Fix expressions involving a variable (or property) of type number/string wrongly rejected when an operator like + was used after them (#6467)

* For example, "Your score is " + NumberVariable + " points" was rejected, because the second operator type was not properly inferred. * If something does not work in your game anymore, double check if your expressions in the events sheets are not underlined in red. Sometimes, adding `ToString(` or `ToNumber(` around it might be required.
2025-10-15 10:19:04 +00:00 · 2024-03-28 09:42:41 +01:00
parent 0dd4650aae
commit 7e8b44af2e
3 changed files with 478 additions and 6 deletions
--- a/Core/GDCore/IDE/Events/ExpressionValidator.h
+++ b/Core/GDCore/IDE/Events/ExpressionValidator.h
@@ -86,8 +86,10 @@ class GD_CORE_API ExpressionValidator : public ExpressionParser2NodeWorker {
  void OnVisitOperatorNode(OperatorNode& node) override {
    ReportAnyError(node);

+    // The "required" type ("parentType")  will be used when visiting the first operand.
+    // Note that it may be refined thanks to this first operand (see later).
    node.leftHandSide->Visit(*this);
-    const Type leftType = childType;
+    const Type leftType = childType; // Store the type of the first operand.

    if (leftType == Type::Number) {
      if (node.op == ' ') {
@@ -120,15 +122,19 @@ class GD_CORE_API ExpressionValidator : public ExpressionParser2NodeWorker {
            node.rightHandSide->location);
    }

-    parentType = leftType;
+    // The "required" type ("parentType") of the second operator is decided by:
+    // - the parent type. Unless it can (`number|string`) or should (`unknown`) be refined, then:
+    // - the first operand.
+    parentType = ShouldTypeBeRefined(parentType) ? leftType : parentType;
    node.rightHandSide->Visit(*this);
    const Type rightType = childType;

-    // The type is decided by the first operand, unless it can (`number|string`)
-    // or should (`unknown`) be refined, in which case we go for the right
-    // operand (which got visited knowing the type of the first operand, so it's
+    // The type of the overall operator ("childType") is decided by:
+    // - the parent type. Unless it can (`number|string`) or should (`unknown`) be refined, then:
+    // - the first operand. Unless it can (`number|string`) or should (`unknown`) be refined, then:
+    // - the right operand (which got visited knowing the type of the first operand, so it's
    // equal or strictly more precise than the left operand).
-    childType = (leftType == Type::Unknown || leftType == Type::NumberOrString) ? leftType : rightType;
+    childType = ShouldTypeBeRefined(parentType) ? (ShouldTypeBeRefined(leftType) ? leftType : rightType) : parentType;
  }
  void OnVisitUnaryOperatorNode(UnaryOperatorNode& node) override {
    ReportAnyError(node);
@@ -395,6 +401,10 @@ class GD_CORE_API ExpressionValidator : public ExpressionParser2NodeWorker {
    }
  }

+  static bool ShouldTypeBeRefined(Type type) {
+    return (type == Type::Unknown || type == Type::NumberOrString);
+  }
+
  static Type StringToType(const gd::String &type);
  static const gd::String &TypeToString(Type type);
  static const gd::String unknownTypeString;
--- a/Core/tests/ExpressionCodeGenerator.cpp
+++ b/Core/tests/ExpressionCodeGenerator.cpp
@@ -30,6 +30,21 @@ TEST_CASE("ExpressionCodeGenerator", "[common][events]") {
  layout1.GetVariables().InsertNew("MySceneBooleanVariable").SetBool(true);
  layout1.GetVariables().InsertNew("MySceneStructureVariable").GetChild("MyChild");
  layout1.GetVariables().InsertNew("MySceneStructureVariable2").GetChild("MyChild");
+  layout1.GetVariables().InsertNew("MySceneEmptyArrayVariable").CastTo(gd::Variable::Type::Array);
+  {
+    auto& variable = layout1.GetVariables().InsertNew("MySceneNumberArrayVariable");
+    variable.CastTo(gd::Variable::Type::Array);
+    variable.PushNew().SetValue(1);
+    variable.PushNew().SetValue(2);
+    variable.PushNew().SetValue(3);
+  }
+  {
+    auto& variable = layout1.GetVariables().InsertNew("MySceneStringArrayVariable");
+    variable.CastTo(gd::Variable::Type::Array);
+    variable.PushNew().SetString("1");
+    variable.PushNew().SetString("2");
+    variable.PushNew().SetString("3");
+  }

