Fix interaction between serialization and c++1z feature.

In c++1z, static_assert is not required to have a StringLiteral message, where
previously it was required.  Update the AST Reader to be able to handle a
null StringLiteral.

llvm-svn: 281286

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index d68d6d308a7..686c7f2e347 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -2239,7 +2239,7 @@ void ASTDeclReader::VisitStaticAssertDecl(StaticAssertDecl *D) {
   VisitDecl(D);
   D->AssertExprAndFailed.setPointer(Reader.ReadExpr(F));
   D->AssertExprAndFailed.setInt(Record[Idx++]);
-  D->Message = cast<StringLiteral>(Reader.ReadExpr(F));
+  D->Message = cast_or_null<StringLiteral>(Reader.ReadExpr(F));
   D->RParenLoc = ReadSourceLocation(Record, Idx);
 }