diff --git a/boot/ast.cc b/boot/ast.cc
index 8358abb..c565bda 100644
--- a/boot/ast.cc
+++ b/boot/ast.cc
@@ -44,30 +44,25 @@ namespace boot
         definition->body().accept(this);
     }
 
-    void empty_visitor::visit(call_expression *expression)
+    void empty_visitor::visit(procedure_call *call)
     {
-        for (struct expression *const argument : expression->arguments)
+        for (expression *const argument : call->arguments)
         {
             argument->accept(this);
         }
     }
 
+    void empty_visitor::visit(traits_expression *trait)
+    {
+        trait->type().accept(this);
+    }
+
     void empty_visitor::visit(cast_expression *expression)
     {
         expression->target().accept(this);
         expression->value().accept(this);
     }
 
-    void empty_visitor::visit(type_expression *expression)
-    {
-        expression->body().accept(this);
-    }
-
-    void empty_visitor::visit(call_statement *statement)
-    {
-        statement->body().accept(this);
-    }
-
     void empty_visitor::visit(assign_statement *statement)
     {
         statement->rvalue().accept(this);
@@ -249,13 +244,11 @@ namespace boot
         return this->source_position;
     }
 
-    statement::statement(const struct position position)
-        : node(position)
+    statement::statement()
     {
     }
 
-    expression::expression(const struct position position)
-        : node(position)
+    expression::expression()
     {
     }
 
@@ -539,13 +532,12 @@ namespace boot
         }
     }
 
-    literal::literal(const struct position position)
-        : expression(position)
+    literal::literal()
     {
     }
 
     defer_statement::defer_statement(const struct position position)
-        : statement(position)
+        : node(position)
     {
     }
 
@@ -562,13 +554,12 @@ namespace boot
         }
     }
 
-    designator_expression::designator_expression(const struct position position)
-        : expression(position)
+    designator_expression::designator_expression()
     {
     }
 
     variable_expression::variable_expression(const struct position position, const std::string& name)
-        : designator_expression(position), m_name(name)
+        : node(position), name(name)
     {
     }
 
@@ -577,11 +568,6 @@ namespace boot
         visitor->visit(this);
     }
 
-    const std::string& variable_expression::name() const
-    {
-        return m_name;
-    }
-
     variable_expression *variable_expression::is_variable()
     {
         return this;
@@ -589,7 +575,7 @@ namespace boot
 
     array_access_expression::array_access_expression(const struct position position,
             expression *base, expression *index)
-        : designator_expression(position), m_base(base), m_index(index)
+        : node(position), m_base(base), m_index(index)
     {
     }
 
@@ -621,7 +607,7 @@ namespace boot
 
     field_access_expression::field_access_expression(const struct position position,
             expression *base, const std::string& field)
-        : designator_expression(position), m_base(base), m_field(field)
+        : node(position), m_base(base), m_field(field)
     {
     }
 
@@ -652,7 +638,7 @@ namespace boot
 
     dereference_expression::dereference_expression(const struct position position,
             expression *base)
-        : designator_expression(position), m_base(base)
+        : node(position), m_base(base)
     {
     }
 
@@ -678,7 +664,7 @@ namespace boot
 
     binary_expression::binary_expression(const struct position position, expression *lhs,
             expression *rhs, const binary_operator operation)
-        : expression(position), m_lhs(lhs), m_rhs(rhs), m_operator(operation)
+        : node(position), m_lhs(lhs), m_rhs(rhs), m_operator(operation)
     {
     }
 
@@ -710,7 +696,7 @@ namespace boot
 
     unary_expression::unary_expression(const struct position position, expression *operand,
             const unary_operator operation)
-        : expression(position), m_operand(std::move(operand)), m_operator(operation)
+        : node(position), m_operand(std::move(operand)), m_operator(operation)
     {
     }
 
@@ -734,22 +720,22 @@ namespace boot
         delete m_operand;
     }
 
-    call_expression::call_expression(const struct position position, designator_expression *callable)
-        : expression(position), m_callable(callable)
+    procedure_call::procedure_call(const struct position position, designator_expression *callable)
+        : node(position), m_callable(callable)
     {
     }
 
