[Compiler] ValidateNoDerivedComputationsInEffects test cases

Summary:
This creates the test cases we expect this first iteration of calculate in render to catch

The goal is to have tests that will be in a good state once we have the first iteration of the calculate in render validation working, which should be pretty limited in what its capturing.

Test Plan:
Test cases

Author: jorge-cab

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

@@ -103,6 +103,7 @@ import {validateNoFreezingKnownMutableFunctions} from '../Validation/ValidateNoF
 import {inferMutationAliasingEffects} from '../Inference/InferMutationAliasingEffects';
 import {inferMutationAliasingRanges} from '../Inference/InferMutationAliasingRanges';
 import {validateNoDerivedComputationsInEffects} from '../Validation/ValidateNoDerivedComputationsInEffects';
+import {validateNoDerivedComputationsInEffects_exp} from '../Validation/ValidateNoDerivedComputationsInEffects_exp';
 import {nameAnonymousFunctions} from '../Transform/NameAnonymousFunctions';
 
 export type CompilerPipelineValue =
@@ -275,6 +276,10 @@ function runWithEnvironment(
       validateNoDerivedComputationsInEffects(hir);
     }
 
+    if (env.config.validateNoDerivedComputationsInEffects_exp) {
+      validateNoDerivedComputationsInEffects_exp(hir);
+    }
+
     if (env.config.validateNoSetStateInEffects) {
       env.logErrors(validateNoSetStateInEffects(hir, env));
     }

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

@@ -334,6 +334,12 @@ export const EnvironmentConfigSchema = z.object({
    */
   validateNoDerivedComputationsInEffects: z.boolean().default(false),
 
+  /**
+   * Experimental: Validates that effects are not used to calculate derived data which could instead be computed
+   * during render. Generates a custom error message for each type of violation.
+   */
+  validateNoDerivedComputationsInEffects_exp: z.boolean().default(false),
+
   /**
    * Validates against creating JSX within a try block and recommends using an error boundary
    * instead.

