diff --git a/src/language/ast/ASTNodeAffectationExpressionBuilder.cpp b/src/language/ast/ASTNodeAffectationExpressionBuilder.cpp
index 3d9e58f07a0fc8ec1e9af130d886a2cf91aef407..884711c081ded349d32663f80180c06c4911bfba 100644
--- a/src/language/ast/ASTNodeAffectationExpressionBuilder.cpp
+++ b/src/language/ast/ASTNodeAffectationExpressionBuilder.cpp
@@ -2,8 +2,8 @@
 
 #include <algebra/TinyVector.hpp>
 #include <language/PEGGrammar.hpp>
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
 #include <language/node_processor/INodeProcessor.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 #include <language/utils/AffectationMangler.hpp>
 #include <language/utils/OperatorRepository.hpp>
 #include <language/utils/ParseError.hpp>
diff --git a/src/language/ast/ASTNodeBuiltinFunctionExpressionBuilder.cpp b/src/language/ast/ASTNodeBuiltinFunctionExpressionBuilder.cpp
index 6b1fe91ec1006600bf601c737719869497041e2b..731825c1fefa2df0be8d828249017ecb3bf555ee 100644
--- a/src/language/ast/ASTNodeBuiltinFunctionExpressionBuilder.cpp
+++ b/src/language/ast/ASTNodeBuiltinFunctionExpressionBuilder.cpp
@@ -2,8 +2,8 @@
 
 #include <language/PEGGrammar.hpp>
 #include <language/ast/ASTNodeDataTypeFlattener.hpp>
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
 #include <language/node_processor/BuiltinFunctionProcessor.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 #include <language/utils/ParseError.hpp>
 #include <language/utils/SymbolTable.hpp>
 
diff --git a/src/language/ast/ASTNodeDataTypeBuilder.cpp b/src/language/ast/ASTNodeDataTypeBuilder.cpp
index 038ab812739940df934a4e52201b7005a187a53f..018bc94f74160bfcd680df08ac9b2a08c54ba492 100644
--- a/src/language/ast/ASTNodeDataTypeBuilder.cpp
+++ b/src/language/ast/ASTNodeDataTypeBuilder.cpp
@@ -1,7 +1,7 @@
 #include <language/ast/ASTNodeDataTypeBuilder.hpp>
 
 #include <language/PEGGrammar.hpp>
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 #include <language/utils/BuiltinFunctionEmbedder.hpp>
 #include <language/utils/OperatorRepository.hpp>
 #include <language/utils/ParseError.hpp>
diff --git a/src/language/ast/ASTNodeFunctionExpressionBuilder.cpp b/src/language/ast/ASTNodeFunctionExpressionBuilder.cpp
index bb42f7d16380bec2d0eed71d9ad59c8dff7d8d68..0d00f1c82c091137bdb1b9ed143bfd1489a13432 100644
--- a/src/language/ast/ASTNodeFunctionExpressionBuilder.cpp
+++ b/src/language/ast/ASTNodeFunctionExpressionBuilder.cpp
@@ -2,10 +2,10 @@
 
 #include <language/PEGGrammar.hpp>
 #include <language/ast/ASTNodeDataTypeFlattener.hpp>
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
 #include <language/node_processor/FunctionProcessor.hpp>
 #include <language/node_processor/TupleToTinyMatrixProcessor.hpp>
 #include <language/node_processor/TupleToTinyVectorProcessor.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 #include <language/utils/FunctionTable.hpp>
 #include <language/utils/SymbolTable.hpp>
 #include <utils/Exceptions.hpp>
diff --git a/src/language/ast/ASTNodeListAffectationExpressionBuilder.cpp b/src/language/ast/ASTNodeListAffectationExpressionBuilder.cpp
index 9da8319fa5119fa22b3d6ce95e6e1e1084b401f2..d9ae87fd35539c33dcf05014cef9004e43607feb 100644
--- a/src/language/ast/ASTNodeListAffectationExpressionBuilder.cpp
+++ b/src/language/ast/ASTNodeListAffectationExpressionBuilder.cpp
@@ -2,8 +2,8 @@
 
