diff --git a/lang/type_check/include/basic_type_check.hpp b/lang/type_check/include/basic_type_check.hpp
index e5ceb82..ab8eac1 100644
--- a/lang/type_check/include/basic_type_check.hpp
+++ b/lang/type_check/include/basic_type_check.hpp
@@ -1,13 +1,17 @@
 #pragma once
 
 #include "basic_nodes.hpp"
-#include "sources_manager.hpp"
 #include "type_check_utils.hpp"
 
 namespace type_check {
 
 // IN PROGRESS: modifiers ??
-Result check(const nodes::Literal &literal, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+
+template <>
+struct CheckTask<nodes::Literal> : public CheckTaskBase<nodes::Literal> {
+  using CheckTaskBase<nodes::Literal>::CheckTaskBase;
+
+  Result operator()(const nodes::Literal &literal, Arguments &&arguments);
+};
 
 } // namespace type_check
diff --git a/lang/type_check/include/expression_type_check.hpp b/lang/type_check/include/expression_type_check.hpp
index c8f4153..256997d 100644
--- a/lang/type_check/include/expression_type_check.hpp
+++ b/lang/type_check/include/expression_type_check.hpp
@@ -2,84 +2,143 @@
 
 #include "expression_nodes.hpp"
 #include "type_check_utils.hpp"
-#include "type_nodes.hpp"
-#include "utils.hpp"
-
-#include <optional>
 
 // IN PROGRESS
 
 namespace type_check {
 
-// TODO: ???
-// TODO: add State to Executor and Task
-class CheckTask : public Task {
-  using Task::Task;
+template <>
+struct CheckTask<nodes::Expression> : public CheckTaskBase<nodes::Expression> {
+  using CheckTaskBase<nodes::Expression>::CheckTaskBase;
 
   Result operator()(const nodes::Expression &expr,
-                    const Arguments &arguments); // check
+                    const Arguments &args) override;
 };
 
-Result check(const nodes::Expression &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
-
 // --- flow control
 
-Result check(const nodes::Match &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Match> : public CheckTaskBase<nodes::Match> {
+  using CheckTaskBase<nodes::Match>::CheckTaskBase;
 
-Result check(const nodes::Condition &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+  Result operator()(const nodes::Match &expr, const Arguments &args) override;
+};
 
-Result check(const nodes::Loop &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Condition> : public CheckTaskBase<nodes::Condition> {
+  using CheckTaskBase<nodes::Condition>::CheckTaskBase;
+
+  Result operator()(const nodes::Condition &expr,
+                    const Arguments &args) override;
+};
+
+template <> struct CheckTask<nodes::Loop> : public CheckTaskBase<nodes::Loop> {
+  using CheckTaskBase<nodes::Loop>::CheckTaskBase;
+
+  Result operator()(const nodes::Loop &expr, const Arguments &args) override;
+};
 
 // --- containers
 
-Result check(const nodes::Container &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Container> : public CheckTaskBase<nodes::Container> {
+  using CheckTaskBase<nodes::Container>::CheckTaskBase;
+
+  Result CheckArray(const nodes::Container &expr, const Arguments &args);
+
+  Result CheckBlock(const nodes::Container &expr, const Arguments &args);
+
+  Result operator()(const nodes::Container &expr,
+                    const Arguments &args) override;
+};
 
 // --- modifiers
 
-Result check(const nodes::Return &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Return> : public CheckTaskBase<nodes::Return> {
+  using CheckTaskBase<nodes::Return>::CheckTaskBase;
 
-Result check(const nodes::NameDefinition &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+  Result operator()(const nodes::Return &expr, const Arguments &args) override;
+};
 
-Result check(const nodes::Access &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+template <>
+struct CheckTask<nodes::NameDefinition>
+    : public CheckTaskBase<nodes::NameDefinition> {
+  using CheckTaskBase<nodes::NameDefinition>::CheckTaskBase;
 
-Result check(const nodes::LoopControl &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+  Result operator()(const nodes::NameDefinition &expr,
+                    const Arguments &args) override;
+};
 
-Result check(const nodes::ModifierExpression &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Access> : public CheckTaskBase<nodes::Access> {
+  using CheckTaskBase<nodes::Access>::CheckTaskBase;
+
+  Result CheckArrayAccess(const nodes::Access &expr, const Arguments &args);
+
+  Result CheckTupleAccess(const nodes::Access &expr, const Arguments &args);
+
+  Result operator()(const nodes::Access &expr, const Arguments &args) override;
+};
+
+template <>
+struct CheckTask<nodes::LoopControl>
+    : public CheckTaskBase<nodes::LoopControl> {
+  using CheckTaskBase<nodes::LoopControl>::CheckTaskBase;
+
+  Result operator()(const nodes::LoopControl &expr,
+                    const Arguments &args) override;
+};
+
+template <>
+struct CheckTask<nodes::ModifierExpression>
+    : public CheckTaskBase<nodes::ModifierExpression> {
+  using CheckTaskBase<nodes::ModifierExpression>::CheckTaskBase;
+
+  Result operator()(const nodes::ModifierExpression &expr,
+                    const Arguments &args) override;
+};
 
 // --- other
 
-Result check(const nodes::NameExpression &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+template <>
+struct CheckTask<nodes::NameExpression>
+    : public CheckTaskBase<nodes::NameExpression> {
+  using CheckTaskBase<nodes::NameExpression>::CheckTaskBase;
 
-Result check(const nodes::Constructor &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+  Result operator()(const nodes::NameExpression &expr,
+                    const Arguments &args) override;
+};
 
-Result check(const nodes::Lambda &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Constructor>
+    : public CheckTaskBase<nodes::Constructor> {
+  using CheckTaskBase<nodes::Constructor>::CheckTaskBase;
 
-Result check(const nodes::Extra &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments);
+  Result operator()(const nodes::Constructor &expr,
+                    const Arguments &args) override;
+};
 
-Result check(const nodes::EmptyLines &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments);
+template <>
+struct CheckTask<nodes::Lambda> : public CheckTaskBase<nodes::Lambda> {
+  using CheckTaskBase<nodes::Lambda>::CheckTaskBase;
+
+  Result operator()(const nodes::Lambda &expr, const Arguments &args) override;
+};
+
+template <>
+struct CheckTask<nodes::Extra> : public CheckTaskBase<nodes::Extra> {
+  using CheckTaskBase<nodes::Extra>::CheckTaskBase;
+
+  Result operator()(const nodes::Extra &expr, const Arguments &args) override;
+};
+
+template <>
+struct CheckTask<nodes::EmptyLines> : public CheckTaskBase<nodes::EmptyLines> {
+  using CheckTaskBase<nodes::EmptyLines>::CheckTaskBase;
+
+  Result operator()(const nodes::EmptyLines &expr,
+                    const Arguments &args) override;
+};
 
