From b9cb5ce7914f3f5ebdb743a21916b2a7b6d6ffdd Mon Sep 17 00:00:00 2001
From: Doug Gregor <dgregor@apple.com>
Date: Fri, 7 Mar 2025 15:07:45 -0800
Subject: [PATCH] [SE-0458] Disambiguate "unsafe" expression within string
 interpolation

String interpolation uses an end-of-file token, which we weren't
checking for. Fixes rdar://146493296
---
 lib/Parse/ParseExpr.cpp | 2 +-
 test/Unsafe/safe.swift  | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index d3fbc3a614ffc..6acbde2a188c4 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -439,7 +439,7 @@ ParserResult<Expr> Parser::parseExprSequenceElement(Diag<> message,
   if (Tok.isContextualKeyword("unsafe") &&
       !(peekToken().isAtStartOfLine() ||
         peekToken().isAny(tok::r_paren, tok::r_brace, tok::r_square,
-                          tok::equal, tok::colon, tok::comma) ||
+                          tok::equal, tok::colon, tok::comma, tok::eof) ||
         (isExprBasic && peekToken().is(tok::l_brace)) ||
         peekToken().is(tok::period) ||
         (peekToken().isAny(tok::l_paren, tok::l_square) &&
diff --git a/test/Unsafe/safe.swift b/test/Unsafe/safe.swift
index e2e80ccd00c8f..90271a9bca1b6 100644
--- a/test/Unsafe/safe.swift
+++ b/test/Unsafe/safe.swift
@@ -207,6 +207,8 @@ func moreUnsafeFunc(unsafe: [Int]) {
   // expected-warning@-1{{no unsafe operations occur within 'unsafe' expression}}
 
   _ = unsafe[1]
+
+  _ = "\(unsafe)"
 }
 
 func yetMoreUnsafeFunc(unsafe: () -> Void) {