56 lines
2.2 KiB
JavaScript
56 lines
2.2 KiB
JavaScript
// @flow @enableTransitivelyFreezeFunctionExpressions:false @enableNewMutationAliasingModel
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import {arrayPush, setPropertyByKey, Stringify} from 'shared-runtime';
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/**
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* Repro of a bug fixed in the new aliasing model.
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*
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* 1. `InferMutableRanges` derives the mutable range of identifiers and their
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* aliases from `LoadLocal`, `PropertyLoad`, etc
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* - After this pass, y's mutable range only extends to `arrayPush(x, y)`
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* - We avoid assigning mutable ranges to loads after y's mutable range, as
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* these are working with an immutable value. As a result, `LoadLocal y` and
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* `PropertyLoad y` do not get mutable ranges
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* 2. `InferReactiveScopeVariables` extends mutable ranges and creates scopes,
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* as according to the 'co-mutation' of different values
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* - Here, we infer that
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* - `arrayPush(y, x)` might alias `x` and `y` to each other
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* - `setPropertyKey(x, ...)` may mutate both `x` and `y`
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* - This pass correctly extends the mutable range of `y`
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* - Since we didn't run `InferMutableRange` logic again, the LoadLocal /
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* PropertyLoads still don't have a mutable range
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*
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* Note that the this bug is an edge case. Compiler output is only invalid for:
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* - function expressions with
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* `enableTransitivelyFreezeFunctionExpressions:false`
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* - functions that throw and get retried without clearing the memocache
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*
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* Found differences in evaluator results
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* Non-forget (expected):
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* (kind: ok)
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* <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
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* <div>{"cb":{"kind":"Function","result":11},"shouldInvokeFns":true}</div>
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* Forget:
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* (kind: ok)
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* <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
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* <div>{"cb":{"kind":"Function","result":10},"shouldInvokeFns":true}</div>
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*/
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function useFoo({a, b}: {a: number, b: number}) {
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const x = [];
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const y = {value: a};
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arrayPush(x, y); // x and y co-mutate
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const y_alias = y;
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const cb = () => y_alias.value;
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setPropertyByKey(x[0], 'value', b); // might overwrite y.value
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return <Stringify cb={cb} shouldInvokeFns={true} />;
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}
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export const FIXTURE_ENTRYPOINT = {
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fn: useFoo,
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params: [{a: 2, b: 10}],
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sequentialRenders: [
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{a: 2, b: 10},
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{a: 2, b: 11},
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],
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};
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