Fix GDScript analyzer null literal

modules/gdscript/gdscript_analyzer.cpp

@@ -1747,6 +1747,12 @@ void GDScriptAnalyzer::resolve_variable(GDScriptParser::VariableNode *p_variable
 
 		type = p_variable->initializer->get_datatype();
 
+#ifdef DEBUG_ENABLED
+		if (p_variable->initializer->type == GDScriptParser::Node::CALL && type.is_hard_type() && type.kind == GDScriptParser::DataType::BUILTIN && type.builtin_type == Variant::NIL) {
+			parser->push_warning(p_variable->initializer, GDScriptWarning::VOID_ASSIGNMENT, static_cast<GDScriptParser::CallNode *>(p_variable->initializer)->function_name);
+		}
+#endif
+
 		if (p_variable->infer_datatype) {
 			type.type_source = GDScriptParser::DataType::ANNOTATED_INFERRED;
 
@@ -1760,11 +1766,6 @@ void GDScriptAnalyzer::resolve_variable(GDScriptParser::VariableNode *p_variable
 		} else {
 			type.type_source = GDScriptParser::DataType::INFERRED;
 		}
-#ifdef DEBUG_ENABLED
-		if (p_variable->initializer->type == GDScriptParser::Node::CALL && type.kind == GDScriptParser::DataType::BUILTIN && type.builtin_type == Variant::NIL) {
-			parser->push_warning(p_variable->initializer, GDScriptWarning::VOID_ASSIGNMENT, static_cast<GDScriptParser::CallNode *>(p_variable->initializer)->function_name);
-		}
-#endif
 	}
 
 	if (p_variable->datatype_specifier != nullptr) {
@@ -1843,7 +1844,7 @@ void GDScriptAnalyzer::resolve_constant(GDScriptParser::ConstantNode *p_constant
 		type = p_constant->initializer->get_datatype();
 
 #ifdef DEBUG_ENABLED
-		if (p_constant->initializer->type == GDScriptParser::Node::CALL && type.kind == GDScriptParser::DataType::BUILTIN && type.builtin_type == Variant::NIL) {
+		if (p_constant->initializer->type == GDScriptParser::Node::CALL && type.is_hard_type() && type.kind == GDScriptParser::DataType::BUILTIN && type.builtin_type == Variant::NIL) {
 			parser->push_warning(p_constant->initializer, GDScriptWarning::VOID_ASSIGNMENT, static_cast<GDScriptParser::CallNode *>(p_constant->initializer)->function_name);
 		}
 #endif
@@ -2331,7 +2332,7 @@ void GDScriptAnalyzer::reduce_assignment(GDScriptParser::AssignmentNode *p_assig
 	}
 
 #ifdef DEBUG_ENABLED
-	if (p_assignment->assigned_value->type == GDScriptParser::Node::CALL && assigned_value_type.kind == GDScriptParser::DataType::BUILTIN && assigned_value_type.builtin_type == Variant::NIL) {
+	if (p_assignment->assigned_value->type == GDScriptParser::Node::CALL && assigned_value_type.is_hard_type() && assigned_value_type.kind == GDScriptParser::DataType::BUILTIN && assigned_value_type.builtin_type == Variant::NIL) {
 		parser->push_warning(p_assignment->assigned_value, GDScriptWarning::VOID_ASSIGNMENT, static_cast<GDScriptParser::CallNode *>(p_assignment->assigned_value)->function_name);
 	} else if (assignee_type.is_hard_type() && assignee_type.builtin_type == Variant::INT && assigned_value_type.builtin_type == Variant::FLOAT) {
 		parser->push_warning(p_assignment->assigned_value, GDScriptWarning::NARROWING_CONVERSION);
@@ -3979,10 +3980,7 @@ GDScriptParser::DataType GDScriptAnalyzer::type_from_variant(const Variant &p_va
 	result.builtin_type = p_value.get_type();
 	result.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT; // Constant has explicit type.
 
-	if (p_value.get_type() == Variant::NIL) {
-		// A null value is a variant, not void.
-		result.kind = GDScriptParser::DataType::VARIANT;
-	} else if (p_value.get_type() == Variant::OBJECT) {
+	if (p_value.get_type() == Variant::OBJECT) {
 		// Object is treated as a native type, not a builtin type.
 		result.kind = GDScriptParser::DataType::NATIVE;
 

modules/gdscript/tests/scripts/analyzer/features/inferred_return_type.gd

@@ -0,0 +1,9 @@
+# https://github.com/godotengine/godot/issues/61159
+
+func get_param():
+	return null
+
+func test():
+	var v = get_param()
+	v = get_param()
+	print(v)

modules/gdscript/tests/scripts/analyzer/features/inferred_return_type.out

@@ -0,0 +1,2 @@
+GDTEST_OK
+<null>