diff --git a/lang/app/sources_manager.hpp b/lang/app/sources_manager.hpp
index 436318c..ac56fed 100644
--- a/lang/app/sources_manager.hpp
+++ b/lang/app/sources_manager.hpp
@@ -20,18 +20,21 @@ using Exprs = nodes::NodeStorage; // nodes::ExprStorage;
 using Types = nodes::TypeStorage;
 using Names = names::NameTree;
 using Positions = core::DependentStorage<utils::Pos>;
+using NodeTypes =
+    core::DependentStorage<nodes::Type>; // deduce type for each node
 using Printer = printers::Printer;
 
 // TODO: partial host ?? (part of params are stored in each executor, use if
 // constexpr requires) (for Printer, State, ...)
 using ExecutorHost =
-    core::ExecutorHost<Exprs, Types, Names, Positions,
+    core::ExecutorHost<Exprs, Types, Names, Positions, NodeTypes,
                        builders::State /*, type_check::State*/, Printer>;
 
 class SourcesManager {
 public:
   SourcesManager(Log &&log, Printer &&printer)
-      : executor_host_(std::move(log), {}, {}, {}, {}, {}, std::move(printer)),
+      : executor_host_(std::move(log), {}, {}, {}, {}, {}, {},
+                       std::move(printer)),
         statements_{} {}
 
   void AddFile(const std::string &filename) {
diff --git a/lang/builders/include/builders_utils.hpp b/lang/builders/include/builders_utils.hpp
index 5c75857..a7da81b 100644
--- a/lang/builders/include/builders_utils.hpp
+++ b/lang/builders/include/builders_utils.hpp
@@ -55,8 +55,9 @@ template <typename N> struct BuilderTaskUtils : public Task<N> {
     return value;
   }
 
-  template <typename T> Node Build(T value, utils::Pos pos) {
-    auto id = this->template state<Exprs>().Insert(std::move(value));
+  template <typename T> Node Build(T value, bool is_scoped, utils::Pos pos) {
+    auto id =
+        this->template state<Exprs>().Insert({std::move(value), is_scoped});
     this->template state<Positions>().ForceInsert(id, pos);
     return Ext(id);
   }
diff --git a/lang/builders/include/expression_builders.hpp b/lang/builders/include/expression_builders.hpp
index ece199c..b85337b 100644
--- a/lang/builders/include/expression_builders.hpp
+++ b/lang/builders/include/expression_builders.hpp
@@ -96,7 +96,7 @@ struct BuilderTask<nodes::Container, T>
   // '{' (expression ';')* '}'
   // or
   // '[[' expression+ ']]'
-  Node operator()(const ParserNode &parser_node, const Args &) override {
+  Node operator()(const ParserNode &parser_node, const Args &args) override {
     Log::Context logc(executor.log(), Log::Area::kParse);
 
     const auto kind = std::is_same_v<T, utils::BlockTag>
@@ -117,7 +117,7 @@ struct BuilderTask<nodes::Container, T>
             .kind = kind,
             .exprs = std::move(exprs),
         },
-        parser_node.get_pos());
+        args.is_scoped, parser_node.get_pos());
   }
 };
 
@@ -172,7 +172,7 @@ struct BuilderTask<nodes::ModifierExpression, T>
   // _reference_ expression
   // or
   // expression ('?' | '!')
-  Node operator()(const ParserNode &parser_node, const Args &) override {
+  Node operator()(const ParserNode &parser_node, const Args &args) override {
     Log::Context logc(executor.log(), Log::Area::kParse);
 
     const size_t modifier_pos =
@@ -184,7 +184,7 @@ struct BuilderTask<nodes::ModifierExpression, T>
                 RunOther<nodes::Modifier>(parser_node.nth_child(modifier_pos)),
             .expr = Run<Node>(parser_node.nth_named_child(0)),
         },
-        parser_node.get_pos());
+        args.is_scoped, parser_node.get_pos());
   }
 };
 
diff --git a/lang/builders/src/expression_builders.cpp b/lang/builders/src/expression_builders.cpp
index 8d2bf7c..a7e0330 100644
--- a/lang/builders/src/expression_builders.cpp
+++ b/lang/builders/src/expression_builders.cpp
@@ -91,52 +91,53 @@ Node BuilderTask<Node>::operator()(const ParserNode &parser_node,
         nodes::NameExpression{
             .name = RunOther<nodes::Identifier>(parser_node),
         },
-        parser_node.get_pos()); // TODO: is_scoped
+        is_scoped, parser_node.get_pos());
   case tokens::Type::CONSTRUCTOR:
     return Run<nodes::Constructor>(parser_node);
   case tokens::Type::LAMBDA:
     return Run<nodes::Lambda>(parser_node);
   // --- literals
   case tokens::Type::FLOAT_LITERAL:
-    return Build(RunOther<nodes::Literal, float>(parser_node),
+    return Build(RunOther<nodes::Literal, float>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::DOUBLE_LITERAL:
-    return Build(RunOther<nodes::Literal, double>(parser_node),
+    return Build(RunOther<nodes::Literal, double>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::INT_LITERAL:
-    return Build(RunOther<nodes::Literal, int32_t>(parser_node),
+    return Build(RunOther<nodes::Literal, int32_t>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::LONG_LITERAL:
-    return Build(RunOther<nodes::Literal, int64_t>(parser_node),
+    return Build(RunOther<nodes::Literal, int64_t>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::INDEX_LITERAL:
-    return Build(RunOther<nodes::Literal, size_t>(parser_node),
+    return Build(RunOther<nodes::Literal, size_t>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::STRING_LITERAL:
-    return Build(RunOther<nodes::Literal, std::string>(parser_node),
+    return Build(RunOther<nodes::Literal, std::string>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::UNICODE_STRING_LITERAL:
     return Build(RunOther<nodes::Literal, nodes::unicode_string>(parser_node),
-                 parser_node.get_pos());
+                 is_scoped, parser_node.get_pos());
   case tokens::Type::CHAR_LITERAL:
-    return Build(RunOther<nodes::Literal, char>(parser_node),
+    return Build(RunOther<nodes::Literal, char>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::UNICODE_LITERAL:
     return Build(RunOther<nodes::Literal, nodes::unicode>(parser_node),
-                 parser_node.get_pos());
+                 is_scoped, parser_node.get_pos());
   case tokens::Type::BOOL_LITERAL:
-    return Build(RunOther<nodes::Literal, bool>(parser_node),
+    return Build(RunOther<nodes::Literal, bool>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::UNIT_LITERAL:
-    return Build(RunOther<nodes::Literal, nodes::unit>(parser_node),
+    return Build(RunOther<nodes::Literal, nodes::unit>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::NULL_LITERAL:
-    return Build(RunOther<nodes::Literal, nodes::null>(parser_node),
+    return Build(RunOther<nodes::Literal, nodes::null>(parser_node), is_scoped,
                  parser_node.get_pos());
   case tokens::Type::EXTRA:
-    return Build(RunOther<nodes::Extra>(parser_node), parser_node.get_pos());
+    return Build(RunOther<nodes::Extra>(parser_node), is_scoped,
+                 parser_node.get_pos());
   case tokens::Type::EMPTY_LINES:
-    return Build(RunOther<nodes::EmptyLines>(parser_node),
+    return Build(RunOther<nodes::EmptyLines>(parser_node), is_scoped,
                  parser_node.get_pos());
   default:
     break;
@@ -152,7 +153,7 @@ Node BuilderTask<Node>::operator()(const ParserNode &parser_node,
 
