Deoptimize right side in for-of loops

src/ast/nodes/ForOfStatement.ts

@@ -3,7 +3,7 @@ import { NO_SEMICOLON, type RenderOptions } from '../../utils/renderHelpers';
 import type { InclusionContext } from '../ExecutionContext';
 import BlockScope from '../scopes/BlockScope';
 import type Scope from '../scopes/Scope';
-import { EMPTY_PATH } from '../utils/PathTracker';
+import { EMPTY_PATH, UNKNOWN_PATH } from '../utils/PathTracker';
 import type MemberExpression from './MemberExpression';
 import type * as NodeType from './NodeType';
 import type VariableDeclaration from './VariableDeclaration';
@@ -60,6 +60,7 @@ export default class ForOfStatement extends StatementBase {
 	protected applyDeoptimizations(): void {
 		this.deoptimized = true;
 		this.left.deoptimizePath(EMPTY_PATH);
+		this.right.deoptimizePath(UNKNOWN_PATH);
 		this.context.requestTreeshakingPass();
 	}
 }

test/function/samples/deoptimize-loop-element/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'deoptimizes the loop element when it is reassigned'
+};

test/function/samples/deoptimize-loop-element/main.js

@@ -0,0 +1,7 @@
+const foo = [{ value: 1 }];
+
+for (const item of foo) {
+	item.value = 0;
+}
+
+assert.ok(foo[0].value === 0 ? true : false);