[compiler] Repro for object spread and Array.from with mutable iterators (#32520)

See newly added test fixtures. Repros fixed in later prs of this stack
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/32520).
* #32522
* #32521
* __->__ #32520

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-array-spread-mutable-iterator.expect.md

@@ -0,0 +1,87 @@
+
+## Input
+
+```javascript
+/**
+ * TODO: object spreads should have conditionally mutate semantics
+ *   Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) [3,1,5,4]
+ *   [3,1,5,4]
+ *   [4,1,5,4]
+ *   Forget:
+ *   (kind: ok) [3,1,5,4]
+ *   [3,1,5,4]
+ *   [4]
+ */
+
+function useBar({arg}) {
+  'use memo';
+
+  /**
+   * Note that mutableIterator is mutated by the later object spread. Therefore,
+   * `s.values()` should be memoized within the same block as the object spread.
+   * In terms of compiler internals, they should have the same reactive scope.
+   */
+  const s = new Set([1, 5, 4]);
+  const mutableIterator = s.values();
+
+  return [arg, ...mutableIterator];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useBar,
+  params: [{arg: 3}],
+  sequentialRenders: [{arg: 3}, {arg: 3}, {arg: 4}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; /**
+ * TODO: object spreads should have conditionally mutate semantics
+ *   Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) [3,1,5,4]
+ *   [3,1,5,4]
+ *   [4,1,5,4]
+ *   Forget:
+ *   (kind: ok) [3,1,5,4]
+ *   [3,1,5,4]
+ *   [4]
+ */
+
+function useBar(t0) {
+  "use memo";
+  const $ = _c(3);
+  const { arg } = t0;
+  let t1;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    const s = new Set([1, 5, 4]);
+    t1 = s.values();
+    $[0] = t1;
+  } else {
+    t1 = $[0];
+  }
+  const mutableIterator = t1;
+  let t2;
+  if ($[1] !== arg) {
+    t2 = [arg, ...mutableIterator];
+    $[1] = arg;
+    $[2] = t2;
+  } else {
+    t2 = $[2];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useBar,
+  params: [{ arg: 3 }],
+  sequentialRenders: [{ arg: 3 }, { arg: 3 }, { arg: 4 }],
+};
+
+```
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/bug-array-spread-mutable-iterator.js

@@ -0,0 +1,32 @@
+/**
+ * TODO: object spreads should have conditionally mutate semantics
+ *   Found differences in evaluator results
+ *   Non-forget (expected):
+ *   (kind: ok) [3,1,5,4]
+ *   [3,1,5,4]
+ *   [4,1,5,4]
+ *   Forget:
+ *   (kind: ok) [3,1,5,4]
+ *   [3,1,5,4]
+ *   [4]
+ */
+
+function useBar({arg}) {
+  'use memo';
+
+  /**
+   * Note that mutableIterator is mutated by the later object spread. Therefore,
+   * `s.values()` should be memoized within the same block as the object spread.
+   * In terms of compiler internals, they should have the same reactive scope.
+   */
+  const s = new Set([1, 5, 4]);
+  const mutableIterator = s.values();
+
+  return [arg, ...mutableIterator];
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useBar,
+  params: [{arg: 3}],
+  sequentialRenders: [{arg: 3}, {arg: 3}, {arg: 4}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo-granular-iterator-semantics.expect.md

@@ -0,0 +1,96 @@
+
+## Input
+
+```javascript
+import {useIdentity, ValidateMemoization} from 'shared-runtime';
+
+/**
+ * TODO fixture for granular iterator semantics:
+ * 1. ConditionallyMutate the iterator itself, depending on whether the iterator
+ *    is a mutable iterator.
+ * 2. Capture effect on elements within the iterator.
+ */
+function Validate({x, input}) {
+  'use no memo';
+  return (
+    <>
+      <ValidateMemoization inputs={[]} output={x[0]} onlyCheckCompiled={true} />
+      <ValidateMemoization
+        inputs={[input]}
+        output={x[1]}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+function useFoo(input) {
+  'use memo';
+  /**
+   * TODO: We should be able to memoize {} separately from `x`.
+   */
+  const x = Array.from([{}]);
+  useIdentity();
+  x.push([input]);
+  return <Validate x={x} input={input} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [1],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { useIdentity, ValidateMemoization } from "shared-runtime";
+
+/**
+ * TODO fixture for granular iterator semantics:
+ * 1. ConditionallyMutate the iterator itself, depending on whether the iterator
+ *    is a mutable iterator.
+ * 2. Capture effect on elements within the iterator.
+ */
+function Validate({ x, input }) {
+  "use no memo";
+  return (
+    <>
+      <ValidateMemoization inputs={[]} output={x[0]} onlyCheckCompiled={true} />
+      <ValidateMemoization
+        inputs={[input]}
+        output={x[1]}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+function useFoo(input) {
+  "use memo";
+  const $ = _c(3);
+
+  const x = Array.from([{}]);
+  useIdentity();
+  x.push([input]);
+  let t0;
+  if ($[0] !== input || $[1] !== x) {
+    t0 = <Validate x={x} input={input} />;
+    $[0] = input;
+    $[1] = x;
+    $[2] = t0;
+  } else {
+    t0 = $[2];
+  }
+  return t0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [1],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"inputs":[],"output":{}}</div><div>{"inputs":[1],"output":[1]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo-granular-iterator-semantics.js