-    void call_expression::accept(parser_visitor *visitor)
+    void procedure_call::accept(parser_visitor *visitor)
     {
         visitor->visit(this);
     }
 
-    designator_expression& call_expression::callable()
+    designator_expression& procedure_call::callable()
     {
         return *m_callable;
     }
 
-    call_expression::~call_expression()
+    procedure_call::~procedure_call()
     {
         for (expression *const argument : arguments)
         {
@@ -760,7 +746,7 @@ namespace boot
 
     cast_expression::cast_expression(const struct position position,
             std::shared_ptr<top_type> target, expression *value)
-        : expression(position), m_target(target), m_value(value)
+        : node(position), m_target(target), m_value(value)
     {
     }
 
@@ -784,39 +770,20 @@ namespace boot
         delete m_value;
     }
 
-    type_expression::type_expression(const struct position position, std::shared_ptr<top_type> body)
-        : expression(position), m_body(body)
+    traits_expression::traits_expression(const struct position position,
+            const std::string& name, std::shared_ptr<top_type> type)
+        : node(position), m_type(type), name(name)
     {
     }
 
-    void type_expression::accept(parser_visitor *visitor)
+    void traits_expression::accept(parser_visitor *visitor)
     {
         visitor->visit(this);
     }
 
-    top_type& type_expression::body()
+    top_type& traits_expression::type()
     {
-        return *m_body;
-    }
-
-    call_statement::call_statement(const struct position position, call_expression *body)
-        : statement(position), m_body(body)
-    {
-    }
-
-    void call_statement::accept(parser_visitor *visitor)
-    {
-        visitor->visit(this);
-    }
-
-    call_expression& call_statement::body()
-    {
-        return *m_body;
-    }
-
-    call_statement::~call_statement()
-    {
-        delete m_body;
+        return *m_type;
     }
 
     conditional_statements::conditional_statements(expression *prerequisite)
@@ -839,7 +806,7 @@ namespace boot
     }
 
     return_statement::return_statement(const struct position position, expression *return_expression)
-        : statement(position), m_return_expression(return_expression)
+        : node(position), m_return_expression(return_expression)
     {
     }
 
@@ -865,7 +832,7 @@ namespace boot
 
     assign_statement::assign_statement(const struct position position, designator_expression *lvalue,
             expression *rvalue)
-        : statement(position), m_lvalue(lvalue), m_rvalue(rvalue)
+        : node(position), m_lvalue(lvalue), m_rvalue(rvalue)
     {
     }
 
@@ -906,7 +873,7 @@ namespace boot
 
     if_statement::if_statement(const struct position position, conditional_statements *body,
             std::vector<statement *> *alternative)
-        : statement(position), m_body(body), m_alternative(alternative)
+        : node(position), m_body(body), m_alternative(alternative)
     {
     }
 
@@ -936,7 +903,7 @@ namespace boot
     }
 
     while_statement::while_statement(const struct position position, conditional_statements *body)
-        : statement(position), m_body(body)
+        : node(position), m_body(body)
     {
     }
 
diff --git a/boot/lexer.ll b/boot/lexer.ll
index cb8837a..bb7ca06 100644
--- a/boot/lexer.ll
+++ b/boot/lexer.ll
@@ -131,6 +131,9 @@ defer                   {
 [A-Za-z_][A-Za-z0-9_]*  {
                             return yy::parser::make_IDENTIFIER(yytext, this->location);
                         }
+#[A-Za-z_][A-Za-z0-9_]* {
+                            return yy::parser::make_TRAIT(yytext + 1, this->location);
+                        }
 [0-9]+u                 {
                             return yy::parser::make_WORD(strtoul(yytext, NULL, 10), this->location);
                         }
diff --git a/boot/parser.yy b/boot/parser.yy
index 42ea4f2..bbc17fd 100644
--- a/boot/parser.yy
+++ b/boot/parser.yy
@@ -75,6 +75,7 @@ along with GCC; see the file COPYING3.  If not see
 %start program;
 
