### Godot version

4.0.2

### System information

Windows 10

### Issue description

EDIT: this was fixed by removing the offending files listed with the MRP and then dragging them back in from my desktop after opening the project~

I was developing my game then suddenly this started happening. I can no longer playtest my game.
I am not 100% sure what caused this but I believe at the time I was making a new inherited scene, saved it, then moved some scenes in the FileSystem tab?

![image](https://user-images.githubusercontent.com/75141902/235264827-62419c7d-963b-4002-9452-a6493a9bfe25.png)


### Steps to reproduce

No idea aaa- x-x

### Minimal reproduction project

Since I have no idea what caused it here's my early project :'D
https://drive.google.com/file/d/14JFZ420AelUNjBIth78msHY29rNjB55_/view?usp=share_link

I was working on these when the error occurred:
- Slot_0.tcsn
- Slot_Clickable.tscn
- Slot_Orphan.tscn
- Slot_Orphan.gd

IdentifierNode *id = static_cast<IdentifierNode *>(p_previous_operand);
			switch (id->source) {
				case IdentifierNode::LOCAL_VARIABLE:
					source_variable = id->variable_source;
					id->variable_source->usages--;
					break;
				case IdentifierNode::LOCAL_CONSTANT:
					id->constant_source->usages--;
					break;
				case IdentifierNode::FUNCTION_PARAMETER:
					id->parameter_source->usages--;
					break;
				case IdentifierNode::LOCAL_ITERATOR:
				case IdentifierNode::LOCAL_BIND:
					id->bind_source->usages--;
					break;
				default:
					break;
			}
#endif
		} break;
		case Node::SUBSCRIPT:
			
			break;
		default:
			push_error(R"(Only identifier, attribute access, and subscription access can be used as assignment target.)");
			return parse_expression(false); 
	}
	AssignmentNode *assignment = alloc_node<AssignmentNode>();
	reset_extents(assignment, p_previous_operand);