@@ -0,0 +1,36 @@
+import {useIdentity, ValidateMemoization} from 'shared-runtime';
+
+/**
+ * TODO fixture for granular iterator semantics:
+ * 1. ConditionallyMutate the iterator itself, depending on whether the iterator
+ *    is a mutable iterator.
+ * 2. Capture effect on elements within the iterator.
+ */
+function Validate({x, input}) {
+  'use no memo';
+  return (
+    <>
+      <ValidateMemoization inputs={[]} output={x[0]} onlyCheckCompiled={true} />
+      <ValidateMemoization
+        inputs={[input]}
+        output={x[1]}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+function useFoo(input) {
+  'use memo';
+  /**
+   * TODO: We should be able to memoize {} separately from `x`.
+   */
+  const x = Array.from([{}]);
+  useIdentity();
+  x.push([input]);
+  return <Validate x={x} input={input} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [1],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo-type-inference-array-from.expect.md

@@ -0,0 +1,102 @@
+
+## Input
+
+```javascript
+import {useIdentity, ValidateMemoization} from 'shared-runtime';
+
+/**
+ * Fixture to assert that we can infer the type and effects of an array created
+ * with `Array.from`.
+ */
+function Validate({x, val1, val2}) {
+  'use no memo';
+  return (
+    <>
+      <ValidateMemoization
+        inputs={[val1]}
+        output={x[0]}
+        onlyCheckCompiled={true}
+      />
+      <ValidateMemoization
+        inputs={[val2]}
+        output={x[1]}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+function useFoo({val1, val2}) {
+  'use memo';
+  const x = Array.from([]);
+  useIdentity();
+  x.push([val1]);
+  x.push([val2]);
+  return <Validate x={x} val1={val1} val2={val2} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{val1: 1, val2: 2}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { useIdentity, ValidateMemoization } from "shared-runtime";
+
+/**
+ * Fixture to assert that we can infer the type and effects of an array created
+ * with `Array.from`.
+ */
+function Validate({ x, val1, val2 }) {
+  "use no memo";
+  return (
+    <>
+      <ValidateMemoization
+        inputs={[val1]}
+        output={x[0]}
+        onlyCheckCompiled={true}
+      />
+
+      <ValidateMemoization
+        inputs={[val2]}
+        output={x[1]}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+function useFoo(t0) {
+  "use memo";
+  const $ = _c(4);
+  const { val1, val2 } = t0;
+
+  const x = Array.from([]);
+  useIdentity();
+  x.push([val1]);
+  x.push([val2]);
+  let t1;
+  if ($[0] !== val1 || $[1] !== val2 || $[2] !== x) {
+    t1 = <Validate x={x} val1={val1} val2={val2} />;
+    $[0] = val1;
+    $[1] = val2;
+    $[2] = x;
+    $[3] = t1;
+  } else {
+    t1 = $[3];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{ val1: 1, val2: 2 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"inputs":[1],"output":[1]}</div><div>{"inputs":[2],"output":[2]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/todo-type-inference-array-from.js

@@ -0,0 +1,36 @@
+import {useIdentity, ValidateMemoization} from 'shared-runtime';
+
+/**
+ * Fixture to assert that we can infer the type and effects of an array created
+ * with `Array.from`.
+ */
+function Validate({x, val1, val2}) {
+  'use no memo';
+  return (
+    <>
+      <ValidateMemoization
+        inputs={[val1]}
+        output={x[0]}
+        onlyCheckCompiled={true}
+      />
+      <ValidateMemoization
+        inputs={[val2]}
+        output={x[1]}
+        onlyCheckCompiled={true}
+      />
+    </>
+  );
+}
+function useFoo({val1, val2}) {
+  'use memo';
+  const x = Array.from([]);
+  useIdentity();
+  x.push([val1]);
+  x.push([val2]);
+  return <Validate x={x} val1={val1} val2={val2} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [{val1: 1, val2: 2}],
+};

compiler/packages/snap/src/SproutTodoFilter.ts

@@ -462,6 +462,7 @@ const skipFilter = new Set([
 
   // bugs
   'bug-object-expression-computed-key-modified-during-after-construction-hoisted-sequence-expr',
+  'bug-array-spread-mutable-iterator',
   `bug-capturing-func-maybealias-captured-mutate`,
   'bug-aliased-capture-aliased-mutate',
   'bug-aliased-capture-mutate',