 %token <std::string> IDENTIFIER
+%token <std::string> TRAIT
 %token <std::int32_t> INTEGER
 %token <std::uint32_t> WORD
 %token <float> FLOAT
@@ -125,11 +126,12 @@ along with GCC; see the file COPYING3.  If not see
     formal_parameters formal_parameter_list;
 %type <elna::boot::variable_declaration *> formal_parameter
 %type <std::shared_ptr<elna::boot::top_type>> type_expression;
+%type <elna::boot::traits_expression *> traits_expression;
 %type <elna::boot::expression *> expression operand unary;
 %type <std::vector<elna::boot::expression *>> expressions actual_parameter_list;
 %type <elna::boot::designator_expression *> designator_expression;
 %type <elna::boot::assign_statement *> assign_statement;
-%type <elna::boot::call_expression *> call_expression;
+%type <elna::boot::procedure_call*> call_expression;
 %type <elna::boot::while_statement *> while_statement;
 %type <elna::boot::if_statement *> if_statement;
 %type <elna::boot::return_statement *> return_statement;
@@ -227,7 +229,7 @@ assign_statement: designator_expression ":=" expression
         }
 call_expression: designator_expression actual_parameter_list
         {
-            $$ = new elna::boot::call_expression(elna::boot::make_position(@1), $1);
+            $$ = new elna::boot::procedure_call(elna::boot::make_position(@1), $1);
             std::swap($$->arguments, $2);
         }
 cast_expression: "cast" "(" expression ":" type_expression ")"
@@ -313,10 +315,15 @@ literal:
         {
             $$ = new elna::boot::number_literal<std::string>(elna::boot::make_position(@1), $1);
         }
+traits_expression:
+    TRAIT "(" type_expression ")"
+        {
+            $$ = new elna::boot::traits_expression(elna::boot::make_position(@1), $1, $3);
+        }
 operand:
     literal { $$ = $1; }
     | designator_expression { $$ = $1; }
-    | "(" type_expression ")" { $$ = new elna::boot::type_expression(elna::boot::make_position(@1), $2); }
+    | traits_expression { $$ = $1; }
     | cast_expression { $$ = $1; }
     | call_expression { $$ = $1; }
     | "(" expression ")" { $$ = $2; }
@@ -448,10 +455,7 @@ statement:
     | while_statement { $$ = $1; }
     | if_statement { $$ = $1; }
     | return_statement { $$ = $1; }
-    | call_expression
-        {
-            $$ = new elna::boot::call_statement(elna::boot::make_position(@1), $1);
-        }
+    | call_expression { $$ = $1; }
     | defer_statement { $$ = $1; }
 statements:
     statement statements
diff --git a/gcc/elna-generic.cc b/gcc/elna-generic.cc
index 73dcddc..af7c532 100644
--- a/gcc/elna-generic.cc
+++ b/gcc/elna-generic.cc
@@ -84,11 +84,6 @@ namespace gcc
                         list_length(TYPE_ARG_TYPES(symbol_type)) - 1, arguments.size());
                 this->current_expression = error_mark_node;
         }
-        else if (TREE_TYPE(symbol_type) == void_type_node)
-        {
-            append_statement(stmt);
-            this->current_expression = NULL_TREE;
-        }
         else
         {
             this->current_expression = stmt;
@@ -136,10 +131,10 @@ namespace gcc
         }
     }
 
