From 789e0db358c824eaf5a643ef128c9b7d503a0c42 Mon Sep 17 00:00:00 2001
From: Gabriela Araujo Britto <gabrielaa@microsoft.com>
Date: Mon, 2 Dec 2024 16:29:17 -0800
Subject: [PATCH 1/2] fix flow node improper reuse

---
 src/compiler/binder.ts                           |  3 +++
 .../fourslash/unreachableStatementNodeReuse.ts   | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 tests/cases/fourslash/unreachableStatementNodeReuse.ts

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index b071f72b712c2..8e149d912a436 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1104,6 +1104,9 @@ function createBinder(): (file: SourceFile, options: CompilerOptions) => void {
         // and set it before we descend into nodes that could actually be part of an assignment pattern.
         inAssignmentPattern = false;
         if (checkUnreachable(node)) {
+            if ((node as HasFlowNode).flowNode) {
+                (node as HasFlowNode).flowNode = undefined;
+            }
             bindEachChild(node);
             bindJSDoc(node);
             inAssignmentPattern = saveInAssignmentPattern;
diff --git a/tests/cases/fourslash/unreachableStatementNodeReuse.ts b/tests/cases/fourslash/unreachableStatementNodeReuse.ts
new file mode 100644
index 0000000000000..f2191227c948f
--- /dev/null
+++ b/tests/cases/fourslash/unreachableStatementNodeReuse.ts
@@ -0,0 +1,16 @@
+/// <reference path="fourslash.ts" />
+
+//// function test() {
+//// 	return /*a*/abc();
+//// 	return;
+//// }
+//// function abc() { }
+
+verify.noErrors();
+
+goTo.marker("a");
+edit.backspace(1);
+verify.numberOfErrorsInCurrentFile(1);
+
+edit.insert(" ");
+verify.noErrors();
\ No newline at end of file

From 2bdc72d05b73cbd1f490018f187b2fa4d8e9b427 Mon Sep 17 00:00:00 2001
From: Gabriela Araujo Britto <gabrielaa@microsoft.com>
Date: Tue, 3 Dec 2024 09:39:26 -0800
Subject: [PATCH 2/2] use canHaveFlowNode and simplify test

---
 src/compiler/binder.ts                                 | 5 +++--
 tests/cases/fourslash/unreachableStatementNodeReuse.ts | 7 ++-----
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 8e149d912a436..41966df6672e9 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -21,6 +21,7 @@ import {
     BreakOrContinueStatement,
     CallChain,
     CallExpression,
+    canHaveFlowNode,
     canHaveLocals,
     canHaveSymbol,
     CaseBlock,
@@ -1104,8 +1105,8 @@ function createBinder(): (file: SourceFile, options: CompilerOptions) => void {
         // and set it before we descend into nodes that could actually be part of an assignment pattern.
         inAssignmentPattern = false;
         if (checkUnreachable(node)) {
-            if ((node as HasFlowNode).flowNode) {
-                (node as HasFlowNode).flowNode = undefined;
+            if (canHaveFlowNode(node) && node.flowNode) {
+                node.flowNode = undefined;
             }
             bindEachChild(node);
             bindJSDoc(node);
diff --git a/tests/cases/fourslash/unreachableStatementNodeReuse.ts b/tests/cases/fourslash/unreachableStatementNodeReuse.ts
index f2191227c948f..9ede6fd059c95 100644
--- a/tests/cases/fourslash/unreachableStatementNodeReuse.ts
+++ b/tests/cases/fourslash/unreachableStatementNodeReuse.ts
@@ -1,16 +1,13 @@
 /// <reference path="fourslash.ts" />
 
 //// function test() {
-//// 	return /*a*/abc();
+//// 	return/*a*/abc();
 //// 	return;
 //// }
 //// function abc() { }
 
-verify.noErrors();
-
-goTo.marker("a");
-edit.backspace(1);
 verify.numberOfErrorsInCurrentFile(1);
 
+goTo.marker("a")
 edit.insert(" ");
 verify.noErrors();
\ No newline at end of file