 // (':=' | '=:') expression (('??' | 'if') expression)? (_do_ expression)?
 Node BuilderTask<nodes::Match::Case>::operator()(const ParserNode &parser_node,
-                                                 const Args &) {
+                                                 const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   std::string case_kind = parser_node.nth_child(0).get_value();
@@ -186,12 +187,12 @@ Node BuilderTask<nodes::Match::Case>::operator()(const ParserNode &parser_node,
                       ? Run<Node>(expression_node.value())
                       : std::optional<nodes::NodeId>(),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // expression case+
 Node BuilderTask<nodes::Match>::operator()(const ParserNode &parser_node,
-                                           const Args &) {
+                                           const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   std::vector<nodes::NodeId /*nodes::Match::Case*/> cases; // TODO
@@ -209,13 +210,13 @@ Node BuilderTask<nodes::Match>::operator()(const ParserNode &parser_node,
               0)), // TODO: is_scoped info (always false ??)
           .cases = std::move(cases),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // ('??' | 'if') expression _do_ expression (('!!' | 'elif') expression _do_
 // expression)* (('!!=>', 'else') expression)?
 Node BuilderTask<nodes::Condition>::operator()(const ParserNode &parser_node,
-                                               const Args &) {
+                                               const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   size_t named_child_count = parser_node.named_child_count();
@@ -243,31 +244,31 @@ Node BuilderTask<nodes::Condition>::operator()(const ParserNode &parser_node,
                                  named_child_count - 1))
                            : std::optional<Node>(),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // ('@' | 'for') (expression | expression ':' expression)? _do_ expression
 Node BuilderTask<nodes::Loop>::operator()(const ParserNode &parser_node,
-                                          const Args &) {
+                                          const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   size_t named_child_count = parser_node.named_child_count();
 
   if (named_child_count == 1) { // body
     return Build(nodes::Loop(Run<Node>(parser_node.nth_named_child(0))),
-                 parser_node.get_pos());
+                 args.is_scoped, parser_node.get_pos());
   } else if (named_child_count == 2) { // condition,
                                        // body
     return Build(nodes::Loop(Run<Node>(parser_node.nth_named_child(0)),
                              Run<Node>(parser_node.nth_named_child(1))),
-                 parser_node.get_pos());
+                 args.is_scoped, parser_node.get_pos());
   } else if (named_child_count == 3) { // variable,
                                        // interval,
                                        // body
     return Build(nodes::Loop(Run<Node>(parser_node.nth_named_child(0)),
                              Run<Node>(parser_node.nth_named_child(1)),
                              Run<Node>(parser_node.nth_named_child(2))),
-                 parser_node.get_pos());
+                 args.is_scoped, parser_node.get_pos());
   } else {
     logc.Fatal<Log::kProc>({{"Unexpected named expression amount in loop"}},
                            parser_node.get_pos());
@@ -281,16 +282,16 @@ Node BuilderTask<nodes::Loop>::operator()(const ParserNode &parser_node,
 
 // expression ',' expression
 Node BuilderTask<nodes::NameExpression, utils::CommaTag>::operator()(
-    const ParserNode &parser_node, const Args &) {
+    const ParserNode &parser_node, const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
-  std::vector<std::pair<std::optional<std::string>, nodes::NodeId>> args;
+  std::vector<std::pair<std::optional<std::string>, nodes::NodeId>> args_nodes;
 
-  args.emplace_back(std::nullopt,
-                    Run<nodes::NodeId>(parser_node.nth_named_child(0)));
+  args_nodes.emplace_back(std::nullopt,
+                          Run<nodes::NodeId>(parser_node.nth_named_child(0)));
 
-  args.emplace_back(std::nullopt,
-                    Run<nodes::NodeId>(parser_node.nth_named_child(1)));
+  args_nodes.emplace_back(std::nullopt,
+                          Run<nodes::NodeId>(parser_node.nth_named_child(1)));
 
   return Build(
       nodes::NameExpression{
@@ -300,37 +301,38 @@ Node BuilderTask<nodes::NameExpression, utils::CommaTag>::operator()(
                   .kind = nodes::Identifier::kSimpleName,
                   .value = ",",
               },
-          .args = std::move(args),
+          .args = std::move(args_nodes),
           .prefix = {},
           .is_point_call = false,
           .is_operator_call = true,
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // expression operator expression
 Node BuilderTask<nodes::NameExpression, utils::OperatorTag>::operator()(
-    const ParserNode &parser_node, const Args &) {
+    const ParserNode &parser_node, const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   auto name_node = parser_node.child_by_field_name("name");
 
-  std::vector<std::pair<std::optional<std::string>, nodes::NodeId>> args;
+  std::vector<std::pair<std::optional<std::string>, nodes::NodeId>> args_nodes;
 
-  args.emplace_back(std::nullopt,
-                    Run<Node>(name_node.previous_named_sibling()));
+  args_nodes.emplace_back(std::nullopt,
+                          Run<Node>(name_node.previous_named_sibling()));
 
-  args.emplace_back(std::nullopt, Run<Node>(name_node.next_named_sibling()));
+  args_nodes.emplace_back(std::nullopt,
+                          Run<Node>(name_node.next_named_sibling()));
 
   return Build(
       nodes::NameExpression{
           .name = RunOther<nodes::Identifier, utils::OperatorIdTag>(name_node),
-          .args = std::move(args),
+          .args = std::move(args_nodes),
           .prefix = {},
           .is_point_call = false,
           .is_operator_call = true,
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // --- continers
@@ -341,7 +343,7 @@ Node BuilderTask<nodes::NameExpression, utils::OperatorTag>::operator()(
 
 // ('return' | 'bring') expression
 Node BuilderTask<nodes::Return>::operator()(const ParserNode &parser_node,
-                                            const Args &) {
+                                            const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   std::string modifier = parser_node.nth_child(0).get_value();
@@ -352,12 +354,12 @@ Node BuilderTask<nodes::Return>::operator()(const ParserNode &parser_node,
                                        : nodes::Return::BRING,
           .expr = Run<Node>(parser_node.nth_named_child(0)),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // _var_let_ (simple_name_identifier | placeholder)
 Node BuilderTask<nodes::NameDefinition>::operator()(
-    const ParserNode &parser_node, const Args &) {
+    const ParserNode &parser_node, const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   std::string modifier = parser_node.nth_child(0).get_value();
@@ -371,24 +373,24 @@ Node BuilderTask<nodes::NameDefinition>::operator()(
                       : nodes::NameDefinition::VAR,
           .name = RunOther<nodes::Identifier>(name_node),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 } // IN PROGRESS
 
 // expression '[' expression ']'
 Node BuilderTask<nodes::Access, utils::ArrayAccessTag>::operator()(
-    const ParserNode &parser_node, const Args &) {
+    const ParserNode &parser_node, const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   return Build(
       nodes::Access{.kind = nodes::Access::ARRAY,
                     .value = Run<Node>(parser_node.nth_named_child(0)),
                     .index = Run<Node>(parser_node.nth_named_child(1))},
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // expression '.' number_literal
 Node BuilderTask<nodes::Access, utils::TupleAccessTag>::operator()(
-    const ParserNode &parser_node, const Args &) {
+    const ParserNode &parser_node, const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   auto const node = Build(
@@ -400,14 +402,14 @@ Node BuilderTask<nodes::Access, utils::TupleAccessTag>::operator()(
           // .index = Build(build_index_literal(parser_node.nth_named_child(
           //                    1)) /*, false}*/, // ?? is_scoped ??
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 
   return node;
 }
 
 // 'break' | 'continue'
 Node BuilderTask<nodes::LoopControl>::operator()(const ParserNode &parser_node,
-                                                 const Args &) {
+                                                 const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
   return Build(
@@ -416,7 +418,7 @@ Node BuilderTask<nodes::LoopControl>::operator()(const ParserNode &parser_node,
                       ? nodes::LoopControl::BREAK
                       : nodes::LoopControl::CONTINUE,
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // // ModifierExpression -> .hpp
@@ -446,10 +448,10 @@ void build_args_until_end(ParserNode first_parse_node, Executor &executor,
 // (type '.' simple_name | expression '.' simple_name | name | '(' operator
 // ')') (annotation? expression)*
 Node BuilderTask<nodes::NameExpression, utils::FuncCallTag>::operator()(
-    const ParserNode &parser_node, const Args &) {
+    const ParserNode &parser_node, const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
-  std::vector<nodes::AnnotatedArgument> args;
+  std::vector<nodes::AnnotatedArgument> args_nodes;
 
   std::optional<nodes::TypeData> prefix;
 
@@ -474,60 +476,60 @@ Node BuilderTask<nodes::NameExpression, utils::FuncCallTag>::operator()(
       prefix_node = current_node;
     } else {
       is_point_call = true;
-      args.emplace_back(std::nullopt, Run<Node>(current_node));
+      args_nodes.emplace_back(std::nullopt, Run<Node>(current_node));
     }
   }
 
-  build_args_until_end(name_node.next_named_sibling(), executor, args);
+  build_args_until_end(name_node.next_named_sibling(), executor, args_nodes);
 
   return Build(
       nodes::NameExpression{
           .name = RunOther<nodes::Identifier>(name_node),
-          .args = std::move(args),
+          .args = std::move(args_nodes),
           .prefix = prefix_node.has_value()
                         ? RunOther<nodes::Type>(prefix_node.value())
                         : nodes::MaybeType(),
           .is_point_call = is_point_call,
           .is_operator_call = false,
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // type (annotation? expression)*
 Node BuilderTask<nodes::Constructor>::operator()(const ParserNode &parser_node,
-                                                 const Args &) {
+                                                 const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
-  std::vector<nodes::AnnotatedArgument> args;
+  std::vector<nodes::AnnotatedArgument> args_nodes;
 
   build_args_until_end(parser_node
                            .child_by_field_name("ty"
                                                 "p"
                                                 "e")
                            .next_named_sibling(),
-                       executor, args);
+                       executor, args_nodes);
 
   return Build(
       nodes::Constructor{
           .type =
               RunOther<nodes::Type>(parser_node.child_by_field_name("type")),
-          .args = std::move(args),
+          .args = std::move(args_nodes),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 // '\\' argument_name* _do_ expression
 Node BuilderTask<nodes::Lambda>::operator()(const ParserNode &parser_node,
-                                            const Args &) {
+                                            const Args &args) {
   Log::Context logc(executor.log(), Log::Area::kParse);
 
