Parse: Don't crash when default argument in typedef consists of sole '='

We'd crash trying to make the SourceRange for the tokens we'd like to
highlight.  Don't assume there is more than one token makes up the
default argument.

llvm-svn: 225774

1 files changed, 7 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index b84ea7b04f5..510738ea816 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -388,9 +388,14 @@ void Sema::CheckExtraCXXDefaultArguments(Declarator &D) {
         ParmVarDecl *Param = cast<ParmVarDecl>(chunk.Fun.Params[argIdx].Param);
         if (Param->hasUnparsedDefaultArg()) {
           CachedTokens *Toks = chunk.Fun.Params[argIdx].DefaultArgTokens;
+          SourceRange SR;
+          if (Toks->size() > 1)
+            SR = SourceRange((*Toks)[1].getLocation(),
+                             Toks->back().getLocation());
+          else
+            SR = UnparsedDefaultArgLocs[Param];
           Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
-            << SourceRange((*Toks)[1].getLocation(),
-                           Toks->back().getLocation());
+            << SR;
           delete Toks;
           chunk.Fun.Params[argIdx].DefaultArgTokens = nullptr;
         } else if (Param->getDefaultArg()) {