From 562b815ba3bdda764db4ba71bef6f7c44cec4918 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Tue, 13 Aug 2024 19:19:46 +0200
Subject: [PATCH] Add a regression test related to narrowing in plain JS files
 (#59611)

---
 .../reference/narrowingPlainJsNoCrash1.js     | 21 ++++++++
 .../narrowingPlainJsNoCrash1.symbols          | 26 ++++++++++
 .../reference/narrowingPlainJsNoCrash1.types  | 48 +++++++++++++++++++
 .../compiler/narrowingPlainJsNoCrash1.ts      | 13 +++++
 4 files changed, 108 insertions(+)
 create mode 100644 tests/baselines/reference/narrowingPlainJsNoCrash1.js
 create mode 100644 tests/baselines/reference/narrowingPlainJsNoCrash1.symbols
 create mode 100644 tests/baselines/reference/narrowingPlainJsNoCrash1.types
 create mode 100644 tests/cases/compiler/narrowingPlainJsNoCrash1.ts

diff --git a/tests/baselines/reference/narrowingPlainJsNoCrash1.js b/tests/baselines/reference/narrowingPlainJsNoCrash1.js
new file mode 100644
index 00000000000..f83a5c5c010
--- /dev/null
+++ b/tests/baselines/reference/narrowingPlainJsNoCrash1.js
@@ -0,0 +1,21 @@
+//// [tests/cases/compiler/narrowingPlainJsNoCrash1.ts] ////
+
+//// [index.js]
+// https://github.com/microsoft/TypeScript/issues/59594
+
+var a$b = {};
+var c, d;
+d = a$b;
+while (d !== a$b);
+while ((c = a$b != a$b)) c.e;
+
+
+//// [index.js]
+// https://github.com/microsoft/TypeScript/issues/59594
+var a$b = {};
+var c, d;
+d = a$b;
+while (d !== a$b)
+    ;
+while ((c = a$b != a$b))
+    c.e;
diff --git a/tests/baselines/reference/narrowingPlainJsNoCrash1.symbols b/tests/baselines/reference/narrowingPlainJsNoCrash1.symbols
new file mode 100644
index 00000000000..5fc0fbfa238
--- /dev/null
+++ b/tests/baselines/reference/narrowingPlainJsNoCrash1.symbols
@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/narrowingPlainJsNoCrash1.ts] ////
+
+=== index.js ===
+// https://github.com/microsoft/TypeScript/issues/59594
+
+var a$b = {};
+>a$b : Symbol(a$b, Decl(index.js, 2, 3))
+
+var c, d;
+>c : Symbol(c, Decl(index.js, 3, 3))
+>d : Symbol(d, Decl(index.js, 3, 6))
+
+d = a$b;
+>d : Symbol(d, Decl(index.js, 3, 6))
+>a$b : Symbol(a$b, Decl(index.js, 2, 3))
+
+while (d !== a$b);
+>d : Symbol(d, Decl(index.js, 3, 6))
+>a$b : Symbol(a$b, Decl(index.js, 2, 3))
+
+while ((c = a$b != a$b)) c.e;
+>c : Symbol(c, Decl(index.js, 3, 3))
+>a$b : Symbol(a$b, Decl(index.js, 2, 3))
+>a$b : Symbol(a$b, Decl(index.js, 2, 3))
+>c : Symbol(c, Decl(index.js, 3, 3))
+
diff --git a/tests/baselines/reference/narrowingPlainJsNoCrash1.types b/tests/baselines/reference/narrowingPlainJsNoCrash1.types
new file mode 100644
index 00000000000..364d7c4f6de
--- /dev/null
+++ b/tests/baselines/reference/narrowingPlainJsNoCrash1.types
@@ -0,0 +1,48 @@
+//// [tests/cases/compiler/narrowingPlainJsNoCrash1.ts] ////
+
+=== index.js ===
+// https://github.com/microsoft/TypeScript/issues/59594
+
+var a$b = {};
+>a$b : {}
+>    : ^^
+>{} : {}
+>   : ^^
+
+var c, d;
+>c : any
+>d : any
+
+d = a$b;
+>d = a$b : {}
+>        : ^^
+>d : any
+>a$b : {}
+>    : ^^
+
+while (d !== a$b);
+>d !== a$b : boolean
+>          : ^^^^^^^
+>d : {}
+>  : ^^
+>a$b : {}
+>    : ^^
+
+while ((c = a$b != a$b)) c.e;
+>(c = a$b != a$b) : boolean
+>                 : ^^^^^^^
+>c = a$b != a$b : boolean
+>               : ^^^^^^^
+>c : any
+>a$b != a$b : boolean
+>           : ^^^^^^^
+>a$b : {}
+>    : ^^
+>a$b : {}
+>    : ^^
+>c.e : error
+>c : true
+>  : ^^^^
+>e : any
+>  : ^^^
+
diff --git a/tests/cases/compiler/narrowingPlainJsNoCrash1.ts b/tests/cases/compiler/narrowingPlainJsNoCrash1.ts
new file mode 100644
index 00000000000..260d04188ed
--- /dev/null
+++ b/tests/cases/compiler/narrowingPlainJsNoCrash1.ts
@@ -0,0 +1,13 @@
+// @allowJs: true
+// @checkJs: false
+// @outDir: true
+
+// @filename: index.js
+
+// https://github.com/microsoft/TypeScript/issues/59594
+
+var a$b = {};
+var c, d;
+d = a$b;
+while (d !== a$b);
+while ((c = a$b != a$b)) c.e;