[compiler] clarify text for setState-in-effect error

Fixes two related cases of mutation of potentially frozen values.

The first is method calls on frozen values. Previously, we modeled unknown function calls as potentially aliasing their receiver+args into the return value. If the receiver or argument were known to be frozen, then we would downgrade the `Alias` effect into an `ImmutableCapture`. However, within a function expression it's possible to call a function using a frozen value as an argument (that gets `Alias`-ed into the return) but where we don't have the context locally to know that the value is frozen.

This results in cases like this:

```js
const frozen = useContext(...);
useEffect(() => {
  frozen.method().property = true;
  ^^^^^^^^^^^^^^^^^^^^^^^^ cannot mutate frozen value
}, [...]);
```

Within the function we would infer:

```
t0 = MethodCall ...
  Create t0 = mutable
  Alias t0 <- frozen
t1 = PropertyStore ...
  Mutate t0
```

And then transitively infer the function expression as having a `Mutate 'frozen'` effect, which when evaluated against the outer context (`frozen` is frozen) is an error.

The fix is to model unknown function calls as _maybe_ aliasing their receiver/args in the return, and then considering mutations of a maybe-aliased value to only be a conditional mutation of the source:


```
t0 = MethodCall ...
  Create t0 = mutable
  MaybeAlias t0 <- frozen // maybe alias now
t1 = PropertyStore ...
  Mutate t0
```

Then, the `Mutate t0` turns into a `MutateConditional 'frozen'`, which just gets ignored when we process the outer context.

The second, related fix is for known mutation of phis that may be a frozen value. The previous inference model correctly recorded these as errors, the new model does not. We now correctly report a validation error for this case in the new model.

compiler/apps/playground/__tests__/e2e/__snapshots__/page.spec.ts/compilationMode-all-output.txt

@@ -1,5 +1,5 @@
 import { c as _c } from "react/compiler-runtime"; // 
-        @compilationMode:"all"
+@compilationMode:"all"
 function nonReactFn() {
   const $ = _c(1);
   let t0;

compiler/apps/playground/components/Editor/EditorImpl.tsx

@@ -11,6 +11,7 @@ import * as t from '@babel/types';
 import BabelPluginReactCompiler, {
   CompilerError,
   CompilerErrorDetail,
+  CompilerDiagnostic,
   Effect,
   ErrorSeverity,
   parseConfigPragmaForTests,
@@ -141,10 +142,13 @@ const COMMON_HOOKS: Array<[string, Hook]> = [
   ],
 ];
 
-function compile(source: string): [CompilerOutput, 'flow' | 'typescript'] {
+function compile(
+  source: string,
+  mode: 'compiler' | 'linter',
+): [CompilerOutput, 'flow' | 'typescript'] {
   const results = new Map<string, Array<PrintedCompilerPipelineValue>>();
   const error = new CompilerError();
-  const otherErrors: Array<CompilerErrorDetail> = [];
+  const otherErrors: Array<CompilerErrorDetail | CompilerDiagnostic> = [];
   const upsert: (result: PrintedCompilerPipelineValue) => void = result => {
     const entry = results.get(result.name);
     if (Array.isArray(entry)) {
@@ -203,6 +207,22 @@ function compile(source: string): [CompilerOutput, 'flow' | 'typescript'] {
     };
     const parsedOptions = parseConfigPragmaForTests(pragma, {
       compilationMode: 'infer',
+      environment:
+        mode === 'linter'
+          ? {
+              // enabled in compiler
+              validateRefAccessDuringRender: false,
+              // enabled in linter
+              validateNoSetStateInRender: true,
+              validateNoSetStateInEffects: true,
+              validateNoJSXInTryStatements: true,
+              validateNoImpureFunctionsInRender: true,
+              validateStaticComponents: true,
+              validateNoFreezingKnownMutableFunctions: true,
+            }
+          : {
+              /* use defaults for compiler mode */
+            },
     });
     const opts: PluginOptions = parsePluginOptions({
       ...parsedOptions,
@@ -214,7 +234,7 @@ function compile(source: string): [CompilerOutput, 'flow' | 'typescript'] {
         debugLogIRs: logIR,
         logEvent: (_filename: string | null, event: LoggerEvent) => {
           if (event.kind === 'CompileError') {
-            otherErrors.push(new CompilerErrorDetail(event.detail));
+            otherErrors.push(event.detail);
           }
         },
       },
@@ -226,7 +246,7 @@ function compile(source: string): [CompilerOutput, 'flow' | 'typescript'] {
      * (i.e. object shape that is not CompilerError)
      */
     if (err instanceof CompilerError && err.details.length > 0) {
-      error.details.push(...err.details);
+      error.merge(err);
     } else {
       /**
        * Handle unexpected failures by logging (to get a stack trace)
@@ -245,12 +265,15 @@ function compile(source: string): [CompilerOutput, 'flow' | 'typescript'] {
   }
   // Only include logger errors if there weren't other errors
   if (!error.hasErrors() && otherErrors.length !== 0) {
-    otherErrors.forEach(e => error.push(e));
+    otherErrors.forEach(e => error.details.push(e));
   }
   if (error.hasErrors()) {
-    return [{kind: 'err', results, error: error}, language];
+    return [{kind: 'err', results, error}, language];
   }
-  return [{kind: 'ok', results, transformOutput}, language];
+  return [
+    {kind: 'ok', results, transformOutput, errors: error.details},
+    language,
+  ];
 }
 
 export default function Editor(): JSX.Element {
@@ -259,7 +282,11 @@ export default function Editor(): JSX.Element {
   const dispatchStore = useStoreDispatch();
   const {enqueueSnackbar} = useSnackbar();
   const [compilerOutput, language] = useMemo(
-    () => compile(deferredStore.source),
+    () => compile(deferredStore.source, 'compiler'),
+    [deferredStore.source],
+  );
+  const [linterOutput] = useMemo(
+    () => compile(deferredStore.source, 'linter'),
     [deferredStore.source],
   );
 
@@ -285,19 +312,26 @@ export default function Editor(): JSX.Element {
     });
   });
 