-    void generic_visitor::visit(boot::call_expression *expression)
+    void generic_visitor::visit(boot::procedure_call *call)
     {
-        location_t call_location = get_location(&expression->position());
-        expression->callable().accept(this);
+        location_t call_location = get_location(&call->position());
+        call->callable().accept(this);
 
         tree expression_type = TYPE_P(this->current_expression)
             ? this->current_expression
@@ -147,17 +142,17 @@ namespace gcc
 
         if (TYPE_P(this->current_expression) && TREE_CODE(expression_type) == RECORD_TYPE)
         {
-            build_record_call(call_location, this->current_expression, expression->arguments);
+            build_record_call(call_location, this->current_expression, call->arguments);
         }
         else if (TREE_CODE(expression_type) == FUNCTION_TYPE)
         {
             this->current_expression = build1(ADDR_EXPR,
                     build_pointer_type_for_mode(expression_type, VOIDmode, true), this->current_expression);
-            build_procedure_call(call_location, this->current_expression, expression->arguments);
+            build_procedure_call(call_location, this->current_expression, call->arguments);
         }
         else if (is_pointer_type(expression_type) && TREE_CODE(TREE_TYPE(expression_type)) == FUNCTION_TYPE)
         {
-            build_procedure_call(call_location, this->current_expression, expression->arguments);
+            build_procedure_call(call_location, this->current_expression, call->arguments);
         }
         else
         {
@@ -178,11 +173,6 @@ namespace gcc
                 cast_target, this->current_expression);
     }
 
-    void generic_visitor::visit(boot::type_expression *expression)
-    {
-        this->current_expression = build_type(expression->body());
-    }
-
     void generic_visitor::visit(boot::program *program)
     {
         for (boot::constant_definition *const constant : program->constants)
@@ -226,10 +216,7 @@ namespace gcc
             DECL_ARGUMENTS(fndecl) = chainon(DECL_ARGUMENTS(fndecl), declaration_tree);
             parameter_type = TREE_CHAIN(parameter_type);
         }
-        for (boot::statement *const body_statement : program->body)
-        {
-            body_statement->accept(this);
-        }
+        visit_statements(program->body);
         tree set_result = build2(INIT_EXPR, void_type_node, DECL_RESULT(fndecl),
                 build_int_cst_type(integer_type_node, 0));
         tree return_stmt = build1(RETURN_EXPR, void_type_node, set_result);
@@ -248,6 +235,19 @@ namespace gcc
         cgraph_node::finalize_function(fndecl, true);
     }
 
+    void generic_visitor::visit(boot::block *block)
+    {
+        for (boot::constant_definition *const constant : block->constants)
+        {
+            constant->accept(this);
+        }
+        for (boot::variable_declaration *const variable : block->variables)
+        {
+            variable->accept(this);
+        }
+        visit_statements(block->body);
+    }
+
     void generic_visitor::visit(boot::procedure_definition *definition)
     {
         tree declaration_type = build_procedure_type(definition->heading());
@@ -903,13 +903,13 @@ namespace gcc
 
     void generic_visitor::visit(boot::variable_expression *expression)
     {
-        auto symbol = this->lookup(expression->name());
+        auto symbol = this->lookup(expression->name);
 
         if (symbol == NULL_TREE)
         {
             error_at(get_location(&expression->position()),
                     "symbol '%s' not declared in the current scope",
-                    expression->name().c_str());
+                    expression->name.c_str());
             this->current_expression = error_mark_node;
         }
         else
@@ -964,40 +964,40 @@ namespace gcc
         }
     }
 
+    void generic_visitor::visit(boot::traits_expression *trait)
+    {
+        tree type_expression = build_type(trait->type());
+
+        if (trait->name == "size")
+        {
+            this->current_expression = build1(CONVERT_EXPR, elna_word_type_node, size_in_bytes(type_expression));
+        }
+        else if (trait->name == "alignment")
+        {
+            this->current_expression = build_int_cstu(elna_word_type_node, TYPE_ALIGN_UNIT(type_expression));
+        }
+        else if (trait->name == "min" && is_integral_type(type_expression))
+        {
+            this->current_expression = TYPE_MIN_VALUE(type_expression);
+        }
+        else if (trait->name == "max" && is_integral_type(type_expression))
+        {
+            this->current_expression = TYPE_MAX_VALUE(type_expression);
+        }
+        else
+        {
+            error_at(get_location(&trait->position()), "type '%s' does not have property '%s'",
+                    print_type(type_expression).c_str(), trait->name.c_str());
+            this->current_expression = error_mark_node;
+        }
+    }
+
     void generic_visitor::visit(boot::field_access_expression *expression)
     {
         expression->base().accept(this);
         location_t expression_location = get_location(&expression->position());
 
