diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index ae0fa87fc..50a6ea9c4 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -35,6 +35,23 @@ const char* cmTarget::TargetTypeNames[] = {
   "UNKNOWN_LIBRARY"
 };
 
+//----------------------------------------------------------------------------
+struct cmTarget::OutputInfo
+{
+  std::string OutDir;
+  std::string ImpDir;
+};
+
+//----------------------------------------------------------------------------
+struct cmTarget::ImportInfo
+{
+  bool NoSOName;
+  std::string Location;
+  std::string SOName;
+  std::string ImportLibrary;
+  cmTarget::LinkInterface LinkInterface;
+};
+
 //----------------------------------------------------------------------------
 class cmTargetInternals
 {
@@ -58,6 +75,12 @@ public:
   };
   typedef std::map<cmStdString, OptionalLinkInterface> LinkInterfaceMapType;
   LinkInterfaceMapType LinkInterfaceMap;
+
+  typedef std::map<cmStdString, cmTarget::OutputInfo> OutputInfoMapType;
+  OutputInfoMapType OutputInfoMap;
+
+  typedef std::map<cmStdString, cmTarget::ImportInfo> ImportInfoMapType;
+  ImportInfoMapType ImportInfoMap;
 };
 
 //----------------------------------------------------------------------------
@@ -1855,7 +1878,7 @@ void cmTarget::SetProperty(const char* prop, const char* value)
   // information.
   if(this->IsImported() && strncmp(prop, "IMPORTED", 8) == 0)
     {
-    this->ImportInfoMap.clear();
+    this->Internal->ImportInfoMap.clear();
     }
 }
 
@@ -1872,7 +1895,7 @@ void cmTarget::AppendProperty(const char* prop, const char* value)
   // information.
   if(this->IsImported() && strncmp(prop, "IMPORTED", 8) == 0)
     {
-    this->ImportInfoMap.clear();
+    this->Internal->ImportInfoMap.clear();
     }
 }
 
@@ -1974,15 +1997,16 @@ cmTarget::OutputInfo const* cmTarget::GetOutputInfo(const char* config)
     {
     config_upper = cmSystemTools::UpperCase(config);
     }
+  typedef cmTargetInternals::OutputInfoMapType OutputInfoMapType;
   OutputInfoMapType::const_iterator i =
-    this->OutputInfoMap.find(config_upper);
-  if(i == this->OutputInfoMap.end())
+    this->Internal->OutputInfoMap.find(config_upper);
+  if(i == this->Internal->OutputInfoMap.end())
     {
     OutputInfo info;
     this->ComputeOutputDir(config, false, info.OutDir);
     this->ComputeOutputDir(config, true, info.ImpDir);
     OutputInfoMapType::value_type entry(config_upper, info);
-    i = this->OutputInfoMap.insert(entry).first;
+    i = this->Internal->OutputInfoMap.insert(entry).first;
     }
   return &i->second;
 }
@@ -3416,14 +3440,15 @@ cmTarget::GetImportInfo(const char* config)
     {
     config_upper = "NOCONFIG";
     }
+  typedef cmTargetInternals::ImportInfoMapType ImportInfoMapType;
   ImportInfoMapType::const_iterator i =
-    this->ImportInfoMap.find(config_upper);
-  if(i == this->ImportInfoMap.end())
+    this->Internal->ImportInfoMap.find(config_upper);
+  if(i == this->Internal->ImportInfoMap.end())
     {
     ImportInfo info;
     this->ComputeImportInfo(config_upper, info);
     ImportInfoMapType::value_type entry(config_upper, info);
-    i = this->ImportInfoMap.insert(entry).first;
+    i = this->Internal->ImportInfoMap.insert(entry).first;
     }
 
   // If the location is empty then the target is not available for
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index 8b857e07f..ad7e6110d 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -507,27 +507,12 @@ private:
   bool IsImportedTarget;
 
   // Cache target output paths for each configuration.
-  struct OutputInfo
-  {
-    std::string OutDir;
-    std::string ImpDir;
-  };
-  typedef std::map<cmStdString, OutputInfo> OutputInfoMapType;
-  OutputInfoMapType OutputInfoMap;
+  struct OutputInfo;
   OutputInfo const* GetOutputInfo(const char* config);
   void ComputeOutputDir(const char* config, bool implib, std::string& out);
 
   // Cache import information from properties for each configuration.
-  struct ImportInfo
-  {
-    bool NoSOName;
-    std::string Location;
-    std::string SOName;
-    std::string ImportLibrary;
-    cmTarget::LinkInterface LinkInterface;
-  };
-  typedef std::map<cmStdString, ImportInfo> ImportInfoMapType;
-  ImportInfoMapType ImportInfoMap;
+  struct ImportInfo;
   ImportInfo const* GetImportInfo(const char* config);
   void ComputeImportInfo(std::string const& desired_config, ImportInfo& info);