+  let mergedOutput: CompilerOutput;
+  let errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
+  if (compilerOutput.kind === 'ok') {
+    errors = linterOutput.kind === 'ok' ? [] : linterOutput.error.details;
+    mergedOutput = {
+      ...compilerOutput,
+      errors,
+    };
+  } else {
+    mergedOutput = compilerOutput;
+    errors = compilerOutput.error.details;
+  }
   return (
     <>
       <div className="relative flex basis top-14">
         <div className={clsx('relative sm:basis-1/4')}>
-          <Input
-            language={language}
-            errors={
-              compilerOutput.kind === 'err' ? compilerOutput.error.details : []
-            }
-          />
+          <Input language={language} errors={errors} />
         </div>
         <div className={clsx('flex sm:flex flex-wrap')}>
-          <Output store={deferredStore} compilerOutput={compilerOutput} />
+          <Output store={deferredStore} compilerOutput={mergedOutput} />
         </div>
       </div>
     </>

compiler/apps/playground/components/Editor/Input.tsx

@@ -36,13 +36,18 @@ export default function Input({errors, language}: Props): JSX.Element {
     const uri = monaco.Uri.parse(`file:///index.js`);
     const model = monaco.editor.getModel(uri);
     invariant(model, 'Model must exist for the selected input file.');
-    renderReactCompilerMarkers({monaco, model, details: errors});
+    renderReactCompilerMarkers({
+      monaco,
+      model,
+      details: errors,
+      source: store.source,
+    });
     /**
      * N.B. that `tabSize` is a model property, not an editor property.
      * So, the tab size has to be set per model.
      */
     model.updateOptions({tabSize: 2});
-  }, [monaco, errors]);
+  }, [monaco, errors, store.source]);
 
   useEffect(() => {
     /**

compiler/apps/playground/components/Editor/Output.tsx

@@ -11,7 +11,11 @@ import {
   InformationCircleIcon,
 } from '@heroicons/react/outline';
 import MonacoEditor, {DiffEditor} from '@monaco-editor/react';
-import {type CompilerError} from 'babel-plugin-react-compiler';
+import {
+  CompilerErrorDetail,
+  CompilerDiagnostic,
+  type CompilerError,
+} from 'babel-plugin-react-compiler';
 import parserBabel from 'prettier/plugins/babel';
 import * as prettierPluginEstree from 'prettier/plugins/estree';
 import * as prettier from 'prettier/standalone';
@@ -44,6 +48,7 @@ export type CompilerOutput =
       kind: 'ok';
       transformOutput: CompilerTransformOutput;
       results: Map<string, Array<PrintedCompilerPipelineValue>>;
+      errors: Array<CompilerErrorDetail | CompilerDiagnostic>;
     }
   | {
       kind: 'err';
@@ -123,10 +128,36 @@ async function tabify(
       parser: transformOutput.language === 'flow' ? 'babel-flow' : 'babel-ts',
       plugins: [parserBabel, prettierPluginEstree],
     });
+
+    let output: string;
+    let language: string;
+    if (compilerOutput.errors.length === 0) {
+      output = code;
+      language = 'javascript';
+    } else {
+      language = 'markdown';
+      output = `
+# Summary
+
+React Compiler compiled this function successfully, but there are lint errors that indicate potential issues with the original code.
+
+## ${compilerOutput.errors.length} Lint Errors
+
+${compilerOutput.errors.map(e => e.printErrorMessage(source, {eslint: false})).join('\n\n')}
+
+## Output
+
+\`\`\`js
+${code}
+\`\`\`
+`.trim();
+    }
+
     reorderedTabs.set(
-      'JS',
+      'Output',
       <TextTabContent
-        output={code}
+        output={output}
+        language={language}
         diff={null}
         showInfoPanel={false}></TextTabContent>,
     );
@@ -142,6 +173,18 @@ async function tabify(
         </>,
       );
     }
+  } else if (compilerOutput.kind === 'err') {
+    const errors = compilerOutput.error.printErrorMessage(source, {
+      eslint: false,
+    });
+    reorderedTabs.set(
+      'Output',
+      <TextTabContent
+        output={errors}
+        language="markdown"
+        diff={null}
+        showInfoPanel={false}></TextTabContent>,
+    );
   }
   tabs.forEach((tab, name) => {
     reorderedTabs.set(name, tab);
@@ -162,17 +205,32 @@ function getSourceMapUrl(code: string, map: string): string | null {
 }
 
 function Output({store, compilerOutput}: Props): JSX.Element {
-  const [tabsOpen, setTabsOpen] = useState<Set<string>>(() => new Set(['JS']));
+  const [tabsOpen, setTabsOpen] = useState<Set<string>>(
+    () => new Set(['Output']),
+  );
   const [tabs, setTabs] = useState<Map<string, React.ReactNode>>(
     () => new Map(),
   );
+
+  /*
+   * Update the active tab back to the output or errors tab when the compilation state
+   * changes between success/failure.
+   */
+  const [previousOutputKind, setPreviousOutputKind] = useState(
+    compilerOutput.kind,
+  );
+  if (compilerOutput.kind !== previousOutputKind) {
+    setPreviousOutputKind(compilerOutput.kind);
+    setTabsOpen(new Set(['Output']));
+  }
+
   useEffect(() => {
     tabify(store.source, compilerOutput).then(tabs => {
       setTabs(tabs);
     });
   }, [store.source, compilerOutput]);
 
-  const changedPasses: Set<string> = new Set(['JS', 'HIR']); // Initial and final passes should always be bold
+  const changedPasses: Set<string> = new Set(['Output', 'HIR']); // Initial and final passes should always be bold
   let lastResult: string = '';
   for (const [passName, results] of compilerOutput.results) {
     for (const result of results) {
@@ -196,20 +254,6 @@ function Output({store, compilerOutput}: Props): JSX.Element {
         tabs={tabs}
         changedPasses={changedPasses}
       />
-      {compilerOutput.kind === 'err' ? (
-        <div
-          className="flex flex-wrap absolute bottom-0 bg-white grow border-y border-grey-200 transition-all ease-in"
-          style={{width: 'calc(100vw - 650px)'}}>
-          <div className="w-full p-4 basis-full border-b">
-            <h2>COMPILER ERRORS</h2>
-          </div>
-          <pre
-            className="p-4 basis-full text-red-600 overflow-y-scroll whitespace-pre-wrap"
-            style={{width: 'calc(100vw - 650px)', height: '150px'}}>
-            <code>{compilerOutput.error.toString()}</code>
-          </pre>
-        </div>
-      ) : null}
     </>
   );
 }
@@ -218,10 +262,12 @@ function TextTabContent({
   output,
   diff,
   showInfoPanel,
+  language,
 }: {
   output: string;
   diff: string | null;
   showInfoPanel: boolean;
+  language: string;
 }): JSX.Element {
   const [diffMode, setDiffMode] = useState(false);
   return (
@@ -272,7 +318,7 @@ function TextTabContent({
         />
       ) : (
         <MonacoEditor
-          defaultLanguage="javascript"
+          language={language ?? 'javascript'}
           value={output}
           options={{
             ...monacoOptions,

compiler/apps/playground/components/Editor/monacoOptions.ts

@@ -28,5 +28,5 @@ export const monacoOptions: Partial<EditorProps['options']> = {
 
   automaticLayout: true,
   wordWrap: 'on',
-  wrappingIndent: 'deepIndent',
+  wrappingIndent: 'same',
 };