 } // namespace type_check
diff --git a/lang/type_check/include/type_check_utils.hpp b/lang/type_check/include/type_check_utils.hpp
index b2f22dd..0048436 100644
--- a/lang/type_check/include/type_check_utils.hpp
+++ b/lang/type_check/include/type_check_utils.hpp
@@ -10,11 +10,6 @@
 
 namespace type_check {
 
-using Executor = utils::Executor<nodes::ExpressionStorage, nodes::TypeStorage,
-                                 names::NameTree>;
-using Task =
-    utils::Task<nodes::ExpressionStorage, nodes::TypeStorage, names::NameTree>;
-
 class ContextHolder;
 
 class State {
@@ -164,20 +159,27 @@ private:
 
 //
 
+using Exprs = nodes::ExpressionStorage;
+using Types = nodes::TypeStorage;
+using Names = names::NameTree;
+
+using Executor = utils::Executor<Exprs, Types, Names, State>;
+
+//
+
 class Arguments {
 public:
   Arguments() = default;
 
   Arguments expect_builtin(builtin::Type type, Executor &executor) const {
     Arguments copy(*this);
-    copy.expected_types_ = {
-        executor.state<nodes::TypeStorage>().primitive(type)};
+    copy.expected_types_ = {executor.state<Types>().primitive(type)};
     return copy;
   }
 
   Arguments pass_builtin(builtin::Type type, Executor &executor) const {
     Arguments copy(*this);
-    copy.passed_type_ = executor.state<nodes::TypeStorage>().primitive(type);
+    copy.passed_type_ = executor.state<Types>().primitive(type);
     return copy;
   }
 
@@ -340,4 +342,21 @@ nodes::MaybeTypeProxy get_field_type_by_name(nodes::TypeProxy type,
 void type_check_error(const std::string &message, const nodes::Node &node,
                       Executor &executor, bool handle_error = true);
 
+//
+
+template <typename N> using Task = utils::Task<Executor, Result, Arguments, N>;
+
+template <typename N> struct CheckTask {
+  static_assert(false);
+};
+
+template <typename N> struct CheckTaskBase : public Task<N> {
+  using Task<N>::Task;
+
+  template <typename OtherN> Result Run(const OtherN &node, const Arguments &args) {
+    CheckTask<OtherN> task(this->executor);
+    return task(node, args);
+  }
+};
+
 } // namespace type_check
diff --git a/lang/type_check/src/basic_type_check.cpp b/lang/type_check/src/basic_type_check.cpp
index f199229..44d4584 100644
--- a/lang/type_check/src/basic_type_check.cpp
+++ b/lang/type_check/src/basic_type_check.cpp
@@ -3,44 +3,44 @@
 namespace type_check {
 
 nodes::TypeProxy get_literal_type(const nodes::Literal &literal,
-                                  SourcesManager &sources_manager) {
+                                  Executor &executor) {
   switch (literal.get_any()->index()) {
   case 0: // float
-    return sources_manager.types()->primitive(builtin::Type::FLOAT);
+    return executor.state<Types>().primitive(builtin::Type::FLOAT);
   case 1: // double
-    return sources_manager.types()->primitive(builtin::Type::DOUBLE);
+    return executor.state<Types>().primitive(builtin::Type::DOUBLE);
   case 2: // int32_t
-    return sources_manager.types()->primitive(builtin::Type::INT);
+    return executor.state<Types>().primitive(builtin::Type::INT);
   case 3: // int64_t
-    return sources_manager.types()->primitive(builtin::Type::LONG);
+    return executor.state<Types>().primitive(builtin::Type::LONG);
   case 4: // size_t
-    return sources_manager.types()->primitive(builtin::Type::INDEX);
+    return executor.state<Types>().primitive(builtin::Type::INDEX);
   case 5: // std::string
-    return sources_manager.types()->add_array_of(
-        sources_manager.types()->primitive(builtin::Type::CHAR));
+    return executor.state<Types>().add_array_of(
+        executor.state<Types>().primitive(builtin::Type::CHAR));
   case 6: // unicode_string
-    return sources_manager.types()->add_array_of(
-        sources_manager.types()->primitive(builtin::Type::UNICODE));
+    return executor.state<Types>().add_array_of(
+        executor.state<Types>().primitive(builtin::Type::UNICODE));
   case 7: // char
-    return sources_manager.types()->primitive(builtin::Type::CHAR);
+    return executor.state<Types>().primitive(builtin::Type::CHAR);
   case 8: // unicode
-    return sources_manager.types()->primitive(builtin::Type::UNICODE);
+    return executor.state<Types>().primitive(builtin::Type::UNICODE);
   case 9: // bool
-    return sources_manager.types()->primitive(builtin::Type::BOOL);
+    return executor.state<Types>().primitive(builtin::Type::BOOL);
   case 10: // unit
-    return sources_manager.types()->primitive(builtin::Type::UNIT);
+    return executor.state<Types>().primitive(builtin::Type::UNIT);
   case 11: // null
-    return sources_manager.types()->primitive(builtin::Type::NULL_OPTION);
+    return executor.state<Types>().primitive(builtin::Type::NULL_OPTION);
   }
 
-  error_handling::handle_general_error("Unreachable");
+  utils::Assert(true, "Unreachable");
   exit(1); // unreachable
 }
 
-Result check(const nodes::Literal &literal, SourcesManager &sources_manager,
-             State &, const Arguments &arguments) {
-  auto const type = get_literal_type(literal, sources_manager);
-  return type_same_to_expected(type, arguments, literal, sources_manager);
+Result CheckTask<nodes::Literal>::operator()(const nodes::Literal &literal,
+                                             Arguments &&arguments) {
+  auto const type = get_literal_type(literal, this->executor);
+  return type_same_to_expected(type, arguments, literal, this->executor);
 }
 
 } // namespace type_check
diff --git a/lang/type_check/src/expression_type_check.cpp b/lang/type_check/src/expression_type_check.cpp
index aab879f..56f9539 100644
--- a/lang/type_check/src/expression_type_check.cpp
+++ b/lang/type_check/src/expression_type_check.cpp
@@ -1,10 +1,7 @@
 #include "expression_type_check.hpp"
 #include "basic_nodes.hpp"
-#include "basic_type_check.hpp"
 #include "builtin_types.hpp"
-#include "sources_manager.hpp"
 #include "type_nodes.hpp"
-#include "utils.hpp"
 
 // IN PROGRESS
 
@@ -13,26 +10,24 @@
 
 namespace type_check {
 
-Result check(const nodes::Expression &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
+Result CheckTask<nodes::Expression>::operator()(const nodes::Expression &expr,
+                                                const Arguments &arguments) {
   return std::visit(
-      [&sources_manager, &state, &arguments](const auto &arg) -> Result {
-        return check(arg, sources_manager, state, arguments);
+      [this, &arguments](const auto &node) -> Result {
+        return Run(node, arguments);
       },
-      *expression.get_any());
+      *expr.get_any());
 }
 
 // --- flow control
 
-Result check(const nodes::Match &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments) {
-  Result value_result =
-      check(*expression.get_value(), sources_manager, state, Arguments{});
+Result CheckTask<nodes::Match>::operator()(const nodes::Match &expr,
+                                           const Arguments &args) {
+  Result value_result = Run(*expr.get_value(), {});
 
