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use crate::internals::respan::respan;
use proc_macro2::Span;
use quote::ToTokens;
use std::mem;
use syn::punctuated::Punctuated;
use syn::{
parse_quote, Data, DeriveInput, Expr, ExprPath, GenericArgument, GenericParam, Generics, Macro,
Path, PathArguments, QSelf, ReturnType, Token, Type, TypeParamBound, TypePath, WherePredicate,
};
pub fn replace_receiver(input: &mut DeriveInput) {
let self_ty = {
let ident = &input.ident;
let ty_generics = input.generics.split_for_impl().1;
parse_quote!(#ident #ty_generics)
};
let mut visitor = ReplaceReceiver(&self_ty);
visitor.visit_generics_mut(&mut input.generics);
visitor.visit_data_mut(&mut input.data);
}
struct ReplaceReceiver<'a>(&'a TypePath);
impl ReplaceReceiver<'_> {
fn self_ty(&self, span: Span) -> TypePath {
let tokens = self.0.to_token_stream();
let respanned = respan(tokens, span);
syn::parse2(respanned).unwrap()
}
fn self_to_qself(&self, qself: &mut Option<QSelf>, path: &mut Path) {
if path.leading_colon.is_some() || path.segments[0].ident != "Self" {
return;
}
if path.segments.len() == 1 {
self.self_to_expr_path(path);
return;
}
let span = path.segments[0].ident.span();
*qself = Some(QSelf {
lt_token: Token,
ty: Box::new(Type::Path(self.self_ty(span))),
position: 0,
as_token: None,
gt_token: Token,
});
path.leading_colon = Some(**path.segments.pairs().next().unwrap().punct().unwrap());
let segments = mem::replace(&mut path.segments, Punctuated::new());
path.segments = segments.into_pairs().skip(1).collect();
}
fn self_to_expr_path(&self, path: &mut Path) {
let self_ty = self.self_ty(path.segments[0].ident.span());
let variant = mem::replace(path, self_ty.path);
for segment in &mut path.segments {
if let PathArguments::AngleBracketed(bracketed) = &mut segment.arguments {
if bracketed.colon2_token.is_none() && !bracketed.args.is_empty() {
bracketed.colon2_token = Some(<Token![::]>::default());
}
}
}
if variant.segments.len() > 1 {
path.segments.push_punct(<Token![::]>::default());
path.segments.extend(variant.segments.into_pairs().skip(1));
}
}
}
impl ReplaceReceiver<'_> {
// `Self` -> `Receiver`
fn visit_type_mut(&mut self, ty: &mut Type) {
let span = if let Type::Path(node) = ty {
if node.qself.is_none() && node.path.is_ident("Self") {
node.path.segments[0].ident.span()
} else {
self.visit_type_path_mut(node);
return;
}
} else {
self.visit_type_mut_impl(ty);
return;
};
*ty = self.self_ty(span).into();
}
// `Self::Assoc` -> `<Receiver>::Assoc`
fn visit_type_path_mut(&mut self, ty: &mut TypePath) {
if ty.qself.is_none() {
self.self_to_qself(&mut ty.qself, &mut ty.path);
}
self.visit_type_path_mut_impl(ty);
}
// `Self::method` -> `<Receiver>::method`
fn visit_expr_path_mut(&mut self, expr: &mut ExprPath) {
if expr.qself.is_none() {
self.self_to_qself(&mut expr.qself, &mut expr.path);
}
self.visit_expr_path_mut_impl(expr);
}
// Everything below is simply traversing the syntax tree.
