Add module ext::placeholders with placeholder() and PlaceholderExpander.
This commit is contained in:
Jeffrey Seyfried
parent
7a3ae576fa
commit
c07ff8d26a
3 changed files with 182 additions and 39 deletions
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@ -12,8 +12,9 @@ use ast::{Block, Crate, Ident, Mac_, PatKind};
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use ast::{MacStmtStyle, StmtKind, ItemKind};
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use ast;
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use ext::hygiene::Mark;
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use ext::placeholders;
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use attr::{self, HasAttrs};
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use codemap::{dummy_spanned, ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
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use codemap::{ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
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use syntax_pos::{self, Span, ExpnId};
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use config::StripUnconfigured;
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use ext::base::*;
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@ -35,8 +36,8 @@ macro_rules! expansions {
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$(.$fold:ident)* $(lift .$fold_elt:ident)*,
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$(.$visit:ident)* $(lift .$visit_elt:ident)*;)*) => {
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#[derive(Copy, Clone)]
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enum ExpansionKind { OptExpr, $( $kind, )* }
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enum Expansion { OptExpr(Option<P<ast::Expr>>), $( $kind($ty), )* }
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pub enum ExpansionKind { OptExpr, $( $kind, )* }
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pub enum Expansion { OptExpr(Option<P<ast::Expr>>), $( $kind($ty), )* }
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impl ExpansionKind {
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fn name(self) -> &'static str {
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@ -55,20 +56,20 @@ macro_rules! expansions {
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}
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impl Expansion {
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fn make_opt_expr(self) -> Option<P<ast::Expr>> {
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pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
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match self {
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Expansion::OptExpr(expr) => expr,
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_ => panic!("Expansion::make_* called on the wrong kind of expansion"),
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}
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}
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$( fn $make(self) -> $ty {
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$( pub fn $make(self) -> $ty {
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match self {
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Expansion::$kind(ast) => ast,
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_ => panic!("Expansion::make_* called on the wrong kind of expansion"),
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}
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} )*
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fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
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pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
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use self::Expansion::*;
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match self {
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OptExpr(expr) => OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
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@ -434,9 +435,9 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
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// If keep_macs is true, expands to a MacEager::items instead.
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if self.keep_macs {
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Some(reconstruct_macro_rules(&def, &path))
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Some(placeholders::reconstructed_macro_rules(&def, &path))
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} else {
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Some(macro_scope_placeholder())
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Some(placeholders::macro_scope_placeholder())
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}
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}
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@ -650,37 +651,6 @@ impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
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}
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}
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fn macro_scope_placeholder() -> Expansion {
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Expansion::Items(SmallVector::one(P(ast::Item {
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ident: keywords::Invalid.ident(),
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attrs: Vec::new(),
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id: ast::DUMMY_NODE_ID,
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node: ast::ItemKind::Mac(dummy_spanned(ast::Mac_ {
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path: ast::Path { span: syntax_pos::DUMMY_SP, global: false, segments: Vec::new() },
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tts: Vec::new(),
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})),
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vis: ast::Visibility::Inherited,
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span: syntax_pos::DUMMY_SP,
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})))
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}
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fn reconstruct_macro_rules(def: &ast::MacroDef, path: &ast::Path) -> Expansion {
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Expansion::Items(SmallVector::one(P(ast::Item {
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ident: def.ident,
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attrs: def.attrs.clone(),
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id: ast::DUMMY_NODE_ID,
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node: ast::ItemKind::Mac(ast::Mac {
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span: def.span,
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node: ast::Mac_ {
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path: path.clone(),
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tts: def.body.clone(),
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}
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}),
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vis: ast::Visibility::Inherited,
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span: def.span,
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})))
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}
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pub struct ExpansionConfig<'feat> {
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pub crate_name: String,
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pub features: Option<&'feat Features>,
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172
src/libsyntax/ext/placeholders.rs
Normal file
172
src/libsyntax/ext/placeholders.rs
Normal file
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@ -0,0 +1,172 @@
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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use ast;
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use codemap::{DUMMY_SP, dummy_spanned};
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use ext::expand::{Expansion, ExpansionKind};
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use fold::*;
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use parse::token::keywords;
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use ptr::P;
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use util::small_vector::SmallVector;
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use std::collections::HashMap;
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pub fn placeholder(kind: ExpansionKind, id: ast::NodeId) -> Expansion {
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fn mac_placeholder() -> ast::Mac {
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dummy_spanned(ast::Mac_ {
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path: ast::Path { span: DUMMY_SP, global: false, segments: Vec::new() },
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tts: Vec::new(),
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})
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}
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let ident = keywords::Invalid.ident();
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let attrs = Vec::new();
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let vis = ast::Visibility::Inherited;
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let span = DUMMY_SP;
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let expr_placeholder = || P(ast::Expr {
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id: id, span: span,
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attrs: ast::ThinVec::new(),
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node: ast::ExprKind::Mac(mac_placeholder()),
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});
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match kind {
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ExpansionKind::Expr => Expansion::Expr(expr_placeholder()),
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ExpansionKind::OptExpr => Expansion::OptExpr(Some(expr_placeholder())),
