Merge pull request #26573 from godotengine/revert-26562-gdscript-no-implicit-cast

Revert "Forbid implicit type conversion in GDScript"

4 files changed, 110 insertions, 16 deletions

diff --git a/modules/gdscript/gdscript_function.cpp b/modules/gdscript/gdscript_function.cpp
index b2757f1b0b..cff9ba55b8 100644
--- a/modules/gdscript/gdscript_function.cpp
+++ b/modules/gdscript/gdscript_function.cpp
@@ -328,8 +328,8 @@ Variant GDScriptFunction::call(GDScriptInstance *p_instance, const Variant **p_a
 						continue;
 					}
 
-					if (!argument_types[i].is_type(*p_args[i])) {
-						if (argument_types[i].is_type(Variant())) {
+					if (!argument_types[i].is_type(*p_args[i], true)) {
+						if (argument_types[i].is_type(Variant(), true)) {
 							memnew_placement(&stack[i], Variant);
 							continue;
 						} else {
@@ -339,7 +339,12 @@ Variant GDScriptFunction::call(GDScriptInstance *p_instance, const Variant **p_a
 							return Variant();
 						}
 					}
-					memnew_placement(&stack[i], Variant(*p_args[i]));
+					if (argument_types[i].kind == GDScriptDataType::BUILTIN) {
+						Variant arg = Variant::construct(argument_types[i].builtin_type, &p_args[i], 1, r_err);
+						memnew_placement(&stack[i], Variant(arg));
+					} else {
+						memnew_placement(&stack[i], Variant(*p_args[i]));
+					}
 				}
 				for (int i = p_argcount; i < _stack_size; i++) {
 					memnew_placement(&stack[i], Variant);
diff --git a/modules/gdscript/gdscript_function.h b/modules/gdscript/gdscript_function.h
index 34fc51e92a..cefc28d77f 100644
--- a/modules/gdscript/gdscript_function.h
+++ b/modules/gdscript/gdscript_function.h
@@ -55,7 +55,7 @@ struct GDScriptDataType {
 	StringName native_type;
 	Ref<Script> script_type;
 
-	bool is_type(const Variant &p_variant) const {
+	bool is_type(const Variant &p_variant, bool p_allow_implicit_conversion = false) const {
 		if (!has_type) return true; // Can't type check
 
 		switch (kind) {
@@ -63,7 +63,11 @@ struct GDScriptDataType {
 				break;
 			case BUILTIN: {
 				Variant::Type var_type = p_variant.get_type();
-				return builtin_type == var_type;
+				bool valid = builtin_type == var_type;
+				if (!valid && p_allow_implicit_conversion) {
+					valid = Variant::can_convert_strict(var_type, builtin_type);
+				}
+				return valid;
 			} break;
 			case NATIVE: {
 				if (p_variant.get_type() == Variant::NIL) {
diff --git a/modules/gdscript/gdscript_parser.cpp b/modules/gdscript/gdscript_parser.cpp
index 687bf40cdd..5619729c13 100644
--- a/modules/gdscript/gdscript_parser.cpp
+++ b/modules/gdscript/gdscript_parser.cpp
@@ -5801,7 +5801,7 @@ Variant::Operator GDScriptParser::_get_variant_operation(const OperatorNode::Ope
 	}
 }
 
-bool GDScriptParser::_is_type_compatible(const DataType &p_container, const DataType &p_expression) const {
+bool GDScriptParser::_is_type_compatible(const DataType &p_container, const DataType &p_expression, bool p_allow_implicit_conversion) const {
 	// Ignore for completion
 	if (!check_types || for_completion) {
 		return true;
@@ -5817,6 +5817,9 @@ bool GDScriptParser::_is_type_compatible(const DataType &p_container, const Data
 
 	if (p_container.kind == DataType::BUILTIN && p_expression.kind == DataType::BUILTIN) {
 		bool valid = p_container.builtin_type == p_expression.builtin_type;
+		if (p_allow_implicit_conversion) {
+			valid = valid || Variant::can_convert_strict(p_expression.builtin_type, p_container.builtin_type);
+		}
 		return valid;
 	}
 
@@ -6685,7 +6688,7 @@ GDScriptParser::DataType GDScriptParser::_reduce_function_call_type(const Operat
 						arg_type.native_type = mi.arguments[i].class_name;
 					}
 