-  std::vector<nodes::Identifier> args;
+  std::vector<nodes::Identifier> args_nodes;
 
   auto current_node =
       parser_node.nth_child(1); // next to '\\', not null ('=>' should present)
 
   while (current_node.is_named()) { // until _do_
-    args.emplace_back(RunOther<nodes::Identifier>(current_node));
+    args_nodes.emplace_back(RunOther<nodes::Identifier>(current_node));
     current_node = current_node.next_sibling();
   }
 
@@ -536,10 +538,10 @@ Node BuilderTask<nodes::Lambda>::operator()(const ParserNode &parser_node,
 
   return Build(
       nodes::Lambda{
-          .args = std::move(args),
+          .args = std::move(args_nodes),
           .expr = Run<Node>(current_node),
       },
-      parser_node.get_pos());
+      args.is_scoped, parser_node.get_pos());
 }
 
 } // namespace builders
diff --git a/lang/type_check/include/type_check_utils.hpp b/lang/type_check/include/type_check_utils.hpp
index cf03f05..8889aff 100644
--- a/lang/type_check/include/type_check_utils.hpp
+++ b/lang/type_check/include/type_check_utils.hpp
@@ -25,8 +25,8 @@ public:
 public:
   State(Log &log) : log_(log) {}
 
-  bool insert_variable(const std::string &name, nodes::Type type,
-                       nodes::NameDefinition::Kind modifier) {
+  bool InsertVariable(const std::string &name, nodes::Type type,
+                      nodes::NameDefinition::Kind modifier) {
     Log::Context logc(log_, Log::Area::kTypeCheck);
 
     if (contexts_.empty()) {
@@ -39,7 +39,7 @@ public:
         .second;
   }
 
-  std::optional<VariableInfo> find_variable(const std::string &name) {
+  std::optional<VariableInfo> FindVariable(const std::string &name) {
     for (ssize_t i = contexts_.size(); i >= 0; --i) {
       auto iter = contexts_[i].variables.find(name);
       if (iter != contexts_[i].variables.end()) {
@@ -50,7 +50,7 @@ public:
     return std::nullopt;
   }
 
-  bool bring_type(nodes::Type type) {
+  bool BringType(nodes::Type type) {
     Log::Context logc(log_, Log::Area::kTypeCheck);
 
     if (contexts_.empty()) {
@@ -66,7 +66,7 @@ public:
     return true;
   }
 
-  bool return_type(nodes::Type type) {
+  bool ReturnType(nodes::Type type) {
     Log::Context logc(log_, Log::Area::kTypeCheck);
 
     if (contexts_.empty()) {
@@ -83,7 +83,7 @@ public:
   }
 
 private:
-  void enter_context(const utils::Pos &pos) {
+  void EnterContext(const utils::Pos &pos) {
     Log::Context logc(log_, Log::Area::kTypeCheck);
 
     contexts_.emplace_back(pos);
@@ -164,10 +164,14 @@ using Exprs = nodes::NodeStorage;
 using Types = nodes::TypeStorage;
 using Names = names::NameTree;
 using Positions = core::DependentStorage<utils::Pos>;
+using NodeTypes =
+    core::DependentStorage<nodes::Type>; // deduce type for each node
 
-using Executor = core::Executor<Exprs, Types, Names, State, Positions>;
+using Executor =
+    core::Executor<Exprs, Types, Names, State, Positions, NodeTypes>;
 
-using Node = nodes::Node_<nodes::NodePart<utils::Pos>>;
+using Node =
+    nodes::Node_<nodes::NodePart<utils::Pos>, nodes::NodePart<nodes::Type>>;
 
 //
 
@@ -175,52 +179,52 @@ class Args {
 public:
   Args(storage::Id current_id) : current_id(current_id) {};
 
-  Args expect_builtin(builtin::Type type, Executor &executor) const {
+  Args ExpectBuiltin(builtin::Type type, Executor &executor) const {
     Args copy(*this);
     copy.expected_types_ = {executor.state<Types>().primitive(type)};
     return copy;
   }
 
-  Args pass_builtin(builtin::Type type, Executor &executor) const {
+  Args PassBuiltin(builtin::Type type, Executor &executor) const {
     Args copy(*this);
     copy.passed_type_ = executor.state<Types>().primitive(type);
     return copy;
   }
 
-  Args expect(nodes::Types types) const {
+  Args Expect(nodes::Types types) const {
     Args copy(*this);
     copy.expected_types_ = types;
     return copy;
   }
 
-  Args expect(nodes::MaybeType type) const {
+  Args Expect(nodes::MaybeType type) const {
     Args copy(*this);
     copy.expected_types_ =
         (type.has_value() ? nodes::Types{type.value()} : nodes::Types{});
     return copy;
   }
 
-  Args pass(nodes::MaybeType type) const {
+  Args Pass(nodes::MaybeType type) const {
     Args copy(*this);
     copy.passed_type_ = type;
     return copy;
   }
 
-  Args without_expect() const {
+  Args WithoutExpect() const {
     Args copy(*this);
     copy.expected_types_ = {};
     return copy;
   }
 
-  Args without_pass() const {
+  Args WithoutPass() const {
     Args copy(*this);
     copy.passed_type_ = {};
     return copy;
   }
 
-  nodes::Types get_expected() const { return expected_types_; };
+  nodes::Types expected() const { return expected_types_; };
 
-  nodes::MaybeType get_passed() const { return passed_type_; };
+  nodes::MaybeType passed() const { return passed_type_; };
 
   // TODO: add check, that there is no passed type for some nodes ??
   // TODO: args builder ??
@@ -240,7 +244,7 @@ public:
   ContextHolder(State &state, const utils::Pos &pos,
                 nodes::MaybeType *context_exit_type)
       : state_(state), context_exit_type_(context_exit_type) {
-    state.enter_context(pos);
+    state.EnterContext(pos);
   }
 
   ContextHolder(const ContextHolder &) = delete;
@@ -273,14 +277,14 @@ public:
 
   //
 
-  nodes::Type &get() {
+  nodes::Type &Get() {
     utils::Assert(type_.has_value(),
                   "Access to invalid type in TypeCheckResult");
 
     return type_.value();
   }
 
-  const nodes::Type &get() const {
+  const nodes::Type &Get() const {
 
     utils::Assert(type_.has_value(),
                   "Access to invalid type in TypeCheckResult");
@@ -288,7 +292,15 @@ public:
     return type_.value();
   }
 
-  void set(nodes::Type type) { type_ = type; }
+  //
+
+  nodes::MaybeType &MaybeGet() { return type_; }
+
+  const nodes::MaybeType &MaybeGet() const { return type_; }
+
+  //
+
+  void Set(nodes::Type type) { type_ = type; }
 
   //
 
@@ -305,7 +317,7 @@ using MaybeResult = std::optional<Result>;
 
 //
 
-nodes::Type check_same_to_pass_type_in_args(
+nodes::Type CheckSameToPassTypeInArgs(
     nodes::Type type, const Args &args, const utils::Pos &pos,
     Executor &executor,
     const std::string &message = "Different type with passed one",
@@ -316,37 +328,31 @@ nodes::Type check_same_to_pass_type_in_args(
 //     SourcesManager &sources_manager,
 //     const std::string &message = "Type can't be passed to this node");
 
-Result type_same_to_expected(
+Result CheckTypeSameToExpected(
     nodes::Type type, const Args &args, const utils::Pos &pos,
     Executor &executor,
     const std::string &message = "Different type with expected one",
     bool handle_errors = true);
 
-Result type_check_from_args(nodes::Type type, const Args &args,
-                            const utils::Pos &pos, Executor &executor,
-                            bool handle_errors = true);
-
 std::optional<const nodes::TypeDefinition *>
-find_type_definition(const std::string &name, const utils::Pos &pos,
-                     Executor &executor, bool handle_errors = true);
+FindTypeDefinition(const std::string &name, const utils::Pos &pos,
+                   Executor &executor, bool handle_errors = true);
 
 std::optional<const nodes::FunctionDefinition *>
-find_name_definition(const std::string &name, const utils::Pos &pos,
-                     Executor &executor, bool handle_errors = true);
+FindNameDefinition(const std::string &name, const utils::Pos &pos,
+                   Executor &executor, bool handle_errors = true);
 
