Variable in top level block scope is incorrectly captured

For the following snippet placed at the top level:

do {
    let w = "banana";
    function foo(){
        w = "bar";
    }
    foo();
    console.log(w);
} while(0)


JSC prints "banana", instead of "bar".

[Radar WebKit Bug Importer]

<rdar://problem/90639204>

[Jarred Sumner]

This seems to only happen when strict mode is off.


The following code doesn't reproduce the issue in jsc shell:

"use strict";

do {
  let w = "banana";
  function foo() {
    w = "bar";
  }
  foo();
  print(w);
} while (0);

But this code does:

do {
  let w = "banana";
  function foo() {
    w = "bar";
  }
  foo();
  print(w);
} while (0);

The variable is not even visible within the function:

do {
    let w = "banana";
    function foo(){
        console.log(w);
    }
    foo();
} while(0)

Result (unexpected): ReferenceError: Can't find variable: w

Unlike with arrow function:

do {
    let w = "banana";
    foo=()=>{
        console.log(w);
    };
    foo();
} while(0)

Result (as expected): banana