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camc314
f8e6c6ccf8
`packages/codegen` can turn valid JavaScript into unparseable output when a `yield` expression appears in a classic `for` loop initializer and its argument contains an `in` operator.
For example, this input is valid:
```js
function* g(o) {
for (yield (1 in o); false;);
}
```
The JavaScript printer previously dropped the required grouping:
```js
function* g(o) {
for (yield 1 in o; false;);
}
```
An unparenthesized `in` is not allowed at this position in a classic `for` initializer. The same problem affects `yield*`, nested yields, and assignments inside the yield argument.
The printer now preserves the parentheses:
```js
function* g(o) {
for (yield (1 in o); false;);
}
```
The `for` printer already marks its initializer with `CTX_FORBID_IN`, but `printYieldExpression` discarded that context and printed its argument with `CTX_NONE`. The yield dispatch now passes its incoming context to `printYieldExpression`, which forwards only `CTX_FORBID_IN` to the argument when the yield expression is unwrapped. The argument retains its existing `PREC_YIELD` precedence.
When precedence requires parentheses around the entire yield expression, those parentheses already permit `in` inside. The argument context is cleared in that case, avoiding redundant inner parentheses:
```js
// Input
function* g(o) {
for ((yield (1 in o)) + 1; false;);
}
// Output
function* g(o) {
for ((yield 1 in o) + 1; false;);
}
```
Both `yield` and `yield*` use this path. Outside a restricted initializer, ordinary yields continue to omit unnecessary grouping: `yield (1 in o)` prints as `yield 1 in o`.
The correction applies to both ordinary and source-map-enabled builds and brings the JavaScript printer in line with the Rust fix in #26413.
16 lines
426 B
JavaScript
16 lines
426 B
JavaScript
function* g(o) {
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for (yield (1 in o); false;);
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for (x = yield (1 in o); false;);
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for (yield yield (1 in o); false;);
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for (yield (x = (1 in o)); false;);
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for ((yield (1 in o)) + 1; false;);
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yield (1 in o);
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for (yield* (1 in o); false;);
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for (x = yield* (1 in o); false;);
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for (yield* yield (1 in o); false;);
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for (yield* (x = (1 in o)); false;);
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for ((yield* (1 in o)) + 1; false;);
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yield* (1 in o);
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}
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