-nodes::MaybeType unfold_user_defined_type(nodes::Type type,
-                                          const utils::Pos &pos,
-                                          Executor &executor,
-                                          bool handle_errors = true);
+nodes::MaybeType UnfoldUserDefinedType(nodes::Type type, const utils::Pos &pos,
+                                       Executor &executor,
+                                       bool handle_errors = true);
 
-nodes::MaybeType get_field_type_by_name(nodes::Type type,
-                                        const std::string &field,
-                                        const utils::Pos &pos,
-                                        Executor &executor,
-                                        bool handle_errors = true);
+nodes::MaybeType FieldTypeByName(nodes::Type type, const std::string &field,
+                                 const utils::Pos &pos, Executor &executor,
+                                 bool handle_errors = true);
 
-void type_check_error(const std::string &message, const utils::Pos &pos,
-                      Executor &executor, bool handle_error = true);
+inline nodes::MaybeType Curry(MaybeResult result) {
+  return result.has_value() ? result->Get() : nodes::MaybeType{};
+}
 
 //
 
@@ -366,12 +372,47 @@ template <typename N> struct CheckTaskBase : public Task<N> {
 
   Node Ext(storage::Id id) {
     return Node(id, this->template state<Exprs>(),
-                this->template state<Positions>());
+                this->template state<Positions>(),
+                this->template state<NodeTypes>());
   }
 
   utils::Pos PosOf(storage::Id id) {
     return Ext(id).template part<utils::Pos>();
   }
+
+  //
+
+  void TypeCheckError(const std::string &message, const utils::Pos &,
+                      bool handle_errors = true) {
+    Log::Context logc(Task<N>::executor.log(), Log::Area::kTypeCheck);
+
+    if (not handle_errors) {
+      return;
+    }
+
+    logc.Error<Log::kProc>({{message}} /* TODO: use pos */);
+  }
+
+  Result TypeCheckFromArgs(nodes::Type type, const Args &args,
+                           const utils::Pos &pos, bool handle_errors = true) {
+    Log::Context logc(Task<N>::executor.log(), Log::Area::kTypeCheck);
+
+    /* TODO FIXME */
+    logc.Fatal<Log::kSys>({{"Not implemented yet"}});
+    throw std::exception(); // unreachable
+  }
+
+  bool CheckNoPassTypeInArgs(const Args &args, const utils::Pos &pos,
+                             const std::string &message, bool handle_errors) {
+    Log::Context logc(Task<N>::executor.log(), Log::Area::kTypeCheck);
+
+    if (args.passed().has_value()) {
+      TypeCheckError(message, pos, handle_errors);
+      return false;
+    }
+
+    return true;
+  }
 };
 
 } // namespace type_check
diff --git a/lang/type_check/src/basic_type_check.cpp b/lang/type_check/src/basic_type_check.cpp
index 2b197f0..6a27d8c 100644
--- a/lang/type_check/src/basic_type_check.cpp
+++ b/lang/type_check/src/basic_type_check.cpp
@@ -4,6 +4,8 @@ namespace type_check {
 
 nodes::Type get_literal_type(const nodes::Literal &literal,
                              Executor &executor) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   switch (literal.value.index()) {
   case 0: // float
     return executor.state<Types>().primitive(builtin::Type::FLOAT);
@@ -39,9 +41,11 @@ nodes::Type get_literal_type(const nodes::Literal &literal,
 
 Result CheckTask<nodes::Literal>::operator()(const nodes::Literal &literal,
                                              const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   auto const type = get_literal_type(literal, this->executor);
-  return type_same_to_expected(type, args, {},
-                               this->executor); // TODO: add pos ??
+  return CheckTypeSameToExpected(type, args, {},
+                                 this->executor); // TODO: add pos ??
 }
 
 } // namespace type_check
diff --git a/lang/type_check/src/expression_type_check.cpp b/lang/type_check/src/expression_type_check.cpp
index ab08d0f..600b1d5 100644
--- a/lang/type_check/src/expression_type_check.cpp
+++ b/lang/type_check/src/expression_type_check.cpp
@@ -35,16 +35,19 @@ Result CheckTask<nodes::NodeData>::operator()(const nodes::NodeData &expr,
 
 Result CheckTask<nodes::Match>::operator()(const nodes::Match &expr,
                                            const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
   const auto current_pos = PosOf(args.current_id);
 
+  //
+
   Result value_result = Run(expr.value, {expr.value});
 
   // x :=/=: ...
   if (value_result.is_invalid()) {
-    type_check_error("Match value is invalid", current_pos, executor);
+    TypeCheckError("Match value is invalid", current_pos);
   }
 
-  MaybeResult expression_result;
+  MaybeResult expr_result;
 
   bool at_least_one_case_with_expression = false;
   bool at_least_one_case_without_expression = false;
@@ -54,95 +57,101 @@ Result CheckTask<nodes::Match>::operator()(const nodes::Match &expr,
         Ext(current_case_id).get<nodes::Match::Case>();
 
     // :=/=: x ...
-    Run(current_case.value,
-        Args{current_case.value}
-            .expect_builtin(builtin::Type::BOOL, executor)
-            .pass(value_result.is_invalid() ? nodes::MaybeType{}
-                                            : expression_result.value().get()));
-    // TODO: use type modifiers ??
+    switch (
+        current_case.kind) { // TODO: FIXME think about passed, brought types
+    case nodes::Match::Case::PATTERN_VALUE:
+      if (not value_result.is_invalid()) {
+        Run(current_case.value,
+            Args{current_case.value}
+                .ExpectBuiltin(builtin::Type::BOOL, executor)
+                .Pass(value_result.Get()));
+      }
+      break;
+    case nodes::Match::Case::VALUE_PATTERN:
+      Run(current_case.value, Args{current_case.value}
+                                  .ExpectBuiltin(builtin::Type::BOOL, executor)
+                                  .Pass(value_result.MaybeGet()));
+      break;
+    }
 
     // ... ?? x ...
     if (current_case.condition.has_value()) {
-      Run(current_case.condition.value(),
-          Args{current_case.condition.value()}.expect_builtin(
-              builtin::Type::BOOL, executor));
+      const auto &cond = current_case.condition.value();
+      Run(cond, Args{cond}.ExpectBuiltin(builtin::Type::BOOL, executor));
     }
 
     // ... -> x
     if (current_case.expr.has_value()) {
+      const auto &expr = current_case.expr.value();
       at_least_one_case_with_expression = true;
-      Result case_result = Run(current_case.expr.value(),
-                               Args{current_case.expr.value()}.expect(
-                                   expression_result.has_value()
-                                       ? expression_result.value().get()
-                                       : nodes::MaybeType{}));
 
-      if (!expression_result.has_value() && !case_result.is_invalid()) {
-        expression_result = std::move(case_result);
+      Result case_result = Run(expr, Args{expr}.Expect(Curry(expr_result)));
+
+      if (not expr_result.has_value() and not case_result.is_invalid()) {
+        expr_result = std::move(case_result);
       }
     } else {
       at_least_one_case_without_expression = true;
     }
   }
 
-  if (at_least_one_case_with_expression &&
+  if (at_least_one_case_with_expression and
       at_least_one_case_without_expression) {
-    type_check_error(
+    TypeCheckError(
         "All cases should be with or without expression at the same time",
-        current_pos, executor);
-    expression_result = Result::invalid();
+        current_pos);
+    expr_result = Result::invalid();
   }
 
-  if (!expression_result.has_value()) {
-    expression_result = Result{state<Types>().primitive(builtin::Type::UNIT)};
+  if (not expr_result.has_value()) {
+    expr_result = Result{state<Types>().primitive(builtin::Type::UNIT)};
   }
 
-  return type_check_from_args(
-      state<Types>().add_array_of(expression_result.value().get()), args,
-      current_pos, executor);
+  return TypeCheckFromArgs(expr_result.value().Get(), args, current_pos);
 }
 
 Result CheckTask<nodes::Condition>::operator()(const nodes::Condition &expr,
                                                const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
   const auto current_pos = PosOf(args.current_id);
 
-  MaybeResult expression_result;
+  //
+
+  MaybeResult expr_result;
 
   for (const auto &current_case : expr.cases) {
+    // condition
     Run(current_case.first,
-        Args{current_case.first}.expect_builtin(builtin::Type::BOOL, executor));
+        Args{current_case.first}.ExpectBuiltin(builtin::Type::BOOL, executor));
 
+    // expression
     Result case_result =
         Run(current_case.second,
-            Args{current_case.second}.expect(
-                expression_result.has_value() ? expression_result.value().get()
-                                              : nodes::MaybeType{}));
+            Args{current_case.second}.Expect(Curry(expr_result)));
 
