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 generics = ast::Generics::default();
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::Mac(mac_placeholder()),
39 let ty = || P(ast::Ty { id, kind: ast::TyKind::Mac(mac_placeholder()), span });
40 let pat = || P(ast::Pat { id, kind: ast::PatKind::Mac(mac_placeholder()), span });
43 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
44 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
45 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
51 kind: ast::ItemKind::Mac(mac_placeholder()),
54 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![P(ast::AssocItem {
61 kind: ast::AssocItemKind::Macro(mac_placeholder()),
62 defaultness: ast::Defaultness::Final,
65 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![P(ast::AssocItem {
72 kind: ast::AssocItemKind::Macro(mac_placeholder()),
73 defaultness: ast::Defaultness::Final,
76 AstFragmentKind::ForeignItems => {
77 AstFragment::ForeignItems(smallvec![P(ast::ForeignItem {
83 kind: ast::ForeignItemKind::Macro(mac_placeholder()),
87 AstFragmentKind::Pat => {
88 AstFragment::Pat(P(ast::Pat { id, span, kind: ast::PatKind::Mac(mac_placeholder()) }))
90 AstFragmentKind::Ty => {
91 AstFragment::Ty(P(ast::Ty { id, span, kind: ast::TyKind::Mac(mac_placeholder()) }))
93 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
94 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ast::AttrVec::new()));
95 ast::Stmt { id, span, kind: ast::StmtKind::Mac(mac) }
97 AstFragmentKind::Arms => AstFragment::Arms(smallvec![ast::Arm {
98 attrs: Default::default(),
99 body: expr_placeholder(),
104 is_placeholder: true,
106 AstFragmentKind::Fields => AstFragment::Fields(smallvec![ast::Field {
107 attrs: Default::default(),
108 expr: expr_placeholder(),
113 is_placeholder: true,
115 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![ast::FieldPat {
116 attrs: Default::default(),
122 is_placeholder: true,
124 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
126 attrs: Default::default(),
127 bounds: Default::default(),
130 is_placeholder: true,
131 kind: ast::GenericParamKind::Lifetime,
134 AstFragmentKind::Params => AstFragment::Params(smallvec![ast::Param {
135 attrs: Default::default(),
140 is_placeholder: true,
142 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![ast::StructField {
143 attrs: Default::default(),
149 is_placeholder: true,
151 AstFragmentKind::Variants => AstFragment::Variants(smallvec![ast::Variant {
152 attrs: Default::default(),
153 data: ast::VariantData::Struct(Default::default(), false),
159 is_placeholder: true,
164 pub struct PlaceholderExpander<'a, 'b> {
165 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
166 cx: &'a mut ExtCtxt<'b>,
170 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
171 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
172 PlaceholderExpander { cx, expanded_fragments: FxHashMap::default(), monotonic }
175 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
176 fragment.mut_visit_with(self);
177 self.expanded_fragments.insert(id, fragment);
180 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
181 self.expanded_fragments.remove(&id).unwrap()
185 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
186 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
187 if arm.is_placeholder {
188 self.remove(arm.id).make_arms()
190 noop_flat_map_arm(arm, self)
194 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
195 if field.is_placeholder {
196 self.remove(field.id).make_fields()
198 noop_flat_map_field(field, self)
202 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
203 if fp.is_placeholder {
204 self.remove(fp.id).make_field_patterns()
206 noop_flat_map_field_pattern(fp, self)
210 fn flat_map_generic_param(
212 param: ast::GenericParam,
213 ) -> SmallVec<[ast::GenericParam; 1]> {
214 if param.is_placeholder {
215 self.remove(param.id).make_generic_params()
217 noop_flat_map_generic_param(param, self)
221 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
222 if p.is_placeholder {
223 self.remove(p.id).make_params()
225 noop_flat_map_param(p, self)
229 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
230 if sf.is_placeholder {
231 self.remove(sf.id).make_struct_fields()
233 noop_flat_map_struct_field(sf, self)
237 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
238 if variant.is_placeholder {
239 self.remove(variant.id).make_variants()
241 noop_flat_map_variant(variant, self)
245 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
247 ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
248 ast::ItemKind::MacroDef(_) => return smallvec![item],
252 noop_flat_map_item(item, self)
255 fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
257 ast::AssocItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
258 _ => noop_flat_map_assoc_item(item, self),
262 fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
264 ast::AssocItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
265 _ => noop_flat_map_assoc_item(item, self),
269 fn flat_map_foreign_item(
271 item: P<ast::ForeignItem>,
272 ) -> SmallVec<[P<ast::ForeignItem>; 1]> {
274 ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
275 _ => noop_flat_map_foreign_item(item, self),
279 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
281 ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
282 _ => noop_visit_expr(expr, self),
286 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
288 ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
289 _ => noop_filter_map_expr(expr, self),
293 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
294 let (style, mut stmts) = match stmt.kind {
295 ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
296 _ => return noop_flat_map_stmt(stmt, self),
299 if style == ast::MacStmtStyle::Semicolon {
300 if let Some(stmt) = stmts.pop() {
301 stmts.push(stmt.add_trailing_semicolon());
308 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
310 ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
311 _ => noop_visit_pat(pat, self),
315 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
317 ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
318 _ => noop_visit_ty(ty, self),
322 fn visit_block(&mut self, block: &mut P<ast::Block>) {
323 noop_visit_block(block, self);
325 for stmt in block.stmts.iter_mut() {
327 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
328 stmt.id = self.cx.resolver.next_node_id();
333 fn visit_mod(&mut self, module: &mut ast::Mod) {
334 noop_visit_mod(module, self);
335 module.items.retain(|item| match item.kind {
336 ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
341 fn visit_mac(&mut self, _mac: &mut ast::Mac) {