| use proc_macro2::{Group, TokenStream, TokenTree}; |
| use std::mem; |
| use syn::punctuated::Punctuated; |
| use syn::visit_mut::{self, VisitMut}; |
| use syn::{ |
| parse_quote, Block, Error, ExprPath, ExprStruct, Ident, Item, Macro, Path, PathArguments, |
| QSelf, Receiver, Signature, Type, TypePath, WherePredicate, |
| }; |
| |
| pub fn has_self_in_sig(sig: &mut Signature) -> bool { |
| let mut visitor = HasSelf(false); |
| visitor.visit_signature_mut(sig); |
| visitor.0 |
| } |
| |
| pub fn has_self_in_where_predicate(where_predicate: &mut WherePredicate) -> bool { |
| let mut visitor = HasSelf(false); |
| visitor.visit_where_predicate_mut(where_predicate); |
| visitor.0 |
| } |
| |
| pub fn has_self_in_block(block: &mut Block) -> bool { |
| let mut visitor = HasSelf(false); |
| visitor.visit_block_mut(block); |
| visitor.0 |
| } |
| |
| struct HasSelf(bool); |
| |
| impl VisitMut for HasSelf { |
| fn visit_expr_path_mut(&mut self, expr: &mut ExprPath) { |
| self.0 |= expr.path.segments[0].ident == "Self"; |
| visit_mut::visit_expr_path_mut(self, expr); |
| } |
| |
| fn visit_type_path_mut(&mut self, ty: &mut TypePath) { |
| self.0 |= ty.path.segments[0].ident == "Self"; |
| visit_mut::visit_type_path_mut(self, ty); |
| } |
| |
| fn visit_receiver_mut(&mut self, _arg: &mut Receiver) { |
| self.0 = true; |
| } |
| |
| fn visit_item_mut(&mut self, _: &mut Item) { |
| // Do not recurse into nested items. |
| } |
| } |
| |
| pub struct ReplaceReceiver { |
| pub with: Type, |
| pub as_trait: Option<Path>, |
| } |
| |
| impl ReplaceReceiver { |
| pub fn with(ty: Type) -> Self { |
| ReplaceReceiver { |
| with: ty, |
| as_trait: None, |
| } |
| } |
| |
| pub fn with_as_trait(ty: Type, as_trait: Path) -> Self { |
| ReplaceReceiver { |
| with: ty, |
| as_trait: Some(as_trait), |
| } |
| } |
| |
| fn self_to_qself_type(&self, qself: &mut Option<QSelf>, path: &mut Path) { |
| let include_as_trait = true; |
| self.self_to_qself(qself, path, include_as_trait); |
| } |
| |
| fn self_to_qself_expr(&self, qself: &mut Option<QSelf>, path: &mut Path) { |
| let include_as_trait = false; |
| self.self_to_qself(qself, path, include_as_trait); |
| } |
| |
| fn self_to_qself(&self, qself: &mut Option<QSelf>, path: &mut Path, include_as_trait: bool) { |
| if path.leading_colon.is_some() { |
| return; |
| } |
| |
| let first = &path.segments[0]; |
| if first.ident != "Self" || !first.arguments.is_empty() { |
| return; |
| } |
| |
| if path.segments.len() == 1 { |
| self.self_to_expr_path(path); |
| return; |
| } |
| |
| *qself = Some(QSelf { |
| lt_token: Default::default(), |
| ty: Box::new(self.with.clone()), |
| position: 0, |
| as_token: None, |
| gt_token: Default::default(), |
| }); |
| |
| if include_as_trait && self.as_trait.is_some() { |
| let as_trait = self.as_trait.as_ref().unwrap().clone(); |
| path.leading_colon = as_trait.leading_colon; |
| qself.as_mut().unwrap().position = as_trait.segments.len(); |
| |
| let segments = mem::replace(&mut path.segments, as_trait.segments); |
| path.segments.push_punct(Default::default()); |
| path.segments.extend(segments.into_pairs().skip(1)); |
| } else { |
| 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) { |
| if let Type::Path(with) = &self.with { |
| *path = with.path.clone(); |
| 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(Default::default()); |
| } |
| } |
| } |
| } else { |
| let span = path.segments[0].ident.span(); |
| let msg = "Self type of this impl is unsupported in expression position"; |
| let error = Error::new(span, msg).to_compile_error(); |
| *path = parse_quote!(::core::marker::PhantomData::<#error>); |
| } |
| } |
| } |
| |
| impl VisitMut for ReplaceReceiver { |
| // `Self` -> `Receiver` |
| fn visit_type_mut(&mut self, ty: &mut Type) { |
| if let Type::Path(node) = ty { |
| if node.qself.is_none() && node.path.is_ident("Self") { |
| *ty = self.with.clone(); |
| } else { |
| self.visit_type_path_mut(node); |
| } |
| } else { |
| visit_mut::visit_type_mut(self, ty); |
| } |
| } |
| |
| // `Self::Assoc` -> `<Receiver>::Assoc` |
| fn visit_type_path_mut(&mut self, ty: &mut TypePath) { |
| if ty.qself.is_none() { |
| self.self_to_qself_type(&mut ty.qself, &mut ty.path); |
| } |
| visit_mut::visit_type_path_mut(self, ty); |
| } |
| |
| // `Self::method` -> `<Receiver>::method` |
| fn visit_expr_path_mut(&mut self, expr: &mut ExprPath) { |
| if expr.qself.is_none() { |
| prepend_underscore_to_self(&mut expr.path.segments[0].ident); |
| self.self_to_qself_expr(&mut expr.qself, &mut expr.path); |
| } |
| visit_mut::visit_expr_path_mut(self, expr); |
| } |
| |
| fn visit_expr_struct_mut(&mut self, expr: &mut ExprStruct) { |
| if expr.path.is_ident("Self") { |
| self.self_to_expr_path(&mut expr.path); |
| } |
| visit_mut::visit_expr_struct_mut(self, expr); |
| } |
| |
| fn visit_item_mut(&mut self, _: &mut Item) { |
| // Do not recurse into nested items. |
| } |
| |
| fn visit_macro_mut(&mut self, i: &mut Macro) { |
| // We can't tell in general whether `self` inside a macro invocation |
| // refers to the self in the argument list or a different self |
| // introduced within the macro. Heuristic: if the macro input contains |
| // `fn`, then `self` is more likely to refer to something other than the |
| // outer function's self argument. |
| if !contains_fn(i.tokens.clone()) { |
| i.tokens = fold_token_stream(i.tokens.clone()); |
| } |
| } |
| } |
| |
| fn contains_fn(tokens: TokenStream) -> bool { |
| tokens.into_iter().any(|tt| match tt { |
| TokenTree::Ident(ident) => ident == "fn", |
| TokenTree::Group(group) => contains_fn(group.stream()), |
| _ => false, |
| }) |
| } |
| |
| fn fold_token_stream(tokens: TokenStream) -> TokenStream { |
| tokens |
| .into_iter() |
| .map(|tt| match tt { |
| TokenTree::Ident(mut ident) => { |
| prepend_underscore_to_self(&mut ident); |
| TokenTree::Ident(ident) |
| } |
| TokenTree::Group(group) => { |
| let content = fold_token_stream(group.stream()); |
| TokenTree::Group(Group::new(group.delimiter(), content)) |
| } |
| other => other, |
| }) |
| .collect() |
| } |
| |
| fn prepend_underscore_to_self(ident: &mut Ident) { |
| if ident == "self" { |
| *ident = Ident::new("_self", ident.span()); |
| } |
| } |