEvaluation of Arguments.
5. ReturnIfAbrupt(func).
6. Let result be ? Construct(func, argList, newTarget).
7. Let thisER be GetThisEnvironment().
8. Return ? thisER.BindThisValue(result). 

Suggestion

SuperCall : super Arguments

1. Let newTarget be GetNewTarget().
2. Assert: Type(newTarget) is Object.
3. Let argList be ? ArgumentListEvaluation of Arguments.
4. Let func be ? GetSuperConstructor().
5. Let result be ? Construct(func, argList, newTarget).
6. Let thisER be GetThisEnvironment().
7. Return ? thisER.BindThisValue(result). 

Code wise:

var x = 0;
class C extends null {
  constructor() {
    super(x = 1);
  }
}

try {
  new C;
} catch {}

x === 1; // Current: false
// proposed + suggestion: true

Also:

var x = 0;
class C extends Object {
  constructor() {
    super(x = 1);
  }
}

Object.setPrototypeOf(C, parseInt);

try {
  new C;
} catch {}

x === 1; // Current: false
// proposed + suggestion: true

Suggested effects:

var x = 0;
var getproto = false;
class C extends null {
  constructor() {
    super(x = 1);
  }
}

var P = new Proxy(C, {
  getPrototypeOf() {
    getproto = true;
    return null;
  }
});

try {
  new P;
} catch {}

x === 1; // Current spec: false (x === 0)
// proposed + suggestion: true

getproto; // Current: true
// proposed in the PR: getproto is true
// w/ suggested spec: getproto is false