1 files changed, 2 insertions, 2 deletions
diff --git a/Source/cmGeneratorExpression.h b/Source/cmGeneratorExpression.h
index 4eab2dd..489b052 100644
--- a/Source/cmGeneratorExpression.h
+++ b/Source/cmGeneratorExpression.h
@@ -90,7 +90,7 @@ public:
   std::set<cmTarget*> const& GetTargets() const
     { return this->Targets; }
 
-  std::map<cmStdString, cmStdString> const& GetSeenTargetProperties() const
+  std::set<cmStdString> const& GetSeenTargetProperties() const
     { return this->SeenTargetProperties; }
 
   ~cmCompiledGeneratorExpression();
@@ -124,7 +124,7 @@ private:
   bool NeedsParsing;
 
   mutable std::set<cmTarget*> Targets;
-  mutable std::map<cmStdString, cmStdString> SeenTargetProperties;
+  mutable std::set<cmStdString> SeenTargetProperties;
   mutable std::string Output;
   mutable bool HadContextSensitiveCondition;
 };