Index: src/ResolvExpr/ConversionCost.cc
===================================================================
--- src/ResolvExpr/ConversionCost.cc	(revision 2d80111cda56c1eaa64c85ead71201dfe6b1b5b8)
+++ src/ResolvExpr/ConversionCost.cc	(revision 4f5a8a2441acf4d1cea809cdd5b210abd06f4f3f)
@@ -98,5 +98,5 @@
 	}
 
-	Cost convertToReferenceCost( const Type * src, const Type * dest, int diff, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
+	static Cost convertToReferenceCost( const Type * src, const Type * dest, int diff, const SymTab::Indexer & indexer, const TypeEnvironment & env, PtrsFunction func ) {
 		PRINT( std::cerr << "convert to reference cost... diff " << diff << " " << src << " / " << dest << std::endl; )
 		if ( diff > 0 ) {
@@ -534,6 +534,6 @@
 }
 
-Cost convertToReferenceCost( const ast::Type * src, const ast::Type * dst, int diff,
-		const ast::SymbolTable & symtab, const ast::TypeEnvironment & env,
+static Cost convertToReferenceCost( const ast::Type * src, const ast::Type * dst,
+		int diff, const ast::SymbolTable & symtab, const ast::TypeEnvironment & env,
 		NumCostCalculation func ) {
 	if ( 0 < diff ) {