1 files changed, 4 insertions, 0 deletions
diff --git a/lib/Lex/PPExpressions.cpp b/lib/Lex/PPExpressions.cpp
index c4ab143aaa..8d8fe316e7 100644
--- a/lib/Lex/PPExpressions.cpp
+++ b/lib/Lex/PPExpressions.cpp
@@ -251,6 +251,10 @@ static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
   case tok::wide_char_constant: {   // L'x'
   case tok::utf16_char_constant:    // u'x'
   case tok::utf32_char_constant:    // U'x'
+    // Complain about, and drop, any ud-suffix.
+    if (PeekTok.hasUDSuffix())
+      PP.Diag(PeekTok, diag::err_pp_invalid_char_udl);
+
     SmallString<32> CharBuffer;
     bool CharInvalid = false;
     StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);