-        if (TYPE_P(this->current_expression))
-        {
-            if (expression->field() == "size")
-            {
-                this->current_expression = build1(CONVERT_EXPR, elna_word_type_node,
-                        size_in_bytes(this->current_expression));
-            }
-            else if (expression->field() == "alignment")
-            {
-                this->current_expression = build_int_cstu(elna_word_type_node,
-                        TYPE_ALIGN_UNIT(this->current_expression));
-            }
-            else if (expression->field() == "min" && is_integral_type(this->current_expression))
-            {
-                this->current_expression = TYPE_MIN_VALUE(this->current_expression);
-            }
-            else if (expression->field() == "max" && is_integral_type(this->current_expression))
-            {
-                this->current_expression =  TYPE_MAX_VALUE(this->current_expression);
-            }
-            else
-            {
-                error_at(expression_location, "type '%s' does not have property '%s'",
-                        print_type(this->current_expression).c_str(), expression->field().c_str());
-                this->current_expression = error_mark_node;
-            }
-
-        }
-        else if (is_aggregate_type(TREE_TYPE(this->current_expression)))
+        if (is_aggregate_type(TREE_TYPE(this->current_expression)))
         {
             tree field_declaration = TYPE_FIELDS(TREE_TYPE(this->current_expression));
 
@@ -1026,6 +1026,12 @@ namespace gcc
                         field_declaration, NULL_TREE);
             }
         }
+        else
+        {
+            error_at(expression_location, "type '%s' does not have a field named '%s'",
+                    print_type(TREE_TYPE(this->current_expression)).c_str(), expression->field().c_str());
+            this->current_expression = error_mark_node;
+        }
     }
 
     void generic_visitor::visit(boot::dereference_expression *expression)
@@ -1049,7 +1055,7 @@ namespace gcc
         if (TREE_CODE(lvalue) == CONST_DECL)
         {
             error_at(statement_location, "cannot modify constant '%s'",
-                    statement->lvalue().is_variable()->name().c_str());
+                    statement->lvalue().is_variable()->name.c_str());
             this->current_expression = error_mark_node;
         }
         else if (is_assignable_from(TREE_TYPE(lvalue), rvalue))
@@ -1083,10 +1089,7 @@ namespace gcc
         if (statement->alternative() != nullptr)
         {
             enter_scope();
-            for (const auto body_statement : *statement->alternative())
-            {
-                body_statement->accept(this);
-            }
+            visit_statements(*statement->alternative());
             tree mapping = leave_scope();
             append_statement(mapping);
         }
@@ -1120,10 +1123,7 @@ namespace gcc
         append_statement(then_label_expr);
         enter_scope();
 
-        for (const auto body_statement : branch.statements)
-        {
-            body_statement->accept(this);
-        }
+        visit_statements(branch.statements);
         tree mapping = leave_scope();
         append_statement(mapping);
         append_statement(goto_endif);
@@ -1160,11 +1160,18 @@ namespace gcc
         this->current_expression = NULL_TREE;
     }
 
-    void generic_visitor::visit(boot::call_statement *statement)
+    void generic_visitor::visit_statements(const std::vector<boot::statement *>& statements)
     {
-        statement->body().accept(this);
-        append_statement(this->current_expression);
-        this->current_expression = NULL_TREE;
+        for (boot::statement *const statement : statements)
+        {
+            statement->accept(this);
+
+            if (this->current_expression != NULL_TREE && this->current_expression != error_mark_node)
+            {
+                append_statement(this->current_expression);
+                this->current_expression = NULL_TREE;
+            }
+        }
     }
 
