Reset scopes from AnalyzeFunctions in InferReactiveScopeVariables

Updates InferReactiveScopeVariables to first prune scopes attached during 
AnalyzeFunctions. This ensures that after this pass the only scopes that exist 
on identifiers in the outer program are those that the pass explicitly inferred, 
and not accidentally leftover.

compiler/packages/babel-plugin-react-forget/src/ReactiveScopes/InferReactiveScopeVariables.ts

@@ -9,7 +9,6 @@ import { Environment } from "../HIR";
 import {
   HIRFunction,
   Identifier,
-  IdentifierId,
   Instruction,
   makeInstructionId,
   Place,
@@ -17,8 +16,10 @@ import {
 } from "../HIR/HIR";
 import {
   doesPatternContainSpreadElement,
+  eachInstructionLValue,
   eachInstructionOperand,
   eachPatternOperand,
+  eachTerminalOperand,
 } from "../HIR/visitors";
 import DisjointSet from "../Utils/DisjointSet";
 import { assertExhaustive } from "../Utils/utils";
@@ -80,6 +81,27 @@ import { assertExhaustive } from "../Utils/utils";
  * ```
  */
 export function inferReactiveScopeVariables(fn: HIRFunction): void {
+  // First reset any scopes that may have been created from inner functions
+  for (const [, block] of fn.body.blocks) {
+    for (const phi of block.phis) {
+      phi.id.scope = null;
+      for (const [, operand] of phi.operands) {
+        operand.scope = null;
+      }
+    }
+    for (const instr of block.instructions) {
+      for (const lvalue of eachInstructionLValue(instr)) {
+        lvalue.identifier.scope = null;
+      }
+      for (const operand of eachInstructionOperand(instr)) {
+        operand.identifier.scope = null;
+      }
+    }
+    for (const operand of eachTerminalOperand(block.terminal)) {
+      operand.identifier.scope = null;
+    }
+  }
+
   /*
    * Represents the set of reactive scopes as disjoint sets of identifiers
    * that mutate together.
@@ -189,10 +211,6 @@ export function findDisjointMutableValues(
   fn: HIRFunction
 ): DisjointSet<Identifier> {
   const scopeIdentifiers = new DisjointSet<Identifier>();
-  const declarations: Map<IdentifierId, Place> | null = fn.env.config
-    .enableForest
-    ? new Map()
-    : null;
   for (const [_, block] of fn.body.blocks) {
     /*
      * If a phi is mutated after creation, then we need to alias all of its operands such that they
@@ -221,14 +239,7 @@ export function findDisjointMutableValues(
       if (range.end > range.start + 1 || mayAllocate(fn.env, instr)) {
         operands.push(instr.lvalue!.identifier);
       }
-      if (instr.value.kind === "DeclareLocal") {
-        if (declarations !== null) {
-          declarations.set(
-            instr.value.lvalue.place.identifier.id,
-            instr.value.lvalue.place
-          );
-        }
-      } else if (
+      if (
         instr.value.kind === "StoreLocal" ||
         instr.value.kind === "StoreContext"
       ) {
@@ -244,27 +255,6 @@ export function findDisjointMutableValues(
         ) {
           operands.push(instr.value.value.identifier);
         }
-        if (declarations !== null) {
-          const declaration = declarations.get(
-            instr.value.lvalue.place.identifier.id
-          );
-          if (declaration !== undefined) {
-            declaration.identifier.mutableRange.end = makeInstructionId(
-              Math.max(
-                declaration.identifier.mutableRange.end,
-                instr.value.lvalue.place.identifier.mutableRange.end
-              )
-            );
-            instr.value.lvalue.place.identifier.mutableRange.start =
-              makeInstructionId(
-                Math.min(
-                  declaration.identifier.mutableRange.start,
-                  instr.value.lvalue.place.identifier.mutableRange.start
-                )
-              );
-            operands.push(declaration.identifier);
-          }
-        }
       } else if (instr.value.kind === "Destructure") {
         for (const place of eachPatternOperand(instr.value.lvalue.pattern)) {
           if (

compiler/packages/babel-plugin-react-forget/src/__tests__/fixtures/compiler/repro-mutable-range-shared-inner-outer-function.expect.md

@@ -34,34 +34,36 @@ export const FIXTURE_ENTRYPOINT = {
 import { unstable_useMemoCache as useMemoCache } from "react"; // @enableAssumeHooksFollowRulesOfReact @enableTransitivelyFreezeFunctionExpressions
 let cond = true;
 function Component(props) {
-  const $ = useMemoCache(1);
+  const $ = useMemoCache(2);
+  let a;
+  let b;
   let t0;
   if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = Symbol.for("react.early_return_sentinel");
-    bb8: {
-      let a;
-      let b;
-      const f = () => {
-        if (cond) {
-          a = {};
-          b = [];
-        } else {
-          a = {};
-          b = [];
-        }
-        a.property = true;
-        b.push(false);
-      };
-      t0 = <div onClick={f} />;
-      break bb8;
-    }
+    t0 = () => {
+      if (cond) {
+        a = {};
+        b = [];
+      } else {
+        a = {};
+        b = [];
+      }
+
+      a.property = true;
+      b.push(false);
+    };
     $[0] = t0;
   } else {
     t0 = $[0];
   }
-  if (t0 !== Symbol.for("react.early_return_sentinel")) {
-    return t0;
+  const f = t0;
+  let t1;
+  if ($[1] === Symbol.for("react.memo_cache_sentinel")) {
+    t1 = <div onClick={f} />;
+    $[1] = t1;
+  } else {
+    t1 = $[1];
   }
+  return t1;
 }
 
 export const FIXTURE_ENTRYPOINT = {