1 use crate::expand::{self, AstFragment, Invocation};
2 use crate::module::DirOwnership;
5 use rustc_ast::token::{self, Nonterminal};
6 use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, LazyTokenStream, TokenStream};
7 use rustc_ast::visit::{AssocCtxt, Visitor};
8 use rustc_ast::{self as ast, AstLike, Attribute, Item, NodeId, PatKind};
9 use rustc_attr::{self as attr, Deprecation, Stability};
10 use rustc_data_structures::fx::FxHashMap;
11 use rustc_data_structures::sync::{self, Lrc};
12 use rustc_errors::{DiagnosticBuilder, ErrorReported};
13 use rustc_lint_defs::builtin::PROC_MACRO_BACK_COMPAT;
14 use rustc_lint_defs::BuiltinLintDiagnostics;
15 use rustc_parse::{self, nt_to_tokenstream, parser, MACRO_ARGUMENTS};
16 use rustc_session::{parse::ParseSess, Limit, Session};
17 use rustc_span::def_id::DefId;
18 use rustc_span::edition::Edition;
19 use rustc_span::hygiene::{AstPass, ExpnData, ExpnId, ExpnKind};
20 use rustc_span::source_map::SourceMap;
21 use rustc_span::symbol::{kw, sym, Ident, Symbol};
22 use rustc_span::{FileName, MultiSpan, Span, DUMMY_SP};
23 use smallvec::{smallvec, SmallVec};
25 use std::default::Default;
27 use std::path::PathBuf;
30 crate use rustc_span::hygiene::MacroKind;
32 #[derive(Debug, Clone)]
33 pub enum Annotatable {
35 TraitItem(P<ast::AssocItem>),
36 ImplItem(P<ast::AssocItem>),
37 ForeignItem(P<ast::ForeignItem>),
41 ExprField(ast::ExprField),
42 PatField(ast::PatField),
43 GenericParam(ast::GenericParam),
45 FieldDef(ast::FieldDef),
46 Variant(ast::Variant),
49 impl AstLike for Annotatable {
50 fn attrs(&self) -> &[Attribute] {
52 Annotatable::Item(ref item) => &item.attrs,
53 Annotatable::TraitItem(ref trait_item) => &trait_item.attrs,
54 Annotatable::ImplItem(ref impl_item) => &impl_item.attrs,
55 Annotatable::ForeignItem(ref foreign_item) => &foreign_item.attrs,
56 Annotatable::Stmt(ref stmt) => stmt.attrs(),
57 Annotatable::Expr(ref expr) => &expr.attrs,
58 Annotatable::Arm(ref arm) => &arm.attrs,
59 Annotatable::ExprField(ref field) => &field.attrs,
60 Annotatable::PatField(ref fp) => &fp.attrs,
61 Annotatable::GenericParam(ref gp) => &gp.attrs,
62 Annotatable::Param(ref p) => &p.attrs,
63 Annotatable::FieldDef(ref sf) => &sf.attrs,
64 Annotatable::Variant(ref v) => &v.attrs(),
68 fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
70 Annotatable::Item(item) => item.visit_attrs(f),
71 Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
72 Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
73 Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
74 Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
75 Annotatable::Expr(expr) => expr.visit_attrs(f),
76 Annotatable::Arm(arm) => arm.visit_attrs(f),
77 Annotatable::ExprField(field) => field.visit_attrs(f),
78 Annotatable::PatField(fp) => fp.visit_attrs(f),
79 Annotatable::GenericParam(gp) => gp.visit_attrs(f),
80 Annotatable::Param(p) => p.visit_attrs(f),
81 Annotatable::FieldDef(sf) => sf.visit_attrs(f),
82 Annotatable::Variant(v) => v.visit_attrs(f),
86 fn tokens_mut(&mut self) -> Option<&mut Option<LazyTokenStream>> {
88 Annotatable::Item(item) => item.tokens_mut(),
89 Annotatable::TraitItem(trait_item) => trait_item.tokens_mut(),
90 Annotatable::ImplItem(impl_item) => impl_item.tokens_mut(),
91 Annotatable::ForeignItem(foreign_item) => foreign_item.tokens_mut(),
92 Annotatable::Stmt(stmt) => stmt.tokens_mut(),
93 Annotatable::Expr(expr) => expr.tokens_mut(),
94 Annotatable::Arm(arm) => arm.tokens_mut(),
95 Annotatable::ExprField(field) => field.tokens_mut(),