     void generic_visitor::visit(boot::return_statement *statement)
@@ -1181,15 +1188,14 @@ namespace gcc
                 this->current_expression);
         tree return_stmt = build1(RETURN_EXPR, void_type_node, set_result);
         append_statement(return_stmt);
+
+        this->current_expression = NULL_TREE;
     }
 
     void generic_visitor::visit(boot::defer_statement *statement)
     {
         enter_scope();
-        for (boot::statement *const body_statement : statement->statements)
-        {
-            body_statement->accept(this);
-        }
+        visit_statements(statement->statements);
         defer(leave_scope());
     }
 }
diff --git a/include/elna/boot/ast.h b/include/elna/boot/ast.h
index 83f1afb..2e9902f 100644
--- a/include/elna/boot/ast.h
+++ b/include/elna/boot/ast.h
@@ -58,14 +58,13 @@ namespace boot
     class constant_definition;
     class procedure_definition;
     class type_definition;
-    class call_expression;
+    class procedure_call;
     class cast_expression;
-    class type_expression;
     class assign_statement;
     class if_statement;
     class while_statement;
     class return_statement;
-    class call_statement;
+    class traits_expression;
     class block;
     class program;
     class binary_expression;
@@ -93,10 +92,9 @@ namespace boot
         virtual void visit(constant_definition *) = 0;
         virtual void visit(procedure_definition *) = 0;
         virtual void visit(type_definition *) = 0;
-        virtual void visit(call_expression *) = 0;
+        virtual void visit(procedure_call *) = 0;
         virtual void visit(cast_expression *) = 0;
-        virtual void visit(type_expression *) = 0;
-        virtual void visit(call_statement *) = 0;
+        virtual void visit(traits_expression *) = 0;
         virtual void visit(assign_statement *) = 0;
         virtual void visit(if_statement *) = 0;
         virtual void visit(while_statement *) = 0;
@@ -134,10 +132,9 @@ namespace boot
         virtual void visit(constant_definition *definition) override;
         virtual void visit(procedure_definition *definition) override;
         virtual void visit(type_definition *definition) override;
-        virtual void visit(call_expression *expression) override;
+        virtual void visit(traits_expression *trait) override;
+        virtual void visit(procedure_call *call) override;
         virtual void visit(cast_expression *expression) override;
-        virtual void visit(type_expression *expression) override;
-        virtual void visit(call_statement *statement) override;
         virtual void visit(assign_statement *statement) override;
         virtual void visit(if_statement *) override;
         virtual void visit(while_statement *) override;
@@ -189,22 +186,16 @@ namespace boot
         const struct position& position() const;
     };
 
-    class statement : public node
+    class statement : public virtual node
     {
     protected:
-        /**
-         * \param position Source code position.
-         */
-        explicit statement(const struct position position);
+        statement();
     };
 
-    class expression : public node
+    class expression : public virtual node
     {
     protected:
-        /**
-         * \param position Source code position.
-         */
-        explicit expression(const struct position position);
+        expression();
     };
 
     /**
@@ -331,7 +322,7 @@ namespace boot
     class literal : public expression
     {
     protected:
-        explicit literal(const struct position position);
+        literal();
     };
 
     /**
@@ -435,31 +426,17 @@ namespace boot
         virtual ~cast_expression() override;
     };
 
-    /**
-     * Type inside an expression.
-     */
-    class type_expression : public expression
+    class traits_expression : public expression
     {
-        std::shared_ptr<top_type> m_body;
+        std::shared_ptr<top_type> m_type;
 
     public:
-        type_expression(const struct position position, std::shared_ptr<top_type> body);
+        const std::string name;
+
+        traits_expression(const struct position position, const std::string& name, std::shared_ptr<top_type> type);
         virtual void accept(parser_visitor *visitor) override;
 
-        top_type& body();
-    };
-
-    class call_statement : public statement
-    {
-        call_expression *m_body;
-
-    public:
-        call_statement(const struct position position, call_expression *body);
-        virtual void accept(parser_visitor *visitor) override;
-
-        call_expression& body();
-
-        virtual ~call_statement() override;
+        top_type& type();
     };
 
