diff --git a/src/execute_visitor.cpp b/src/execute_visitor.cpp
index 1b0e278..ff2a219 100644
--- a/src/execute_visitor.cpp
+++ b/src/execute_visitor.cpp
@@ -603,14 +603,32 @@ void ExecuteVisitor::Visit(FunctionCallExpression* node) {
   size_t index_shift = (node->is_method_of_first_argument_ ? 1 : 0);
 
   // handle arguments
-  for (size_t i = index_shift; i < node->arguments.size(); ++i) {
-    Visitor::Visit(node->arguments[i].second);
+  bool all_arguments = function_declaration->type->types.size() <= node->arguments.size() + 1 - index_shift;
 
-    // function arguments can't  be changed inside function
-    current_value_ = context_manager_.ToModifiedValue(current_value_, utils::ValueType::Const);
-    if (!context_manager_.DefineVariable(function_definition->definition->arguments[i - index_shift],
-                                         current_value_)) {
-      error_handling::HandleRuntimeError("Variable redefinition (function argument)", node->base);
+  {
+    size_t i = index_shift; // function call argument id
+    size_t j = 0; // actual argument id
+    for (; j + 1 < function_declaration->type->types.size(); ++j) { // last type in function declaration is return type
+      if (!all_arguments && i < node->arguments.size() && !node->arguments[i].first.has_value()) {
+        error_handling::HandleRuntimeError("Function call argument has no annotation (in function with part of arguments)", node->base);
+      }
+
+      if (i < node->arguments.size() && (all_arguments || (function_declaration->type->types[j].first.has_value() && function_declaration->type->types[j].first.value() == node->arguments[i].first.value()))) {
+        Visitor::Visit(node->arguments[i].second);
+        ++i;
+
+        // function arguments can't be changed inside function
+        current_value_ = context_manager_.ToModifiedValue(current_value_, utils::ValueType::Const);
+      } else {
+        current_value_ = context_manager_.AddValue(info::value::OptionalValue(std::nullopt,
+                                                                              context_manager_.GetValueManager()),
+                                                   utils::ValueType::Const);
+      }
+
+      if (!context_manager_.DefineVariable(function_definition->definition->arguments[j],
+                                           current_value_)) {
+        error_handling::HandleRuntimeError("Variable redefinition (function argument)", node->base);
+      }
     }
   }
 
diff --git a/src/type_check_visitor.cpp b/src/type_check_visitor.cpp
index 66faced..6b676d9 100644
--- a/src/type_check_visitor.cpp
+++ b/src/type_check_visitor.cpp
@@ -794,10 +794,11 @@ void TypeCheckVisitor::Visit(FunctionCallExpression* node) {
 
   // check & collect parmeters
   if (function_declaration->parameters.size() != node->parameters.size()) {
-    if (node->parameters.size() != 0) {
+    // if (node->parameters.size() != 0) {
       error_handling::HandleTypecheckError("Mismatched parameter count in function call expression", node->base);
-    }
-    deduce_parameters = true;
+    // }
+    // deduce_parameters = true;
+    // TODO: paramters deduction
   }
   for (size_t i = 0; i < node->parameters.size(); ++i) {
     Visit(node->parameters[i].get());
@@ -823,25 +824,66 @@ void TypeCheckVisitor::Visit(FunctionCallExpression* node) {
   size_t index_shift = (node->is_method_of_first_argument_ ? 1 : 0);
 
   // check arguments
-  if (function_declaration->type->types.size() != node->arguments.size() + 1 - index_shift) {
+  if (function_declaration->type->types.size() < node->arguments.size() + 1 - index_shift) {
     error_handling::HandleTypecheckError("Mismatched argument count in function call expression", node->base);
   }
 
-  for (size_t i = index_shift; i < node->arguments.size(); ++i) {
-    Visit(function_declaration->type->types[i - index_shift].second.get());
-    utils::IdType argument_type = TypeInContext(current_type_, context);
+  bool all_arguments = function_declaration->type->types.size() <= node->arguments.size() + 1 - index_shift;
 