   // x :=/=: ...
   if (value_result.is_invalid()) {
-    type_check_error("Match value is invalid", expression, sources_manager);
+    type_check_error("Match value is invalid", expr, executor);
   }
 
   MaybeResult expression_result;
@@ -40,32 +35,31 @@ Result check(const nodes::Match &expression, SourcesManager &sources_manager,
   bool at_least_one_case_with_expression = false;
   bool at_least_one_case_without_expression = false;
 
-  for (size_t i = 0; i < expression.cases_size(); ++i) {
-    const nodes::Match::Case *current_case = expression.get_case(i);
+  for (size_t i = 0; i < expr.cases_size(); ++i) {
+    const nodes::Match::Case *current_case = expr.get_case(i);
 
     // :=/=: x ...
-    check(*current_case->get_value(), sources_manager, state,
-          Arguments{}
-              .expect_builtin(builtin::Type::BOOL, sources_manager)
-              .pass(value_result.is_invalid()
-                        ? nodes::MaybeTypeProxy{}
-                        : expression_result.value().get()));
+    Run(*current_case->get_value(),
+        Arguments{}
+            .expect_builtin(builtin::Type::BOOL, executor)
+            .pass(value_result.is_invalid() ? nodes::MaybeTypeProxy{}
+                                            : expression_result.value().get()));
     // TODO: use type modifiers ??
 
     // ... ?? x ...
     if (current_case->get_condition().has_value()) {
-      check(*current_case->get_condition().value(), sources_manager, state,
-            Arguments{}.expect_builtin(builtin::Type::BOOL, sources_manager));
+      Run(*current_case->get_condition().value(),
+          Arguments{}.expect_builtin(builtin::Type::BOOL, executor));
     }
 
     // ... -> x
     if (current_case->get_expression().has_value()) {
       at_least_one_case_with_expression = true;
       Result case_result =
-          check(*current_case->get_condition().value(), sources_manager, state,
-                Arguments{}.expect(expression_result.has_value()
-                                       ? expression_result.value().get()
-                                       : nodes::MaybeTypeProxy{}));
+          Run(*current_case->get_condition().value(),
+              Arguments{}.expect(expression_result.has_value()
+                                     ? expression_result.value().get()
+                                     : nodes::MaybeTypeProxy{}));
 
       if (!expression_result.has_value() && !case_result.is_invalid()) {
         expression_result = std::move(case_result);
@@ -78,76 +72,73 @@ Result check(const nodes::Match &expression, SourcesManager &sources_manager,
   if (at_least_one_case_with_expression &&
       at_least_one_case_without_expression) {
     type_check_error(
-        "All cases should be with or without expression at the same time",
-        expression, sources_manager);
+        "All cases should be with or without expression at the same time", expr,
+        executor);
     expression_result = Result::invalid();
   }
 
   if (!expression_result.has_value()) {
-    expression_result =
-        Result{sources_manager.types()->primitive(builtin::Type::UNIT)};
+    expression_result = Result{state<Types>().primitive(builtin::Type::UNIT)};
   }
 
   return type_check_from_arguments(
-      sources_manager.types()->add_array_of(expression_result.value().get()),
-      arguments, expression, sources_manager);
+      state<Types>().add_array_of(expression_result.value().get()), args, expr,
+      executor);
 }
 
-Result check(const nodes::Condition &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
+Result CheckTask<nodes::Condition>::operator()(const nodes::Condition &expr,
+                                               const Arguments &args) {
   MaybeResult expression_result;
 
-  for (size_t i = 0; i < expression.cases_size(); ++i) {
-    check(*expression.get_case(i).first, sources_manager, state,
-          Arguments{}.expect_builtin(builtin::Type::BOOL, sources_manager));
+  for (size_t i = 0; i < expr.cases_size(); ++i) {
+    Run(*expr.get_case(i).first,
+        Arguments{}.expect_builtin(builtin::Type::BOOL, executor));
 
     Result case_result =
-        check(*expression.get_case(i).first, sources_manager, state,
-              Arguments{}.expect(expression_result.has_value()
-                                     ? expression_result.value().get()
-                                     : nodes::MaybeTypeProxy{}));
+        Run(*expr.get_case(i).first,
+            Arguments{}.expect(expression_result.has_value()
+                                   ? expression_result.value().get()
+                                   : nodes::MaybeTypeProxy{}));
 
     if (!expression_result.has_value() && !case_result.is_invalid()) {
       expression_result = std::move(case_result);
     }
   }
 
-  if (expression.get_else_case().has_value()) {
-    check(*expression.get_else_case().value(), sources_manager, state,
-          Arguments{}.expect(expression_result.has_value()
-                                 ? expression_result.value().get()
-                                 : nodes::MaybeTypeProxy{}));
+  if (expr.get_else_case().has_value()) {
+    Run(*expr.get_else_case().value(),
+        Arguments{}.expect(expression_result.has_value()
+                               ? expression_result.value().get()
+                               : nodes::MaybeTypeProxy{}));
   }
 
   if (!expression_result.has_value()) {
-    type_check_error("There should be at least one case in if statement",
-                     expression, sources_manager);
+    type_check_error("There should be at least one case in if statement", expr,
+                     executor);
     expression_result = Result::invalid();
   }
 
   return type_check_from_arguments(
-      sources_manager.types()->add_array_of(expression_result.value().get()),
-      arguments, expression, sources_manager);
+      state<Types>().add_array_of(expression_result.value().get()), args, expr,
+      executor);
 }
 
-Result check(const nodes::Loop &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments) {
+Result CheckTask<nodes::Loop>::operator()(const nodes::Loop &expr,
+                                          const Arguments &args) {
   // TODO: ranges ??
 
   MaybeResult interval_result;
 
   MaybeResult variable_result;
 
-  Result expression_result =
-      check(*expression.get_expression(), sources_manager, state, Arguments{});
+  Result expression_result = Run(*expr.get_expression(), {});
 
-  switch (expression.get_type()) {
+  switch (expr.get_type()) {
   case nodes::Loop::LOOP: // infinity loop, no params
     break;
   case nodes::Loop::WHILE:
-    check(*expression.get_condition().value(), sources_manager, state,
-          Arguments{}.expect_builtin(builtin::Type::BOOL, sources_manager));
+    Run(*expr.get_condition().value(),
+        Arguments{}.expect_builtin(builtin::Type::BOOL, executor));
 
     // --- type check is independent from loop itself ---
     // if (condition_result.value().is_invalid()) {
@@ -157,9 +148,9 @@ Result check(const nodes::Loop &expression, SourcesManager &sources_manager,
     break;
   case nodes::Loop::FOR:
     // TODO: expect range ??
-    interval_result = check(
-        *expression.get_interval().value(), sources_manager, state,
-        Arguments{}.expect_builtin(builtin::Type::ARRAY, sources_manager));
+    interval_result =
+        Run(*expr.get_interval().value(),
+            Arguments{}.expect_builtin(builtin::Type::ARRAY, executor));
 
     if (interval_result.value().is_invalid()) {
       // --- type check is independent from loop itself ---
@@ -168,9 +159,9 @@ Result check(const nodes::Loop &expression, SourcesManager &sources_manager,
     }
 
     variable_result =
-        check(*expression.get_variable().value(), sources_manager, state,
-              Arguments{}.expect(
-                  interval_result.value().get().get()->get_parameter_proxy(0)));
+        Run(*expr.get_variable().value(),
+            Arguments{}.expect(
+                interval_result.value().get().get()->get_parameter_proxy(0)));
 