  auto &mySpriteObject = layout1.InsertNewObject(project, "MyExtension::Sprite", "MySpriteObject", 0);
  mySpriteObject.GetVariables().InsertNew("MyNumberVariable").SetValue(123);
@@ -1295,6 +1310,221 @@ TEST_CASE("ExpressionCodeGenerator", "[common][events]") {
      REQUIRE(output == "getVariableForObject(MySpriteObject, MyOtherSpriteObject).getChild(\"Child\").getChild(\"Grandchild\")");
    }
  }
+  SECTION("Type conversions (valid operators with variables having different types than the expression)") {
+    SECTION("Expression/parent type is 'string'") {
+      {
+        auto node =
+          parser.ParseExpression("\"You have \" + MySceneVariable + \" points\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "\"You have \" + getLayoutVariable(MySceneVariable).getAsString() + \" points\"");
+      }
+      {
+        auto node =
+          parser.ParseExpression("MySceneVariable + MySceneStringVariable");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "getLayoutVariable(MySceneVariable).getAsString() + getLayoutVariable(MySceneStringVariable).getAsString()");
+      }
+    }
+    SECTION("Expression/parent type is 'string' (with an unknown variable)") {
+      {
+        auto node =
+          parser.ParseExpression("\"You have \" + MySceneStructureVariable.MyChild.CantKnownTheTypeSoStayGeneric + \" points\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "\"You have \" + getLayoutVariable(MySceneStructureVariable).getChild(\"MyChild\").getChild(\"CantKnownTheTypeSoStayGeneric\").getAsString() + \" points\"");
+      }
+    }
+    SECTION("Expression/parent type is 'string' (2 number variables)") {
+      {
+        auto node =
+          parser.ParseExpression("MySceneVariable + MySceneVariable2 + \"world\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "getLayoutVariable(MySceneVariable).getAsString() + getLayoutVariable(MySceneVariable2).getAsString() + \"world\"");
+      }
+      {
+        auto node =
+          parser.ParseExpression("MySceneVariable + MySceneVariable2 + MySceneStringVariable");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "getLayoutVariable(MySceneVariable).getAsString() + getLayoutVariable(MySceneVariable2).getAsString() + getLayoutVariable(MySceneStringVariable).getAsString()");
+      }
+    }
+    SECTION("Expression/parent type is 'string' (array variable)") {
+      {
+        auto node =
+          parser.ParseExpression("\"hello\" + MySceneNumberArrayVariable[2] + \"world\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "\"hello\" + getLayoutVariable(MySceneNumberArrayVariable).getChild(2).getAsString() + \"world\"");
+      }
+      {
+        auto node =
+          parser.ParseExpression("\"hello\" + MySceneEmptyArrayVariable[2] + \"world\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "\"hello\" + getLayoutVariable(MySceneEmptyArrayVariable).getChild(2).getAsString() + \"world\"");
+      }
+    }
+
+    SECTION("Expression/parent type is 'number'") {
+      {
+        auto node =
+          parser.ParseExpression("123 + MySceneVariable + 456");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "123 + getLayoutVariable(MySceneVariable).getAsNumber() + 456");
+      }
+      {
+        auto node =
+          parser.ParseExpression("MySceneStringVariable + MySceneVariable");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "getLayoutVariable(MySceneStringVariable).getAsNumber() + getLayoutVariable(MySceneVariable).getAsNumber()");
+      }
+    }
+    SECTION("Expression/parent type is 'string' (with an unknown variable)") {
+      {
+        auto node =
+          parser.ParseExpression("123 + MySceneStructureVariable.MyChild.CantKnownTheTypeSoStayGeneric + 456");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "123 + getLayoutVariable(MySceneStructureVariable).getChild(\"MyChild\").getChild(\"CantKnownTheTypeSoStayGeneric\").getAsNumber() + 456");
+      }
+    }
+    SECTION("Expression/parent type is 'number' (2 string variables)") {
+      {
+        auto node =
+          parser.ParseExpression("MySceneStringVariable + MySceneStringVariable + 456");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "getLayoutVariable(MySceneStringVariable).getAsNumber() + getLayoutVariable(MySceneStringVariable).getAsNumber() + 456");
+      }
+      {
+        auto node =
+          parser.ParseExpression("MySceneStringVariable + MySceneStringVariable + MySceneVariable");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "getLayoutVariable(MySceneStringVariable).getAsNumber() + getLayoutVariable(MySceneStringVariable).getAsNumber() + getLayoutVariable(MySceneVariable).getAsNumber()");
+      }
+    }
+    SECTION("Expression/parent type is 'number' (array variable)") {
+      {
+        auto node =
+          parser.ParseExpression("123 + MySceneNumberArrayVariable[2] + 456");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "123 + getLayoutVariable(MySceneNumberArrayVariable).getChild(2).getAsNumber() + 456");
+      }
+      {
+        auto node =
+          parser.ParseExpression("123 + MySceneEmptyArrayVariable[2] + 456");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("number",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "123 + getLayoutVariable(MySceneEmptyArrayVariable).getChild(2).getAsNumber() + 456");
+      }
+    }
+
+
+    SECTION("Multiple type conversions in sub expressions or same expression") {
+      {
+        auto node =
+          parser.ParseExpression("\"hello\" + MySceneNumberArrayVariable[2 + MySceneStringVariable] + \"world\" + MySceneVariable + \"world 2\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "\"hello\" + getLayoutVariable(MySceneNumberArrayVariable).getChild(2 + getLayoutVariable(MySceneStringVariable).getAsNumber()).getAsString() + \"world\" + getLayoutVariable(MySceneVariable).getAsString() + \"world 2\"");
+      }
+      {
+        auto node =
+          parser.ParseExpression("\"hello\" + MySceneNumberArrayVariable[\"foo\" + MySceneVariable + \"bar\"] + \"world\" + MySceneVariable + \"world 2\"");
+        gd::ExpressionCodeGenerator expressionCodeGenerator("string",
+                                                            "",
+                                                            codeGenerator,
+                                                            context);
+
+        REQUIRE(node);
+        node->Visit(expressionCodeGenerator);
+        REQUIRE(expressionCodeGenerator.GetOutput() == "\"hello\" + getLayoutVariable(MySceneNumberArrayVariable).getChild(\"foo\" + getLayoutVariable(MySceneVariable).getAsString() + \"bar\").getAsString() + \"world\" + getLayoutVariable(MySceneVariable).getAsString() + \"world 2\"");
+      }
+    }
+  }
  SECTION("Mixed test (1)") {
    {
      auto node = parser.ParseExpression("-+-MyExtension::MouseX(,)");
--- a/Core/tests/ExpressionParser2.cpp
+++ b/Core/tests/ExpressionParser2.cpp
@@ -2954,6 +2954,238 @@ TEST_CASE("ExpressionParser2", "[common][events]") {
    }
  }

