[hir] Use types to infer constant declarations

compiler/forget/src/ReactiveScopes/PropagateScopeDependencies.ts

@@ -10,6 +10,7 @@ import {
   InstructionId,
   InstructionKind,
   InstructionValue,
+  isPrimitiveType,
   LValue,
   makeInstructionId,
   Place,
@@ -287,7 +288,9 @@ function visitInstruction(context: Context, instr: ReactiveInstruction): void {
     const range = lvalue.place.identifier.mutableRange;
     // TODO: only assign Const if the value is never reassigned
     const kind =
-      range.end === range.start + 1 ? valueKind(instr.value) : DeclKind.Dynamic;
+      range.end === range.start + 1
+        ? valueKind(lvalue.place.identifier)
+        : DeclKind.Dynamic;
     context.declare(lvalue.place.identifier, {
       kind,
       id: lvalue.place.identifier.mutableRange.start,
@@ -295,31 +298,6 @@ function visitInstruction(context: Context, instr: ReactiveInstruction): void {
   }
 }
 
-function valueKind(value: InstructionValue): DeclKind {
-  switch (value.kind) {
-    case "BinaryExpression":
-    case "JSXText":
-    case "Primitive": {
-      return DeclKind.Const;
-    }
-    case "ComputedLoad":
-    case "ComputedStore":
-    case "PropertyStore":
-    case "PropertyLoad":
-    case "Identifier":
-    case "ArrayExpression":
-    case "CallExpression":
-    case "JsxExpression":
-    case "JsxFragment":
-    case "NewExpression":
-    case "ObjectExpression":
-    case "FunctionExpression":
-    case "OtherStatement":
-    case "UnaryExpression": {
-      return DeclKind.Dynamic;
-    }
-    default: {
-      assertExhaustive(value, `Unexpected value kind '${(value as any).kind}'`);
-    }
-  }
+function valueKind(id: Identifier): DeclKind {
+  return isPrimitiveType(id) ? DeclKind.Const : DeclKind.Dynamic;
 }

compiler/forget/src/__tests__/fixtures/hir/type-test-polymorphic.expect.md

@@ -41,20 +41,18 @@ function component() {
     o = $[1];
   }
 
-  const c_2 = $[2] !== p;
-  const c_3 = $[3] !== o;
+  const c_2 = $[2] !== o;
   let x;
 
-  if (c_2 || c_3) {
+  if (c_2) {
     x = {};
     x.t = p;
     const z = x.t;
     x.t = o;
-    $[2] = p;
-    $[3] = o;
-    $[4] = x;
+    $[2] = o;
+    $[3] = x;
   } else {
-    x = $[4];
+    x = $[3];
   }
 
   const y = x.t;