     // --- type check is independent from loop itself ---
     // if (variable_result.value().is_invalid()) {
@@ -186,28 +177,26 @@ Result check(const nodes::Loop &expression, SourcesManager &sources_manager,
   // TODO: modifier checks ??, modifiers ??
 
   return type_check_from_arguments(
-      sources_manager.types()->add_array_of(expression_result.get()), arguments,
-      expression, sources_manager);
+      state<Types>().add_array_of(expression_result.get()), args, expr,
+      executor);
 } // IN PROGRESS
 
 // --- containers
 
-Result type_check_array(const nodes::Container &expression,
-                        SourcesManager &sources_manager, State &state,
-                        const Arguments &arguments) {
+Result CheckTask<nodes::Container>::CheckArray(const nodes::Container &expr,
+                                               const Arguments &args) {
   MaybeResult last_expression_result;
 
-  for (size_t i = 0; i < expression.expressions_size(); ++i) {
+  for (size_t i = 0; i < expr.expressions_size(); ++i) {
     // elements should have same type, but type is not expected
-    auto expression_result = check(*expression.get_expression(i),
-                                   sources_manager, state, Arguments{});
+    auto expression_result = Run(*expr.get_expression(i), {});
 
     if (!last_expression_result.has_value()) {
       last_expression_result = expression_result;
     } else {
       if (last_expression_result.value().get() != expression_result.get()) {
         type_check_error("Elements in array should have same type",
-                         *expression.get_expression(i), sources_manager);
+                         *expr.get_expression(i), executor);
         // return TypeCheckResult::construct_invalid_result(); // max
         // possible checks, so no return
       }
@@ -215,129 +204,121 @@ Result type_check_array(const nodes::Container &expression,
   }
 
   if (!last_expression_result.has_value()) {
-    type_check_error("Array with zero elements", expression, sources_manager);
+    type_check_error("Array with zero elements", expr, executor);
     return Result::invalid();
   }
 
-  return type_check_from_arguments(sources_manager.types()->add_array_of(
-                                       last_expression_result.value().get()),
-                                   arguments, expression, sources_manager);
+  return type_check_from_arguments(
+      state<Types>().add_array_of(last_expression_result.value().get()), args,
+      expr, executor);
 }
 
-Result type_check_block(const nodes::Container &expression,
-                        SourcesManager &sources_manager, State &state,
-                        const Arguments &arguments) {
+Result CheckTask<nodes::Container>::CheckBlock(const nodes::Container &expr,
+                                               const Arguments &args) {
   nodes::MaybeTypeProxy context_exit_type;
 
   {
     ContextHolder context_holder(
-        state, expression, *sources_manager.errors(),
+        state<State>(), expr,
         &context_exit_type); // TODO: is brought type returned
 
-    for (size_t i = 0; i < expression.expressions_size(); ++i) {
+    for (size_t i = 0; i < expr.expressions_size(); ++i) {
       // result types in block are discarded
-      check(*expression.get_expression(i), sources_manager, state, Arguments{});
+      Run(*expr.get_expression(i), {});
     }
   }
 
   Result block_brought_type =
       context_exit_type.has_value()
           ? Result(context_exit_type.value())
-          : Result(sources_manager.types()->primitive(builtin::Type::UNIT));
+          : Result(state<Types>().primitive(builtin::Type::UNIT));
 
   return type_check_from_arguments(
-      sources_manager.types()->add_array_of(block_brought_type.get()),
-      arguments, expression, sources_manager);
+      state<Types>().add_array_of(block_brought_type.get()), args, expr,
+      executor);
 }
 
-Result check(const nodes::Container &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
-  switch (expression.get_type()) {
+Result CheckTask<nodes::Container>::operator()(const nodes::Container &expr,
+                                               const Arguments &args) {
+  switch (expr.get_type()) {
   case nodes::Container::ARRAY:
-    return type_check_array(expression, sources_manager, state, arguments);
+    return CheckArray(expr, args);
   case nodes::Container::BLOCK:
-    return type_check_block(expression, sources_manager, state, arguments);
+    return CheckBlock(expr, args);
   }
 }
 
 // --- modifiers
 
-Result check(const nodes::Return &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments) {
-  auto returned_result =
-      check(*expression.get_expression(), sources_manager, state, Arguments{});
+Result CheckTask<nodes::Return>::operator()(const nodes::Return &expr,
+                                            const Arguments &args) {
+  auto returned_result = Run(*expr.get_expression(), {});
 
   if (returned_result.is_invalid()) {
     return returned_result;
   }
 
-  switch (expression.get_type()) {
+  switch (expr.get_type()) {
   case nodes::Return::BRING:
-    if (state.bring_type(returned_result.get())) {
-      type_check_error("Different brought type to current one", expression,
-                       sources_manager);
+    if (state<State>().bring_type(returned_result.get())) {
+      type_check_error("Different brought type to current one", expr, executor);
       return Result::invalid();
     }
     break;
   case nodes::Return::RETURN:
-    if (!state.return_type(returned_result.get())) {
-      type_check_error("Different returned type to current one", expression,
-                       sources_manager);
+    if (!state<State>().return_type(returned_result.get())) {
+      type_check_error("Different returned type to current one", expr,
+                       executor);
       return Result::invalid();
     }
     break;
   }
 
   return type_check_from_arguments(
-      sources_manager.types()->primitive(builtin::Type::UNIT), arguments,
-      expression, sources_manager);
+      state<Types>().primitive(builtin::Type::UNIT), args, expr, executor);
 }
 
 // TODO: warning if name is same to package prefix, function prefix, etc. ??
-Result check(const nodes::NameDefinition &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
-  if (!arguments.get_passed().has_value()) {
-    type_check_error("Can't deduce type of new variable from context",
-                     expression, sources_manager);
+Result
+CheckTask<nodes::NameDefinition>::operator()(const nodes::NameDefinition &expr,
+                                             const Arguments &args) {
+  if (!args.get_passed().has_value()) {
+    type_check_error("Can't deduce type of new variable from context", expr,
+                     executor);
   }
 
   // assigned type shold be one of <-, <>, -- (can't be ->)
-  const auto variable_type = arguments.get_passed().value();
+  const auto variable_type = args.get_passed().value();
   if (nodes::utils::modifier_contains_OUT(
           variable_type.get()
               ->get_modifier())) { // TODO: utils::modifier_contains_OUT
-    type_check_error("Variable can't be assigned from out (->) value",
-                     expression, sources_manager);
+    type_check_error("Variable can't be assigned from out (->) value", expr,
+                     executor);
   }
 
