Source code
Revision control
Copy as Markdown
Other Tools
// |jit-test| --fast-warmup; --no-threads
// Tests for an uninitialized-lexical in a frame slot.
// |y| holds the uninitialized-lexical magic across both suspends.
function* tdzLocal(x) {
yield x;
yield x + 1;
let y = x * 2;
return y;
}
// Several uninitialized locals, plus a live expression stack.
function* tdzManyLocals(x) {
let a = x + (yield x);
yield a;
let b = a + 1;
const c = b + 1;
let d = c + 1;
return d;
}
function drive(g, expected) {
let out = [], r;
while (!(r = g.next(1)).done) {
out.push(String(r.value));
}
out.push(String(r.value));
assertEq(out.join(","), expected);
}
for (let i = 0; i < 200; i++) {
drive(tdzLocal(3), "3,4,6");
drive(tdzManyLocals(5), "5,6,9");
}
// Reading the binding on the resume path, while it is still uninitialized,
// must throw.
function* tdzThrows(x) {
yield x;
y;
let y = x;
}
for (let i = 0; i < 200; i++) {
let g = tdzThrows(1);
assertEq(g.next().value, 1);
let caught = null;
try {
g.next();
} catch (e) {
caught = e;
}
assertEq(caught instanceof ReferenceError, true);
assertEq(caught.message.includes("can't access lexical declaration"), true);
}