1 use crate::base::ExtCtxt;
2 use crate::expand::{AstFragment, AstFragmentKind};
5 use rustc_ast::mut_visit::*;
7 use rustc_span::source_map::{dummy_spanned, DUMMY_SP};
8 use rustc_span::symbol::Ident;
10 use smallvec::{smallvec, SmallVec};
12 use rustc_data_structures::fx::FxHashMap;
15 kind: AstFragmentKind,
17 vis: Option<ast::Visibility>,
19 fn mac_placeholder() -> ast::MacCall {
21 path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
22 args: P(ast::MacArgs::Empty),
23 prior_type_ascription: None,
27 let ident = Ident::invalid();
28 let attrs = Vec::new();
29 let vis = vis.unwrap_or_else(|| dummy_spanned(ast::VisibilityKind::Inherited));
31 let expr_placeholder = || {
35 attrs: ast::AttrVec::new(),
36 kind: ast::ExprKind::MacCall(mac_placeholder()),
40 let ty = || P(ast::Ty { id, kind: ast::TyKind::MacCall(mac_placeholder()), span });
41 let pat = || P(ast::Pat { id, kind: ast::PatKind::MacCall(mac_placeholder()), span });
44 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
45 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
46 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
52 kind: ast::ItemKind::MacCall(mac_placeholder()),
55 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![P(ast::AssocItem {
61 kind: ast::AssocItemKind::MacCall(mac_placeholder()),
64 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![P(ast::AssocItem {
70 kind: ast::AssocItemKind::MacCall(mac_placeholder()),
73 AstFragmentKind::ForeignItems => {
74 AstFragment::ForeignItems(smallvec![P(ast::ForeignItem {
80 kind: ast::ForeignItemKind::MacCall(mac_placeholder()),
84 AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
87 kind: ast::PatKind::MacCall(mac_placeholder()),
89 AstFragmentKind::Ty => {
90 AstFragment::Ty(P(ast::Ty { id, span, kind: ast::TyKind::MacCall(mac_placeholder()) }))
92 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
93 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ast::AttrVec::new()));
94 ast::Stmt { id, span, kind: ast::StmtKind::MacCall(mac) }
96 AstFragmentKind::Arms => AstFragment::Arms(smallvec![ast::Arm {
97 attrs: Default::default(),
98 body: expr_placeholder(),
103 is_placeholder: true,
105 AstFragmentKind::Fields => AstFragment::Fields(smallvec![ast::Field {
106 attrs: Default::default(),
107 expr: expr_placeholder(),
112 is_placeholder: true,
114 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![ast::FieldPat {
115 attrs: Default::default(),
121 is_placeholder: true,
123 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
125 attrs: Default::default(),
126 bounds: Default::default(),
129 is_placeholder: true,
130 kind: ast::GenericParamKind::Lifetime,
133 AstFragmentKind::Params => AstFragment::Params(smallvec![ast::Param {
134 attrs: Default::default(),
139 is_placeholder: true,
141 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![ast::StructField {
142 attrs: Default::default(),
148 is_placeholder: true,
150 AstFragmentKind::Variants => AstFragment::Variants(smallvec![ast::Variant {
151 attrs: Default::default(),
152 data: ast::VariantData::Struct(Default::default(), false),
158 is_placeholder: true,
163 pub struct PlaceholderExpander<'a, 'b> {
164 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
165 cx: &'a mut ExtCtxt<'b>,
169 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
170 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
171 PlaceholderExpander { cx, expanded_fragments: FxHashMap::default(), monotonic }
174 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
175 fragment.mut_visit_with(self);
176 self.expanded_fragments.insert(id, fragment);
179 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
180 self.expanded_fragments.remove(&id).unwrap()
184 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
185 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
186 if arm.is_placeholder {
187 self.remove(arm.id).make_arms()
189 noop_flat_map_arm(arm, self)
193 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
194 if field.is_placeholder {
195 self.remove(field.id).make_fields()
197 noop_flat_map_field(field, self)
201 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
202 if fp.is_placeholder {
203 self.remove(fp.id).make_field_patterns()
205 noop_flat_map_field_pattern(fp, self)
209 fn flat_map_generic_param(
211 param: ast::GenericParam,
212 ) -> SmallVec<[ast::GenericParam; 1]> {
213 if param.is_placeholder {
214 self.remove(param.id).make_generic_params()
216 noop_flat_map_generic_param(param, self)
220 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
221 if p.is_placeholder {
222 self.remove(p.id).make_params()
224 noop_flat_map_param(p, self)
228 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
229 if sf.is_placeholder {
230 self.remove(sf.id).make_struct_fields()
232 noop_flat_map_struct_field(sf, self)
236 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
237 if variant.is_placeholder {
238 self.remove(variant.id).make_variants()
240 noop_flat_map_variant(variant, self)
244 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
246 ast::ItemKind::MacCall(_) => return self.remove(item.id).make_items(),
247 ast::ItemKind::MacroDef(_) => return smallvec![item],
251 noop_flat_map_item(item, self)
254 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
256 ast::AssocItemKind::MacCall(_) => self.remove(item.id).make_trait_items(),
257 _ => noop_flat_map_assoc_item(item, self),
261 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
263 ast::AssocItemKind::MacCall(_) => self.remove(item.id).make_impl_items(),
264 _ => noop_flat_map_assoc_item(item, self),
268 fn flat_map_foreign_item(
270 item: P<ast::ForeignItem>,
271 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
273 ast::ForeignItemKind::MacCall(_) => self.remove(item.id).make_foreign_items(),
274 _ => noop_flat_map_foreign_item(item, self),
278 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
280 ast::ExprKind::MacCall(_) => *expr = self.remove(expr.id).make_expr(),
281 _ => noop_visit_expr(expr, self),
285 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
287 ast::ExprKind::MacCall(_) => self.remove(expr.id).make_opt_expr(),
288 _ => noop_filter_map_expr(expr, self),
292 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
293 let (style, mut stmts) = match stmt.kind {
294 ast::StmtKind::MacCall(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
295 _ => return noop_flat_map_stmt(stmt, self),
298 if style == ast::MacStmtStyle::Semicolon {
299 if let Some(stmt) = stmts.pop() {
300 stmts.push(stmt.add_trailing_semicolon());
307 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
309 ast::PatKind::MacCall(_) => *pat = self.remove(pat.id).make_pat(),
310 _ => noop_visit_pat(pat, self),
314 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
316 ast::TyKind::MacCall(_) => *ty = self.remove(ty.id).make_ty(),
317 _ => noop_visit_ty(ty, self),
321 fn visit_block(&mut self, block: &mut P<ast::Block>) {
322 noop_visit_block(block, self);
324 for stmt in block.stmts.iter_mut() {
326 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
327 stmt.id = self.cx.resolver.next_node_id();
332 fn visit_mod(&mut self, module: &mut ast::Mod) {
333 noop_visit_mod(module, self);
334 module.items.retain(|item| match item.kind {
335 ast::ItemKind::MacCall(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
340 fn visit_mac(&mut self, _mac: &mut ast::MacCall) {