From 027f773179756bab308af2b3f0965f2dba36a067 Mon Sep 17 00:00:00 2001
From: mofeiZ <34200447+mofeiZ@users.noreply.github.com>
Date: Mon, 27 Mar 2023 13:27:58 -0400
Subject: [PATCH] [rhir] Patch for reactive computed loads

We need to check reactivity of both the operand and its resolved source (if
operand is produced by a LoadLocal / PropertyLoad / ComputedLoad).

Both the operand and its source can have reactivity.

e.g.

```js

const o = makeObject(); // source has no reactivity

const x = o[props.x];   // x is reactive

```
---
 .../ReactiveScopes/InferReactiveIdentifiers.ts   | 16 +++++++++++++---
 ...puted-load-primitive-as-dependency.expect.md} | 16 ++++++++++------
 ... => computed-load-primitive-as-dependency.js} |  0
 3 files changed, 23 insertions(+), 9 deletions(-)
 rename compiler/forget/src/__tests__/fixtures/compiler/{_bug.primitive-computed-load.expect.md => computed-load-primitive-as-dependency.expect.md} (65%)
 rename compiler/forget/src/__tests__/fixtures/compiler/{_bug.primitive-computed-load.js => computed-load-primitive-as-dependency.js} (100%)

diff --git a/compiler/forget/src/ReactiveScopes/InferReactiveIdentifiers.ts b/compiler/forget/src/ReactiveScopes/InferReactiveIdentifiers.ts
index c921d8e138..d5fc8a5e20 100644
--- a/compiler/forget/src/ReactiveScopes/InferReactiveIdentifiers.ts
+++ b/compiler/forget/src/ReactiveScopes/InferReactiveIdentifiers.ts
@@ -45,9 +45,19 @@ class Visitor extends ReactiveFunctionVisitor<State> {
       if (operand.effect === Effect.Store) {
         continue;
       }
-      const resolvedId: IdentifierId =
-        state.temporaries.get(operand.identifier.id) ?? operand.identifier.id;
-      if (state.reactivityMap.get(resolvedId)) {
+      const ownId = operand.identifier.id;
+      const resolvedId = state.temporaries.get(ownId);
+      // We need to check reactivity of both the operand and its resolved source (if operand is
+      // produced by a LoadLocal / PropertyLoad / ComputedLoad). Both the operand and its source
+      // can have reactivity. e.g.
+      // ```js
+      //   const o = makeObject(); // source has no reactivity
+      //   const x = o[props.x];   // x is reactive
+      // ```
+      if (
+        state.reactivityMap.get(ownId) ||
+        (resolvedId && state.reactivityMap.get(resolvedId))
+      ) {
         hasReactiveInput = true;
         break;
       }
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/_bug.primitive-computed-load.expect.md b/compiler/forget/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.expect.md
similarity index 65%
rename from compiler/forget/src/__tests__/fixtures/compiler/_bug.primitive-computed-load.expect.md
rename to compiler/forget/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.expect.md
index 7886b720d0..12aa0694f9 100644
--- a/compiler/forget/src/__tests__/fixtures/compiler/_bug.primitive-computed-load.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.expect.md
@@ -18,16 +18,20 @@ function Component(props) {
 
 ```javascript
 function Component(props) {
-  const $ = React.unstable_useMemoCache(1);
+  const $ = React.unstable_useMemoCache(2);
   const a = foo();
-  let t0;
-  if ($[0] === Symbol.for("react.memo_cache_sentinel")) {
-    t0 = bar(a[props.a] + 1);
+
+  const t0 = a[props.a] + 1;
+  const c_0 = $[0] !== t0;
+  let t1;
+  if (c_0) {
+    t1 = bar(t0);
     $[0] = t0;
+    $[1] = t1;
   } else {
-    t0 = $[0];
+    t1 = $[1];
   }
-  const b = t0;
+  const b = t1;
   return b;
 }
 
diff --git a/compiler/forget/src/__tests__/fixtures/compiler/_bug.primitive-computed-load.js b/compiler/forget/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.js
similarity index 100%
rename from compiler/forget/src/__tests__/fixtures/compiler/_bug.primitive-computed-load.js
rename to compiler/forget/src/__tests__/fixtures/compiler/computed-load-primitive-as-dependency.js