compiler/apps/playground/lib/reactCompilerMonacoDiagnostics.ts

@@ -6,7 +6,11 @@
  */
 
 import {Monaco} from '@monaco-editor/react';
-import {CompilerErrorDetail, ErrorSeverity} from 'babel-plugin-react-compiler';
+import {
+  CompilerDiagnostic,
+  CompilerErrorDetail,
+  ErrorSeverity,
+} from 'babel-plugin-react-compiler';
 import {MarkerSeverity, type editor} from 'monaco-editor';
 
 function mapReactCompilerSeverityToMonaco(
@@ -22,38 +26,46 @@ function mapReactCompilerSeverityToMonaco(
 }
 
 function mapReactCompilerDiagnosticToMonacoMarker(
-  detail: CompilerErrorDetail,
+  detail: CompilerErrorDetail | CompilerDiagnostic,
   monaco: Monaco,
+  source: string,
 ): editor.IMarkerData | null {
-  if (detail.loc == null || typeof detail.loc === 'symbol') {
+  const loc = detail.primaryLocation();
+  if (loc == null || typeof loc === 'symbol') {
     return null;
   }
   const severity = mapReactCompilerSeverityToMonaco(detail.severity, monaco);
-  let message = detail.printErrorMessage();
+  let message = detail.printErrorMessage(source, {eslint: true});
   return {
     severity,
     message,
-    startLineNumber: detail.loc.start.line,
-    startColumn: detail.loc.start.column + 1,
-    endLineNumber: detail.loc.end.line,
-    endColumn: detail.loc.end.column + 1,
+    startLineNumber: loc.start.line,
+    startColumn: loc.start.column + 1,
+    endLineNumber: loc.end.line,
+    endColumn: loc.end.column + 1,
   };
 }
 
 type ReactCompilerMarkerConfig = {
   monaco: Monaco;
   model: editor.ITextModel;
-  details: Array<CompilerErrorDetail>;
+  details: Array<CompilerErrorDetail | CompilerDiagnostic>;
+  source: string;
 };
 let decorations: Array<string> = [];
 export function renderReactCompilerMarkers({
   monaco,
   model,
   details,
+  source,
 }: ReactCompilerMarkerConfig): void {
   const markers: Array<editor.IMarkerData> = [];
   for (const detail of details) {
-    const marker = mapReactCompilerDiagnosticToMonacoMarker(detail, monaco);
+    const marker = mapReactCompilerDiagnosticToMonacoMarker(
+      detail,
+      monaco,
+      source,
+    );
     if (marker == null) {
       continue;
     }

compiler/packages/babel-plugin-react-compiler/src/Babel/BabelPlugin.ts

@@ -84,9 +84,7 @@ export default function BabelPluginReactCompiler(
             }
           } catch (e) {
             if (e instanceof CompilerError) {
-              throw new Error(
-                e.printErrorMessage(pass.file.code, {eslint: false}),
-              );
+              throw e.withPrintedMessage(pass.file.code, {eslint: false});
             }
             throw e;
           }

compiler/packages/babel-plugin-react-compiler/src/CompilerError.ts

@@ -262,6 +262,7 @@ export class CompilerErrorDetail {
 
 export class CompilerError extends Error {
   details: Array<CompilerErrorDetail | CompilerDiagnostic> = [];
+  printedMessage: string | null = null;
 
   static invariant(
     condition: unknown,
@@ -347,18 +348,29 @@ export class CompilerError extends Error {
   }
 
   override get message(): string {
-    return this.toString();
+    return this.printedMessage ?? this.toString();
   }
 
   override set message(_message: string) {}
 
   override toString(): string {
+    if (this.printedMessage) {
+      return this.printedMessage;
+    }
     if (Array.isArray(this.details)) {
       return this.details.map(detail => detail.toString()).join('\n\n');
     }
     return this.name;
   }
 
+  withPrintedMessage(
+    source: string,
+    options: PrintErrorMessageOptions,
+  ): CompilerError {
+    this.printedMessage = this.printErrorMessage(source, options);
+    return this;
+  }
+
   printErrorMessage(source: string, options: PrintErrorMessageOptions): string {
     if (options.eslint && this.details.length === 1) {
       return this.details[0].printErrorMessage(source, options);

compiler/packages/babel-plugin-react-compiler/src/Entrypoint/Suppression.ts

@@ -8,8 +8,8 @@
 import {NodePath} from '@babel/core';
 import * as t from '@babel/types';
 import {
+  CompilerDiagnostic,
   CompilerError,
-  CompilerErrorDetail,
   CompilerSuggestionOperation,
   ErrorSeverity,
 } from '../CompilerError';
@@ -181,12 +181,11 @@ export function suppressionsToCompilerError(
           'Unhandled suppression source',
         );
     }
-    error.pushErrorDetail(
-      new CompilerErrorDetail({
-        reason: `${reason}. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior`,
-        description: suppressionRange.disableComment.value.trim(),
+    error.pushDiagnostic(
+      CompilerDiagnostic.create({
+        category: reason,
+        description: `React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression \`${suppressionRange.disableComment.value.trim()}\``,
         severity: ErrorSeverity.InvalidReact,
-        loc: suppressionRange.disableComment.loc ?? null,
         suggestions: [
           {
             description: suggestion,
@@ -197,6 +196,10 @@ export function suppressionsToCompilerError(
             op: CompilerSuggestionOperation.Remove,
           },
         ],
+      }).withDetail({
+        kind: 'error',
+        loc: suppressionRange.disableComment.loc ?? null,
+        message: 'Found React rule suppression',
       }),
     );
   }

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

@@ -943,7 +943,10 @@ export function printAliasingEffect(effect: AliasingEffect): string {
       return `Assign ${printPlaceForAliasEffect(effect.into)} = ${printPlaceForAliasEffect(effect.from)}`;
     }
     case 'Alias': {
-      return `Alias ${printPlaceForAliasEffect(effect.into)} = ${printPlaceForAliasEffect(effect.from)}`;
+      return `Alias ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
+    }
+    case 'MaybeAlias': {
+      return `MaybeAlias ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;
     }
     case 'Capture': {
       return `Capture ${printPlaceForAliasEffect(effect.into)} <- ${printPlaceForAliasEffect(effect.from)}`;

