[compiler] Delete global mutation effects for objects passed as props

[gsathya]

Stack from ghstack (oldest at bottom):

• -> [compiler] Delete global mutation effects for objects passed as props #30458
• [compiler] Propogate effects stored in object props #30457
• [compiler] Add tests for incorrect global mutation detection #30456

With the tracked list of effects from the previous PR, we delete the
global mutation effects of object expressions that are passed as props.

To make this deletion easier, this PR changes the FunctionEffects to be
a Set.

While using the identity of the effect for comparison may seem less than
ideal, adding extra infrastructure for this purpose doesn't seem
worthwhile for now.

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Name	Status	Preview	Comments	Updated (UTC)
react-compiler-playground	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jul 25, 2024 1:14pm

[gsathya]

This is the key line, rest of the PR is about switching from Array to Set

[gsathya]

I considered other types not just object expressions, but we can't really be sure they're not synchronously invoking the captured function. Only object expressions seem safe.

[mvitousek]

I'm not sure that deleting the effect makes sense to me here. In particular, just because the GlobalMutation effect shouldn't be triggered by passing to JSX doesn't mean that it can't be triggered elsewhere--consider

// @flow

let global = 42;

component Foo() {
  const x = { f() { global = 23 } };
  x.f();
  return <Bar x={x} />;
}

I believe this approach would result in no error being raised here, which is definitely not what we want!

I wonder if instead it would make sense for objects (and arrays?) to track the effects of their properties separately, just like functions themselves do; when we reference the properties we'd add the effects to the effects of the object rather than the enclosing function, and we'd then add the effects to the function when we reference the object -- unless we're referencing it in a JSX prop, just like how we handle function expressions.