-    if (!expression_result.has_value() && !case_result.is_invalid()) {
-      expression_result = std::move(case_result);
+    if (not expr_result.has_value() and not case_result.is_invalid()) {
+      expr_result = std::move(case_result);
     }
   }
 
   if (expr.else_case.has_value()) {
     Run(expr.else_case.value(),
-        Args{expr.else_case.value()}.expect(
-            expression_result.has_value() ? expression_result.value().get()
-                                          : nodes::MaybeType{}));
+        Args{expr.else_case.value()}.Expect(Curry(expr_result)));
   }
 
-  if (!expression_result.has_value()) {
-    type_check_error("There should be at least one case in if statement",
-                     current_pos, executor);
-    expression_result = Result::invalid();
+  if (!expr_result.has_value()) {
+    TypeCheckError("There should be at least one case in if statement",
+                   current_pos);
+    expr_result = Result::invalid();
   }
 
-  return type_check_from_args(
-      state<Types>().add_array_of(expression_result.value().get()), args,
-      current_pos, executor);
+  return TypeCheckFromArgs(expr_result.value().Get(), args, current_pos);
 }
 
 Result CheckTask<nodes::Loop>::operator()(const nodes::Loop &expr,
                                           const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   // TODO: ranges ??
@@ -157,7 +166,7 @@ Result CheckTask<nodes::Loop>::operator()(const nodes::Loop &expr,
   case nodes::Loop::LOOP: // infinity loop, no params
     break;
   case nodes::Loop::WHILE:
-    Run(expr.condition.value(), Args{expr.condition.value()}.expect_builtin(
+    Run(expr.condition.value(), Args{expr.condition.value()}.ExpectBuiltin(
                                     builtin::Type::BOOL, executor));
 
     // --- type check is independent from loop itself ---
@@ -169,7 +178,7 @@ Result CheckTask<nodes::Loop>::operator()(const nodes::Loop &expr,
   case nodes::Loop::FOR:
     // TODO: expect range ??
     interval_result =
-        Run(expr.interval.value(), Args{expr.interval.value()}.expect_builtin(
+        Run(expr.interval.value(), Args{expr.interval.value()}.ExpectBuiltin(
                                        builtin::Type::ARRAY, executor));
 
     if (interval_result.value().is_invalid()) {
@@ -180,8 +189,8 @@ Result CheckTask<nodes::Loop>::operator()(const nodes::Loop &expr,
 
     variable_result =
         Run(expr.variable.value(),
-            Args{expr.variable.value()}.expect(
-                interval_result.value().get().get()->get_parameter_proxy(0)));
+            Args{expr.variable.value()}.Expect(
+                interval_result.value().Get().get()->get_parameter_proxy(0)));
 
     // --- type check is independent from loop itself ---
     // if (variable_result.value().is_invalid()) {
@@ -196,15 +205,16 @@ Result CheckTask<nodes::Loop>::operator()(const nodes::Loop &expr,
 
   // TODO: modifier checks ??, modifiers ??
 
-  return type_check_from_args(
-      state<Types>().add_array_of(expression_result.get()), args, current_pos,
-      executor);
+  return TypeCheckFromArgs(state<Types>().add_array_of(expression_result.Get()),
+                           args, current_pos);
 } // IN PROGRESS
 
 // --- containers
 
 Result CheckTask<nodes::Container>::CheckArray(const nodes::Container &expr,
                                                const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   MaybeResult last_expr_result;
@@ -216,9 +226,9 @@ Result CheckTask<nodes::Container>::CheckArray(const nodes::Container &expr,
     if (!last_expr_result.has_value()) {
       last_expr_result = expr_result;
     } else {
-      if (last_expr_result.value().get() != expr_result.get()) {
-        type_check_error("Elements in array should have same type",
-                         PosOf(args.current_id), executor);
+      if (last_expr_result.value().Get() != expr_result.Get()) {
+        TypeCheckError("Elements in array should have same type",
+                       PosOf(args.current_id));
         // return TypeCheckResult::construct_invalid_result(); // max
         // possible checks, so no return
       }
@@ -226,17 +236,19 @@ Result CheckTask<nodes::Container>::CheckArray(const nodes::Container &expr,
   }
 
   if (!last_expr_result.has_value()) {
-    type_check_error("Array with zero elements", current_pos, executor);
+    TypeCheckError("Array with zero elements", current_pos);
     return Result::invalid();
   }
 
-  return type_check_from_args(
-      state<Types>().add_array_of(last_expr_result.value().get()), args,
-      current_pos, executor);
+  return TypeCheckFromArgs(
+      state<Types>().add_array_of(last_expr_result.value().Get()), args,
+      current_pos);
 }
 
 Result CheckTask<nodes::Container>::CheckBlock(const nodes::Container &expr,
                                                const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   nodes::MaybeType context_exit_type;
@@ -257,9 +269,8 @@ Result CheckTask<nodes::Container>::CheckBlock(const nodes::Container &expr,
           ? Result(context_exit_type.value())
           : Result(state<Types>().primitive(builtin::Type::UNIT));
 
-  return type_check_from_args(
-      state<Types>().add_array_of(block_brought_type.get()), args, current_pos,
-      executor);
+  return TypeCheckFromArgs(
+      state<Types>().add_array_of(block_brought_type.Get()), args, current_pos);
 }
 
 Result CheckTask<nodes::Container>::operator()(const nodes::Container &expr,
@@ -276,6 +287,8 @@ Result CheckTask<nodes::Container>::operator()(const nodes::Container &expr,
 
 Result CheckTask<nodes::Return>::operator()(const nodes::Return &expr,
                                             const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   auto returned_result = Run(expr.expr, {expr.expr});
@@ -286,70 +299,71 @@ Result CheckTask<nodes::Return>::operator()(const nodes::Return &expr,
 
   switch (expr.kind) {
   case nodes::Return::BRING:
-    if (state<State>().bring_type(returned_result.get())) {
-      type_check_error("Different brought type to current one", current_pos,
-                       executor);
+    if (state<State>().BringType(returned_result.Get())) {
+      TypeCheckError("Different brought type to current one", current_pos);
       return Result::invalid();
     }
     break;
   case nodes::Return::RETURN:
-    if (!state<State>().return_type(returned_result.get())) {
-      type_check_error("Different returned type to current one", current_pos,
-                       executor);
+    if (!state<State>().ReturnType(returned_result.Get())) {
+      TypeCheckError("Different returned type to current one", current_pos);
       return Result::invalid();
     }
     break;
   }
 
-  return type_check_from_args(state<Types>().primitive(builtin::Type::UNIT),
-                              args, current_pos, executor);
+  return TypeCheckFromArgs(state<Types>().primitive(builtin::Type::UNIT), args,
+                           current_pos);
 }
 
 // TODO: warning if name is same to package prefix, function prefix, etc. ??
 Result
 CheckTask<nodes::NameDefinition>::operator()(const nodes::NameDefinition &expr,
                                              const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
-  if (!args.get_passed().has_value()) {
-    type_check_error("Can't deduce type of new variable from context",
-                     current_pos, executor);
+  if (!args.passed().has_value()) {
+    TypeCheckError("Can't deduce type of new variable from context",
+                   current_pos);
   }
 
   // assigned type shold be one of <-, <>, -- (can't be ->)
-  const auto variable_type = args.get_passed().value();
+  const auto variable_type = args.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",
-                     current_pos, executor);
+    TypeCheckError("Variable can't be assigned from out (->) value",
+                   current_pos);
   }
 
   // variable accessible by reference by default ??
   state<Types>().add_modification_of(variable_type, nodes::Modifier::REF);
 
-  if (!state<State>().insert_variable(expr.name.value, variable_type,
-                                      expr.kind)) {
-    type_check_error("Variable is already defined in this context", current_pos,
-                     executor);
+  if (!state<State>().InsertVariable(expr.name.value, variable_type,
+                                     expr.kind)) {
+    TypeCheckError("Variable is already defined in this context", current_pos);
   }
 
   // Return BOOL as any := / =: expression
-  return type_check_from_args(state<Types>().primitive(builtin::Type::BOOL),
-                              args, current_pos, executor);
+  return TypeCheckFromArgs(state<Types>().primitive(builtin::Type::BOOL), args,
+                           current_pos);
 }
 
 Result CheckTask<nodes::Access>::CheckArrayAccess(const nodes::Access &expr,
                                                   const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   auto index_result =
       Run(expr.index,
-          Args{expr.index}.expect_builtin(builtin::Type::INDEX, executor));
+          Args{expr.index}.ExpectBuiltin(builtin::Type::INDEX, executor));
 
   auto value_result =
       Run(expr.value,
-          Args{expr.value}.expect_builtin(builtin::Type::ARRAY, executor));
+          Args{expr.value}.ExpectBuiltin(builtin::Type::ARRAY, executor));
 
   if (index_result.is_invalid()) {
     return index_result;
@@ -361,17 +375,19 @@ Result CheckTask<nodes::Access>::CheckArrayAccess(const nodes::Access &expr,
 
   // TODO: modifier checks ??
 