 #include <language/PEGGrammar.hpp>
 #include <language/ast/ASTNodeDataTypeFlattener.hpp>
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
 #include <language/node_processor/AffectationProcessor.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 #include <language/utils/ParseError.hpp>
 
 template <typename OperatorT>
diff --git a/src/language/ast/CMakeLists.txt b/src/language/ast/CMakeLists.txt
index 458690fbd4fa341b257fcfe997e489048d1f961c..a901d7c09679c37d54420f51d347537fe5e18aef 100644
--- a/src/language/ast/CMakeLists.txt
+++ b/src/language/ast/CMakeLists.txt
@@ -9,7 +9,6 @@ add_library(PugsLanguageAST
   ASTNodeBuiltinFunctionExpressionBuilder.cpp
   ASTNodeDataTypeBuilder.cpp
   ASTNodeDataTypeChecker.cpp
-#  ASTNodeDataType.cpp
   ASTNodeDataTypeFlattener.cpp
   ASTNodeDeclarationToAffectationConverter.cpp
   ASTNodeEmptyBlockCleaner.cpp
@@ -19,7 +18,6 @@ add_library(PugsLanguageAST
   ASTNodeIncDecExpressionBuilder.cpp
   ASTNodeJumpPlacementChecker.cpp
   ASTNodeListAffectationExpressionBuilder.cpp
-  ASTNodeNaturalConversionChecker.cpp
   ASTNodeUnaryOperatorExpressionBuilder.cpp
   ASTSymbolInitializationChecker.cpp
   ASTSymbolTableBuilder.cpp
diff --git a/src/language/node_processor/AffectationProcessor.hpp b/src/language/node_processor/AffectationProcessor.hpp
index 83e721786414628ab97990405c3335e0fa81846d..cf3f5f65949d571f9cc2b48c402827680c4e9e0e 100644
--- a/src/language/node_processor/AffectationProcessor.hpp
+++ b/src/language/node_processor/AffectationProcessor.hpp
@@ -699,7 +699,7 @@ class AffectationToTupleFromListProcessor final : public INodeProcessor
                     [&](auto&& Ajk) {
                       using Ti = std::decay_t<decltype(Ajk)>;
                       if constexpr (std::is_convertible_v<Ti, typename ValueT::data_type>) {
-                        A(k, k) = Ajk;
+                        A(j, k) = Ajk;
                       } else {
                         // LCOV_EXCL_START
                         throw ParseError("unexpected error: unexpected right hand side type in affectation",
@@ -710,7 +710,7 @@ class AffectationToTupleFromListProcessor final : public INodeProcessor
                     child_value[l]);
                 }
               }
-            } else if constexpr (std::is_same_v<T, int64_t>) {
+            } else if constexpr (std::is_arithmetic_v<T>) {
               if constexpr (std::is_same_v<ValueT, TinyMatrix<1>>) {
                 tuple_value[i](0, 0) = child_value;
               } else {
diff --git a/src/language/ast/ASTNodeNaturalConversionChecker.cpp b/src/language/utils/ASTNodeNaturalConversionChecker.cpp
similarity index 94%
rename from src/language/ast/ASTNodeNaturalConversionChecker.cpp
rename to src/language/utils/ASTNodeNaturalConversionChecker.cpp
index eca854ac598856af53b7f3fd2e76e8bd8e0c3895..7a1a30c9ca5d582aea9a47458bd95c93ab80465a 100644
--- a/src/language/ast/ASTNodeNaturalConversionChecker.cpp
+++ b/src/language/utils/ASTNodeNaturalConversionChecker.cpp
@@ -1,4 +1,4 @@
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 
 #include <language/PEGGrammar.hpp>
 #include <language/utils/ParseError.hpp>
@@ -25,7 +25,9 @@ ASTNodeNaturalConversionChecker<RToR1Conversion>::_checkIsNaturalTypeConversion(
                   << rang::fg::reset;
 