-					if (!_is_type_compatible(arg_type, par_types[i])) {
+					if (!_is_type_compatible(arg_type, par_types[i], true)) {
 						types_match = false;
 						break;
 					} else {
@@ -6927,7 +6930,7 @@ GDScriptParser::DataType GDScriptParser::_reduce_function_call_type(const Operat
 			if (par_type.may_yield && p_call->arguments[i]->type == Node::TYPE_OPERATOR) {
 				_add_warning(GDScriptWarning::FUNCTION_MAY_YIELD, p_call->line, _find_function_name(static_cast<OperatorNode *>(p_call->arguments[i])));
 			}
-		} else if (!_is_type_compatible(arg_types[i - arg_diff], par_type)) {
+		} else if (!_is_type_compatible(arg_types[i - arg_diff], par_type, true)) {
 			// Supertypes are acceptable for dynamic compliance
 			if (!_is_type_compatible(par_type, arg_types[i - arg_diff])) {
 				_set_error("At '" + callee_name + "()' call, argument " + itos(i - arg_diff + 1) + ". Assigned type (" +
@@ -7390,6 +7393,33 @@ void GDScriptParser::_check_class_level_types(ClassNode *p_class) {
 				// Try supertype test
 				if (_is_type_compatible(expr_type, v.data_type)) {
 					_mark_line_as_unsafe(v.line);
+				} else {
+					// Try with implicit conversion
+					if (v.data_type.kind != DataType::BUILTIN || !_is_type_compatible(v.data_type, expr_type, true)) {
+						_set_error("Assigned expression type (" + expr_type.to_string() + ") doesn't match the variable's type (" +
+										   v.data_type.to_string() + ").",
+								v.line);
+						return;
+					}
+
+					// Replace assignment with implict conversion
+					BuiltInFunctionNode *convert = alloc_node<BuiltInFunctionNode>();
+					convert->line = v.line;
+					convert->function = GDScriptFunctions::TYPE_CONVERT;
+
+					ConstantNode *tgt_type = alloc_node<ConstantNode>();
+					tgt_type->line = v.line;
+					tgt_type->value = (int)v.data_type.builtin_type;
+
+					OperatorNode *convert_call = alloc_node<OperatorNode>();
+					convert_call->line = v.line;
+					convert_call->op = OperatorNode::OP_CALL;
+					convert_call->arguments.push_back(convert);
+					convert_call->arguments.push_back(v.expression);
+					convert_call->arguments.push_back(tgt_type);
+
+					v.expression = convert_call;
+					v.initial_assignment->arguments.write[1] = convert_call;
 				}
 			}
 
@@ -7430,7 +7460,7 @@ void GDScriptParser::_check_class_level_types(ClassNode *p_class) {
 		// Check export hint
 		if (v.data_type.has_type && v._export.type != Variant::NIL) {
 			DataType export_type = _type_from_property(v._export);
-			if (!_is_type_compatible(v.data_type, export_type)) {
+			if (!_is_type_compatible(v.data_type, export_type, true)) {
 				_set_error("Export hint type (" + export_type.to_string() + ") doesn't match the variable's type (" +
 								   v.data_type.to_string() + ").",
 						v.line);
@@ -7551,7 +7581,7 @@ void GDScriptParser::_check_function_types(FunctionNode *p_function) {
 			} else {
 				p_function->return_type = _resolve_type(p_function->return_type, p_function->line);
 
-				if (!_is_type_compatible(p_function->argument_types[i], def_type)) {
+				if (!_is_type_compatible(p_function->argument_types[i], def_type, true)) {
 					String arg_name = p_function->arguments[i];
 					_set_error("Value type (" + def_type.to_string() + ") doesn't match the type of argument '" +
 									   arg_name + "' (" + p_function->arguments[i] + ")",
@@ -7739,13 +7769,41 @@ void GDScriptParser::_check_block_types(BlockNode *p_block) {
 					}
 #endif // DEBUG_ENABLED
 