fn visit_type_mut_impl(&mut self, ty: &mut Type) {
match ty {
#![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
Type::Array(ty) => {
self.visit_type_mut(&mut ty.elem);
self.visit_expr_mut(&mut ty.len);
}
Type::BareFn(ty) => {
for arg in &mut ty.inputs {
self.visit_type_mut(&mut arg.ty);
}
self.visit_return_type_mut(&mut ty.output);
}
Type::Group(ty) => self.visit_type_mut(&mut ty.elem),
Type::ImplTrait(ty) => {
for bound in &mut ty.bounds {
self.visit_type_param_bound_mut(bound);
}
}
Type::Macro(ty) => self.visit_macro_mut(&mut ty.mac),
Type::Paren(ty) => self.visit_type_mut(&mut ty.elem),
Type::Path(ty) => {
if let Some(qself) = &mut ty.qself {
self.visit_type_mut(&mut qself.ty);
}
self.visit_path_mut(&mut ty.path);
}
Type::Ptr(ty) => self.visit_type_mut(&mut ty.elem),
Type::Reference(ty) => self.visit_type_mut(&mut ty.elem),
Type::Slice(ty) => self.visit_type_mut(&mut ty.elem),
Type::TraitObject(ty) => {
for bound in &mut ty.bounds {
self.visit_type_param_bound_mut(bound);
}
}
Type::Tuple(ty) => {
for elem in &mut ty.elems {
self.visit_type_mut(elem);
}
}
Type::Infer(_) | Type::Never(_) | Type::Verbatim(_) => {}
_ => {}
}
}
fn visit_type_path_mut_impl(&mut self, ty: &mut TypePath) {
if let Some(qself) = &mut ty.qself {
self.visit_type_mut(&mut qself.ty);
}
self.visit_path_mut(&mut ty.path);
}
fn visit_expr_path_mut_impl(&mut self, expr: &mut ExprPath) {
if let Some(qself) = &mut expr.qself {
self.visit_type_mut(&mut qself.ty);
}
self.visit_path_mut(&mut expr.path);
}
fn visit_path_mut(&mut self, path: &mut Path) {
for segment in &mut path.segments {
self.visit_path_arguments_mut(&mut segment.arguments);
}
}
fn visit_path_arguments_mut(&mut self, arguments: &mut PathArguments) {
match arguments {
PathArguments::None => {}
PathArguments::AngleBracketed(arguments) => {
for arg in &mut arguments.args {
match arg {
#![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
GenericArgument::Type(arg) => self.visit_type_mut(arg),
GenericArgument::AssocType(arg) => self.visit_type_mut(&mut arg.ty),
GenericArgument::Lifetime(_)
| GenericArgument::Const(_)
| GenericArgument::AssocConst(_)
| GenericArgument::Constraint(_) => {}
_ => {}
}
}
}
PathArguments::Parenthesized(arguments) => {
for argument in &mut arguments.inputs {
self.visit_type_mut(argument);
}
self.visit_return_type_mut(&mut arguments.output);
}
}
}
fn visit_return_type_mut(&mut self, return_type: &mut ReturnType) {
match return_type {
ReturnType::Default => {}
ReturnType::Type(_, output) => self.visit_type_mut(output),
}
}
fn visit_type_param_bound_mut(&mut self, bound: &mut TypeParamBound) {
match bound {
#![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
TypeParamBound::Trait(bound) => self.visit_path_mut(&mut bound.path),
TypeParamBound::Lifetime(_) | TypeParamBound::Verbatim(_) => {}
_ => {}
}
}
fn visit_generics_mut(&mut self, generics: &mut Generics) {
for param in &mut generics.params {
match param {
GenericParam::Type(param) => {
for bound in &mut param.bounds {
self.visit_type_param_bound_mut(bound);
}
}
GenericParam::Lifetime(_) | GenericParam::Const(_) => {}
}
}
if let Some(where_clause) = &mut generics.where_clause {
for predicate in &mut where_clause.predicates {
match predicate {
#![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
WherePredicate::Type(predicate) => {
self.visit_type_mut(&mut predicate.bounded_ty);
for bound in &mut predicate.bounds {
self.visit_type_param_bound_mut(bound);
}
}
WherePredicate::Lifetime(_) => {}
_ => {}
}
}
}
}
fn visit_data_mut(&mut self, data: &mut Data) {
match data {
Data::Struct(data) => {
for field in &mut data.fields {
self.visit_type_mut(&mut field.ty);
}
}
Data::Enum(data) => {
for variant in &mut data.variants {
for field in &mut variant.fields {
self.visit_type_mut(&mut field.ty);
}
}
}
Data::Union(_) => {}
}
}
fn visit_expr_mut(&mut self, expr: &mut Expr) {
match expr {
Expr::Binary(expr) => {
self.visit_expr_mut(&mut expr.left);
self.visit_expr_mut(&mut expr.right);
}
Expr::Call(expr) => {
self.visit_expr_mut(&mut expr.func);
for arg in &mut expr.args {
self.visit_expr_mut(arg);
}
}
Expr::Cast(expr) => {
self.visit_expr_mut(&mut expr.expr);
self.visit_type_mut(&mut expr.ty);
}
Expr::Field(expr) => self.visit_expr_mut(&mut expr.base),
Expr::Index(expr) => {
self.visit_expr_mut(&mut expr.expr);
self.visit_expr_mut(&mut expr.index);
}
Expr::Paren(expr) => self.visit_expr_mut(&mut expr.expr),
Expr::Path(expr) => self.visit_expr_path_mut(expr),
Expr::Unary(expr) => self.visit_expr_mut(&mut expr.expr),
_ => {}
}
}
fn visit_macro_mut(&mut self, _mac: &mut Macro) {}
}