   // variable accessible by reference by default ??
-  sources_manager.types()->add_modification_of(variable_type,
-                                               nodes::Modifier::REF);
+  state<Types>().add_modification_of(variable_type, nodes::Modifier::REF);
 
-  if (!state.insert_variable(*expression.get_name()->get(), variable_type,
-                             expression.get_modifier())) {
-    type_check_error("Variable is already defined in this context", expression,
-                     sources_manager);
+  if (!state<State>().insert_variable(*expr.get_name()->get(), variable_type,
+                                      expr.get_modifier())) {
+    type_check_error("Variable is already defined in this context", expr,
+                     executor);
   }
 
   // Return BOOL as any := / =: expression
   return type_check_from_arguments(
-      sources_manager.types()->primitive(builtin::Type::BOOL), arguments,
-      expression, sources_manager);
+      state<Types>().primitive(builtin::Type::BOOL), args, expr, executor);
 }
 
-Result type_check_array_access(const nodes::Access &expression,
-                               SourcesManager &sources_manager, State &state,
-                               const Arguments &arguments) {
+Result CheckTask<nodes::Access>::CheckArrayAccess(const nodes::Access &expr,
+                                                  const Arguments &args) {
   auto index_result =
-      check(*expression.get_index(), sources_manager, state,
-            Arguments{}.expect_builtin(builtin::Type::INDEX, sources_manager));
+      Run(*expr.get_index(),
+          Arguments{}.expect_builtin(builtin::Type::INDEX, executor));
 
   auto value_result =
-      check(*expression.get_value(), sources_manager, state,
-            Arguments{}.expect_builtin(builtin::Type::ARRAY, sources_manager));
+      Run(*expr.get_value(),
+          Arguments{}.expect_builtin(builtin::Type::ARRAY, executor));
 
   if (index_result.is_invalid()) {
     return index_result;
@@ -350,22 +331,20 @@ Result type_check_array_access(const nodes::Access &expression,
   // TODO: modifier checks ??
 
   return type_check_from_arguments(
-      value_result.get().get()->get_parameter_proxy(0), arguments, expression,
-      sources_manager);
+      value_result.get().get()->get_parameter_proxy(0), args, expr, executor);
 }
 
-Result type_check_tuple_access(const nodes::Access &expression,
-                               SourcesManager &sources_manager, State &state,
-                               const Arguments &arguments) {
+Result CheckTask<nodes::Access>::CheckTupleAccess(const nodes::Access &expr,
+                                                  const Arguments &args) {
   auto value_result =
-      check(*expression.get_value(), sources_manager, state,
-            Arguments{}.expect_builtin(builtin::Type::TUPLE, sources_manager));
+      Run(*expr.get_value(),
+          Arguments{}.expect_builtin(builtin::Type::TUPLE, executor));
 
   if (value_result.is_invalid()) {
     return value_result;
   }
 
-  size_t index = *expression.get_index()
+  size_t index = *expr.get_index()
                       ->get<nodes::Literal>()
                       .value()
                       ->get<size_t>() // Index type
@@ -374,46 +353,40 @@ Result type_check_tuple_access(const nodes::Access &expression,
   // TODO: modifier checks ??
 
   return type_check_from_arguments(
-      value_result.get().get()->get_parameter_proxy(index), arguments,
-      expression, sources_manager);
+      value_result.get().get()->get_parameter_proxy(index), args, expr,
+      executor);
 }
 
-Result check(const nodes::Access &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments) {
-  switch (expression.get_type()) {
+Result CheckTask<nodes::Access>::operator()(const nodes::Access &expr,
+                                            const Arguments &args) {
+  switch (expr.get_type()) {
   case nodes::Access::ARRAY:
-    return type_check_array_access(expression, sources_manager, state,
-                                   arguments);
+    return CheckArrayAccess(expr, args);
   case nodes::Access::TUPLE:
-    return type_check_tuple_access(expression, sources_manager, state,
-                                   arguments);
+    return CheckTupleAccess(expr, args);
   }
 }
 
-Result check(const nodes::LoopControl &expression,
-             SourcesManager &sources_manager, State &,
-             const Arguments &arguments) {
+Result CheckTask<nodes::LoopControl>::operator()(const nodes::LoopControl &expr,
+                                                 const Arguments &args) {
   return type_check_from_arguments(
-      sources_manager.types()->primitive(builtin::Type::UNIT), arguments,
-      expression, sources_manager);
+      state<Types>().primitive(builtin::Type::UNIT), args, expr, executor);
 }
 
-Result check(const nodes::ModifierExpression &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
-  auto modified_result =
-      check(*expression.get_expression(), sources_manager, state, Arguments{});
+Result CheckTask<nodes::ModifierExpression>::operator()(
+    const nodes::ModifierExpression &expr, const Arguments &args) {
+  auto modified_result = Run(*expr.get_expression(), {});
 
   if (modified_result.is_invalid()) {
     return Result::invalid();
   }
 
   if (nodes::utils::is_suffix_modifier(
-          expression.get_modifier())) { // optional, result
-                                        // '?' - open optional / result in ->
-                                        // (execute or not execute pattern
-                                        // matching expression) / (value /
-                                        // return) (TODO: alternative for bring)
+          expr.get_modifier())) { // optional, result
+                                  // '?' - open optional / result in ->
+                                  // (execute or not execute pattern
+                                  // matching expression) / (value /
+                                  // return) (TODO: alternative for bring)
 
     // '!' - open optional / result -> value / panic
 
@@ -424,29 +397,27 @@ Result check(const nodes::ModifierExpression &expression,
       modified_result.set(modified_result.get().get()->get_parameter_proxy(0));
       break;
     default:
-      type_check_error("Can unwrap only Optional or Result", expression,
-                       sources_manager);
+      type_check_error("Can unwrap only Optional or Result", expr, executor);
       return Result::invalid();
     }
   } else {
     // TODO: check that modifier can be applied
-    modified_result.set(sources_manager.types()->add_modification_of(
-        modified_result.get(), expression.get_modifier()));
+    modified_result.set(state<Types>().add_modification_of(
+        modified_result.get(), expr.get_modifier()));
   }
 
-  return type_check_from_arguments(modified_result.get(), arguments, expression,
-                                   sources_manager);
+  return type_check_from_arguments(modified_result.get(), args, expr, executor);
 } // IN PROGRESS
 
 // --- other
 
 // TODO
-Result check(const nodes::NameExpression &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
+Result
+CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
+                                             const Arguments &args) {
   // TODO: constraints ??
 