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

@@ -0,0 +1,240 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {CompilerError, SourceLocation} from '..';
+import {ErrorCategory} from '../CompilerError';
+import {
+  ArrayExpression,
+  BlockId,
+  FunctionExpression,
+  HIRFunction,
+  IdentifierId,
+  isSetStateType,
+  isUseEffectHookType,
+} from '../HIR';
+import {
+  eachInstructionValueOperand,
+  eachTerminalOperand,
+} from '../HIR/visitors';
+
+/**
+ * Validates that useEffect is not used for derived computations which could/should
+ * be performed in render.
+ *
+ * See https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state
+ *
+ * Example:
+ *
+ * ```
+ * // 🔴 Avoid: redundant state and unnecessary Effect
+ * const [fullName, setFullName] = useState('');
+ * useEffect(() => {
+ *   setFullName(firstName + ' ' + lastName);
+ * }, [firstName, lastName]);
+ * ```
+ *
+ * Instead use:
+ *
+ * ```
+ * // ✅ Good: calculated during rendering
+ * const fullName = firstName + ' ' + lastName;
+ * ```
+ */
+export function validateNoDerivedComputationsInEffects_exp(
+  fn: HIRFunction,
+): void {
+  const candidateDependencies: Map<IdentifierId, ArrayExpression> = new Map();
+  const functions: Map<IdentifierId, FunctionExpression> = new Map();
+  const locals: Map<IdentifierId, IdentifierId> = new Map();
+
+  const errors = new CompilerError();
+
+  for (const block of fn.body.blocks.values()) {
+    for (const instr of block.instructions) {
+      const {lvalue, value} = instr;
+      if (value.kind === 'LoadLocal') {
+        locals.set(lvalue.identifier.id, value.place.identifier.id);
+      } else if (value.kind === 'ArrayExpression') {
+        candidateDependencies.set(lvalue.identifier.id, value);
+      } else if (value.kind === 'FunctionExpression') {
+        functions.set(lvalue.identifier.id, value);
+      } else if (
+        value.kind === 'CallExpression' ||
+        value.kind === 'MethodCall'
+      ) {
+        const callee =
+          value.kind === 'CallExpression' ? value.callee : value.property;
+        if (
+          isUseEffectHookType(callee.identifier) &&
+          value.args.length === 2 &&
+          value.args[0].kind === 'Identifier' &&
+          value.args[1].kind === 'Identifier'
+        ) {
+          const effectFunction = functions.get(value.args[0].identifier.id);
+          const deps = candidateDependencies.get(value.args[1].identifier.id);
+          if (
+            effectFunction != null &&
+            deps != null &&
+            deps.elements.length !== 0 &&
+            deps.elements.every(element => element.kind === 'Identifier')
+          ) {
+            const dependencies: Array<IdentifierId> = deps.elements.map(dep => {
+              CompilerError.invariant(dep.kind === 'Identifier', {
+                reason: `Dependency is checked as a place above`,
+                description: null,
+                details: [
+                  {
+                    kind: 'error',
+                    loc: value.loc,
+                    message: 'this is checked as a place above',
+                  },
+                ],
+              });
+              return locals.get(dep.identifier.id) ?? dep.identifier.id;
+            });
+            validateEffect(
+              effectFunction.loweredFunc.func,
+              dependencies,
+              errors,
+            );
+          }
+        }
+      }
+    }
+  }
+  if (errors.hasAnyErrors()) {
+    throw errors;
+  }
+}
+
+function validateEffect(
+  effectFunction: HIRFunction,
+  effectDeps: Array<IdentifierId>,
+  errors: CompilerError,
+): void {
+  for (const operand of effectFunction.context) {
+    if (isSetStateType(operand.identifier)) {
+      continue;
+    } else if (effectDeps.find(dep => dep === operand.identifier.id) != null) {
+      continue;
+    } else {
+      // Captured something other than the effect dep or setState
+      return;
+    }
+  }
+  for (const dep of effectDeps) {
+    if (
+      effectFunction.context.find(operand => operand.identifier.id === dep) ==
+      null
+    ) {
+      // effect dep wasn't actually used in the function
+      return;
+    }
+  }
+
+  const seenBlocks: Set<BlockId> = new Set();
+  const values: Map<IdentifierId, Array<IdentifierId>> = new Map();
+  for (const dep of effectDeps) {
+    values.set(dep, [dep]);
+  }
+
+  const setStateLocations: Array<SourceLocation> = [];
+  for (const block of effectFunction.body.blocks.values()) {
+    for (const pred of block.preds) {
+      if (!seenBlocks.has(pred)) {
+        // skip if block has a back edge
+        return;
+      }
+    }
+    for (const phi of block.phis) {
+      const aggregateDeps: Set<IdentifierId> = new Set();
+      for (const operand of phi.operands.values()) {
+        const deps = values.get(operand.identifier.id);
+        if (deps != null) {
+          for (const dep of deps) {
+            aggregateDeps.add(dep);
+          }
+        }
+      }
+      if (aggregateDeps.size !== 0) {
+        values.set(phi.place.identifier.id, Array.from(aggregateDeps));
+      }
+    }
+    for (const instr of block.instructions) {
+      switch (instr.value.kind) {
+        case 'Primitive':
+        case 'JSXText':
+        case 'LoadGlobal': {
+          break;
+        }
+        case 'LoadLocal': {
+          const deps = values.get(instr.value.place.identifier.id);
+          if (deps != null) {
+            values.set(instr.lvalue.identifier.id, deps);
+          }
+          break;
+        }
+        case 'ComputedLoad':
+        case 'PropertyLoad':
+        case 'BinaryExpression':
+        case 'TemplateLiteral':
+        case 'CallExpression':
+        case 'MethodCall': {
+          const aggregateDeps: Set<IdentifierId> = new Set();
+          for (const operand of eachInstructionValueOperand(instr.value)) {
+            const deps = values.get(operand.identifier.id);
+            if (deps != null) {
+              for (const dep of deps) {
+                aggregateDeps.add(dep);
+              }
+            }
+          }
+          if (aggregateDeps.size !== 0) {
+            values.set(instr.lvalue.identifier.id, Array.from(aggregateDeps));
+          }
+
+          if (
+            instr.value.kind === 'CallExpression' &&
+            isSetStateType(instr.value.callee.identifier) &&
+            instr.value.args.length === 1 &&
+            instr.value.args[0].kind === 'Identifier'
+          ) {
+            const deps = values.get(instr.value.args[0].identifier.id);
+            if (deps != null && new Set(deps).size === effectDeps.length) {
+              setStateLocations.push(instr.value.callee.loc);
+            } else {
+              // doesn't depend on any deps
+              return;
+            }
+          }
+          break;
+        }
+        default: {
+          return;
+        }
+      }
+    }
+    for (const operand of eachTerminalOperand(block.terminal)) {
+      if (values.has(operand.identifier.id)) {
+        //
+        return;
+      }
+    }
+    seenBlocks.add(block.id);
+  }
+
+  for (const loc of setStateLocations) {
+    errors.push({
+      category: ErrorCategory.EffectDerivationsOfState,
+      reason:
+        'Values derived from props and state should be calculated during render, not in an effect. (https://react.dev/learn/you-might-not-need-an-effect#updating-state-based-on-props-or-state)',
+      description: null,
+      loc,
+      suggestions: null,
+    });
+  }
+}

