refactor(furc): mark AST nodes as final

furc/include/furc/ast/declaration.hpp

@@ -42,7 +42,7 @@ protected:
     front::token m_name;
 };
 
-class function_definition_node : public function_declaration_node {
+class function_definition_node final : public function_declaration_node {
 public:
     function_definition_node(front::token name, body_h&& body)
       : function_declaration_node(name), m_body(std::move(body)) {}

furc/include/furc/ast/expression.hpp

@@ -27,7 +27,7 @@ protected:
     bool equal(const node& rhs) const override;
 };
 
-class var_read_expression_node : public expression_node {
+class var_read_expression_node final : public expression_node {
 public:
     var_read_expression_node(handle<std::string_view>&& name)
       : m_name(std::move(name)) {}
@@ -55,7 +55,7 @@ enum class unaryop_expression_node_t {
     PostfixDecrement,
 };
 
-class unaryop_expression_node : public expression_node {
+class unaryop_expression_node final : public expression_node {
 public:
     unaryop_expression_node(unaryop_expression_node_t type, expression_node_h&& node)
       : m_type(type), m_node(std::move(node)) {}
@@ -95,7 +95,7 @@ enum class binop_expression_node_t {
     GreaterEqual,
 };
 
-class binop_expression_node : public expression_node {
+class binop_expression_node final : public expression_node {
 public:
     binop_expression_node(binop_expression_node_t type, expression_node_h&& lhs, expression_node_h&& rhs)
       : m_type(type), m_lhs(std::move(lhs)), m_rhs(std::move(rhs)) {}
@@ -121,7 +121,7 @@ private:
     expression_node_h       m_rhs;
 };
 
-class var_assign_expression_node : public expression_node {
+class var_assign_expression_node final : public expression_node {
 public:
     var_assign_expression_node(expression_node_h&& lhs, expression_node_h&& rhs)
       : m_compound(binop_expression_node_t::None), m_lhs(std::move(lhs)), m_rhs(std::move(rhs)) {}

furc/include/furc/ast/literal.hpp

@@ -24,7 +24,7 @@ protected:
     bool equal(const node& rhs) const override;
 };
 
-class string_literal_node : public literal_node {
+class string_literal_node final : public literal_node {
 public:
     string_literal_node(handle<std::string_view>&& value)
       : m_value(std::move(value)) {}
@@ -42,7 +42,7 @@ private:
     handle<std::string_view> m_value;
 };
 
-class integer_literal_node : public literal_node {
+class integer_literal_node final : public literal_node {
 public:
     integer_literal_node(handle<front::integer_token>&& value)
       : m_value(std::move(value)) {}

furc/include/furc/ast/program.hpp

@@ -9,7 +9,7 @@
 namespace furc {
 namespace ast {
 
-class program_node : public node {
+class program_node final : public node {
 public:
     program_node() = default;
 

furc/include/furc/ast/statement.hpp

@@ -23,7 +23,7 @@ protected:
     bool equal(const node& rhs) const override;
 };
 
-class return_statement_node : public statement_node {
+class return_statement_node final : public statement_node {
 public:
     return_statement_node() = default;
 
@@ -43,7 +43,7 @@ private:
     expression_node_h m_value;
 };
 
-class if_statement_node : public statement_node {
+class if_statement_node final : public statement_node {
 public:
     if_statement_node(expression_node_h&& cond, statement_node_h&& then)
       : m_cond(std::move(cond)), m_then(std::move(then)) {}
@@ -68,7 +68,7 @@ private:
     statement_node_h  m_else;
 };
 
-class compound_statement_node : public statement_node {
+class compound_statement_node final : public statement_node {
 public:
     compound_statement_node(body_h&& body)
       : m_body(std::move(body)) {}