-					if (check_types && !_is_type_compatible(lv->datatype, assign_type)) {
+					if (!_is_type_compatible(lv->datatype, assign_type)) {
 						// Try supertype test
 						if (_is_type_compatible(assign_type, lv->datatype)) {
 							_mark_line_as_unsafe(lv->line);
 						} else {
-							_set_error("Assigned value type (" + assign_type.to_string() + ") does not match variable type (" + lv->datatype.to_string() + ")", lv->line);
-							return;
+							// Try implict conversion
+							if (lv->datatype.kind != DataType::BUILTIN || !_is_type_compatible(lv->datatype, assign_type, true)) {
+								_set_error("Assigned value type (" + assign_type.to_string() + ") doesn't match the variable's type (" +
+												   lv->datatype.to_string() + ").",
+										lv->line);
+								return;
+							}
+							// Replace assignment with implict conversion
+							BuiltInFunctionNode *convert = alloc_node<BuiltInFunctionNode>();
+							convert->line = lv->line;
+							convert->function = GDScriptFunctions::TYPE_CONVERT;
+
+							ConstantNode *tgt_type = alloc_node<ConstantNode>();
+							tgt_type->line = lv->line;
+							tgt_type->value = (int)lv->datatype.builtin_type;
+
+							OperatorNode *convert_call = alloc_node<OperatorNode>();
+							convert_call->line = lv->line;
+							convert_call->op = OperatorNode::OP_CALL;
+							convert_call->arguments.push_back(convert);
+							convert_call->arguments.push_back(lv->assign);
+							convert_call->arguments.push_back(tgt_type);
+
+							lv->assign = convert_call;
+							lv->assign_op->arguments.write[1] = convert_call;
+#ifdef DEBUG_ENABLED
+							if (lv->datatype.builtin_type == Variant::INT && assign_type.builtin_type == Variant::REAL) {
+								_add_warning(GDScriptWarning::NARROWING_CONVERSION, lv->line);
+							}
+#endif // DEBUG_ENABLED
 						}
 					}
 					if (lv->datatype.infer_type) {
@@ -7847,8 +7905,35 @@ void GDScriptParser::_check_block_types(BlockNode *p_block) {
 							if (_is_type_compatible(rh_type, lh_type)) {
 								_mark_line_as_unsafe(op->line);
 							} else {
-								_set_error("Assigned value type (" + rh_type.to_string() + ") does not match variable type (" + lh_type.to_string() + ")", op->line);
-								return;
+								// Try implict conversion
+								if (lh_type.kind != DataType::BUILTIN || !_is_type_compatible(lh_type, rh_type, true)) {
+									_set_error("Assigned value type (" + rh_type.to_string() + ") doesn't match the variable's type (" +
+													   lh_type.to_string() + ").",
+											op->line);
+									return;
+								}
+								// Replace assignment with implict conversion
+								BuiltInFunctionNode *convert = alloc_node<BuiltInFunctionNode>();
+								convert->line = op->line;
+								convert->function = GDScriptFunctions::TYPE_CONVERT;
+
+								ConstantNode *tgt_type = alloc_node<ConstantNode>();
+								tgt_type->line = op->line;
+								tgt_type->value = (int)lh_type.builtin_type;
+
+								OperatorNode *convert_call = alloc_node<OperatorNode>();
+								convert_call->line = op->line;
+								convert_call->op = OperatorNode::OP_CALL;
+								convert_call->arguments.push_back(convert);
+								convert_call->arguments.push_back(op->arguments[1]);
+								convert_call->arguments.push_back(tgt_type);
+
+								op->arguments.write[1] = convert_call;
+#ifdef DEBUG_ENABLED
+								if (lh_type.builtin_type == Variant::INT && rh_type.builtin_type == Variant::REAL) {
+									_add_warning(GDScriptWarning::NARROWING_CONVERSION, op->line);
+								}
+#endif // DEBUG_ENABLED
 							}
 						}
 #ifdef DEBUG_ENABLED
diff --git a/modules/gdscript/gdscript_parser.h b/modules/gdscript/gdscript_parser.h
index 167132e390..809bff8f20 100644
--- a/modules/gdscript/gdscript_parser.h
+++ b/modules/gdscript/gdscript_parser.h
@@ -607,7 +607,7 @@ private:
 	Variant::Operator _get_variant_operation(const OperatorNode::Operator &p_op) const;
 	bool _get_function_signature(DataType &p_base_type, const StringName &p_function, DataType &r_return_type, List<DataType> &r_arg_types, int &r_default_arg_count, bool &r_static, bool &r_vararg) const;
 	bool _get_member_type(const DataType &p_base_type, const StringName &p_member, DataType &r_member_type) const;
-	bool _is_type_compatible(const DataType &p_container, const DataType &p_expression) const;
+	bool _is_type_compatible(const DataType &p_container, const DataType &p_expression, bool p_allow_implicit_conversion = false) const;
 
 	DataType _reduce_node_type(Node *p_node);
 	DataType _reduce_function_call_type(const OperatorNode *p_call);