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-conditionally-in-effect.expect.md

@@ -0,0 +1,79 @@
+
+## Input
+
+```javascript
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({value, enabled}) {
+  const [localValue, setLocalValue] = useState('');
+
+  useEffect(() => {
+    if (enabled) {
+      setLocalValue(value);
+    } else {
+      setLocalValue('disabled');
+    }
+  }, [value, enabled]);
+
+  return <div>{localValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 'test', enabled: true}],
+};
+
+```
+
+## Code
+
+```javascript
+import { c as _c } from "react/compiler-runtime"; // @validateNoDerivedComputationsInEffects_exp
+import { useEffect, useState } from "react";
+
+function Component(t0) {
+  const $ = _c(6);
+  const { value, enabled } = t0;
+  const [localValue, setLocalValue] = useState("");
+  let t1;
+  let t2;
+  if ($[0] !== enabled || $[1] !== value) {
+    t1 = () => {
+      if (enabled) {
+        setLocalValue(value);
+      } else {
+        setLocalValue("disabled");
+      }
+    };
+
+    t2 = [value, enabled];
+    $[0] = enabled;
+    $[1] = value;
+    $[2] = t1;
+    $[3] = t2;
+  } else {
+    t1 = $[2];
+    t2 = $[3];
+  }
+  useEffect(t1, t2);
+  let t3;
+  if ($[4] !== localValue) {
+    t3 = <div>{localValue}</div>;
+    $[4] = localValue;
+    $[5] = t3;
+  } else {
+    t3 = $[5];
+  }
+  return t3;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{ value: "test", enabled: true }],
+};
+
+```
+      
+### Eval output
+(kind: ok) <div>test</div>

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/effect-derived-computations/derived-state-conditionally-in-effect.js

@@ -0,0 +1,21 @@
+// @validateNoDerivedComputationsInEffects_exp
+import {useEffect, useState} from 'react';
+
+function Component({value, enabled}) {
+  const [localValue, setLocalValue] = useState('');
+
+  useEffect(() => {
+    if (enabled) {
+      setLocalValue(value);
+    } else {
+      setLocalValue('disabled');
+    }
+  }, [value, enabled]);
+
+  return <div>{localValue}</div>;
+}
+
+export const FIXTURE_ENTRYPOINT = {
+  fn: Component,
+  params: [{value: 'test', enabled: true}],
+};