-  const auto name = expression.get_name();
+  const auto name = expr.get_name();
 
   {
     const auto fragments = name->get_fragments();
@@ -459,7 +430,7 @@ Result check(const nodes::NameExpression &expression,
         current_prefix.append_after(fragments[i]);
       }
 
-      maybe_variable = state.find_variable(*current_prefix.get());
+      maybe_variable = state<State>().find_variable(*current_prefix.get());
 
       if (maybe_variable.has_value()) {
         break;
@@ -483,8 +454,8 @@ Result check(const nodes::NameExpression &expression,
         // TODO: switch by type types: Variant, Tuple, ...
         // Tuple -> try to find field
         // Others -> try to open / builtin fields ?
-        const auto maybe_field_type = get_field_type_by_name(
-            type, *fragments[i].get(), expression, sources_manager);
+        const auto maybe_field_type =
+            get_field_type_by_name(type, *fragments[i].get(), expr, executor);
 
         if (maybe_field_type.has_value()) {
           type = maybe_field_type.value();
@@ -506,7 +477,7 @@ Result check(const nodes::NameExpression &expression,
   // TODO: check, if there is variable with this name
   // TODO: check var + fields
   const auto maybe_function_definition =
-      find_name_definition(*name->get(), expression, sources_manager);
+      find_name_definition(*name->get(), expr, executor);
   if (!maybe_function_definition.has_value()) {
     return Result::invalid();
   }
@@ -516,7 +487,7 @@ Result check(const nodes::NameExpression &expression,
   // TODO: count passed type, if needed
   // TODO: manage situation with one out type at any position
   // TODO + 1 - returned type - somtimes (can be ==)
-  const auto arguments_given = expression.arguments_size();
+  const auto arguments_given = expr.arguments_size();
   const auto arguments_defined = function_definition->arguments_size();
   if (arguments_given + 1 < arguments_defined ||
       arguments_given > arguments_defined) { // other, when there is passed type
@@ -528,7 +499,7 @@ Result check(const nodes::NameExpression &expression,
                             ? (" or " + std::to_string(arguments_defined - 1))
                             : ""} +
             ")",
-        expression, sources_manager);
+        expr, executor);
     return Result::invalid();
     // TODO: try return correct type (function return type), when possible
   }
@@ -544,11 +515,11 @@ Result check(const nodes::NameExpression &expression,
     if (!argument->get_type().has_value()) {
       type_check_error("Function argument type is not defined for argument " +
                            std::to_string(i),
-                       expression, sources_manager);
+                       expr, executor);
       continue;
     }
 
-    const auto annotation = expression.get_argument_annotation(i);
+    const auto annotation = expr.get_argument_annotation(i);
     const auto expected_annotation = argument->get_annotation();
 
     if (annotation.has_value() != expected_annotation.has_value()) {
@@ -556,7 +527,7 @@ Result check(const nodes::NameExpression &expression,
                            std::string{expected_annotation.has_value()
                                            ? *expected_annotation.value()
                                            : "[none]"},
-                       *expression.get_argument_value(i), sources_manager);
+                       *expr.get_argument_value(i), executor);
     }
 
     if (annotation.has_value() &&
@@ -564,18 +535,18 @@ Result check(const nodes::NameExpression &expression,
       type_check_error(
           "Wrong function argument type annotation: " + *annotation.value() +
               " instead of " + *expected_annotation.value(),
-          *expression.get_argument_value(i), sources_manager);
+          *expr.get_argument_value(i), executor);
     }
 
     function_argument_results.push_back(
-        check(*expression.get_argument_value(i), sources_manager, state,
-              Arguments{}.expect(argument->get_type_proxy().value())));
+        Run(*expr.get_argument_value(i),
+            Arguments{}.expect(argument->get_type_proxy().value())));
   }
 
   if (function_definition->arguments_size() == 0) {
     type_check_error(
-        "Function arguments size is zero. Returned type is not defined",
-        expression, sources_manager);
+        "Function arguments size is zero. Returned type is not defined", expr,
+        executor);
     return Result::invalid();
   }
 
@@ -589,31 +560,30 @@ Result check(const nodes::NameExpression &expression,
     // TODO: invert modifier ??
     if (!returned->get_type().has_value()) {
       type_check_error(
-          "Function argument type is not defined for returned type", expression,
-          sources_manager);
+          "Function argument type is not defined for returned type", expr,
+          executor);
       return Result::invalid();
     }
 
     // TODO: invert modifier ??
     // TODO: generic types should be deduced from arguments
-    return type_check_from_arguments(returned->get_type_proxy().value(),
-                                     arguments, expression, sources_manager);
+    return type_check_from_arguments(returned->get_type_proxy().value(), args,
+                                     expr, executor);
   }
 
   // checks for universal call syntax ??
 
-  // TODO: riturn result
+  // TODO: return result
 } // IN PROGRESS
 
 // TODO
-Result check(const nodes::Constructor &expression,
-             SourcesManager &sources_manager, State &state,
-             const Arguments &arguments) {
+Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
+                                                 const Arguments &args) {
   // TODO: constraints ??
 
   // TODO: use pass type
-  const auto maybe_type_definition = find_type_definition(
-      *expression.get_type()->get_name()->get(), expression, sources_manager);
+  const auto maybe_type_definition =
+      find_type_definition(*expr.get_type()->get_name()->get(), expr, executor);
   if (!maybe_type_definition.has_value()) {
     return Result::invalid();
   }
@@ -622,7 +592,7 @@ Result check(const nodes::Constructor &expression,
   if (!type_definition->get_type().has_value()) {
     type_check_error(
         "Type defenition for constructor type not found (declaration only)",
-        expression, sources_manager);
+        expr, executor);
     return Result::invalid();
   }
 
@@ -634,9 +604,9 @@ Result check(const nodes::Constructor &expression,
 
   // TODO: work with different parametric types: tuple, variant, ...
 
-  if (expression.arguments_size() == 0) {
-    type_check_error("Number of type constructor arguments should be > 0",
-                     expression, sources_manager);
+  if (expr.arguments_size() == 0) {
+    type_check_error("Number of type constructor arguments should be > 0", expr,
+                     executor);
     return Result::invalid();
     // TODO: try return correct type (constructor's type), when possible (not
     // generic)
@@ -649,13 +619,13 @@ Result check(const nodes::Constructor &expression,
   { // check arguments size, ets.
     switch (builtin_type) {
     case builtin::Type::TUPLE:
-      if (expression.arguments_size() != type.get()->parameters_size()) {
+      if (expr.arguments_size() != type.get()->parameters_size()) {
         type_check_error(
             "Number of type constructor arguments is different from expected "
             "(" +
-                std::to_string(expression.arguments_size()) + " instead of " +
+                std::to_string(expr.arguments_size()) + " instead of " +
                 std::to_string(type.get()->parameters_size()) + ")",
-            expression, sources_manager);
+            expr, executor);
         return Result::invalid();
         // TODO: try return correct type (constructor's type), when possible
         // (not generic)
@@ -667,11 +637,11 @@ Result check(const nodes::Constructor &expression,
     case builtin::Type::ERROR:
     case builtin::Type::FUNCTION:
     case builtin::Type::NONE:
-      if (expression.arguments_size() != 1) { // TODO: better to_string
+      if (expr.arguments_size() != 1) { // TODO: better to_string
         type_check_error("Number of type constructor arguments should be = 1 "
                          "(builtin type " +
                              std::to_string(uint(builtin_type)) + ")",
-                         expression, sources_manager);
+                         expr, executor);
         return Result::invalid();
         // TODO: try return correct type (constructor's type), when possible
         // (not generic)
@@ -684,8 +654,8 @@ Result check(const nodes::Constructor &expression,
     if (builtin::types::get_parameters_count(builtin_type).has_value() &&
         type.get()->parameters_size() !=
             builtin::types::get_parameters_count(builtin_type).value()) {
-      type_check_error("Wrong amount of parametars for builtin type",
-                       expression, sources_manager);
+      type_check_error("Wrong amount of parametars for builtin type", expr,
+                       executor);
 
       return Result::invalid();
       // TODO: try return correct type (constructor's type), when possible (not
@@ -697,12 +667,12 @@ Result check(const nodes::Constructor &expression,
 
