Index: lib/Format/TokenAnnotator.cpp
===================================================================
--- lib/Format/TokenAnnotator.cpp
+++ lib/Format/TokenAnnotator.cpp
@@ -285,6 +285,16 @@
         else
           Left->PackingKind = PPK_OnePerLine;
 
+        if (MightBeObjCForRangeLoop) {
+          FormatToken *ForInToken = Left;
+          while (ForInToken && ForInToken != CurrentToken) {
+            if (ForInToken->is(Keywords.kw_in)) {
+              ForInToken->Type = TT_ObjCForIn;
+              break;
+            }
+            ForInToken = ForInToken->Next;
+          }
+        }
         next();
         return true;
       }
@@ -303,8 +313,6 @@
         Contexts.back().IsExpression = false;
       if (CurrentToken->isOneOf(tok::semi, tok::colon))
         MightBeObjCForRangeLoop = false;
-      if (MightBeObjCForRangeLoop && CurrentToken->is(Keywords.kw_in))
-        CurrentToken->Type = TT_ObjCForIn;
       // When we discover a 'new', we set CanBeExpression to 'false' in order to
       // parse the type correctly. Reset that after a comma.
       if (CurrentToken->is(tok::comma))
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -11999,6 +11999,31 @@
   EXPECT_EQ(FormatStyle::LK_Cpp, guessLanguage("foo.h", "[[foo::bar, ...]]"));
 }
 
+TEST_F(FormatTest, GuessLanguageWithForIn) {
+  EXPECT_EQ(FormatStyle::LK_Cpp,
+            guessLanguage("foo.h", "for (Foo *x = 0; x != in; x++) {}"));
+  EXPECT_EQ(FormatStyle::LK_ObjC,
+            guessLanguage("foo.h", "for (Foo *x in bar) {}"));
+  EXPECT_EQ(FormatStyle::LK_ObjC,
+            guessLanguage("foo.h", "for (Foo *x in [bar baz]) {}"));
+  EXPECT_EQ(FormatStyle::LK_ObjC,
+            guessLanguage("foo.h", "for (Foo *x in [bar baz:blech]) {}"));
+  EXPECT_EQ(
+      FormatStyle::LK_ObjC,
+      guessLanguage("foo.h", "for (Foo *x in [bar baz:blech, 1, 2, 3, 0]) {}"));
+  EXPECT_EQ(FormatStyle::LK_ObjC,
+            guessLanguage("foo.h", "for (Foo *x in [bar baz:^{[uh oh];}]) {}"));
+  EXPECT_EQ(FormatStyle::LK_Cpp,
+            guessLanguage("foo.h", "Foo *x; for (x = 0; x != in; x++) {}"));
+  EXPECT_EQ(FormatStyle::LK_ObjC,
+            guessLanguage("foo.h", "Foo *x; for (x in y) {}"));
+  EXPECT_EQ(
+      FormatStyle::LK_Cpp,
+      guessLanguage(
+          "foo.h",
+          "for (const Foo<Bar>& baz = in.value(); !baz.at_end(); ++baz) {}"));
+}
+
 } // end namespace
 } // end namespace format
 } // end namespace clang