compiler/packages/babel-plugin-react-compiler/src/Inference/AliasingEffects.ts

@@ -90,6 +90,23 @@ export type AliasingEffect =
    * c could be mutating a.
    */
   | {kind: 'Alias'; from: Place; into: Place}
+
+  /**
+   * Indicates the potential for information flow from `from` to `into`. This is used for a specific
+   * case: functions with unknown signatures. If the compiler sees a call such as `foo(x)`, it has to
+   * consider several possibilities (which may depend on the arguments):
+   * - foo(x) returns a new mutable value that does not capture any information from x.
+   * - foo(x) returns a new mutable value that *does* capture information from x.
+   * - foo(x) returns x itself, ie foo is the identity function
+   *
+   * The same is true of functions that take multiple arguments: `cond(a, b, c)` could conditionally
+   * return b or c depending on the value of a.
+   *
+   * To represent this case, MaybeAlias represents the fact that an aliasing relationship could exist.
+   * Any mutations that flow through this relationship automatically become conditional.
+   */
+  | {kind: 'MaybeAlias'; from: Place; into: Place}
+
   /**
    * Records direct assignment: `into = from`.
    */
@@ -183,7 +200,8 @@ export function hashEffect(effect: AliasingEffect): string {
     case 'ImmutableCapture':
     case 'Assign':
     case 'Alias':
-    case 'Capture': {
+    case 'Capture':
+    case 'MaybeAlias': {
       return [
         effect.kind,
         effect.from.identifier.id,

compiler/packages/babel-plugin-react-compiler/src/Inference/AnalyseFunctions.ts

@@ -85,7 +85,8 @@ function lowerWithMutationAliasing(fn: HIRFunction): void {
       case 'Assign':
       case 'Alias':
       case 'Capture':
-      case 'CreateFrom': {
+      case 'CreateFrom':
+      case 'MaybeAlias': {
         capturedOrMutated.add(effect.from.identifier.id);
         break;
       }

compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingEffects.ts

@@ -691,6 +691,7 @@ function applyEffect(
       }
       break;
     }
+    case 'MaybeAlias':
     case 'Alias':
     case 'Capture': {
       CompilerError.invariant(
@@ -955,7 +956,7 @@ function applyEffect(
             context,
             state,
             // OK: recording information flow
-            {kind: 'Alias', from: operand, into: effect.into},
+            {kind: 'MaybeAlias', from: operand, into: effect.into},
             initialized,
             effects,
           );
@@ -1323,7 +1324,7 @@ class InferenceState {
             return 'mutate-global';
           }
           case ValueKind.MaybeFrozen: {
-            return 'none';
+            return 'mutate-frozen';
           }
           default: {
             assertExhaustive(kind, `Unexpected kind ${kind}`);
@@ -2376,6 +2377,7 @@ function computeEffectsForSignature(
   // Apply substitutions
   for (const effect of signature.effects) {
     switch (effect.kind) {
+      case 'MaybeAlias':
       case 'Assign':
       case 'ImmutableCapture':
       case 'Alias':

compiler/packages/babel-plugin-react-compiler/src/Inference/InferMutationAliasingRanges.ts

@@ -160,6 +160,8 @@ export function inferMutationAliasingRanges(
           state.assign(index++, effect.from, effect.into);
         } else if (effect.kind === 'Alias') {
           state.assign(index++, effect.from, effect.into);
+        } else if (effect.kind === 'MaybeAlias') {
+          state.maybeAlias(index++, effect.from, effect.into);
         } else if (effect.kind === 'Capture') {
           state.capture(index++, effect.from, effect.into);
         } else if (
@@ -346,7 +348,8 @@ export function inferMutationAliasingRanges(
           case 'Assign':
           case 'Alias':
           case 'Capture':
-          case 'CreateFrom': {
+          case 'CreateFrom':
+          case 'MaybeAlias': {
             const isMutatedOrReassigned =
               effect.into.identifier.mutableRange.end > instr.id;
             if (isMutatedOrReassigned) {
@@ -567,7 +570,12 @@ type Node = {
   createdFrom: Map<Identifier, number>;
   captures: Map<Identifier, number>;
   aliases: Map<Identifier, number>;
-  edges: Array<{index: number; node: Identifier; kind: 'capture' | 'alias'}>;
+  maybeAliases: Map<Identifier, number>;
+  edges: Array<{
+    index: number;
+    node: Identifier;
+    kind: 'capture' | 'alias' | 'maybeAlias';
+  }>;
   transitive: {kind: MutationKind; loc: SourceLocation} | null;
   local: {kind: MutationKind; loc: SourceLocation} | null;
   lastMutated: number;
@@ -585,6 +593,7 @@ class AliasingState {
       createdFrom: new Map(),
       captures: new Map(),
       aliases: new Map(),
+      maybeAliases: new Map(),
       edges: [],
       transitive: null,
       local: null,
@@ -630,6 +639,18 @@ class AliasingState {
     }
   }
 
+  maybeAlias(index: number, from: Place, into: Place): void {
+    const fromNode = this.nodes.get(from.identifier);
+    const toNode = this.nodes.get(into.identifier);
+    if (fromNode == null || toNode == null) {
+      return;
+    }
+    fromNode.edges.push({index, node: into.identifier, kind: 'maybeAlias'});
+    if (!toNode.maybeAliases.has(from.identifier)) {
+      toNode.maybeAliases.set(from.identifier, index);
+    }
+  }
+
   render(index: number, start: Identifier, errors: CompilerError): void {
     const seen = new Set<Identifier>();
     const queue: Array<Identifier> = [start];
@@ -673,22 +694,24 @@ class AliasingState {
     // Null is used for simulated mutations
     end: InstructionId | null,
     transitive: boolean,
-    kind: MutationKind,
+    startKind: MutationKind,
     loc: SourceLocation,
     errors: CompilerError,
   ): void {
-    const seen = new Set<Identifier>();
+    const seen = new Map<Identifier, MutationKind>();
     const queue: Array<{
       place: Identifier;
       transitive: boolean;
       direction: 'backwards' | 'forwards';
-    }> = [{place: start, transitive, direction: 'backwards'}];
+      kind: MutationKind;
+    }> = [{place: start, transitive, direction: 'backwards', kind: startKind}];
     while (queue.length !== 0) {
-      const {place: current, transitive, direction} = queue.pop()!;
-      if (seen.has(current)) {
+      const {place: current, transitive, direction, kind} = queue.pop()!;
+      const previousKind = seen.get(current);
+      if (previousKind != null && previousKind >= kind) {
         continue;
       }
-      seen.add(current);
+      seen.set(current, kind);
       const node = this.nodes.get(current);
       if (node == null) {
         continue;
@@ -724,13 +747,18 @@ class AliasingState {
         if (edge.index >= index) {
           break;
         }
-        queue.push({place: edge.node, transitive, direction: 'forwards'});
+        queue.push({place: edge.node, transitive, direction: 'forwards', kind});
       }
       for (const [alias, when] of node.createdFrom) {
         if (when >= index) {
           continue;
         }
-        queue.push({place: alias, transitive: true, direction: 'backwards'});
+        queue.push({
+          place: alias,
+          transitive: true,
+          direction: 'backwards',
+          kind,
+        });
       }
       if (direction === 'backwards' || node.value.kind !== 'Phi') {
         /**
@@ -747,7 +775,25 @@ class AliasingState {
           if (when >= index) {
             continue;
           }
-          queue.push({place: alias, transitive, direction: 'backwards'});
+          queue.push({place: alias, transitive, direction: 'backwards', kind});
+        }
+        /**
+         * MaybeAlias indicates potential data flow from unknown function calls,
+         * so we downgrade mutations through these aliases to consider them
+         * conditional. This means we'll consider them for mutation *range*
+         * purposes but not report validation errors for mutations, since
+         * we aren't sure that the `from` value could actually be aliased.
+         */
+        for (const [alias, when] of node.maybeAliases) {
+          if (when >= index) {
+            continue;
+          }
+          queue.push({
+            place: alias,
+            transitive,
+            direction: 'backwards',
+            kind: MutationKind.Conditional,
+          });
         }
       }
       /**
@@ -758,7 +804,12 @@ class AliasingState {
           if (when >= index) {
             continue;
           }
-          queue.push({place: capture, transitive, direction: 'backwards'});
+          queue.push({
+            place: capture,
+            transitive,
+            direction: 'backwards',
+            kind,
+          });
         }
       }
     }

