diff --git a/Source/cmSourceFileLocation.cxx b/Source/cmSourceFileLocation.cxx
index 30a53cbd0..3e78b299e 100644
--- a/Source/cmSourceFileLocation.cxx
+++ b/Source/cmSourceFileLocation.cxx
@@ -16,6 +16,42 @@
 #include "cmGlobalGenerator.h"
 #include "cmSystemTools.h"
 
+#include "assert.h"
+
+//----------------------------------------------------------------------------
+cmSourceFileLocation::cmSourceFileLocation()
+  : Makefile(0), AmbiguousDirectory(true), AmbiguousExtension(true)
+{
+
+}
+
+//----------------------------------------------------------------------------
+cmSourceFileLocation::cmSourceFileLocation(const cmSourceFileLocation& loc)
+  : Makefile(loc.Makefile)
+{
+  this->AmbiguousDirectory = loc.AmbiguousDirectory;
+  this->AmbiguousExtension = loc.AmbiguousExtension;
+  this->Directory = loc.Directory;
+  this->Name = loc.Name;
+}
+
+//----------------------------------------------------------------------------
+cmSourceFileLocation&
+cmSourceFileLocation::operator=(const cmSourceFileLocation& loc)
+{
+  if(this == &loc)
+    {
+    return *this;
+    }
+  this->Makefile = loc.Makefile;
+  this->AmbiguousDirectory = loc.AmbiguousDirectory;
+  this->AmbiguousExtension = loc.AmbiguousExtension;
+  this->Directory = loc.Directory;
+  this->Name = loc.Name;
+  this->UpdateExtension(this->Name);
+  return *this;
+}
+
 //----------------------------------------------------------------------------
 cmSourceFileLocation
 ::cmSourceFileLocation(cmMakefile const* mf, const std::string& name)
@@ -59,6 +95,7 @@ void cmSourceFileLocation::Update(cmSourceFileLocation const& loc)
 //----------------------------------------------------------------------------
 void cmSourceFileLocation::DirectoryUseSource()
 {
+  assert(this->Makefile);
   if(this->AmbiguousDirectory)
     {
     this->Directory =
@@ -71,6 +108,7 @@ void cmSourceFileLocation::DirectoryUseSource()
 //----------------------------------------------------------------------------
 void cmSourceFileLocation::DirectoryUseBinary()
 {
+  assert(this->Makefile);
   if(this->AmbiguousDirectory)
     {
     this->Directory =
@@ -83,6 +121,7 @@ void cmSourceFileLocation::DirectoryUseBinary()
 //----------------------------------------------------------------------------
 void cmSourceFileLocation::UpdateExtension(const std::string& name)
 {
+  assert(this->Makefile);
   // Check the extension.
   std::string ext = cmSystemTools::GetFilenameLastExtension(name);
   if(!ext.empty()) { ext = ext.substr(1); }
@@ -152,6 +191,7 @@ bool
 cmSourceFileLocation
 ::MatchesAmbiguousExtension(cmSourceFileLocation const& loc) const
 {
+  assert(this->Makefile);
   // This location's extension is not ambiguous but loc's extension
   // is.  See if the names match as-is.
   if(this->Name == loc.Name)
@@ -188,6 +228,7 @@ cmSourceFileLocation
 //----------------------------------------------------------------------------
 bool cmSourceFileLocation::Matches(cmSourceFileLocation const& loc)
 {
+  assert(this->Makefile);
   if(this->AmbiguousExtension && loc.AmbiguousExtension)
     {
     // Both extensions are ambiguous.  Since only the old fixed set of
diff --git a/Source/cmSourceFileLocation.h b/Source/cmSourceFileLocation.h
index c83e8c0f8..82a62ab4f 100644
--- a/Source/cmSourceFileLocation.h
+++ b/Source/cmSourceFileLocation.h
@@ -34,6 +34,9 @@ public:
    * instance with an initial name.
    */
   cmSourceFileLocation(cmMakefile const* mf, const std::string& name);
+  cmSourceFileLocation();
+  cmSourceFileLocation(const cmSourceFileLocation& loc);
+  cmSourceFileLocation& operator=(const cmSourceFileLocation& loc);
 
   /**
    * Return whether the givne source file location could refers to the