Add virtual destructors on base classes.

1 files changed, 2 insertions, 0 deletions

diff --git a/libjulia/optimiser/ASTWalker.h b/libjulia/optimiser/ASTWalker.h
index 97891381..f09c2ff1 100644
--- a/libjulia/optimiser/ASTWalker.h
+++ b/libjulia/optimiser/ASTWalker.h
@@ -42,6 +42,7 @@ namespace julia
 class ASTWalker: public boost::static_visitor<>
 {
 public:
+	virtual ~ASTWalker() = default;
 	virtual void operator()(Literal const&) {}
 	virtual void operator()(Instruction const&) { solAssert(false, ""); }
 	virtual void operator()(Identifier const&) {}
@@ -82,6 +83,7 @@ protected:
 class ASTModifier: public boost::static_visitor<>
 {
 public:
+	virtual ~ASTModifier() = default;
 	virtual void operator()(Literal&) {}
 	virtual void operator()(Instruction&) { solAssert(false, ""); }
 	virtual void operator()(Identifier&) {}