[compiler][cleanup] Remove unused enableReactiveScopesInHIR flag

Reactive scopes in HIR has been stable for over 3 months now and is the future direction of react compiler, removing this flag to reduce implementation forks.

ghstack-source-id: 65cdf63cf76029fa22d40fd85aba0ac976dcfc08
Pull Request resolved: #30891

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

@@ -46,18 +46,13 @@ import {instructionReordering} from '../Optimization/InstructionReordering';
 import {
   CodegenFunction,
   alignObjectMethodScopes,
-  alignReactiveScopesToBlockScopes,
   assertScopeInstructionsWithinScopes,
   assertWellFormedBreakTargets,
-  buildReactiveBlocks,
   buildReactiveFunction,
   codegenFunction,
   extractScopeDeclarationsFromDestructuring,
-  flattenReactiveLoops,
-  flattenScopesWithHooksOrUse,
   inferReactiveScopeVariables,
   memoizeFbtAndMacroOperandsInSameScope,
-  mergeOverlappingReactiveScopes,
   mergeReactiveScopesThatInvalidateTogether,
   promoteUsedTemporaries,
   propagateEarlyReturns,
@@ -300,54 +295,52 @@ function* runWithEnvironment(
     value: hir,
   });
 
-  if (env.config.enableReactiveScopesInHIR) {
-    pruneUnusedLabelsHIR(hir);
-    yield log({
-      kind: 'hir',
-      name: 'PruneUnusedLabelsHIR',
-      value: hir,
-    });
+  pruneUnusedLabelsHIR(hir);
+  yield log({
+    kind: 'hir',
+    name: 'PruneUnusedLabelsHIR',
+    value: hir,
+  });
 
-    alignReactiveScopesToBlockScopesHIR(hir);
-    yield log({
-      kind: 'hir',
-      name: 'AlignReactiveScopesToBlockScopesHIR',
-      value: hir,
-    });
+  alignReactiveScopesToBlockScopesHIR(hir);
+  yield log({
+    kind: 'hir',
+    name: 'AlignReactiveScopesToBlockScopesHIR',
+    value: hir,
+  });
 
-    mergeOverlappingReactiveScopesHIR(hir);
-    yield log({
-      kind: 'hir',
-      name: 'MergeOverlappingReactiveScopesHIR',
-      value: hir,
-    });
-    assertValidBlockNesting(hir);
+  mergeOverlappingReactiveScopesHIR(hir);
+  yield log({
+    kind: 'hir',
+    name: 'MergeOverlappingReactiveScopesHIR',
+    value: hir,
+  });
+  assertValidBlockNesting(hir);
 
-    buildReactiveScopeTerminalsHIR(hir);
-    yield log({
-      kind: 'hir',
-      name: 'BuildReactiveScopeTerminalsHIR',
-      value: hir,
-    });
+  buildReactiveScopeTerminalsHIR(hir);
+  yield log({
+    kind: 'hir',
+    name: 'BuildReactiveScopeTerminalsHIR',
+    value: hir,
+  });
 
-    assertValidBlockNesting(hir);
+  assertValidBlockNesting(hir);
 
-    flattenReactiveLoopsHIR(hir);
-    yield log({
-      kind: 'hir',
-      name: 'FlattenReactiveLoopsHIR',
-      value: hir,
-    });
+  flattenReactiveLoopsHIR(hir);
+  yield log({
+    kind: 'hir',
+    name: 'FlattenReactiveLoopsHIR',
+    value: hir,
+  });
 