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ExpansionKind::Items => Expansion::Items(SmallVector::one(P(ast::Item {
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id: id, span: span, ident: ident, vis: vis, attrs: attrs,
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node: ast::ItemKind::Mac(mac_placeholder()),
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}))),
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ExpansionKind::TraitItems => Expansion::TraitItems(SmallVector::one(ast::TraitItem {
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id: id, span: span, ident: ident, attrs: attrs,
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node: ast::TraitItemKind::Macro(mac_placeholder()),
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})),
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ExpansionKind::ImplItems => Expansion::ImplItems(SmallVector::one(ast::ImplItem {
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id: id, span: span, ident: ident, vis: vis, attrs: attrs,
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node: ast::ImplItemKind::Macro(mac_placeholder()),
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defaultness: ast::Defaultness::Final,
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})),
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ExpansionKind::Pat => Expansion::Pat(P(ast::Pat {
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id: id, span: span, node: ast::PatKind::Mac(mac_placeholder()),
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})),
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ExpansionKind::Ty => Expansion::Ty(P(ast::Ty {
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id: id, span: span, node: ast::TyKind::Mac(mac_placeholder()),
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})),
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ExpansionKind::Stmts => Expansion::Stmts(SmallVector::one({
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let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ast::ThinVec::new()));
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ast::Stmt { id: id, span: span, node: ast::StmtKind::Mac(mac) }
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})),
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}
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}
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pub fn macro_scope_placeholder() -> Expansion {
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placeholder(ExpansionKind::Items, ast::DUMMY_NODE_ID)
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}
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pub struct PlaceholderExpander {
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expansions: HashMap<ast::NodeId, Expansion>,
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}
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impl PlaceholderExpander {
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pub fn new(expansions: HashMap<ast::NodeId, Expansion>) -> Self {
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PlaceholderExpander {
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expansions: expansions,
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}
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}
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pub fn remove(&mut self, id: ast::NodeId) -> Expansion {
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let expansion = self.expansions.remove(&id).unwrap();
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expansion.fold_with(self)
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}
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}
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impl Folder for PlaceholderExpander {
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fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
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match item.node {
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// Scope placeholder
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ast::ItemKind::Mac(_) if item.id == ast::DUMMY_NODE_ID => SmallVector::one(item),
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ast::ItemKind::Mac(_) => self.remove(item.id).make_items(),
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_ => noop_fold_item(item, self),
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}
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}
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fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
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match item.node {
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ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
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_ => noop_fold_trait_item(item, self),
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}
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}
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fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
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match item.node {
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ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
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_ => noop_fold_impl_item(item, self),
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}
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}
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fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
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match expr.node {
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ast::ExprKind::Mac(_) => self.remove(expr.id).make_expr(),
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_ => expr.map(|expr| noop_fold_expr(expr, self)),
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}
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}
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fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
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match expr.node {
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ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
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_ => noop_fold_opt_expr(expr, self),
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}
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}
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fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
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let (style, mut expansion) = match stmt.node {
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ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
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_ => return noop_fold_stmt(stmt, self),
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};
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if style == ast::MacStmtStyle::Semicolon {
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if let Some(stmt) = expansion.pop() {
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expansion.push(stmt.add_trailing_semicolon());
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}
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}
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expansion
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}
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fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
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match pat.node {
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ast::PatKind::Mac(_) => self.remove(pat.id).make_pat(),
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_ => noop_fold_pat(pat, self),
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}
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}
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fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
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match ty.node {
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ast::TyKind::Mac(_) => self.remove(ty.id).make_ty(),
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_ => noop_fold_ty(ty, self),
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}
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}
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}
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pub fn reconstructed_macro_rules(def: &ast::MacroDef, path: &ast::Path) -> Expansion {
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Expansion::Items(SmallVector::one(P(ast::Item {
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ident: def.ident,
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attrs: def.attrs.clone(),
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id: ast::DUMMY_NODE_ID,
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node: ast::ItemKind::Mac(ast::Mac {
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span: def.span,
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node: ast::Mac_ {
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path: path.clone(),
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tts: def.body.clone(),
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}
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}),
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vis: ast::Visibility::Inherited,
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span: def.span,
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})))
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}
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@ -126,6 +126,7 @@ pub mod ext {
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pub mod base;
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pub mod build;
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pub mod expand;
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pub mod placeholders;
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pub mod hygiene;
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pub mod proc_macro_shim;
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pub mod quote;
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