1 use crate::base::ExtCtxt;
2 use crate::expand::{AstFragment, AstFragmentKind};
5 use syntax::source_map::{DUMMY_SP, dummy_spanned};
6 use syntax::mut_visit::*;
10 use smallvec::{smallvec, SmallVec};
12 use rustc_data_structures::fx::FxHashMap;
14 pub fn placeholder(kind: AstFragmentKind, id: ast::NodeId, vis: Option<ast::Visibility>)
16 fn mac_placeholder() -> ast::Mac {
18 path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
19 args: P(ast::MacArgs::Empty),
20 prior_type_ascription: None,
24 let ident = ast::Ident::invalid();
25 let attrs = Vec::new();
26 let generics = ast::Generics::default();
27 let vis = vis.unwrap_or_else(|| dummy_spanned(ast::VisibilityKind::Inherited));
29 let expr_placeholder = || P(ast::Expr {
31 attrs: ThinVec::new(),
32 kind: ast::ExprKind::Mac(mac_placeholder()),
34 let ty = || P(ast::Ty {
36 kind: ast::TyKind::Mac(mac_placeholder()),
39 let pat = || P(ast::Pat {
41 kind: ast::PatKind::Mac(mac_placeholder()),
46 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
47 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
48 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
49 id, span, ident, vis, attrs,
50 kind: ast::ItemKind::Mac(mac_placeholder()),
53 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![ast::TraitItem {
54 id, span, ident, vis, attrs, generics,
55 kind: ast::TraitItemKind::Macro(mac_placeholder()),
58 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![ast::ImplItem {
59 id, span, ident, vis, attrs, generics,
60 kind: ast::ImplItemKind::Macro(mac_placeholder()),
61 defaultness: ast::Defaultness::Final,
64 AstFragmentKind::ForeignItems =>
65 AstFragment::ForeignItems(smallvec![ast::ForeignItem {
66 id, span, ident, vis, attrs,
67 kind: ast::ForeignItemKind::Macro(mac_placeholder()),
69 AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
70 id, span, kind: ast::PatKind::Mac(mac_placeholder()),
72 AstFragmentKind::Ty => AstFragment::Ty(P(ast::Ty {
73 id, span, kind: ast::TyKind::Mac(mac_placeholder()),
75 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
76 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ThinVec::new()));
77 ast::Stmt { id, span, kind: ast::StmtKind::Mac(mac) }
79 AstFragmentKind::Arms => AstFragment::Arms(smallvec![
81 attrs: Default::default(),
82 body: expr_placeholder(),
90 AstFragmentKind::Fields => AstFragment::Fields(smallvec![
92 attrs: Default::default(),
93 expr: expr_placeholder(),
101 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![
103 attrs: Default::default(),
109 is_placeholder: true,
112 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
114 attrs: Default::default(),
115 bounds: Default::default(),
118 is_placeholder: true,
119 kind: ast::GenericParamKind::Lifetime,
122 AstFragmentKind::Params => AstFragment::Params(smallvec![
124 attrs: Default::default(),
129 is_placeholder: true,
132 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![
134 attrs: Default::default(),
140 is_placeholder: true,
143 AstFragmentKind::Variants => AstFragment::Variants(smallvec![
145 attrs: Default::default(),
146 data: ast::VariantData::Struct(Default::default(), false),
152 is_placeholder: true,
158 pub struct PlaceholderExpander<'a, 'b> {
159 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
160 cx: &'a mut ExtCtxt<'b>,
164 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
165 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
166 PlaceholderExpander {
168 expanded_fragments: FxHashMap::default(),
173 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
174 fragment.mut_visit_with(self);
175 self.expanded_fragments.insert(id, fragment);
178 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
179 self.expanded_fragments.remove(&id).unwrap()
183 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
184 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
185 if arm.is_placeholder {
186 self.remove(arm.id).make_arms()
188 noop_flat_map_arm(arm, self)
192 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
193 if field.is_placeholder {
194 self.remove(field.id).make_fields()
196 noop_flat_map_field(field, self)
200 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
201 if fp.is_placeholder {
202 self.remove(fp.id).make_field_patterns()
204 noop_flat_map_field_pattern(fp, self)
208 fn flat_map_generic_param(
210 param: ast::GenericParam
211 ) -> 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::Mac(_) => 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: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
256 ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
257 _ => noop_flat_map_trait_item(item, self),
261 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
263 ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
264 _ => noop_flat_map_impl_item(item, self),
268 fn flat_map_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVec<[ast::ForeignItem; 1]> {
270 ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
271 _ => noop_flat_map_foreign_item(item, self),
275 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
277 ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
278 _ => noop_visit_expr(expr, self),
282 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
284 ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
285 _ => noop_filter_map_expr(expr, self),
289 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
290 let (style, mut stmts) = match stmt.kind {
291 ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
292 _ => return noop_flat_map_stmt(stmt, self),
295 if style == ast::MacStmtStyle::Semicolon {
296 if let Some(stmt) = stmts.pop() {
297 stmts.push(stmt.add_trailing_semicolon());
304 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
306 ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
307 _ => noop_visit_pat(pat, self),
311 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
313 ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
314 _ => noop_visit_ty(ty, self),
318 fn visit_block(&mut self, block: &mut P<ast::Block>) {
319 noop_visit_block(block, self);
321 for stmt in block.stmts.iter_mut() {
323 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
324 stmt.id = self.cx.resolver.next_node_id();
329 fn visit_mod(&mut self, module: &mut ast::Mod) {
330 noop_visit_mod(module, self);
331 module.items.retain(|item| match item.kind {
332 ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
337 fn visit_mac(&mut self, _mac: &mut ast::Mac) {