   { // check annotations
     const auto check_same_annotation =
-        [&expression, &sources_manager](
+        [&expr, &executor = this->executor](
             size_t i, std::optional<const std::string *> expected_annotation,
             bool log_errors) {
           bool is_same = true;
 
-          const auto annotation = expression.get_argument_annotation(i);
+          const auto annotation = expr.get_argument_annotation(i);
 
           if (annotation.has_value() != expected_annotation.has_value()) {
             if (log_errors) {
@@ -711,7 +681,7 @@ Result check(const nodes::Constructor &expression,
                       std::string{expected_annotation.has_value()
                                       ? *expected_annotation.value()
                                       : "[none]"},
-                  *expression.get_argument_value(i), sources_manager);
+                  *expr.get_argument_value(i), executor);
             }
             is_same = false;
           }
@@ -722,8 +692,7 @@ Result check(const nodes::Constructor &expression,
               type_check_error("Wrong function argument type annotation: " +
                                    *annotation.value() + " instead of " +
                                    *expected_annotation.value(),
-                               *expression.get_argument_value(i),
-                               sources_manager);
+                               *expr.get_argument_value(i), executor);
             }
 
             is_same = false;
@@ -733,12 +702,12 @@ Result check(const nodes::Constructor &expression,
         };
 
     const auto check_no_annotation =
-        [&expression, &sources_manager](size_t i, bool log_errors) {
-          if (expression.get_argument_annotation(i).has_value()) {
+        [&expr, &executor = this->executor](size_t i, bool log_errors) {
+          if (expr.get_argument_annotation(i).has_value()) {
             if (log_errors) {
               type_check_error(
                   "Type constructor argument annotation not expected there",
-                  *expression.get_argument_value(i), sources_manager);
+                  *expr.get_argument_value(i), executor);
             }
             return false;
           }
@@ -747,7 +716,7 @@ Result check(const nodes::Constructor &expression,
 
     switch (builtin_type) {
     case builtin::Type::TUPLE:
-      for (size_t i = 0; i < expression.arguments_size(); ++i) {
+      for (size_t i = 0; i < expr.arguments_size(); ++i) {
         check_same_annotation(i, type.get()->get_parameter(i)->get_annotation(),
                               true /*log errors*/);
       }
@@ -767,7 +736,7 @@ Result check(const nodes::Constructor &expression,
           !check_no_annotation(0, false /*do not log errors*/)) {
         type_check_error("Wrong type constructor argument annotation in "
                          "constructor of variant type",
-                         *expression.get_argument_value(0), sources_manager);
+                         *expr.get_argument_value(0), executor);
       }
       break;
     case builtin::Type::ERROR: // no anotations ??
@@ -788,89 +757,85 @@ Result check(const nodes::Constructor &expression,
   { // type check arguments
     switch (builtin_type) {
     case builtin::Type::TUPLE:
-      for (size_t i = 0; i < expression.arguments_size(); ++i) {
-        check(*expression.get_argument_value(i), sources_manager, state,
-              Arguments{}.expect(type.get()->get_parameter_proxy(i)));
+      for (size_t i = 0; i < expr.arguments_size(); ++i) {
+        Run(*expr.get_argument_value(i),
+            Arguments{}.expect(type.get()->get_parameter_proxy(i)));
       }
       break;
     case builtin::Type::VARIANT:
       if (chosen_variant_option.has_value()) {
-        check(*expression.get_argument_value(0), sources_manager, state,
-              Arguments{}.expect(type.get()->get_parameter_proxy(
-                  chosen_variant_option.value())));
+        Run(*expr.get_argument_value(0),
+            Arguments{}.expect(type.get()->get_parameter_proxy(
+                chosen_variant_option.value())));
       } else { // TODO: error, if there is more then one possible variant in
                // answer
         nodes::TypeProxies possible_options;
         for (size_t i = 0; i < type.get()->parameters_size(); ++i) {
           possible_options.push_back(type.get()->get_parameter_proxy(i));
         }
-        check(*expression.get_argument_value(0), sources_manager, state,
-              Arguments{}.expect(possible_options));
+        Run(*expr.get_argument_value(0), Arguments{}.expect(possible_options));
       }
       break;
     case builtin::Type::OPTIONAL:
       // first parameter or NULL
-      check(*expression.get_argument_value(0), sources_manager, state,
-            Arguments{}.expect({type.get()->get_parameter_proxy(0),
-                                sources_manager.types()->primitive(
-                                    builtin::Type::NULL_OPTION)}));
+      Run(*expr.get_argument_value(0),
+          Arguments{}.expect(
+              {type.get()->get_parameter_proxy(0),
+               state<Types>().primitive(builtin::Type::NULL_OPTION)}));
       break;
     case builtin::Type::RESULT:
       // first parameter or ERROR[second parameter]
-      check(*expression.get_argument_value(0), sources_manager, state,
-            Arguments{}.expect({type.get()->get_parameter_proxy(0),
-                                sources_manager.types()->add_error_of(
-                                    type.get()->get_parameter_proxy(1))}));
+      Run(*expr.get_argument_value(0),
+          Arguments{}.expect({type.get()->get_parameter_proxy(0),
+                              state<Types>().add_error_of(
+                                  type.get()->get_parameter_proxy(1))}));
       break;
     case builtin::Type::ERROR:
       // first parameter
-      check(*expression.get_argument_value(0), sources_manager, state,
-            Arguments{}.expect(type.get()->get_parameter_proxy(0)));
+      Run(*expr.get_argument_value(0),
+          Arguments{}.expect(type.get()->get_parameter_proxy(0)));
       break;
     case builtin::Type::FUNCTION:
     case builtin::Type::NONE:
       // type itself
-      check(*expression.get_argument_value(0), sources_manager, state,
-            Arguments{}.expect(type));
+      Run(*expr.get_argument_value(0), Arguments{}.expect(type));
       break;
     default: // array, basic types
-      type_check_error("Type can't be constructed", expression,
-                       sources_manager);
+      type_check_error("Type can't be constructed", expr, executor);
       break;
     }
   }
 
   // TODO: deduce generic parts in type
-  return type_check_from_arguments(expression.get_type_proxy(), arguments,
-                                   expression, sources_manager);
+  return type_check_from_arguments(expr.get_type_proxy(), args, expr, executor);
   // TODO: add <- modifiier to type ??
 
