diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 2e1188164d..fd165aca89 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -2768,7 +2768,7 @@ ExprResult Sema::ActOnNumericConstant(const Token &Tok, Scope *UDLScope) {
       SourceLocation TokLoc = Tok.getLocation();
       unsigned Length = Literal.getUDSuffixOffset();
       QualType StrTy = Context.getConstantArrayType(
-          Context.CharTy, llvm::APInt(32, Length + 1),
+          Context.CharTy.withConst(), llvm::APInt(32, Length + 1),
           ArrayType::Normal, 0);
       Expr *Lit = StringLiteral::Create(
           Context, StringRef(TokSpelling.data(), Length), StringLiteral::Ascii,