-    flattenScopesWithHooksOrUseHIR(hir);
-    yield log({
-      kind: 'hir',
-      name: 'FlattenScopesWithHooksOrUseHIR',
-      value: hir,
-    });
-    assertTerminalSuccessorsExist(hir);
-    assertTerminalPredsExist(hir);
-  }
+  flattenScopesWithHooksOrUseHIR(hir);
+  yield log({
+    kind: 'hir',
+    name: 'FlattenScopesWithHooksOrUseHIR',
+    value: hir,
+  });
+  assertTerminalSuccessorsExist(hir);
+  assertTerminalPredsExist(hir);
 
   const reactiveFunction = buildReactiveFunction(hir);
   yield log({
@@ -364,44 +357,6 @@ function* runWithEnvironment(
     name: 'PruneUnusedLabels',
     value: reactiveFunction,
   });
-
-  if (!env.config.enableReactiveScopesInHIR) {
-    alignReactiveScopesToBlockScopes(reactiveFunction);
-    yield log({
-      kind: 'reactive',
-      name: 'AlignReactiveScopesToBlockScopes',
-      value: reactiveFunction,
-    });
-
-    mergeOverlappingReactiveScopes(reactiveFunction);
-    yield log({
-      kind: 'reactive',
-      name: 'MergeOverlappingReactiveScopes',
-      value: reactiveFunction,
-    });
-
-    buildReactiveBlocks(reactiveFunction);
-    yield log({
-      kind: 'reactive',
-      name: 'BuildReactiveBlocks',
-      value: reactiveFunction,
-    });
-
-    flattenReactiveLoops(reactiveFunction);
-    yield log({
-      kind: 'reactive',
-      name: 'FlattenReactiveLoops',
-      value: reactiveFunction,
-    });
-
-    flattenScopesWithHooksOrUse(reactiveFunction);
-    yield log({
-      kind: 'reactive',
-      name: 'FlattenScopesWithHooks',
-      value: reactiveFunction,
-    });
-  }
-
   assertScopeInstructionsWithinScopes(reactiveFunction);
 
   propagateScopeDependencies(reactiveFunction);

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

@@ -222,8 +222,6 @@ const EnvironmentConfigSchema = z.object({
    */
   enableUseTypeAnnotations: z.boolean().default(false),
 
-  enableReactiveScopesInHIR: z.boolean().default(true),
-
   /**
    * Enables inference of optional dependency chains. Without this flag
    * a property chain such as `props?.items?.foo` will infer as a dep on

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/align-scopes-within-nested-valueblock-in-array.expect.md

@@ -2,8 +2,6 @@
 ## Input
 
 ```javascript
-// @enableReactiveScopesInHIR:false
-
 import {Stringify, identity, makeArray, mutate} from 'shared-runtime';
 
 /**
@@ -37,8 +35,7 @@ export const FIXTURE_ENTRYPOINT = {
 ## Code
 
 ```javascript
-import { c as _c } from "react/compiler-runtime"; // @enableReactiveScopesInHIR:false
-
+import { c as _c } from "react/compiler-runtime";
 import { Stringify, identity, makeArray, mutate } from "shared-runtime";
 
 /**
@@ -52,11 +49,12 @@ import { Stringify, identity, makeArray, mutate } from "shared-runtime";
  * handles this correctly.
  */
 function Foo(t0) {
-  const $ = _c(4);
+  const $ = _c(3);
   const { cond1, cond2 } = t0;
-  const arr = makeArray({ a: 2 }, 2, []);
   let t1;
-  if ($[0] !== cond1 || $[1] !== cond2 || $[2] !== arr) {
+  if ($[0] !== cond1 || $[1] !== cond2) {
+    const arr = makeArray({ a: 2 }, 2, []);
+
     t1 = cond1 ? (
       <>
         <div>{identity("foo")}</div>
@@ -65,10 +63,9 @@ function Foo(t0) {
     ) : null;
     $[0] = cond1;
     $[1] = cond2;
-    $[2] = arr;
-    $[3] = t1;
+    $[2] = t1;
   } else {
-    t1 = $[3];
+    t1 = $[2];
   }
   return t1;
 }

compiler/packages/babel-plugin-react-compiler/src/__tests__/fixtures/compiler/align-scopes-within-nested-valueblock-in-array.tsx

@@ -1,5 +1,3 @@
-// @enableReactiveScopesInHIR:false
-
 import {Stringify, identity, makeArray, mutate} from 'shared-runtime';
 
 /**