compiler/packages/babel-plugin-react-compiler/src/Inference/MUTABILITY_ALIASING_MODEL.md

@@ -153,6 +153,10 @@ This is somewhat the inverse of `Capture`. The `CreateFrom` effect describes tha
 
 Describes immutable data flow from one value to another. This is not currently used for anything, but is intended to eventually power a more sophisticated escape analysis.
 
+### MaybeAlias
+
+Describes potential data flow that the compiler knows may occur behind a function call, but cannot be sure about. For example, `foo(x)` _may_ be the identity function and return `x`, or `cond(a, b, c)` may conditionally return `b` or `c` depending on the value of `a`, but those functions could just as easily return new mutable values and not capture any information from their arguments. MaybeAlias represents that we have to consider the potential for data flow when deciding mutable ranges, but should be conservative about reporting errors. For example, `foo(someFrozenValue).property = true` should not error since we don't know for certain that foo returns its input.
+
 ### State-Changing Effects
 
 The following effects describe state changes to specific values, not data flow. In many cases, JavaScript semantics will involve a combination of both data-flow effects *and* state-change effects. For example, `object.property = value` has data flow (`Capture object <- value`) and mutation (`Mutate object`).
@@ -347,6 +351,17 @@ a.b = b; // capture
 mutate(a); // can transitively mutate b
 ```
 
+### MaybeAlias makes mutation conditional
+
+Because we don't know for certain that the aliasing occurs, we consider the mutation conditional against the source.
+
+```
+MaybeAlias a <- b
+Mutate a
+=>
+MutateConditional b
+```
+
 ### Freeze Does Not Freeze the Value
 
 Freeze does not freeze the value itself:

compiler/packages/babel-plugin-react-compiler/src/Utils/TestUtils.ts

@@ -113,8 +113,13 @@ function* splitPragma(
  */
 function parseConfigPragmaEnvironmentForTest(
   pragma: string,
+  defaultConfig: PartialEnvironmentConfig,
 ): EnvironmentConfig {
-  const maybeConfig: Partial<Record<keyof EnvironmentConfig, unknown>> = {};
+  // throw early if the defaults are invalid
+  EnvironmentConfigSchema.parse(defaultConfig);
+
+  const maybeConfig: Partial<Record<keyof EnvironmentConfig, unknown>> =
+    defaultConfig;
 
   for (const {key, value: val} of splitPragma(pragma)) {
     if (!hasOwnProperty(EnvironmentConfigSchema.shape, key)) {
@@ -174,9 +179,13 @@ export function parseConfigPragmaForTests(
   pragma: string,
   defaults: {
     compilationMode: CompilationMode;
+    environment?: PartialEnvironmentConfig;
   },
 ): PluginOptions {
-  const environment = parseConfigPragmaEnvironmentForTest(pragma);
+  const environment = parseConfigPragmaEnvironmentForTest(
+    pragma,
+    defaults.environment ?? {},
+  );
   const options: Record<keyof PluginOptions, unknown> = {
     ...defaultOptions,
     panicThreshold: 'all_errors',

compiler/packages/babel-plugin-react-compiler/src/Validation/ValidateNoSetStateInEffects.ts

@@ -97,16 +97,21 @@ export function validateNoSetStateInEffects(
                 errors.pushDiagnostic(
                   CompilerDiagnostic.create({
                     category:
-                      'Calling setState within an effect can trigger cascading renders',
+                      'Calling setState synchronously within an effect can trigger cascading renders',
                     description:
-                      'Calling setState directly within a useEffect causes cascading renders that can hurt performance, and is not recommended. Consider alternatives to useEffect. (https://react.dev/learn/you-might-not-need-an-effect)',
+                      'Effects are intended to synchronize state between React and external systems such as manually updating the DOM, state management libraries, or other platform APIs. ' +
+                      'In general, the body of an effect should do one or both of the following:\n' +
+                      '* Update external systems with the latest state from React.\n' +
+                      '* Subscribe for updates from some external system, calling setState in a callback function when external state changes.\n\n' +
+                      'Calling setState synchronously within an effect body causes cascading renders that can hurt performance, and is not recommended. ' +
+                      '(https://react.dev/learn/you-might-not-need-an-effect)',
                     severity: ErrorSeverity.InvalidReact,
                     suggestions: null,
                   }).withDetail({
                     kind: 'error',
                     loc: setState.loc,
                     message:
-                      'Avoid calling setState() in the top-level of an effect',
+                      'Avoid calling setState() directly within an effect',
                   }),
                 );
               }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.bailout-on-flow-suppression.expect.md

@@ -18,15 +18,15 @@ function Foo(props) {
 ```
 Found 1 error:
 
-Error: React Compiler has skipped optimizing this component because one or more React rule violations were reported by Flow. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React rule violations were reported by Flow
 
-$FlowFixMe[react-rule-hook].
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `$FlowFixMe[react-rule-hook]`
 
 error.bailout-on-flow-suppression.ts:4:2
   2 |
   3 | function Foo(props) {
 > 4 |   // $FlowFixMe[react-rule-hook]
-    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React rule violations were reported by Flow. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   5 |   useX();
   6 |   return null;
   7 | }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.bailout-on-suppression-of-custom-rule.expect.md