-  return type_check_from_args(value_result.get().get()->get_parameter_proxy(0),
-                              args, current_pos, executor);
+  return TypeCheckFromArgs(value_result.Get().get()->get_parameter_proxy(0),
+                           args, current_pos);
 }
 
 Result CheckTask<nodes::Access>::CheckTupleAccess(const nodes::Access &expr,
                                                   const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   auto value_result =
       Run(expr.value,
-          Args{expr.value}.expect_builtin(builtin::Type::TUPLE, executor));
+          Args{expr.value}.ExpectBuiltin(builtin::Type::TUPLE, executor));
 
   if (value_result.is_invalid()) {
     return value_result;
@@ -384,13 +400,14 @@ Result CheckTask<nodes::Access>::CheckTupleAccess(const nodes::Access &expr,
 
   // TODO: modifier checks ??
 
-  return type_check_from_args(
-      value_result.get().get()->get_parameter_proxy(index), args, current_pos,
-      executor);
+  return TypeCheckFromArgs(value_result.Get().get()->get_parameter_proxy(index),
+                           args, current_pos);
 }
 
 Result CheckTask<nodes::Access>::operator()(const nodes::Access &expr,
                                             const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   switch (expr.kind) {
   case nodes::Access::ARRAY:
     return CheckArrayAccess(expr, args);
@@ -401,14 +418,18 @@ Result CheckTask<nodes::Access>::operator()(const nodes::Access &expr,
 
 Result CheckTask<nodes::LoopControl>::operator()(const nodes::LoopControl &expr,
                                                  const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
-  return type_check_from_args(state<Types>().primitive(builtin::Type::UNIT),
-                              args, current_pos, executor);
+  return TypeCheckFromArgs(state<Types>().primitive(builtin::Type::UNIT), args,
+                           current_pos);
 }
 
 Result CheckTask<nodes::ModifierExpression>::operator()(
     const nodes::ModifierExpression &expr, const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   auto modified_result = Run(expr.expr, {expr.expr});
@@ -426,25 +447,23 @@ Result CheckTask<nodes::ModifierExpression>::operator()(
 
     // '!' - open optional / result -> value / panic
 
-    switch (modified_result.get().get()->to_builtin()) {
+    switch (modified_result.Get().get()->to_builtin()) {
     case builtin::Type::OPTIONAL:
     case builtin::Type::RESULT:
       // TODO: how to unwrap external modifier ??
-      modified_result.set(modified_result.get().get()->get_parameter_proxy(0));
+      modified_result.Set(modified_result.Get().get()->get_parameter_proxy(0));
       break;
     default:
-      type_check_error("Can unwrap only Optional or Result", current_pos,
-                       executor);
+      TypeCheckError("Can unwrap only Optional or Result", current_pos);
       return Result::invalid();
     }
   } else {
     // TODO: check that modifier can be applied
-    modified_result.set(state<Types>().add_modification_of(
-        modified_result.get(), expr.modifier));
+    modified_result.Set(state<Types>().add_modification_of(
+        modified_result.Get(), expr.modifier));
   }
 
-  return type_check_from_args(modified_result.get(), args, current_pos,
-                              executor);
+  return TypeCheckFromArgs(modified_result.Get(), args, current_pos);
 } // IN PROGRESS
 
 // --- other
@@ -453,6 +472,8 @@ Result CheckTask<nodes::ModifierExpression>::operator()(
 Result
 CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
                                              const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   // TODO: constraints ??
@@ -470,7 +491,7 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
         current_prefix.append_after(fragments[i]);
       }
 
-      maybe_variable = state<State>().find_variable(current_prefix.value);
+      maybe_variable = state<State>().FindVariable(current_prefix.value);
 
       if (maybe_variable.has_value()) {
         break;
@@ -494,8 +515,8 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
         // 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].value, current_pos, executor);
+        const auto maybe_field_type =
+            FieldTypeByName(type, fragments[i].value, current_pos, executor);
 
         if (maybe_field_type.has_value()) {
           type = maybe_field_type.value();
@@ -517,7 +538,7 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
   // TODO: check, if there is variable with this name
   // TODO: check var + fields
   const auto maybe_function_definition =
-      find_name_definition(name.value, current_pos, executor);
+      FindNameDefinition(name.value, current_pos, executor);
   if (!maybe_function_definition.has_value()) {
     return Result::invalid();
   }
@@ -531,15 +552,13 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
   const auto args_defined = function_definition->args.size();
   if (args_given + 1 < args_defined ||
       args_given > args_defined) { // other, when there is passed type
-    type_check_error(
-        "Number of function args is different from expected (" +
-            std::to_string(args_given) + " instead of " +
-            std::to_string(args_defined) +
-            std::string{args_defined > 0
-                            ? (" or " + std::to_string(args_defined - 1))
-                            : ""} +
-            ")",
-        current_pos, executor);
+    TypeCheckError(std::format("Number of function args is different from "
+                               "expected ({} instead of {}{})",
+                               args_given, args_defined,
+                               args_defined > 0
+                                   ? (" or " + std::to_string(args_defined - 1))
+                                   : ""),
+                   current_pos);
     return Result::invalid();
     // TODO: try return correct type (function return type), when possible
   }
@@ -553,9 +572,10 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
         function_definition->args.at(i);
 
     if (!argument.type.has_value()) {
-      type_check_error("Function argument type is not defined for argument " +
-                           std::to_string(i),
-                       current_pos, executor);
+      TypeCheckError(
+          std::format("Function argument type is not defined for argument {}",
+                      i),
+          current_pos);
       continue;
     }
 
@@ -563,30 +583,31 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
     const auto expected_annotation = argument.annotation;
 
     if (annotation.has_value() != expected_annotation.has_value()) {
-      type_check_error("Wrong function argument annotation: should be " +
-                           std::string{expected_annotation.has_value()
-                                           ? expected_annotation.value()
-                                           : "[none]"},
-                       PosOf(expr.args.at(i).second), executor);
+      TypeCheckError("Wrong function argument annotation: should be " +
+                         std::string{expected_annotation.has_value()
+                                         ? expected_annotation.value()
+                                         : "[none]"},
+                     PosOf(expr.args.at(i).second));
     }
 
     if (annotation.has_value() &&
         annotation.value() != expected_annotation.value()) {
-      type_check_error(
-          "Wrong function argument type annotation: " + annotation.value() +
-              " instead of " + expected_annotation.value(),
-          PosOf(expr.args.at(i).second), executor);
+      TypeCheckError(
+          std::format(
+              "Wrong function argument type annotation: {} instead of {}",
+              annotation.value(), expected_annotation.value()),
+          PosOf(expr.args.at(i).second));
     }
 
     function_argument_results.push_back(
         Run(expr.args.at(i).second,
-            Args{expr.args.at(i).second}.expect(argument.type.value())));
+            Args{expr.args.at(i).second}.Expect(argument.type.value())));
   }
 
   if (function_definition->args.size() == 0) {
-    type_check_error(
+    TypeCheckError(
         "Function arguments size is zero. Returned type is not defined",
-        current_pos, executor);
+        current_pos);
     return Result::invalid();
   }
 
@@ -598,16 +619,14 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
 
     // TODO: invert modifier ??
     if (!returned.type.has_value()) {
-      type_check_error(
-          "Function argument type is not defined for returned type",
-          current_pos, executor);
+      TypeCheckError("Function argument type is not defined for returned type",
+                     current_pos);
       return Result::invalid();
     }
 
     // TODO: invert modifier ??
     // TODO: generic types should be deduced from args
-    return type_check_from_args(returned.type.value(), args, current_pos,
-                                executor);
+    return TypeCheckFromArgs(returned.type.value(), args, current_pos);
   }
 
   // checks for universal call syntax ??
@@ -618,12 +637,14 @@ CheckTask<nodes::NameExpression>::operator()(const nodes::NameExpression &expr,
 // TODO
 Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
                                                  const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
   // TODO: constraints ??
 
