Disallow await before exponential #12441
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JLHwung
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PR: Spec Compliance 👓
JLHwung
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Dec 2, 2020
| @@ -387,7 +387,7 @@ export type YieldExpression = NodeBase & { | |||
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| export type AwaitExpression = NodeBase & { | |||
| type: "AwaitExpression", | |||
| argument: ?Expression, | |||
| argument: Expression, | |||
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While yield is a yield expression, await is never valid and thus the argument here can not be null.
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Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/44668/ |
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nicolo-ribaudo
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Dec 3, 2020
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✔️ (After 3 months I have completely forgotten the context of this PR) |
This was referenced Mar 29, 2021
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Babel does not throw for await before exponential:
async () => await -1 ** 1, REPL,See here for the real diff.This PR forbids await expression when it is the
leftof an exponential expression. In the first commit we refactor current check so we don't have to checknode.left.typeandextra.parenthesized, instead we check it when an AwaitExpression / UnaryExpression is parsed. Then we forbid exponential after an await is parsed.This approach is also implemented in V8 (here) and acorn (here)