     if ((data_type == ASTNodeDataType::undefined_t) or (target_data_type == ASTNodeDataType::undefined_t)) {
+      // LCOV_EXCL_START
       throw UnexpectedError(error_message.str());
+      // LCOV_EXCL_STOP
     } else {
       throw ParseError(error_message.str(), node.begin());
     }
@@ -129,8 +131,10 @@ ASTNodeNaturalConversionChecker<RToR1Conversion>::_checkIsNaturalExpressionConve
     if (node.m_data_type == ASTNodeDataType::tuple_t) {
       this->_checkIsNaturalExpressionConversion(node, data_type.contentType(), target_content_type);
     } else if (node.m_data_type == ASTNodeDataType::list_t) {
-      if ((target_data_type.contentType() == ASTNodeDataType::vector_t) and
-          (target_data_type.contentType().dimension() == 1)) {
+      if (((target_data_type.contentType() == ASTNodeDataType::vector_t) and
+           (target_data_type.contentType().dimension() == 1)) or
+          ((target_data_type.contentType() == ASTNodeDataType::matrix_t) and
+           (target_data_type.contentType().nbRows() == 1) and (target_data_type.contentType().nbColumns() == 1))) {
         for (const auto& child : node.children) {
           if (not isNaturalConversion(child->m_data_type, target_data_type)) {
             this->_checkIsNaturalExpressionConversion(*child, child->m_data_type,
diff --git a/src/language/ast/ASTNodeNaturalConversionChecker.hpp b/src/language/utils/ASTNodeNaturalConversionChecker.hpp
similarity index 100%
rename from src/language/ast/ASTNodeNaturalConversionChecker.hpp
rename to src/language/utils/ASTNodeNaturalConversionChecker.hpp
diff --git a/src/language/utils/AffectationProcessorBuilder.hpp b/src/language/utils/AffectationProcessorBuilder.hpp
index 0668b566b925a8d23621a962b5c9f70b9c9eb79a..8d11599a01c67566e0f88fcb34cad581bc76de45 100644
--- a/src/language/utils/AffectationProcessorBuilder.hpp
+++ b/src/language/utils/AffectationProcessorBuilder.hpp
@@ -4,6 +4,7 @@
 #include <algebra/TinyVector.hpp>
 #include <language/PEGGrammar.hpp>
 #include <language/node_processor/AffectationProcessor.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 #include <language/utils/IAffectationProcessorBuilder.hpp>
 
 #include <type_traits>
@@ -50,6 +51,7 @@ class AffectationToTupleFromListProcessorBuilder final : public IAffectationProc
   std::unique_ptr<INodeProcessor>
   getNodeProcessor(ASTNode& node) const
   {
+    ASTNodeNaturalConversionChecker(*node.children[1], node.children[0]->m_data_type);
     return std::make_unique<AffectationToTupleFromListProcessor<ValueT>>(node);
   }
 };
diff --git a/src/language/utils/CMakeLists.txt b/src/language/utils/CMakeLists.txt
index eb24e0d935f4d351adf90fd35baf372eaacd1fca..22c0ae52f184a7f18d852057cbe9b0616f1905e3 100644
--- a/src/language/utils/CMakeLists.txt
+++ b/src/language/utils/CMakeLists.txt
@@ -11,6 +11,7 @@ add_library(PugsLanguageUtils
   ASTDotPrinter.cpp
   ASTExecutionInfo.cpp
   ASTNodeDataType.cpp
+  ASTNodeNaturalConversionChecker.cpp
   ASTPrinter.cpp
   BinaryOperatorRegisterForB.cpp
   BinaryOperatorRegisterForN.cpp
diff --git a/tests/test_ASTNodeNaturalConversionChecker.cpp b/tests/test_ASTNodeNaturalConversionChecker.cpp
index ed1e834c016ac9e7c6f3d796a7018ce290aa9324..7bf6e8b890b391b92d05f0f2d39c0d9387d24eb7 100644
--- a/tests/test_ASTNodeNaturalConversionChecker.cpp
+++ b/tests/test_ASTNodeNaturalConversionChecker.cpp
@@ -2,7 +2,7 @@
 
 #include <language/PEGGrammar.hpp>
 #include <language/ast/ASTNode.hpp>
-#include <language/ast/ASTNodeNaturalConversionChecker.hpp>
+#include <language/utils/ASTNodeNaturalConversionChecker.hpp>
 
 namespace language
 {