From 8b0b49840d4f04f3d17a07038ad16a0f096e463d Mon Sep 17 00:00:00 2001
From: CountBleck <Mr.YouKnowWhoIAm@protonmail.com>
Date: Sat, 9 Mar 2024 18:20:27 -0800
Subject: [PATCH] Compile incrementors in for loops within the initializer's
 flow

It turns out that incrementors were compiled with the body's flow, which
meant that the incrementor had access to local variables declared in the
body. Now, incrementors no longer have access to such variables.

Fixes #2825.
---
 src/compiler.ts                 | 1 +
 tests/compiler/issues/2825.json | 5 +++++
 tests/compiler/issues/2825.ts   | 3 +++
 3 files changed, 9 insertions(+)
 create mode 100644 tests/compiler/issues/2825.json
 create mode 100644 tests/compiler/issues/2825.ts

diff --git a/src/compiler.ts b/src/compiler.ts
index 648b6fa24d..8e5ee85615 100644
--- a/src/compiler.ts
+++ b/src/compiler.ts
@@ -2600,6 +2600,7 @@ export class Compiler extends DiagnosticEmitter {
     if (possiblyLoops) {
       let incrementor = statement.incrementor;
       if (incrementor) {
+        this.currentFlow = flow;
         bodyStmts.push(
           this.compileExpression(incrementor, Type.void, Constraints.ConvImplicit | Constraints.WillDrop)
         );
diff --git a/tests/compiler/issues/2825.json b/tests/compiler/issues/2825.json
new file mode 100644
index 0000000000..f5f36f2649
--- /dev/null
+++ b/tests/compiler/issues/2825.json
@@ -0,0 +1,5 @@
+{
+  "stderr": [
+    "TS2304: Cannot find name 'j'."
+  ]
+}
\ No newline at end of file
diff --git a/tests/compiler/issues/2825.ts b/tests/compiler/issues/2825.ts
new file mode 100644
index 0000000000..810b1fcade
--- /dev/null
+++ b/tests/compiler/issues/2825.ts
@@ -0,0 +1,3 @@
+for (let i = 0; i < 2; j++) {
+  let j = 0;
+}
\ No newline at end of file