[rhir] Add dependencies produced by active (incomplete) scopes

--- 

> If this operand is used in a scope, has a dynamic value, and was defined 
before this scope, then its a dependency of the scope. 

> (from current comments in PropagateScopeDependencies::visitDependency) 

A reactive scope can take a dependency from a definition produced by an 
incomplete parent scope. Our tests previously did not cover this, since most 
object types aliased together and remained mutable throughout a ReactiveScope. 

e.g. our tests did not have 

``` 

scope @0 (deps=...,  declarations=[x, y]) { 

x = {}; 

// define a reactive, immutable value that is not aliased to become mutable 

const immutableVal = ...; 

scope @1 (deps=immutableVal, declarations=[y]) { 

y = read(immutableVal) 

} 

mutateX(x, ...); 

} 

``` 

We should not add a dependency if it is produced in exactly the same scope as 
the one it is used. It is safe (and correct) to depend on values produced by a 
parent scope. 

--- 

Note that we still should check for whether a defining scope is active to 
determine whether it should be added as a output of that scope 
([src](https://github.com/facebook/react-forget/blob/b608ab20d57229b528deeffa19f1ee08a4bad37a/forget/src/ReactiveScopes/PropagateScopeDependencies.ts#L469-L478)). 

Access of an identifier produced by a parent scope (i.e. adding a variable 
defined by a scope's parent as its own dependency) does not require adding that 
identifier to the parent's `declarations`, since that identifier is already 
valid to access via identifier binding rules.

compiler/forget/src/ReactiveScopes/PropagateScopeDependencies.ts

@@ -505,7 +505,7 @@ class Context {
       currentDeclaration !== undefined &&
       currentDeclaration.id < currentScope.range.start &&
       (currentDeclaration.scope == null ||
-        !this.#isScopeActive(currentDeclaration.scope))
+        currentDeclaration.scope !== currentScope)
     ) {
       // Check if there is an existing dependency that describes this operand
       // We do not try to join/reduce dependencies here due to missing info

compiler/forget/src/__tests__/fixtures/hir/allocating-primitive-as-dep.expect.md

@@ -53,7 +53,7 @@ function AllocatingPrimitiveAsDep(props) {
 }
 
 function PrimitiveAsDepNested(props) {
-  const $ = React.unstable_useMemoCache(8);
+  const $ = React.unstable_useMemoCache(10);
   const c_0 = $[0] !== props.b;
   const c_1 = $[1] !== props.a;
   let x;
@@ -69,12 +69,15 @@ function PrimitiveAsDepNested(props) {
     } else {
       t0 = $[4];
     }
+    const t1 = t0 + 1;
+    const c_5 = $[5] !== t1;
     let y;
-    if ($[5] === Symbol.for("react.memo_cache_sentinel")) {
-      y = foo(t0 + 1);
-      $[5] = y;
+    if (c_5) {
+      y = foo(t1);
+      $[5] = t1;
+      $[6] = y;
     } else {
-      y = $[5];
+      y = $[6];
     }
     mutate(x, props.a);
     $[0] = props.b;
@@ -83,16 +86,18 @@ function PrimitiveAsDepNested(props) {
   } else {
     x = $[2];
   }
-  const c_6 = $[6] !== x;
-  let t1;
-  if (c_6) {
-    t1 = [x, y];
-    $[6] = x;
-    $[7] = t1;
+  const c_7 = $[7] !== x;
+  const c_8 = $[8] !== y;
+  let t2;
+  if (c_7 || c_8) {
+    t2 = [x, y];
+    $[7] = x;
+    $[8] = y;
+    $[9] = t2;
   } else {
-    t1 = $[7];
+    t2 = $[9];
   }
-  return t1;
+  return t2;
 }
 
 ```

compiler/forget/src/__tests__/fixtures/hir/primitive-as-dep.expect.md

@@ -46,19 +46,22 @@ function PrimitiveAsDep(props) {
 }
 
 function PrimitiveAsDepNested(props) {
-  const $ = React.unstable_useMemoCache(6);
+  const $ = React.unstable_useMemoCache(8);
   const c_0 = $[0] !== props.b;
   const c_1 = $[1] !== props.a;
   let x;
   if (c_0 || c_1) {
     x = {};
     mutate(x);
+    const t0 = props.b + 1;
+    const c_3 = $[3] !== t0;
     let y;
-    if ($[3] === Symbol.for("react.memo_cache_sentinel")) {
-      y = foo(props.b + 1);
-      $[3] = y;
+    if (c_3) {
+      y = foo(t0);
+      $[3] = t0;
+      $[4] = y;
     } else {
-      y = $[3];
+      y = $[4];
     }
     mutate(x, props.a);
     $[0] = props.b;
@@ -67,16 +70,18 @@ function PrimitiveAsDepNested(props) {
   } else {
     x = $[2];
   }
-  const c_4 = $[4] !== x;
-  let t0;
-  if (c_4) {
-    t0 = [x, y];
-    $[4] = x;
-    $[5] = t0;
+  const c_5 = $[5] !== x;
+  const c_6 = $[6] !== y;
+  let t1;
+  if (c_5 || c_6) {
+    t1 = [x, y];
+    $[5] = x;
+    $[6] = y;
+    $[7] = t1;
   } else {
-    t0 = $[5];
+    t1 = $[7];
   }
-  return t0;
+  return t1;
 }
 
 ```