+  SECTION("Valid operators with variables having different types than the expression") {
+    SECTION("Expression/parent type is 'string'") {
+      // A trivial test (everything is a string).
+      {
+        auto node = parser.ParseExpression("\"You have \" + MySceneStringVariable + \" points\"");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "string");
+        node->Visit(validator);
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+      // A string concatenated with a number variable (will have to be casted to a string in code generation)
+      {
+        auto node = parser.ParseExpression("\"You have \" + MySceneNumberVariable");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "string");
+        node->Visit(validator);
+
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+      // A string concatenated with a number variable (will have to be casted to a string in code generation)
+      // and then with a string again.
+      {
+        auto node = parser.ParseExpression("\"You have \" + MySceneNumberVariable + \" points\"");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "string");
+        node->Visit(validator);
+
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+      // A string concatenated with an unknown variable (will have to be casted to a string in code generation)
+      // and then with a string again.
+      {
+        auto node = parser.ParseExpression("\"You have \" + MySceneStructureVariable.MyChild.CantKnownTheTypeSoStayGeneric + \" points\"");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "string");
+        node->Visit(validator);
+
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+    }
+    SECTION("Expression/parent type is 'number'") {
+      // A trivial test (everything is a string).
+      {
+        auto node = parser.ParseExpression("123 + MySceneNumberVariable + 456");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "number");
+        node->Visit(validator);
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+      // A number concatenated with a string variable (will have to be casted to a number in code generation)
+      {
+        auto node = parser.ParseExpression("123 + MySceneStringVariable");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "number");
+        node->Visit(validator);
+
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+      // A number concatenated with a string variable (will have to be casted to a number in code generation)
+      // and then with a number again.
+      {
+        auto node = parser.ParseExpression("123 + MySceneStringVariable + 456");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "number");
+        node->Visit(validator);
+
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+      // A number concatenated with an unknown variable (will have to be casted to a number in code generation)
+      // and then with a number again.
+      {
+        auto node = parser.ParseExpression("123 + MySceneStructureVariable.MyChild.CantKnownTheTypeSoStayGeneric + 456");
+        REQUIRE(node != nullptr);
+
+        gd::ExpressionValidator validator(platform, projectScopedContainers, "number");
+        node->Visit(validator);
+
+        REQUIRE(validator.GetFatalErrors().size() == 0);
+      }
+    }
+    SECTION("Expression/parent type is 'number|string'") {
+      SECTION("Expression/parent inferred type is 'string'") {
+        // A trivial test (everything is a string).
+        {
+          auto node = parser.ParseExpression("\"You have \" + MySceneStringVariable + \" points\"");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+        // A string concatenated with a number variable (will have to be casted to a string in code generation)
+        {
+          auto node = parser.ParseExpression("\"You have \" + MySceneNumberVariable");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+        // A string concatenated with a number variable (will have to be casted to a string in code generation)
+        // and then with a string again.
+        {
+          auto node = parser.ParseExpression("\"You have \" + MySceneNumberVariable + \" points\"");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+        // A string concatenated with an unknown variable (will have to be casted to a string in code generation)
+        // and then with a string again.
+        {