   // TODO: use pass type
-  const auto maybe_type_definition = find_type_definition(
+  const auto maybe_type_definition = FindTypeDefinition(
       expr.type.get()->get_name()->value, current_pos, executor);
   if (!maybe_type_definition.has_value()) {
     return Result::invalid();
@@ -631,9 +652,9 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
   const nodes::TypeDefinition *type_definition = maybe_type_definition.value();
 
   if (!type_definition->type.has_value()) {
-    type_check_error(
+    TypeCheckError(
         "Type defenition for constructor type not found (declaration only)",
-        current_pos, executor);
+        current_pos);
     return Result::invalid();
   }
 
@@ -646,8 +667,8 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
   // TODO: work with different parametric types: tuple, variant, ...
 
   if (expr.args.size() == 0) {
-    type_check_error("Number of type constructor arguments should be > 0",
-                     current_pos, executor);
+    TypeCheckError("Number of type constructor arguments should be > 0",
+                   current_pos);
     return Result::invalid();
     // TODO: try return correct type (constructor's type), when possible (not
     // generic)
@@ -661,12 +682,12 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
     switch (builtin_type) {
     case builtin::Type::TUPLE:
       if (expr.args.size() != type.get()->parameters_size()) {
-        type_check_error(
+        TypeCheckError(
             "Number of type constructor arguments is different from expected "
             "(" +
                 std::to_string(expr.args.size()) + " instead of " +
                 std::to_string(type.get()->parameters_size()) + ")",
-            current_pos, executor);
+            current_pos);
         return Result::invalid();
         // TODO: try return correct type (constructor's type), when possible
         // (not generic)
@@ -679,10 +700,10 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
     case builtin::Type::FUNCTION:
     case builtin::Type::NONE:
       if (expr.args.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)) + ")",
-                         current_pos, executor);
+        TypeCheckError(std::format("Number of type constructor arguments "
+                                   "should be = 1 (builtin type {})",
+                                   uint(builtin_type)),
+                       current_pos);
         return Result::invalid();
         // TODO: try return correct type (constructor's type), when possible
         // (not generic)
@@ -695,8 +716,8 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
     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",
-                       current_pos, executor);
+      TypeCheckError("Wrong amount of parametars for builtin type",
+                     current_pos);
 
       return Result::invalid();
       // TODO: try return correct type (constructor's type), when possible (not
@@ -717,12 +738,12 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
 
           if (annotation.has_value() != expected_annotation.has_value()) {
             if (log_errors) {
-              type_check_error(
+              TypeCheckError(
                   "Wrong type constructor argument annotation: should be " +
                       std::string{expected_annotation.has_value()
                                       ? *expected_annotation.value()
                                       : "[none]"},
-                  PosOf(expr.args.at(i).second), executor);
+                  PosOf(expr.args.at(i).second));
             }
             is_same = false;
           }
@@ -730,10 +751,10 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
           if (annotation.has_value() &&
               annotation.value() != *expected_annotation.value()) {
             if (log_errors) {
-              type_check_error("Wrong function argument type annotation: " +
-                                   annotation.value() + " instead of " +
-                                   *expected_annotation.value(),
-                               PosOf(expr.args.at(i).second), executor);
+              TypeCheckError("Wrong function argument type annotation: " +
+                                 annotation.value() + " instead of " +
+                                 *expected_annotation.value(),
+                             PosOf(expr.args.at(i).second));
             }
 
             is_same = false;
@@ -745,9 +766,9 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
     const auto check_no_annotation = [&expr, this](size_t i, bool log_errors) {
       if (expr.args.at(i).first.has_value()) {
         if (log_errors) {
-          type_check_error(
+          TypeCheckError(
               "Type constructor argument annotation not expected there",
-              PosOf(expr.args.at(i).second), executor);
+              PosOf(expr.args.at(i).second));
         }
         return false;
       }
@@ -774,9 +795,9 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
 
       if (!chosen_variant_option.has_value() &&
           !check_no_annotation(0, false /*do not log errors*/)) {
-        type_check_error("Wrong type constructor argument annotation in "
-                         "constructor of variant type",
-                         PosOf(expr.args.front().second), executor);
+        TypeCheckError("Wrong type constructor argument annotation in "
+                       "constructor of variant type",
+                       PosOf(expr.args.front().second));
       }
       break;
     case builtin::Type::ERROR: // no anotations ??
@@ -798,13 +819,13 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
     switch (builtin_type) {
     case builtin::Type::TUPLE:
       for (size_t i = 0; i < expr.args.size(); ++i) {
-        Run(expr.args.at(i).second, Args{expr.args.at(i).second}.expect(
+        Run(expr.args.at(i).second, Args{expr.args.at(i).second}.Expect(
                                         type.get()->get_parameter_proxy(i)));
       }
       break;
     case builtin::Type::VARIANT:
       if (chosen_variant_option.has_value()) {
-        Run(expr.args.front().second, Args{expr.args.front().second}.expect(
+        Run(expr.args.front().second, Args{expr.args.front().second}.Expect(
                                           type.get()->get_parameter_proxy(
                                               chosen_variant_option.value())));
       } else { // TODO: error, if there is more then one possible variant in
@@ -814,43 +835,43 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
           possible_options.push_back(type.get()->get_parameter_proxy(i));
         }
         Run(expr.args.front().second,
-            Args{expr.args.front().second}.expect(possible_options));
+            Args{expr.args.front().second}.Expect(possible_options));
       }
       break;
     case builtin::Type::OPTIONAL:
       // first parameter or NULL
       Run(expr.args.front().second,
-          Args{expr.args.front().second}.expect(
+          Args{expr.args.front().second}.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]
       Run(expr.args.front().second,
-          Args{expr.args.front().second}.expect(
+          Args{expr.args.front().second}.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
-      Run(expr.args.front().second, Args{expr.args.front().second}.expect(
+      Run(expr.args.front().second, Args{expr.args.front().second}.Expect(
                                         type.get()->get_parameter_proxy(0)));
       break;
     case builtin::Type::FUNCTION:
     case builtin::Type::NONE:
       // type itself
       Run(expr.args.front().second,
-          Args{expr.args.front().second}.expect(type));
+          Args{expr.args.front().second}.Expect(type));
       break;
     default: // array, basic types
-      type_check_error("Type can't be constructed", current_pos, executor);
+      TypeCheckError("Type can't be constructed", current_pos);
       break;
     }
   }
 
   // TODO: deduce generic parts in type
-  return type_check_from_args(expr.type, args, current_pos, executor);
+  return TypeCheckFromArgs(expr.type, args, current_pos);
   // TODO: add <- modifiier to type ??
 
 } // IN PROGRESS
@@ -858,71 +879,74 @@ Result CheckTask<nodes::Constructor>::operator()(const nodes::Constructor &expr,
 // TODO
 Result CheckTask<nodes::Lambda>::operator()(const nodes::Lambda &expr,
                                             const Args &args) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   const auto current_pos = PosOf(args.current_id);
 
-  if (args.get_expected().empty()) {
-    type_check_error("Can't deduce type of lambda function from context: no "
-                     "one type expected",
-                     current_pos, executor);
+  if (args.expected().empty()) {
+    TypeCheckError("Can't deduce type of lambda function from context: no "
+                   "one type expected",
+                   current_pos);
   }
 
-  if (args.get_expected().size() !=
+  if (args.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",
-                     current_pos, executor);
+    TypeCheckError("Can't deduce type of lambda function from context; too "
+                   "much possible types",
+                   current_pos);
   }
 
-  const auto expected_type = args.get_expected().front();
+  const auto expected_type = args.expected().front();
   if (!expected_type.get()->is_builtin(builtin::Type::FUNCTION)) {
-    type_check_error("Type of lambda function should be function", current_pos,
-                     executor);
+    TypeCheckError("Type of lambda function should be function", current_pos);
   }
 
   // TODO: deal with return type (+1 sometimes), etc
   const auto args_given = expr.args.size();
   const auto args_defined = expected_type.get()->parameters_size();
   if (args_given != args_defined) {
-    type_check_error(
-        "Number of function arguments is different from expected (" +
-            std::to_string(args_given) + " instead of " +
-            std::to_string(args_defined) +
-            std::string{args_defined > 0
-                            ? (" or " + std::to_string(args_defined - 1))
-                            : ""} +
-            ")",
-        current_pos, executor);
+    TypeCheckError(std::format("Number of function arguments is different from "
+                               "expected ({} istead of {}{})",
+                               args_given, args_defined,
+                               args_defined > 0
+                                   ? (" or " + std::to_string(args_defined - 1))
+                                   : ""),
+                   current_pos);
   }
 
   // TODO: set another context (for expression typecheck and vars)
 
   for (size_t i = 0; i < args_given; ++i) {
-    if (!state<State>().insert_variable(
+    if (!state<State>().InsertVariable(
             expr.args.at(i).value, expected_type.get()->get_parameter_proxy(i),
             nodes::NameDefinition::Kind::LET)) {
       // TODO: which modifier ??
-      type_check_error("Variable is already defined in this context",
-                       current_pos, executor);
+      TypeCheckError("Variable is already defined in this context",
+                     current_pos);
     }
   }
 
