Index: clang-tools-extra/unittests/clangd/SymbolCollectorTests.cpp
===================================================================
--- clang-tools-extra/unittests/clangd/SymbolCollectorTests.cpp
+++ clang-tools-extra/unittests/clangd/SymbolCollectorTests.cpp
@@ -109,6 +109,7 @@
     File.Filename = FileName;
     File.HeaderCode = HeaderCode;
     File.Code = Code;
+    File.ExtraArgs.push_back("-std=c++14");
     AST = File.build();
   }
 
Index: clang/test/Index/print-type-size.cpp
===================================================================
--- clang/test/Index/print-type-size.cpp
+++ clang/test/Index/print-type-size.cpp
@@ -1,6 +1,6 @@
 // from SemaCXX/class-layout.cpp
-// RUN: c-index-test -test-print-type-size %s -target x86_64-pc-linux-gnu | FileCheck -check-prefix=CHECK64 %s
-// RUN: c-index-test -test-print-type-size %s -target i386-apple-darwin9 | FileCheck -check-prefix=CHECK32 %s
+// RUN: c-index-test -test-print-type-size %s -target x86_64-pc-linux-gnu -std=c++14 | FileCheck -check-prefix=CHECK64 %s
+// RUN: c-index-test -test-print-type-size %s -target i386-apple-darwin9 -std=c++14 | FileCheck -check-prefix=CHECK32 %s
 
 namespace basic {