-    if (node->arguments[i].first.has_value()) {
-      if (!function_declaration->type->types[i - index_shift].first.has_value()) {
-        error_handling::HandleTypecheckError("Declared argument has no annotation (argument " + std::to_string(i - index_shift + 1) + ")", node->base);
-      } else if (node->arguments[i].first.value() != function_declaration->type->types[i - index_shift].first.value()) {
-        error_handling::HandleTypecheckError("Wrong argument annotation (argument " + std::to_string(i - index_shift + 1) + ")", node->base);
+  {
+    size_t i = index_shift; // function call argument id
+    size_t j = 0; // actual argument id
+    for (; i < node->arguments.size() && j + 1 < function_declaration->type->types.size(); ++j)  { // last type in function declaration is return type
+      if (!all_arguments) {
+        if (!node->arguments[i].first.has_value()) { // function calls with part of arguments should have annotations for all arguments
+          error_handling::HandleTypecheckError("Not all arguments annotated in function call expression with part of arguments (argument " + std::to_string(j + 1) + ")", node->base);
+        }
+
+        if (!function_declaration->type->types[j].first.has_value() || function_declaration->type->types[j].first.value() != node->arguments[i].first.value()) {
+          if (!function_declaration->type->types[j].second->references.empty() ||
+              !std::holds_alternative<std::unique_ptr<TypeExpression>>(function_declaration->type->types[j].second->type) ||
+              !std::get<std::unique_ptr<TypeExpression>>(function_declaration->type->types[j].second->type)->is_optional
+          ) {
+            // TODO: make separated OptionalType ??
+            error_handling::HandleTypecheckError("All missed arguments should be optionals in function call expression with part of arguments (argument " + std::to_string(j + 1) + ")", node->base);
+          }
+          continue;
+        }
       }
+
+      Visit(function_declaration->type->types[j].second.get());
+      utils::IdType argument_type = TypeInContext(current_type_, context);
+
+      if (node->arguments[i].first.has_value()) {
+        if (!function_declaration->type->types[j].first.has_value()) {
+          error_handling::HandleTypecheckError("Declared argument has no annotation (argument " + std::to_string(j + 1) + ")", node->base);
+        } else if (node->arguments[i].first.value() != function_declaration->type->types[j].first.value()) {
+          error_handling::HandleTypecheckError("Wrong argument annotation (argument " + std::to_string(j + 1) + ")", node->base);
+        }
+      }
+
+      Visitor::Visit(node->arguments[i].second);
+      if (!context_manager_.AddValueRequirement(current_type_, argument_type)) {
+        error_handling::HandleTypecheckError("Wrong argument type (argument " + std::to_string(j + 1) + ")", node->base);
+      }
+
+      ++i;
     }
 
-    Visitor::Visit(node->arguments[i].second);
-    if (!context_manager_.AddValueRequirement(current_type_, argument_type)) {
-      error_handling::HandleTypecheckError("Wrong argument type (argument " + std::to_string(i - index_shift + 1) + ")", node->base);
+    if (i < node->arguments.size()) {
+      error_handling::HandleTypecheckError("More arguments then needed in function call expression", node->base);
+    }
+
+    if (j + 1 < function_declaration->type->types.size()) { // last type is return type
+      for (; j + 1 < function_declaration->type->types.size(); ++j) {
+        if (!function_declaration->type->types[j].second->references.empty() ||
+            !std::holds_alternative<std::unique_ptr<TypeExpression>>(function_declaration->type->types[j].second->type) ||
+            !std::get<std::unique_ptr<TypeExpression>>(function_declaration->type->types[j].second->type)->is_optional
+        ) {
+          // TODO: make separated OptionalType ??
+          error_handling::HandleTypecheckError("All missed arguments should be optionals in function call expression with part of arguments (after last argument)", node->base);
+        }
+      }
     }
   }
 
diff --git a/tests/test_code.lang b/tests/test_code.lang
index 27d0eb8..e963ab7 100644
--- a/tests/test_code.lang
+++ b/tests/test_code.lang
@@ -213,9 +213,15 @@ def ( -- ) : begin end = {
 decl scan-int : -> \int
 def scan-int = \int..read: (\io..scan:)
 
-decl print-int : ::x \int -> \unit
+decl print-int : \int -> \unit
 def print-int : x = \io..print: (x..show:)
 
+decl print-int-with-comment : ::i \int -> \string? -> \unit
+def print-int-with-comment : i maybe-comment = {
+  ; \io..print: (i..show:)
+  var comment? = maybe-comment in \io..print: comment
+}
+
 decl scan-anything 'a[#read] : -> 'a
 def scan-anything = 'a..read: (\io..scan:)
 
@@ -272,7 +278,7 @@ exec main {
 
   ; print-anything:[int] n
 
-  ; print-int: ::x 123
+  ; print-int-with-comment: ::i 123
 
   var & a & b & c = scan-three-t:
   ; \io..print: b