+          auto node = parser.ParseExpression("\"You have \" + MySceneStructureVariable.MyChild.CantKnownTheTypeSoStayGeneric + \" points\"");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+      }
+      SECTION("Expression/parent inferred type is 'number'") {
+        // A trivial test (everything is a string).
+        {
+          auto node = parser.ParseExpression("123 + MySceneNumberVariable + 456");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+        // A number concatenated with a string variable (will have to be casted to a number in code generation)
+        {
+          auto node = parser.ParseExpression("123 + MySceneStringVariable");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+        // A number concatenated with a string variable (will have to be casted to a number in code generation)
+        // and then with a number again.
+        {
+          auto node = parser.ParseExpression("123 + MySceneStringVariable + 456");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+        // A number concatenated with an unknown variable (will have to be casted to a number in code generation)
+        // and then with a number again.
+        {
+          auto node = parser.ParseExpression("123 + MySceneStructureVariable.MyChild.CantKnownTheTypeSoStayGeneric + 456");
+          REQUIRE(node != nullptr);
+
+          gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+          node->Visit(validator);
+
+          REQUIRE(validator.GetFatalErrors().size() == 0);
+        }
+      }
+    }
+  }
+
+  SECTION("Invalid operators with variables having different types than the expression") {
+    // Try to do a sum between numbers in a string expression
+    {
+      auto node = parser.ParseExpression("\"You have \" + MySceneNumberVariable + 2 + \" points\"");
+      REQUIRE(node != nullptr);
+
+      gd::ExpressionValidator validator(platform, projectScopedContainers, "string");
+      node->Visit(validator);
+
+      REQUIRE(validator.GetFatalErrors().size() == 1);
+      REQUIRE(validator.GetFatalErrors()[0]->GetMessage() == "You entered a number, but a text was expected (in quotes).");
+      REQUIRE(validator.GetFatalErrors()[0]->GetStartPosition() == 38);
+      REQUIRE(validator.GetFatalErrors()[0]->GetEndPosition() == 39);
+    }
+    // Try to do a sum between numbers in a number|string expression (that is inferred as a string with the first operand)
+    {
+      auto node = parser.ParseExpression("\"You have \" + MySceneNumberVariable + 2 + \" points\"");
+      REQUIRE(node != nullptr);
+
+      gd::ExpressionValidator validator(platform, projectScopedContainers, "string");
+      node->Visit(validator);
+
+      REQUIRE(validator.GetFatalErrors().size() == 1);
+      REQUIRE(validator.GetFatalErrors()[0]->GetMessage() == "You entered a number, but a text was expected (in quotes).");
+      REQUIRE(validator.GetFatalErrors()[0]->GetStartPosition() == 38);
+      REQUIRE(validator.GetFatalErrors()[0]->GetEndPosition() == 39);
+    }
+    // Try to do a string concatenation in a number expression
+    {
+      auto node = parser.ParseExpression("123 + MySceneStringVariable + \"hello\" + 456");
+      REQUIRE(node != nullptr);
+
+      gd::ExpressionValidator validator(platform, projectScopedContainers, "number");
+      node->Visit(validator);
+
+      REQUIRE(validator.GetFatalErrors().size() == 1);
+      REQUIRE(validator.GetFatalErrors()[0]->GetMessage() == "You entered a text, but a number was expected.");
+      REQUIRE(validator.GetFatalErrors()[0]->GetStartPosition() == 30);
+      REQUIRE(validator.GetFatalErrors()[0]->GetEndPosition() == 37);
+    }
+    // Try to do a string concatenation in a number|string expression (that is inferred as a number with the first operand)
+    {
+      auto node = parser.ParseExpression("123 + MySceneStringVariable + \"hello\" + 456");
+      REQUIRE(node != nullptr);
+
+      gd::ExpressionValidator validator(platform, projectScopedContainers, "number|string");
+      node->Visit(validator);
+
+      REQUIRE(validator.GetFatalErrors().size() == 1);
+      REQUIRE(validator.GetFatalErrors()[0]->GetMessage() == "You entered a text, but a number was expected.");
+      REQUIRE(validator.GetFatalErrors()[0]->GetStartPosition() == 30);
+      REQUIRE(validator.GetFatalErrors()[0]->GetEndPosition() == 37);
+    }
+  }
+
  SECTION("Valid function call with object variable") {
    {
      // Note that in this test we need to use an expression with "objectvar",