diff --git a/Source/cmListFileCache.cxx b/Source/cmListFileCache.cxx
index 1097dc2cc..bff298615 100644
--- a/Source/cmListFileCache.cxx
+++ b/Source/cmListFileCache.cxx
@@ -398,7 +398,7 @@ bool cmListFileParser::AddArgument(cmListFileLexer_Token* token,
     }
 }
 
-void cmListFileBacktrace::PrintTitle(std::ostream& out)
+void cmListFileBacktrace::PrintTitle(std::ostream& out) const
 {
   if (!this->Snapshot.IsValid())
     {
@@ -412,7 +412,7 @@ void cmListFileBacktrace::PrintTitle(std::ostream& out)
   out << (lfc.Line ? " at " : " in ") << lfc;
 }
 
-void cmListFileBacktrace::PrintCallStack(std::ostream& out)
+void cmListFileBacktrace::PrintCallStack(std::ostream& out) const
 {
   if (!this->Snapshot.IsValid())
     {
diff --git a/Source/cmListFileCache.h b/Source/cmListFileCache.h
index aa8a34c6c..0afd7f5d3 100644
--- a/Source/cmListFileCache.h
+++ b/Source/cmListFileCache.h
@@ -95,8 +95,8 @@ class cmListFileBacktrace
     {
     }
 
-    void PrintTitle(std::ostream& out);
-    void PrintCallStack(std::ostream& out);
+    void PrintTitle(std::ostream& out) const;
+    void PrintCallStack(std::ostream& out) const;
   private:
     cmCommandContext Context;
     cmState::Snapshot Snapshot;