1 use crate::base::ExtCtxt;
2 use crate::expand::{AstFragment, AstFragmentKind};
4 use rustc_span::source_map::{dummy_spanned, DUMMY_SP};
6 use syntax::mut_visit::*;
9 use smallvec::{smallvec, SmallVec};
11 use rustc_data_structures::fx::FxHashMap;
14 kind: AstFragmentKind,
16 vis: Option<ast::Visibility>,
18 fn mac_placeholder() -> ast::Mac {
20 path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
21 args: P(ast::MacArgs::Empty),
22 prior_type_ascription: None,
26 let ident = ast::Ident::invalid();
27 let attrs = Vec::new();
28 let vis = vis.unwrap_or_else(|| dummy_spanned(ast::VisibilityKind::Inherited));
30 let expr_placeholder = || {
34 attrs: ast::AttrVec::new(),
35 kind: ast::ExprKind::Mac(mac_placeholder()),
38 let ty = || P(ast::Ty { id, kind: ast::TyKind::Mac(mac_placeholder()), span });
39 let pat = || P(ast::Pat { id, kind: ast::PatKind::Mac(mac_placeholder()), span });
42 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
43 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
44 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
50 kind: ast::ItemKind::Mac(mac_placeholder()),
53 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![P(ast::AssocItem {
59 kind: ast::AssocItemKind::Macro(mac_placeholder()),
60 defaultness: ast::Defaultness::Final,
63 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![P(ast::AssocItem {
69 kind: ast::AssocItemKind::Macro(mac_placeholder()),
70 defaultness: ast::Defaultness::Final,
73 AstFragmentKind::ForeignItems => {
74 AstFragment::ForeignItems(smallvec![P(ast::ForeignItem {
80 kind: ast::ForeignItemKind::Macro(mac_placeholder()),
84 AstFragmentKind::Pat => {
85 AstFragment::Pat(P(ast::Pat { id, span, kind: ast::PatKind::Mac(mac_placeholder()) }))
87 AstFragmentKind::Ty => {
88 AstFragment::Ty(P(ast::Ty { id, span, kind: ast::TyKind::Mac(mac_placeholder()) }))
90 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
91 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ast::AttrVec::new()));
92 ast::Stmt { id, span, kind: ast::StmtKind::Mac(mac) }
94 AstFragmentKind::Arms => AstFragment::Arms(smallvec![ast::Arm {
95 attrs: Default::default(),
96 body: expr_placeholder(),
101 is_placeholder: true,
103 AstFragmentKind::Fields => AstFragment::Fields(smallvec![ast::Field {
104 attrs: Default::default(),
105 expr: expr_placeholder(),
110 is_placeholder: true,
112 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![ast::FieldPat {
113 attrs: Default::default(),
119 is_placeholder: true,
121 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
123 attrs: Default::default(),
124 bounds: Default::default(),
127 is_placeholder: true,
128 kind: ast::GenericParamKind::Lifetime,
131 AstFragmentKind::Params => AstFragment::Params(smallvec![ast::Param {
132 attrs: Default::default(),
137 is_placeholder: true,
139 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![ast::StructField {
140 attrs: Default::default(),
146 is_placeholder: true,
148 AstFragmentKind::Variants => AstFragment::Variants(smallvec![ast::Variant {
149 attrs: Default::default(),
150 data: ast::VariantData::Struct(Default::default(), false),
156 is_placeholder: true,
161 pub struct PlaceholderExpander<'a, 'b> {
162 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
163 cx: &'a mut ExtCtxt<'b>,
167 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
168 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
169 PlaceholderExpander { cx, expanded_fragments: FxHashMap::default(), monotonic }
172 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
173 fragment.mut_visit_with(self);
174 self.expanded_fragments.insert(id, fragment);
177 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
178 self.expanded_fragments.remove(&id).unwrap()
182 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
183 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
184 if arm.is_placeholder {
185 self.remove(arm.id).make_arms()
187 noop_flat_map_arm(arm, self)
191 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
192 if field.is_placeholder {
193 self.remove(field.id).make_fields()
195 noop_flat_map_field(field, self)
199 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
200 if fp.is_placeholder {
201 self.remove(fp.id).make_field_patterns()
203 noop_flat_map_field_pattern(fp, self)
207 fn flat_map_generic_param(
209 param: ast::GenericParam,
210 ) -> SmallVec<[ast::GenericParam; 1]> {
211 if param.is_placeholder {
212 self.remove(param.id).make_generic_params()
214 noop_flat_map_generic_param(param, self)
218 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
219 if p.is_placeholder {
220 self.remove(p.id).make_params()
222 noop_flat_map_param(p, self)
226 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
227 if sf.is_placeholder {
228 self.remove(sf.id).make_struct_fields()
230 noop_flat_map_struct_field(sf, self)
234 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
235 if variant.is_placeholder {
236 self.remove(variant.id).make_variants()
238 noop_flat_map_variant(variant, self)
242 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
244 ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
245 ast::ItemKind::MacroDef(_) => return smallvec![item],
249 noop_flat_map_item(item, self)
252 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
254 ast::AssocItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
255 _ => noop_flat_map_assoc_item(item, self),
259 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
261 ast::AssocItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
262 _ => noop_flat_map_assoc_item(item, self),
266 fn flat_map_foreign_item(
268 item: P<ast::ForeignItem>,
269 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
271 ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
272 _ => noop_flat_map_foreign_item(item, self),
276 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
278 ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
279 _ => noop_visit_expr(expr, self),
283 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
285 ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
286 _ => noop_filter_map_expr(expr, self),
290 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
291 let (style, mut stmts) = match stmt.kind {
292 ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
293 _ => return noop_flat_map_stmt(stmt, self),
296 if style == ast::MacStmtStyle::Semicolon {
297 if let Some(stmt) = stmts.pop() {
298 stmts.push(stmt.add_trailing_semicolon());
305 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
307 ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
308 _ => noop_visit_pat(pat, self),
312 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
314 ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
315 _ => noop_visit_ty(ty, self),
319 fn visit_block(&mut self, block: &mut P<ast::Block>) {
320 noop_visit_block(block, self);
322 for stmt in block.stmts.iter_mut() {
324 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
325 stmt.id = self.cx.resolver.next_node_id();
330 fn visit_mod(&mut self, module: &mut ast::Mod) {
331 noop_visit_mod(module, self);
332 module.items.retain(|item| match item.kind {
333 ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
338 fn visit_mac(&mut self, _mac: &mut ast::Mac) {