   // TODO: out type is can be not last
   if (args_given + 1 == args_defined) {
     Run(expr.expr,
-        Args{expr.expr}.expect(
+        Args{expr.expr}.Expect(
             expected_type.get()->get_parameter_proxy(args_defined - 1)));
   }
 
   // TODO: needed ?? (only passed type check required ??)
-  return type_check_from_args(expected_type, args, current_pos, executor);
+  return TypeCheckFromArgs(expected_type, args, current_pos);
 } // IN PROGRESS
 
 Result CheckTask<nodes::Extra>::operator()(const nodes::Extra &, const Args &) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   return Result(state<Types>().primitive(builtin::Type::UNIT));
 }
 
 Result CheckTask<nodes::EmptyLines>::operator()(const nodes::EmptyLines &,
                                                 const Args &) {
+  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
+
   return Result(state<Types>().primitive(builtin::Type::UNIT));
 }
 
diff --git a/lang/type_check/src/type_check_utils.cpp b/lang/type_check/src/type_check_utils.cpp
index 722d8e2..1b837ce 100644
--- a/lang/type_check/src/type_check_utils.cpp
+++ b/lang/type_check/src/type_check_utils.cpp
@@ -6,43 +6,29 @@ namespace type_check {
 
 // pass type -> compare types, return bool
 // no pass type -> return type
-nodes::Type check_same_to_pass_type_in_args(nodes::Type type, const Args &args,
-                                            const utils::Pos &,
-                                            Executor &executor,
-                                            const std::string &message,
-                                            bool handle_errors) {
+nodes::Type CheckSameToPassTypeInArgs(nodes::Type type, const Args &args,
+                                      const utils::Pos &, Executor &executor,
+                                      const std::string &message,
+                                      bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
-  if (not args.get_passed().has_value()) {
+  if (not args.passed().has_value()) {
     return type;
   }
 
-  if (type != args.get_passed().value() and handle_errors) {
+  if (type != args.passed().value() and handle_errors) {
     logc.Error<Log::kProc>({{message}} /* TODO: node */);
   }
 
   return executor.state<Types>().primitive(builtin::Type::BOOL);
 }
 
-bool check_no_pass_type_in_args(const Args &args, const utils::Pos &pos,
-                                Executor &executor, const std::string &message,
-                                bool handle_errors) {
+Result CheckTypeSameToExpected(nodes::Type type, const Args &args,
+                               const utils::Pos &, Executor &executor,
+                               const std::string &message, bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
-  if (args.get_passed().has_value()) {
-    type_check_error(message, pos, executor, handle_errors);
-    return false;
-  }
-
-  return true;
-}
-
-Result type_same_to_expected(nodes::Type type, const Args &args,
-                             const utils::Pos &, Executor &executor,
-                             const std::string &message, bool handle_errors) {
-  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
-
-  const auto &expected = args.get_expected();
+  const auto &expected = args.expected();
 
   if (expected.empty()) {
     return Result{type};
@@ -60,22 +46,12 @@ Result type_same_to_expected(nodes::Type type, const Args &args,
   return Result{expected.front()}; // any can be choosen
 }
 
-Result type_check_from_args(nodes::Type /*type*/, const Args & /*args*/,
-                            const utils::Pos &, Executor &executor,
-                            bool /*handle_errors*/) {
-  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
-
-  /* TODO FIXME */
-  logc.Fatal<Log::kSys>({{"Not implemented yet"}});
-  throw std::exception(); // unreachable
-}
-
 template <typename T>
 std::optional<const T *>
-find_statement(const std::string &name, const utils::Pos &, Executor &executor,
-               const std::string &message_not_found,
-               const std::string &message_different_statement,
-               bool handle_errors) {
+FindStatement(const std::string &name, const utils::Pos &, Executor &executor,
+              const std::string &message_not_found,
+              const std::string &message_different_statement,
+              bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
   const auto maybe_any_statement = executor.state<names::NameTree>().find(name);
@@ -98,32 +74,32 @@ find_statement(const std::string &name, const utils::Pos &, Executor &executor,
 }
 
 std::optional<const nodes::TypeDefinition *>
-find_type_definition(const std::string &name, const utils::Pos &pos,
-                     Executor &executor, bool handle_errors) {
+FindTypeDefinition(const std::string &name, const utils::Pos &pos,
+                   Executor &executor, bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
-  return find_statement<nodes::TypeDefinition>(
+  return FindStatement<nodes::TypeDefinition>(
       name, pos, executor, "No type definition found in name tree",
       "Node in name tree is not type definition", handle_errors);
 }
 
 std::optional<const nodes::FunctionDefinition *>
-find_name_definition(const std::string &name, const utils::Pos &pos,
-                     Executor &executor, bool handle_errors) {
+FindNameDefinition(const std::string &name, const utils::Pos &pos,
+                   Executor &executor, bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
-  return find_statement<nodes::FunctionDefinition>(
+  return FindStatement<nodes::FunctionDefinition>(
       name, pos, executor, "No name definition found in name tree",
       "Node in name tree is not name definition", handle_errors);
 }
 
-std::optional<nodes::Type> unfold_user_defined_type(nodes::Type type,
-                                                    const utils::Pos &pos,
-                                                    Executor &executor,
-                                                    bool handle_errors) {
+std::optional<nodes::Type> UnfoldUserDefinedType(nodes::Type type,
+                                                 const utils::Pos &pos,
+                                                 Executor &executor,
+                                                 bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
-  const auto maybe_type_definition = find_type_definition(
+  const auto maybe_type_definition = FindTypeDefinition(
       type.get()->get_name()->value, pos, executor, handle_errors);
 
   if (!maybe_type_definition.has_value()) {
@@ -146,11 +122,9 @@ std::optional<nodes::Type> unfold_user_defined_type(nodes::Type type,
   return maybe_type_definition.value()->type.value();
 }
 
-std::optional<nodes::Type> get_field_type_by_name(nodes::Type type,
-                                                  const std::string &field,
-                                                  const utils::Pos &pos,
-                                                  Executor &executor,
-                                                  bool handle_errors) {
+std::optional<nodes::Type>
+FieldTypeByName(nodes::Type type, const std::string &field,
+                const utils::Pos &pos, Executor &executor, bool handle_errors) {
   Log::Context logc(executor.log(), Log::Area::kTypeCheck);
 
   switch (type.get()->to_builtin()) {
@@ -170,13 +144,13 @@ std::optional<nodes::Type> get_field_type_by_name(nodes::Type type,
 
     // remove recursion ??
     const auto maybe_internal_type =
-        unfold_user_defined_type(type, pos, executor, handle_errors);
+        UnfoldUserDefinedType(type, pos, executor, handle_errors);
     if (!maybe_internal_type.has_value()) {
       return std::nullopt;
     }
 
-    return get_field_type_by_name(maybe_internal_type.value(), field, pos,
-                                  executor, handle_errors);
+    return FieldTypeByName(maybe_internal_type.value(), field, pos, executor,
+                           handle_errors);
   }
   default: // variant, function, optional, result, error (TODO: add message
            // field?), array (TODO: add length field ?), basic types
@@ -191,16 +165,4 @@ std::optional<nodes::Type> get_field_type_by_name(nodes::Type type,
   }
 }
 
-// FIXME: replace with direct log calls
-void type_check_error(const std::string &message, const utils::Pos &,
-                      Executor &executor, bool handle_error) {
-  Log::Context logc(executor.log(), Log::Area::kTypeCheck);
-
-  if (!handle_error) {
-    return;
-  }
-
-  logc.Error<Log::kProc>({{message}} /* TODO: use pos */);
-}
-
 } // namespace type_check
diff --git a/lang/utils/include/counter.hpp b/lang/utils/include/counter.hpp
index a2457c9..793d691 100644
--- a/lang/utils/include/counter.hpp
+++ b/lang/utils/include/counter.hpp
@@ -3,6 +3,8 @@
 #include "core_utils.hpp"
 #include "log.hpp"
 
+// TODO: use Counter for Tasks
+
 namespace core {
 
 template <typename Tag>
diff --git a/lang/utils/src/log.cpp b/lang/utils/src/log.cpp
index 5ab6f2f..2b20ae2 100644
--- a/lang/utils/src/log.cpp
+++ b/lang/utils/src/log.cpp
@@ -7,8 +7,9 @@
 namespace utils {
 
 std::string to_string(const std::source_location &source_location) {
-  return std::format("{}:{} {}", source_location.file_name(),
-                     source_location.line(), source_location.function_name());
+  return std::format(
+      "{}:{}" /* {}"*/, source_location.file_name(),
+      source_location.line() /*, source_location.function_name()*/);
 }
 
 std::string to_string(Pos::Point point) {