@@ -21,28 +21,28 @@ function lowercasecomponent() {
 ```
 Found 2 errors:
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable my-app/react-rule.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable my-app/react-rule`
 
 error.bailout-on-suppression-of-custom-rule.ts:3:0
   1 | // @eslintSuppressionRules:["my-app","react-rule"]
   2 |
 > 3 | /* eslint-disable my-app/react-rule */
-    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   4 | function lowercasecomponent() {
   5 |   'use forget';
   6 |   const x = [];
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable-next-line my-app/react-rule.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable-next-line my-app/react-rule`
 
 error.bailout-on-suppression-of-custom-rule.ts:7:2
    5 |   'use forget';
    6 |   const x = [];
 >  7 |   // eslint-disable-next-line my-app/react-rule
-     |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+     |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
    8 |   return <div>{x}</div>;
    9 | }
   10 | /* eslint-enable my-app/react-rule */

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-mutate-phi-which-could-be-frozen.expect.md

@@ -0,0 +1,39 @@
+
+## Input
+
+```javascript
+import {useHook} from 'shared-runtime';
+
+function Component(props) {
+  const frozen = useHook();
+  let x;
+  if (props.cond) {
+    x = frozen;
+  } else {
+    x = {};
+  }
+  x.property = true;
+}
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: This value cannot be modified
+
+Modifying a value returned from a hook is not allowed. Consider moving the modification into the hook where the value is constructed.
+
+error.invalid-mutate-phi-which-could-be-frozen.ts:11:2
+   9 |     x = {};
+  10 |   }
+> 11 |   x.property = true;
+     |   ^ value cannot be modified
+  12 | }
+  13 |
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-mutate-phi-which-could-be-frozen.js

@@ -0,0 +1,12 @@
+import {useHook} from 'shared-runtime';
+
+function Component(props) {
+  const frozen = useHook();
+  let x;
+  if (props.cond) {
+    x = frozen;
+  } else {
+    x = {};
+  }
+  x.property = true;
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-sketchy-code-use-forget.expect.md

@@ -19,26 +19,26 @@ function lowercasecomponent() {
 ```
 Found 2 errors:
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable react-hooks/rules-of-hooks.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable react-hooks/rules-of-hooks`
 
 error.invalid-sketchy-code-use-forget.ts:1:0
 > 1 | /* eslint-disable react-hooks/rules-of-hooks */
-    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   2 | function lowercasecomponent() {
   3 |   'use forget';
   4 |   const x = [];
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable-next-line react-hooks/rules-of-hooks.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable-next-line react-hooks/rules-of-hooks`
 
 error.invalid-sketchy-code-use-forget.ts:5:2
   3 |   'use forget';
   4 |   const x = [];
 > 5 |   // eslint-disable-next-line react-hooks/rules-of-hooks
-    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   6 |   return <div>{x}</div>;
   7 | }
   8 | /* eslint-enable react-hooks/rules-of-hooks */

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.invalid-unclosed-eslint-suppression.expect.md

@@ -38,14 +38,14 @@ function CrimesAgainstReact() {
 ```
 Found 1 error:
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable react-hooks/rules-of-hooks.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable react-hooks/rules-of-hooks`
 
 error.invalid-unclosed-eslint-suppression.ts:2:0
   1 | // Note: Everything below this is sketchy
 > 2 | /* eslint-disable react-hooks/rules-of-hooks */
-    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   3 | function lowercasecomponent() {
   4 |   'use forget';
   5 |   const x = [];

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.sketchy-code-exhaustive-deps.expect.md

@@ -22,15 +22,15 @@ function Component() {
 ```
 Found 1 error:
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable-next-line react-hooks/exhaustive-deps.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable-next-line react-hooks/exhaustive-deps`
 
 error.sketchy-code-exhaustive-deps.ts:6:7
   4 |     () => {
   5 |       item.push(1);
 > 6 |     }, // eslint-disable-next-line react-hooks/exhaustive-deps
-    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   7 |     []
   8 |   );
   9 |

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.sketchy-code-rules-of-hooks.expect.md

@@ -23,13 +23,13 @@ export const FIXTURE_ENTRYPOINT = {
 ```
 Found 1 error:
 
-Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+Error: React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled
 
-eslint-disable react-hooks/rules-of-hooks.
+React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior. Found suppression `eslint-disable react-hooks/rules-of-hooks`
 
 error.sketchy-code-rules-of-hooks.ts:1:0
 > 1 | /* eslint-disable react-hooks/rules-of-hooks */
-    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ React Compiler has skipped optimizing this component because one or more React ESLint rules were disabled. React Compiler only works when your components follow all the rules of React, disabling them may result in unexpected or incorrect behavior
+    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Found React rule suppression
   2 | function lowercasecomponent() {
   3 |   const x = [];
   4 |   return <div>{x}</div>;

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-for-loop-with-context-variable-iterator.expect.md

@@ -0,0 +1,61 @@
+
+## Input
+
+```javascript
+import {Stringify, useIdentity} from 'shared-runtime';
+
+function Component() {
+  const data = useIdentity(
+    new Map([
+      [0, 'value0'],
+      [1, 'value1'],
+    ])
+  );
+  const items = [];
+  // NOTE: `i` is a context variable because it's reassigned and also referenced
+  // within a closure, the `onClick` handler of each item
+  // TODO: for loops create a unique environment on each iteration, which means
+  // that if the iteration variable is only updated in the updater, the variable
+  // is effectively const within the body and the "update" acts more like
+  // a re-initialization than a reassignment.
+  // Until we model this "new environment" semantic, we allow this case to error
+  for (let i = MIN; i <= MAX; i += INCREMENT) {
+    items.push(
+      <Stringify key={i} onClick={() => data.get(i)} shouldInvokeFns={true} />
+    );
+  }
+  return <>{items}</>;
+}
+
+const MIN = 0;
+const MAX = 3;
+const INCREMENT = 1;
+
+export const FIXTURE_ENTRYPOINT = {
+  params: [],
+  fn: Component,
+};
+
+```
+
+
+## Error
+
+```
+Found 1 error:
+
+Error: This value cannot be modified
+
+Modifying a value used previously in JSX is not allowed. Consider moving the modification before the JSX.
+
+error.todo-for-loop-with-context-variable-iterator.ts:18:30
+  16 |   // a re-initialization than a reassignment.
+  17 |   // Until we model this "new environment" semantic, we allow this case to error
+> 18 |   for (let i = MIN; i <= MAX; i += INCREMENT) {
+     |                               ^ `i` cannot be modified
+  19 |     items.push(
+  20 |       <Stringify key={i} onClick={() => data.get(i)} shouldInvokeFns={true} />
+  21 |     );
+```
+          
+      

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/error.todo-for-loop-with-context-variable-iterator.js

@@ -10,6 +10,11 @@ function Component() {
   const items = [];
   // NOTE: `i` is a context variable because it's reassigned and also referenced
   // within a closure, the `onClick` handler of each item
+  // TODO: for loops create a unique environment on each iteration, which means
+  // that if the iteration variable is only updated in the updater, the variable
+  // is effectively const within the body and the "update" acts more like
+  // a re-initialization than a reassignment.
+  // Until we model this "new environment" semantic, we allow this case to error
   for (let i = MIN; i <= MAX; i += INCREMENT) {
     items.push(
       <Stringify key={i} onClick={() => data.get(i)} shouldInvokeFns={true} />

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/for-loop-with-context-variable-iterator.expect.md

@@ -1,89 +0,0 @@
-
-## Input
-
-```javascript
-import {Stringify, useIdentity} from 'shared-runtime';
-
-function Component() {
-  const data = useIdentity(
-    new Map([
-      [0, 'value0'],
-      [1, 'value1'],
-    ])
-  );
-  const items = [];
-  // NOTE: `i` is a context variable because it's reassigned and also referenced
-  // within a closure, the `onClick` handler of each item
-  for (let i = MIN; i <= MAX; i += INCREMENT) {
-    items.push(
-      <Stringify key={i} onClick={() => data.get(i)} shouldInvokeFns={true} />
-    );
-  }
-  return <>{items}</>;
-}
-
-const MIN = 0;
-const MAX = 3;
-const INCREMENT = 1;
-
-export const FIXTURE_ENTRYPOINT = {
-  params: [],
-  fn: Component,
-};
-
-```
-
-## Code
-
-```javascript
-import { c as _c } from "react/compiler-runtime";
-import { Stringify, useIdentity } from "shared-runtime";
-
-function Component() {
-  const $ = _c(3);
-  let t0;
-  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = new Map([
-      [0, "value0"],
-      [1, "value1"],
-    ]);
-    $[0] = t0;
-  } else {
-    t0 = $[0];
-  }
-  const data = useIdentity(t0);
-  let t1;
-  if ($[1] !== data) {
-    const items = [];
-    for (let i = MIN; i <= MAX; i = i + INCREMENT, i) {
-      items.push(
-        <Stringify
-          key={i}
-          onClick={() => data.get(i)}
-          shouldInvokeFns={true}
-        />,
-      );
-    }
-
-    t1 = <>{items}</>;
-    $[1] = data;
-    $[2] = t1;
-  } else {
-    t1 = $[2];
-  }
-  return t1;
-}
-
-const MIN = 0;
-const MAX = 3;
-const INCREMENT = 1;
-
-export const FIXTURE_ENTRYPOINT = {
-  params: [],
-  fn: Component,
-};
-
-```
-      
-### Eval output
-(kind: ok) <div>{"onClick":{"kind":"Function","result":"value0"},"shouldInvokeFns":true}</div><div>{"onClick":{"kind":"Function","result":"value1"},"shouldInvokeFns":true}</div><div>{"onClick":{"kind":"Function"},"shouldInvokeFns":true}</div><div>{"onClick":{"kind":"Function"},"shouldInvokeFns":true}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/infer-effect-dependencies/error.wrong-index-no-func.expect.md

@@ -16,6 +16,7 @@ function Component({foo}) {
 
