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: ast.rs
    path of file: ./repos/core/source/loaders/rs_loader/rust/compiler/src
    
    the code of the file until where you have to start completion: use super::rustc_ast::{
    AngleBracketedArg, AngleBracketedArgs, FnRetTy, FnSig, GenericArg, GenericArgs, MutTy, Pat,
    PatKind, TyKind,
};
use super::{Function, FunctionParameter, FunctionType, Mutability, Reference};

pub fn handle_ty(ty: &rustc_ast::Ty) -> FunctionParameter {
    let mut result = FunctionParameter {
        name: String::new(),
        mutability: Mutability::No,
        reference: Reference::No,
        ty: FunctionType::Null,
        generic: vec![],
    };
    match &ty.kind {
        TyKind::P
    
pub fn handle_fn(name: String, sig: &FnSig) -> Function {
    let mut function = Function {
        name,
        ret: None,
        args: vec![],
    };
    // parse input and output
    for arg in &sig.decl.inputs {
        let mut param = handle_ty(&arg.ty);
        // we need to extract the name from pat.
        if let Some(name) = handle_pat(&arg.pat) {
            param.name = name;
        }
        function.args.push(param);
    }

    match &sig.decl.output {
        FnRetTy::Default(_) => function.ret = None,
        FnRetTy::Ty(ty) => {
            function.ret = Some(handle_ty(&ty));
        }
    }
    function
}