diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index e878a96..8267a25 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -934,10 +934,11 @@
 
   if (Right.is(tok::lessless)) {
     if (Left.is(tok::string_literal)) {
-      char LastChar =
-          StringRef(Left.FormatTok.Tok.getLiteralData(),
-                    Left.FormatTok.TokenLength).drop_back(1).rtrim().back();
-      if (LastChar == ':' || LastChar == '=')
+      StringRef Content = StringRef(Left.FormatTok.Tok.getLiteralData(),
+                                    Left.FormatTok.TokenLength);
+      Content = Content.drop_back(1).drop_front(1).trim();
+      if (Content.size() > 1 &&
+          (Content.back() == ':' || Content.back() == '='))
         return 100;
     }
     return prec::Shift;
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index af580dd..3044c69 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -1628,6 +1628,8 @@
       "             << \"ccccccccccccccccc = \" << ccccccccccccccccc\n"
       "             << \"ddddddddddddddddd = \" << ddddddddddddddddd\n"
       "             << \"eeeeeeeeeeeeeeeee = \" << eeeeeeeeeeeeeeeee;");
+  verifyFormat("llvm::outs() << aaaaaaaaaaaaaaaaaaaaaaaa << \"=\"\n"
+               "             << bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb;");
 }
 
 TEST_F(FormatTest, UnderstandsEquals) {