If an ObjCMessageExpr is implicit, there are no source locations for the
selector identifiers.

It was difficult to form a test case for it unfortunately.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148053 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index e7177aa..b94a08d 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -2872,9 +2872,11 @@
     MyArgs[I] = Args[I];
   }
 
-  SelLocsKind = SelLocsK;
-  if (SelLocsK == SelLoc_NonStandard)
-    std::copy(SelLocs.begin(), SelLocs.end(), getStoredSelLocs());
+  if (!isImplicit()) {
+    SelLocsKind = SelLocsK;
+    if (SelLocsK == SelLoc_NonStandard)
+      std::copy(SelLocs.begin(), SelLocs.end(), getStoredSelLocs());
+  }
 }
 
 ObjCMessageExpr *ObjCMessageExpr::Create(ASTContext &Context, QualType T,