 ```
 Found 1 error:
+
 Error: Cannot infer dependencies of this effect. This will break your build!
 
 To resolve, either pass a dependency array or fix reported compiler bailout diagnostics.

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/infer-effect-dependencies/error.wrong-index.expect.md

@@ -23,6 +23,7 @@ function Component({foo}) {
 
 ```
 Found 1 error:
+
 Error: Cannot infer dependencies of this effect. This will break your build!
 
 To resolve, either pass a dependency array or fix reported compiler bailout diagnostics.

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/invalid-setState-in-useEffect-transitive.expect.md

@@ -65,7 +65,7 @@ function _temp(s) {
 ## Logs
 
 ```
-{"kind":"CompileError","detail":{"options":{"category":"Calling setState within an effect can trigger cascading renders","description":"Calling setState directly within a useEffect causes cascading renders that can hurt performance, and is not recommended. Consider alternatives to useEffect. (https://react.dev/learn/you-might-not-need-an-effect)","severity":"InvalidReact","suggestions":null,"details":[{"kind":"error","loc":{"start":{"line":13,"column":4,"index":265},"end":{"line":13,"column":5,"index":266},"filename":"invalid-setState-in-useEffect-transitive.ts","identifierName":"g"},"message":"Avoid calling setState() in the top-level of an effect"}]}},"fnLoc":null}
+{"kind":"CompileError","detail":{"options":{"category":"Calling setState synchronously within an effect can trigger cascading renders","description":"Effects are intended to synchronize state between React and external systems such as manually updating the DOM, state management libraries, or other platform APIs. In general, the body of an effect should do one or both of the following:\n* Update external systems with the latest state from React.\n* Subscribe for updates from some external system, calling setState in a callback function when external state changes.\n\nCalling setState synchronously within an effect body causes cascading renders that can hurt performance, and is not recommended. (https://react.dev/learn/you-might-not-need-an-effect)","severity":"InvalidReact","suggestions":null,"details":[{"kind":"error","loc":{"start":{"line":13,"column":4,"index":265},"end":{"line":13,"column":5,"index":266},"filename":"invalid-setState-in-useEffect-transitive.ts","identifierName":"g"},"message":"Avoid calling setState() directly within an effect"}]}},"fnLoc":null}
 {"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":92},"end":{"line":16,"column":1,"index":293},"filename":"invalid-setState-in-useEffect-transitive.ts"},"fnName":"Component","memoSlots":2,"memoBlocks":2,"memoValues":2,"prunedMemoBlocks":0,"prunedMemoValues":0}
 ```
       

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/invalid-setState-in-useEffect.expect.md

@@ -45,7 +45,7 @@ function _temp(s) {
 ## Logs
 