 } // IN PROGRESS
 
 // TODO
-Result check(const nodes::Lambda &expression, SourcesManager &sources_manager,
-             State &state, const Arguments &arguments) {
-  if (arguments.get_expected().empty()) {
+Result CheckTask<nodes::Lambda>::operator()(const nodes::Lambda &expr,
+                                            const Arguments &args) {
+  if (args.get_expected().empty()) {
     type_check_error("Can't deduce type of lambda function from context: no "
                      "one type expected",
-                     expression, sources_manager);
+                     expr, executor);
   }
 
-  if (arguments.get_expected().size() !=
+  if (args.get_expected().size() !=
       1) { // TODO: check if only one function argument
     type_check_error("Can't deduce type of lambda function from context; too "
                      "much possible types",
-                     expression, sources_manager);
+                     expr, executor);
   }
 
-  const auto expected_type = arguments.get_expected().front();
+  const auto expected_type = args.get_expected().front();
   if (!expected_type.get()->is_builtin(builtin::Type::FUNCTION)) {
-    type_check_error("Type of lambda function should be function", expression,
-                     sources_manager);
+    type_check_error("Type of lambda function should be function", expr,
+                     executor);
   }
 
   // TODO: deal with return type (+1 sometimes), etc
-  const auto arguments_given = expression.arguments_size();
+  const auto arguments_given = expr.arguments_size();
   const auto arguments_defined = expected_type.get()->parameters_size();
   if (arguments_given != arguments_defined) {
     type_check_error(
@@ -881,43 +846,43 @@ Result check(const nodes::Lambda &expression, SourcesManager &sources_manager,
                             ? (" or " + std::to_string(arguments_defined - 1))
                             : ""} +
             ")",
-        expression, sources_manager);
+        expr, executor);
   }
 
   // TODO: set another context (for expression typecheck and vars)
 
   for (size_t i = 0; i < arguments_given; ++i) {
-    if (!state.insert_variable(*expression.get_argument(i)->get(),
-                               expected_type.get()->get_parameter_proxy(i),
-                               nodes::NameDefinition::Modifier::LET)) {
+    if (!state<State>().insert_variable(
+            *expr.get_argument(i)->get(),
+            expected_type.get()->get_parameter_proxy(i),
+            nodes::NameDefinition::Modifier::LET)) {
       // TODO: which modifier ??
-      type_check_error("Variable is already defined in this context",
-                       expression, sources_manager);
+      type_check_error("Variable is already defined in this context", expr,
+                       executor);
     }
   }
 
   // TODO: out type is can be not last
   if (arguments_given + 1 == arguments_defined) {
-    check(*expression.get_expression(), sources_manager, state,
-          Arguments{}.expect(
-              expected_type.get()->get_parameter_proxy(arguments_defined - 1)));
+    Run(*expr.get_expression(),
+        Arguments{}.expect(
+            expected_type.get()->get_parameter_proxy(arguments_defined - 1)));
   }
 
   // TODO: needed ?? (only passed type check required ??)
-  return type_check_from_arguments(expected_type, arguments, expression,
-                                   sources_manager);
+  return type_check_from_arguments(expected_type, args, expr, executor);
 } // IN PROGRESS
 
-Result check(const nodes::Extra &, SourcesManager &sources_manager, State &,
-             const Arguments &) {
+Result CheckTask<nodes::Extra>::operator()(const nodes::Extra &,
+                                           const Arguments &) {
 
-  return Result(sources_manager.types()->primitive(builtin::Type::UNIT));
+  return Result(state<Types>().primitive(builtin::Type::UNIT));
 }
 
-Result check(const nodes::EmptyLines &, SourcesManager &sources_manager,
-             State &, const Arguments &) {
+Result CheckTask<nodes::EmptyLines>::operator()(const nodes::EmptyLines &,
+                                                const Arguments &) {
 
-  return Result(sources_manager.types()->primitive(builtin::Type::UNIT));
+  return Result(state<Types>().primitive(builtin::Type::UNIT));
 }
 
 } // namespace type_check
diff --git a/lang/type_check/src/type_check_utils.cpp b/lang/type_check/src/type_check_utils.cpp
index 546d707..21a121c 100644
--- a/lang/type_check/src/type_check_utils.cpp
+++ b/lang/type_check/src/type_check_utils.cpp
@@ -20,7 +20,7 @@ nodes::TypeProxy check_same_to_pass_type_in_arguments(
     logc.Error<Log::kProc>({{message}} /* TODO: node */);
   }
 
-  return executor.state<nodes::TypeStorage>().primitive(builtin::Type::BOOL);
+  return executor.state<Types>().primitive(builtin::Type::BOOL);
 }
 
 bool check_no_pass_type_in_arguments(const Arguments &arguments,
diff --git a/lang/utils/include/executor.hpp b/lang/utils/include/executor.hpp
index a1d96b2..ad588ac 100644
--- a/lang/utils/include/executor.hpp
+++ b/lang/utils/include/executor.hpp
@@ -1,39 +1,27 @@
 #pragma once
 
-#include <memory>
-#include <vector>
-
 #include "log.hpp"
 
 namespace utils {
 
-template <typename... States> class Task;
+template <typename Exec, typename Ret, typename Args, typename Node> class Task;
 
 template <typename State> class ExecutorState {
 public:
-  struct Tag {};
-
   ExecutorState(State &&state) : state_(std::move(state)) {}
 
-  //
-
-  // State &state(Tag) { return state; }
-  // const State &state(Tag) const { return state; }
-
 protected:
   State state_;
 };
 
 template <typename... States> class Executor : public ExecutorState<States>... {
-  friend class Task<States...>;
-
 public:
   Executor(Log &&log, States &&...states)
       : ExecutorState<States>(std::move(states))..., log_(std::move(log)) {}
 
   //
 
-  template <typename T, typename... Args> T New(Args... args) {
+  template <typename T, typename... Args> T Run(Args... args) {
     return T(*this, args...);
   }
 
@@ -51,17 +39,22 @@ private:
   Log log_;
 };
 
-template <typename... States> class Task {
+template <typename Exec, typename Ret, typename Args, typename Node> class Task {
 public:
-  Task(Executor<States...> &executor) : executor(executor) {}
+  Task(Exec &executor) : executor(executor) {}
 
   virtual ~Task() {}
 
   //
 
-  template <typename T, typename... Args> T New(Args... args) {
-    return executor.template New<T>(std::move(args)...);
-  }
+  // template <typename N, typename NArgs> Ret Run(const N& node, NArgs&& args) {
+  //   Task<Exec, Ret, NArgs, N> task(executor);
+  //   return task(node, std::forward<Args>(args));
+  // }
+
+  //
+
+  virtual Ret operator()(const Node& node, const Args& args) = 0;
 
   //
 
@@ -74,7 +67,7 @@ public:
   const Log &log() const { return executor.log_; }
 
 public:
-  Executor<States...> &executor;
+  Exec &executor;
 };
 
 } // namespace utils
diff --git a/lang/utils/include/utils.hpp b/lang/utils/include/utils.hpp
index 7061251..8e556df 100644
--- a/lang/utils/include/utils.hpp
+++ b/lang/utils/include/utils.hpp
@@ -2,7 +2,6 @@
 
 #include <iostream>
 #include <source_location>
-#include <string>
 
 namespace error_handling {