[compiler] Lower JSXMemberExpression with LoadLocal

`JSXMemberExpression` is currently the only instruction (that I know of) that directly references identifier lvalues without a corresponding `LoadLocal`.

This has some side effects:
- deadcode elimination and constant propagation now reach JSXMemberExpressions
- we can delete `LoweredFunction.dependencies` without dangling references (previously, the only reference to JSXMemberExpression objects in HIR was in function dependencies)
- JSXMemberExpression now is consistent with all other instructions (e.g. has a rvalue-producing LoadLocal)

'

compiler/packages/babel-plugin-react-compiler/src/HIR/BuildHIR.ts

@@ -3186,7 +3186,13 @@ function lowerJsxMemberExpression(
       loc: object.node.loc ?? null,
       suggestions: null,
     });
-    objectPlace = lowerIdentifier(builder, object);
+
+    const kind = getLoadKind(builder, object);
+    objectPlace = lowerValueToTemporary(builder, {
+      kind: kind,
+      place: lowerIdentifier(builder, object),
+      loc: exprPath.node.loc ?? GeneratedSource,
+    });
   }
   const property = exprPath.get('property').node.name;
   return lowerValueToTemporary(builder, {

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/invalid-jsx-lowercase-localvar.expect.md

@@ -0,0 +1,75 @@
+
+## Input
+
+```javascript
+import {Throw} from 'shared-runtime';
+
+/**
+ * Note: this is disabled in the evaluator due to different devmode errors.
+ * Found differences in evaluator results
+ *  Non-forget (expected):
+ *  (kind: ok) <invalidtag val="[object Object]"></invalidtag>
+ *  logs: ['Warning: <%s /> is using incorrect casing. Use PascalCase for React components, or lowercase for HTML elements.%s','invalidTag']
+ *
+ *  Forget:
+ *  (kind: ok) <invalidtag val="[object Object]"></invalidtag>
+ *  logs: [
+ *   'Warning: <%s /> is using incorrect casing. Use PascalCase for React components, or lowercase for HTML elements.%s','invalidTag',
+ *   'Warning: The tag <%s> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.%s','invalidTag',
+ *  ]
+ */
+function useFoo() {
+  const invalidTag = Throw;
+  /**
+   * Need to be careful to not parse `invalidTag` as a localVar (i.e. render
+   * Throw). Note that the jsx transform turns this into a string tag:
+   * `jsx("invalidTag"...
+   */
+  return <invalidTag val={{val: 2}} />;
+}
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { Throw } from "shared-runtime";
+
+/**
+ * Note: this is disabled in the evaluator due to different devmode errors.
+ * Found differences in evaluator results
+ *  Non-forget (expected):
+ *  (kind: ok) <invalidtag val="[object Object]"></invalidtag>
+ *  logs: ['Warning: <%s /> is using incorrect casing. Use PascalCase for React components, or lowercase for HTML elements.%s','invalidTag']
+ *
+ *  Forget:
+ *  (kind: ok) <invalidtag val="[object Object]"></invalidtag>
+ *  logs: [
+ *   'Warning: <%s /> is using incorrect casing. Use PascalCase for React components, or lowercase for HTML elements.%s','invalidTag',
+ *   'Warning: The tag <%s> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.%s','invalidTag',
+ *  ]
+ */
+function useFoo() {
+  const $ = _c(1);
+  let t0;
+  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
+    t0 = <invalidTag val={{ val: 2 }} />;
+    $[0] = t0;
+  } else {
+    t0 = $[0];
+  }
+  return t0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [],
+};
+
+```
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/invalid-jsx-lowercase-localvar.jsx

@@ -0,0 +1,29 @@
+import {Throw} from 'shared-runtime';
+
+/**
+ * Note: this is disabled in the evaluator due to different devmode errors.
+ * Found differences in evaluator results
+ *  Non-forget (expected):
+ *  (kind: ok) <invalidtag val="[object Object]"></invalidtag>
+ *  logs: ['Warning: <%s /> is using incorrect casing. Use PascalCase for React components, or lowercase for HTML elements.%s','invalidTag']
+ *
+ *  Forget:
+ *  (kind: ok) <invalidtag val="[object Object]"></invalidtag>
+ *  logs: [
+ *   'Warning: <%s /> is using incorrect casing. Use PascalCase for React components, or lowercase for HTML elements.%s','invalidTag',
+ *   'Warning: The tag <%s> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.%s','invalidTag',
+ *  ]
+ */
+function useFoo() {
+  const invalidTag = Throw;
+  /**
+   * Need to be careful to not parse `invalidTag` as a localVar (i.e. render
+   * Throw). Note that the jsx transform turns this into a string tag:
+   * `jsx("invalidTag"...
+   */
+  return <invalidTag val={{val: 2}} />;
+}
+export const FIXTURE_ENTRYPOINT = {
+  fn: useFoo,
+  params: [],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-local-memberexpr-tag-conditional.expect.md

@@ -27,11 +27,10 @@ import * as SharedRuntime from "shared-runtime";
 function useFoo(t0) {
   const $ = _c(1);
   const { cond } = t0;
-  const MyLocal = SharedRuntime;
   if (cond) {
     let t1;
     if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-      t1 = <MyLocal.Text value={4} />;
+      t1 = <SharedRuntime.Text value={4} />;
       $[0] = t1;
     } else {
       t1 = $[0];

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-local-memberexpr-tag.expect.md