 ```
-{"kind":"CompileError","detail":{"options":{"category":"Calling setState within an effect can trigger cascading renders","description":"Calling setState directly within a useEffect causes cascading renders that can hurt performance, and is not recommended. Consider alternatives to useEffect. (https://react.dev/learn/you-might-not-need-an-effect)","severity":"InvalidReact","suggestions":null,"details":[{"kind":"error","loc":{"start":{"line":7,"column":4,"index":180},"end":{"line":7,"column":12,"index":188},"filename":"invalid-setState-in-useEffect.ts","identifierName":"setState"},"message":"Avoid calling setState() in the top-level of an effect"}]}},"fnLoc":null}
+{"kind":"CompileError","detail":{"options":{"category":"Calling setState synchronously within an effect can trigger cascading renders","description":"Effects are intended to synchronize state between React and external systems such as manually updating the DOM, state management libraries, or other platform APIs. In general, the body of an effect should do one or both of the following:\n* Update external systems with the latest state from React.\n* Subscribe for updates from some external system, calling setState in a callback function when external state changes.\n\nCalling setState synchronously within an effect body causes cascading renders that can hurt performance, and is not recommended. (https://react.dev/learn/you-might-not-need-an-effect)","severity":"InvalidReact","suggestions":null,"details":[{"kind":"error","loc":{"start":{"line":7,"column":4,"index":180},"end":{"line":7,"column":12,"index":188},"filename":"invalid-setState-in-useEffect.ts","identifierName":"setState"},"message":"Avoid calling setState() directly within an effect"}]}},"fnLoc":null}
 {"kind":"CompileSuccess","fnLoc":{"start":{"line":4,"column":0,"index":92},"end":{"line":10,"column":1,"index":225},"filename":"invalid-setState-in-useEffect.ts"},"fnName":"Component","memoSlots":1,"memoBlocks":1,"memoValues":1,"prunedMemoBlocks":0,"prunedMemoValues":0}
 ```
       

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-mutate-result-of-function-call-with-frozen-argument-in-function-expression.expect.md

@@ -0,0 +1,77 @@
+
+## Input
+
+```javascript
+import {identity, makeObject_Primitives, Stringify} from 'shared-runtime';
+
+function Example(props) {
+  const object = props.object;
+  const f = () => {
+    // The argument maybe-aliases into the return
+    const obj = identity(object);
+    obj.property = props.value;
+    return obj;
+  };
+  const obj = f();
+  return <Stringify obj={obj} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{object: makeObject_Primitives(), value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { identity, makeObject_Primitives, Stringify } from "shared-runtime";
+
+function Example(props) {
+  const $ = _c(7);
+  const object = props.object;
+  let t0;
+  if ($[0] !== object || $[1] !== props.value) {
+    t0 = () => {
+      const obj = identity(object);
+      obj.property = props.value;
+      return obj;
+    };
+    $[0] = object;
+    $[1] = props.value;
+    $[2] = t0;
+  } else {
+    t0 = $[2];
+  }
+  const f = t0;
+  let t1;
+  if ($[3] !== f) {
+    t1 = f();
+    $[3] = f;
+    $[4] = t1;
+  } else {
+    t1 = $[4];
+  }
+  const obj_0 = t1;
+  let t2;
+  if ($[5] !== obj_0) {
+    t2 = <Stringify obj={obj_0} />;
+    $[5] = obj_0;
+    $[6] = t2;
+  } else {
+    t2 = $[6];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{ object: makeObject_Primitives(), value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"obj":{"a":0,"b":"value1","c":true,"property":42}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-mutate-result-of-function-call-with-frozen-argument-in-function-expression.js

@@ -0,0 +1,18 @@
+import {identity, makeObject_Primitives, Stringify} from 'shared-runtime';
+
+function Example(props) {
+  const object = props.object;
+  const f = () => {
+    // The argument maybe-aliases into the return
+    const obj = identity(object);
+    obj.property = props.value;
+    return obj;
+  };
+  const obj = f();
+  return <Stringify obj={obj} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{object: makeObject_Primitives(), value: 42}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-mutate-result-of-method-call-on-frozen-value-in-function-expression.expect.md

@@ -0,0 +1,77 @@
+
+## Input
+
+```javascript
+import {makeObject_Primitives, Stringify} from 'shared-runtime';
+
+function Example(props) {
+  const object = props.object;
+  const f = () => {
+    // The receiver maybe-aliases into the return
+    const obj = object.makeObject();
+    obj.property = props.value;
+    return obj;
+  };
+  const obj = f();
+  return <Stringify obj={obj} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{object: {makeObject: makeObject_Primitives}, value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { makeObject_Primitives, Stringify } from "shared-runtime";
+
+function Example(props) {
+  const $ = _c(7);
+  const object = props.object;
+  let t0;
+  if ($[0] !== object || $[1] !== props.value) {
+    t0 = () => {
+      const obj = object.makeObject();
+      obj.property = props.value;
+      return obj;
+    };
+    $[0] = object;
+    $[1] = props.value;
+    $[2] = t0;
+  } else {
+    t0 = $[2];
+  }
+  const f = t0;
+  let t1;
+  if ($[3] !== f) {
+    t1 = f();
+    $[3] = f;
+    $[4] = t1;
+  } else {
+    t1 = $[4];
+  }
+  const obj_0 = t1;
+  let t2;
+  if ($[5] !== obj_0) {
+    t2 = <Stringify obj={obj_0} />;
+    $[5] = obj_0;
+    $[6] = t2;
+  } else {
+    t2 = $[6];
+  }
+  return t2;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{ object: { makeObject: makeObject_Primitives }, value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"obj":{"a":0,"b":"value1","c":true,"property":42}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-mutate-result-of-method-call-on-frozen-value-in-function-expression.js

@@ -0,0 +1,18 @@
+import {makeObject_Primitives, Stringify} from 'shared-runtime';
+
+function Example(props) {
+  const object = props.object;
+  const f = () => {
+    // The receiver maybe-aliases into the return
+    const obj = object.makeObject();
+    obj.property = props.value;
+    return obj;
+  };
+  const obj = f();
+  return <Stringify obj={obj} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{object: {makeObject: makeObject_Primitives}, value: 42}],
+};

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-mutate-result-of-method-call-on-frozen-value-is-allowed.expect.md

@@ -0,0 +1,57 @@
+
+## Input
+
+```javascript
+import {makeObject_Primitives, Stringify} from 'shared-runtime';
+
+function Example(props) {
+  const obj = props.object.makeObject();
+  obj.property = props.value;
+  return <Stringify obj={obj} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{object: {makeObject: makeObject_Primitives}, value: 42}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime";
+import { makeObject_Primitives, Stringify } from "shared-runtime";
+
+function Example(props) {
+  const $ = _c(5);
+  let obj;
+  if ($[0] !== props.object || $[1] !== props.value) {
+    obj = props.object.makeObject();
+    obj.property = props.value;
+    $[0] = props.object;
+    $[1] = props.value;
+    $[2] = obj;
+  } else {
+    obj = $[2];
+  }
+  let t0;
+  if ($[3] !== obj) {
+    t0 = <Stringify obj={obj} />;
+    $[3] = obj;
+    $[4] = t0;
+  } else {
+    t0 = $[4];
+  }
+  return t0;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{ object: { makeObject: makeObject_Primitives }, value: 42 }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>{"obj":{"a":0,"b":"value1","c":true,"property":42}}</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/repro-mutate-result-of-method-call-on-frozen-value-is-allowed.js

@@ -0,0 +1,12 @@
+import {makeObject_Primitives, Stringify} from 'shared-runtime';
+
+function Example(props) {
+  const obj = props.object.makeObject();
+  obj.property = props.value;
+  return <Stringify obj={obj} />;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Example,
+  params: [{object: {makeObject: makeObject_Primitives}, value: 42}],
+};