You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: lower.rs
    path of file: ./repos/erg/crates/erg_compiler
    
    the code of the file until where you have to start completion: //! implements `ASTLowerer`.
//!
//! ASTLowerer(ASTからHIRへの変換器)を実装
use std::marker::PhantomData;
use std::mem;

use erg_common::config::{ErgConfig, ErgMode};
use erg_common::consts::{EL
    
    fn pop_append_errs(&mut self) {
        let (ctx, errs) = self.module.context.check_decls_and_pop();
        if self.cfg.mode == ErgMode::LanguageServer && !ctx.dir().is_empty() {
            self.module.scope.insert(ctx.name.clone(), ctx);
        }
        self.errs.extend(errs);
    }