From d4f7b3e8a4799ded6f5ad0a1ebfd7e095a493a59 Mon Sep 17 00:00:00 2001
From: Doug Gregor <dgregor@apple.com>
Date: Mon, 24 Feb 2025 16:56:52 -0800
Subject: [PATCH] [SE-0458] Improve disambiguation for "unsafe" effect on
 for..in loop

---
 Sources/SwiftParser/Statements.swift       |  4 ++--
 Tests/SwiftParserTest/StatementTests.swift | 10 ++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/Sources/SwiftParser/Statements.swift b/Sources/SwiftParser/Statements.swift
index 4f9905a13df..bf135e7d73d 100644
--- a/Sources/SwiftParser/Statements.swift
+++ b/Sources/SwiftParser/Statements.swift
@@ -574,8 +574,8 @@ extension Parser {
     if let modifierKeyword = ExpressionModifierKeyword(
       lexeme: self.currentToken,
       experimentalFeatures: self.experimentalFeatures
-    ), modifierKeyword == .unsafe, !self.peek(isAt: .keyword(.in)) {
-      unsafeKeyword = self.consumeAnyToken(remapping: .keyword)
+    ), modifierKeyword == .unsafe, !self.peek(isAt: .keyword(.in), .colon) {
+      unsafeKeyword = self.expectWithoutRecovery(.keyword(.unsafe))
     } else {
       unsafeKeyword = nil
     }
diff --git a/Tests/SwiftParserTest/StatementTests.swift b/Tests/SwiftParserTest/StatementTests.swift
index 23801dfa04b..8c7080de2c9 100644
--- a/Tests/SwiftParserTest/StatementTests.swift
+++ b/Tests/SwiftParserTest/StatementTests.swift
@@ -968,5 +968,15 @@ final class StatementTests: ParserTestCase {
       "for try await unsafe in e { }",
       experimentalFeatures: [.unsafeExpression]
     )
+
+    assertParse(
+      "for unsafe in e { }",
+      experimentalFeatures: [.unsafeExpression]
+    )
+
+    assertParse(
+      "for unsafe: Int in e { }",
+      experimentalFeatures: [.unsafeExpression]
+    )
   }
 }