From 3dd9ef43ce489526e7284d170afec831147ae655 Mon Sep 17 00:00:00 2001
From: David Souther <davidsouther+github@gmail.com>
Date: Mon, 9 May 2022 10:22:22 -0700
Subject: [PATCH] fix(44466): Fixes parsing contextual keyword casts as arrow
 functions

---
 src/compiler/parser.ts                                  | 4 ++++
 tests/baselines/reference/overrideParenVariable.js      | 8 ++++++++
 tests/baselines/reference/overrideParenVariable.symbols | 0
 tests/baselines/reference/overrideParenVariable.types   | 0
 tests/cases/compiler/readonlyParenCast.ts               | 5 +++++
 5 files changed, 17 insertions(+)
 create mode 100644 tests/baselines/reference/overrideParenVariable.js
 create mode 100644 tests/baselines/reference/overrideParenVariable.symbols
 create mode 100644 tests/baselines/reference/overrideParenVariable.types
 create mode 100644 tests/cases/compiler/readonlyParenCast.ts

diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index dd1e7f6431a..35536bb2246 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -4538,6 +4538,10 @@ namespace ts {
                 // isn't actually allowed, but we want to treat it as a lambda so we can provide
                 // a good error message.
                 if (isModifierKind(second) && second !== SyntaxKind.AsyncKeyword && lookAhead(nextTokenIsIdentifier)) {
+                    if (lookAhead(() => nextToken() === SyntaxKind.AsKeyword)) {
+                        // https://github.com/microsoft/TypeScript/issues/44466
+                        return Tristate.False;
+                    }
                     return Tristate.True;
                 }
 
diff --git a/tests/baselines/reference/overrideParenVariable.js b/tests/baselines/reference/overrideParenVariable.js
new file mode 100644
index 00000000000..22eb85b7c31
--- /dev/null
+++ b/tests/baselines/reference/overrideParenVariable.js
@@ -0,0 +1,8 @@
+//// [overrideParenVariable.ts]
+
+let override: any;
+export const a = (override as number);
+
+//// [overrideParenVariable.js]
+
+export const a = override;
diff --git a/tests/baselines/reference/overrideParenVariable.symbols b/tests/baselines/reference/overrideParenVariable.symbols
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/baselines/reference/overrideParenVariable.types b/tests/baselines/reference/overrideParenVariable.types
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/cases/compiler/readonlyParenCast.ts b/tests/cases/compiler/readonlyParenCast.ts
new file mode 100644
index 00000000000..b89372d3924
--- /dev/null
+++ b/tests/cases/compiler/readonlyParenCast.ts
@@ -0,0 +1,5 @@
+//@target: ES5
+
+let readonly: any;
+
+export const a = (readonly as number);
\ No newline at end of file