@@ -22,10 +22,9 @@ import { c as _c } from "react/compiler-runtime";
 import * as SharedRuntime from "shared-runtime";
 function useFoo() {
   const $ = _c(1);
-  const MyLocal = SharedRuntime;
   let t0;
   if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = <MyLocal.Text value={4} />;
+    t0 = <SharedRuntime.Text value={4} />;
     $[0] = t0;
   } else {
     t0 = $[0];

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-lowercase-localvar-memberexpr-in-lambda.expect.md

@@ -0,0 +1,59 @@
+
+## Input
+
+```javascript
+import * as SharedRuntime from 'shared-runtime';
+import {invoke} from 'shared-runtime';
+function useComponentFactory({name}) {
+  const localVar = SharedRuntime;
+  const cb = () => <localVar.Stringify>hello world {name}</localVar.Stringify>;
+  return invoke(cb);
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useComponentFactory,
+  params: [{name: 'sathya'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import * as SharedRuntime from "shared-runtime";
+import { invoke } from "shared-runtime";
+function useComponentFactory(t0) {
+  const $ = _c(4);
+  const { name } = t0;
+  let t1;
+  if ($[0] !== name) {
+    t1 = () => (
+      <SharedRuntime.Stringify>hello world {name}</SharedRuntime.Stringify>
+    );
+    $[0] = name;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  const cb = t1;
+  let t2;
+  if ($[2] !== cb) {
+    t2 = invoke(cb);
+    $[2] = cb;
+    $[3] = t2;
+  } else {
+    t2 = $[3];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useComponentFactory,
+  params: [{ name: "sathya" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"children":["hello world ","sathya"]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-lowercase-localvar-memberexpr-in-lambda.jsx

@@ -0,0 +1,12 @@
+import * as SharedRuntime from 'shared-runtime';
+import {invoke} from 'shared-runtime';
+function useComponentFactory({name}) {
+  const localVar = SharedRuntime;
+  const cb = () => <localVar.Stringify>hello world {name}</localVar.Stringify>;
+  return invoke(cb);
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: useComponentFactory,
+  params: [{name: 'sathya'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-lowercase-localvar-memberexpr.expect.md

@@ -0,0 +1,45 @@
+
+## Input
+
+```javascript
+import * as SharedRuntime from 'shared-runtime';
+function Component({name}) {
+  const localVar = SharedRuntime;
+  return <localVar.Stringify>hello world {name}</localVar.Stringify>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{name: 'sathya'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import * as SharedRuntime from "shared-runtime";
+function Component(t0) {
+  const $ = _c(2);
+  const { name } = t0;
+  let t1;
+  if ($[0] !== name) {
+    t1 = <SharedRuntime.Stringify>hello world {name}</SharedRuntime.Stringify>;
+    $[0] = name;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ name: "sathya" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"children":["hello world ","sathya"]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-lowercase-localvar-memberexpr.jsx

@@ -0,0 +1,10 @@
+import * as SharedRuntime from 'shared-runtime';
+function Component({name}) {
+  const localVar = SharedRuntime;
+  return <localVar.Stringify>hello world {name}</localVar.Stringify>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{name: 'sathya'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-lowercase-memberexpr.expect.md

@@ -0,0 +1,44 @@
+
+## Input
+
+```javascript
+import * as SharedRuntime from 'shared-runtime';
+function Component({name}) {
+  return <SharedRuntime.Stringify>hello world {name}</SharedRuntime.Stringify>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{name: 'sathya'}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import * as SharedRuntime from "shared-runtime";
+function Component(t0) {
+  const $ = _c(2);
+  const { name } = t0;
+  let t1;
+  if ($[0] !== name) {
+    t1 = <SharedRuntime.Stringify>hello world {name}</SharedRuntime.Stringify>;
+    $[0] = name;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
+  }
+  return t1;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ name: "sathya" }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"children":["hello world ","sathya"]}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-lowercase-memberexpr.jsx

@@ -0,0 +1,9 @@
+import * as SharedRuntime from 'shared-runtime';
+function Component({name}) {
+  return <SharedRuntime.Stringify>hello world {name}</SharedRuntime.Stringify>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{name: 'sathya'}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/jsx-memberexpr-tag-in-lambda.expect.md

@@ -25,10 +25,9 @@ import { c as _c } from "react/compiler-runtime";
 import * as SharedRuntime from "shared-runtime";
 function useFoo() {
   const $ = _c(1);
-  const MyLocal = SharedRuntime;
   let t0;
   if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    const callback = () => <MyLocal.Text value={4} />;
+    const callback = () => <SharedRuntime.Text value={4} />;
 
     t0 = callback();
     $[0] = t0;

compiler/packages/snap/src/SproutTodoFilter.ts

@@ -475,6 +475,9 @@ const skipFilter = new Set([
   'rules-of-hooks/rules-of-hooks-93dc5d5e538a',
   'rules-of-hooks/rules-of-hooks-69521d94fa03',
 
+  // false positives
+  'invalid-jsx-lowercase-localvar',
+
   // bugs
   'fbt/bug-fbt-plural-multiple-function-calls',
   'fbt/bug-fbt-plural-multiple-mixed-call-tag',

compiler/packages/snap/src/sprout/shared-runtime.ts

@@ -252,6 +252,9 @@ export function Stringify(props: any): React.ReactElement {
     toJSON(props, props?.shouldInvokeFns),
   );
 }
+export function Throw() {
+  throw new Error();
+}
 
 export function ValidateMemoization({
   inputs,