     /**
@@ -501,19 +478,17 @@ namespace boot
         virtual dereference_expression *is_dereference();
 
     protected:
-        designator_expression(const struct position position);
+        designator_expression();
     };
 
     class variable_expression : public designator_expression
     {
-        std::string m_name;
-
     public:
+        const std::string name;
+
         variable_expression(const struct position position, const std::string& name);
         virtual void accept(parser_visitor *visitor) override;
 
-        const std::string& name() const;
-
         variable_expression *is_variable() override;
     };
 
@@ -570,19 +545,19 @@ namespace boot
     /**
      * Procedure call expression.
      */
-    class call_expression : public expression
+    class procedure_call : public expression, public statement
     {
         designator_expression *m_callable;
 
     public:
         std::vector<expression *> arguments;
 
-        call_expression(const struct position position, designator_expression *callable);
+        procedure_call(const struct position position, designator_expression *callable);
         virtual void accept(parser_visitor *visitor) override;
 
         designator_expression& callable();
 
-        virtual ~call_expression() override;
+        virtual ~procedure_call() override;
     };
 
     class assign_statement : public statement
@@ -676,7 +651,7 @@ namespace boot
         T value;
 
         number_literal(const struct position position, const T& value)
-            : literal(position), value(value)
+            : node(position), value(value)
         {
         }
 
diff --git a/include/elna/gcc/elna-generic.h b/include/elna/gcc/elna-generic.h
index 7fd4115..700ba76 100644
--- a/include/elna/gcc/elna-generic.h
+++ b/include/elna/gcc/elna-generic.h
@@ -60,15 +60,16 @@ namespace gcc
                 tree procedure_address, const std::vector<boot::expression *>& arguments);
         void build_record_call(location_t call_location,
                 tree symbol, const std::vector<boot::expression *>& arguments);
+        void visit_statements(const std::vector<boot::statement *>& statements);
 
     public:
         generic_visitor(std::shared_ptr<symbol_table> symbol_table);
 
         void visit(boot::program *program) override;
         void visit(boot::procedure_definition *definition) override;
-        void visit(boot::call_expression *expression) override;
+        void visit(boot::procedure_call *call) override;
         void visit(boot::cast_expression *expression) override;
-        void visit(boot::type_expression *expression) override;
+        void visit(boot::traits_expression *trait) override;
         void visit(boot::number_literal<std::int32_t> *literal) override;
         void visit(boot::number_literal<std::uint32_t> *literal) override;
         void visit(boot::number_literal<double> *literal) override;
@@ -85,10 +86,10 @@ namespace gcc
         void visit(boot::array_access_expression *expression) override;
         void visit(boot::field_access_expression *expression) override;
         void visit(boot::dereference_expression *expression) override;
+        void visit(boot::block *block) override;
         void visit(boot::assign_statement *statement) override;
         void visit(boot::if_statement *statement) override;
         void visit(boot::while_statement *statement) override;
-        void visit(boot::call_statement *statement) override;
         void visit(boot::return_statement *statement) override;
         void visit(boot::defer_statement *statement) override;
     };
diff --git a/source.elna b/source.elna
index 9225a26..83fcb11 100644
--- a/source.elna
+++ b/source.elna
@@ -658,7 +658,7 @@ begin
   source_code := skip_spaces(source_code)
 
   while source_code.text.length <> 0u do
-	tokens := cast(reallocarray(cast(tokens: ^Byte), tokens_size^ + 1u, Token.size): ^Token)
+	tokens := cast(reallocarray(cast(tokens: ^Byte), tokens_size^ + 1u, #size(Token)): ^Token)
     current_token := tokens + tokens_size^
 	first_char := source_code.text[1u]
 
@@ -832,7 +832,7 @@ var
   result: ^CommandLine
 begin
   i := 1
-  result := cast(malloc(CommandLine.size): ^CommandLine)
+  result := cast(malloc(#size(CommandLine)): ^CommandLine)
   result^.tokenize := false
   result^.syntax_tree := false
   result^.input := nil