96 Annotatable::PatField(fp) => fp.tokens_mut(),
97 Annotatable::GenericParam(gp) => gp.tokens_mut(),
98 Annotatable::Param(p) => p.tokens_mut(),
99 Annotatable::FieldDef(sf) => sf.tokens_mut(),
100 Annotatable::Variant(v) => v.tokens_mut(),
106 pub fn span(&self) -> Span {
108 Annotatable::Item(ref item) => item.span,
109 Annotatable::TraitItem(ref trait_item) => trait_item.span,
110 Annotatable::ImplItem(ref impl_item) => impl_item.span,
111 Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
112 Annotatable::Stmt(ref stmt) => stmt.span,
113 Annotatable::Expr(ref expr) => expr.span,
114 Annotatable::Arm(ref arm) => arm.span,
115 Annotatable::ExprField(ref field) => field.span,
116 Annotatable::PatField(ref fp) => fp.pat.span,
117 Annotatable::GenericParam(ref gp) => gp.ident.span,
118 Annotatable::Param(ref p) => p.span,
119 Annotatable::FieldDef(ref sf) => sf.span,
120 Annotatable::Variant(ref v) => v.span,
124 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
126 Annotatable::Item(item) => visitor.visit_item(item),
127 Annotatable::TraitItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Trait),
128 Annotatable::ImplItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Impl),
129 Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
130 Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
131 Annotatable::Expr(expr) => visitor.visit_expr(expr),
132 Annotatable::Arm(arm) => visitor.visit_arm(arm),
133 Annotatable::ExprField(field) => visitor.visit_expr_field(field),
134 Annotatable::PatField(fp) => visitor.visit_pat_field(fp),
135 Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp),
136 Annotatable::Param(p) => visitor.visit_param(p),
137 Annotatable::FieldDef(sf) => visitor.visit_field_def(sf),
138 Annotatable::Variant(v) => visitor.visit_variant(v),
142 crate fn into_nonterminal(self) -> Nonterminal {
144 Annotatable::Item(item) => token::NtItem(item),
145 Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
146 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
148 Annotatable::ForeignItem(item) => {
149 token::NtItem(P(item.and_then(ast::ForeignItem::into_item)))
151 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
152 Annotatable::Expr(expr) => token::NtExpr(expr),
154 | Annotatable::ExprField(..)
155 | Annotatable::PatField(..)
156 | Annotatable::GenericParam(..)
157 | Annotatable::Param(..)
158 | Annotatable::FieldDef(..)
159 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
163 crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
164 // Tokens of an attribute target may be invalidated by some outer `#[derive]` performing
165 // "full configuration" (attributes following derives on the same item should be the most
166 // common case), that's why synthesizing tokens is allowed.
167 nt_to_tokenstream(&self.into_nonterminal(), sess, CanSynthesizeMissingTokens::Yes)
170 pub fn expect_item(self) -> P<ast::Item> {
172 Annotatable::Item(i) => i,
173 _ => panic!("expected Item"),
177 pub fn expect_trait_item(self) -> P<ast::AssocItem> {
179 Annotatable::TraitItem(i) => i,
180 _ => panic!("expected Item"),
184 pub fn expect_impl_item(self) -> P<ast::AssocItem> {
186 Annotatable::ImplItem(i) => i,
187 _ => panic!("expected Item"),
191 pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
193 Annotatable::ForeignItem(i) => i,
194 _ => panic!("expected foreign item"),
198 pub fn expect_stmt(self) -> ast::Stmt {
200 Annotatable::Stmt(stmt) => stmt.into_inner(),
201 _ => panic!("expected statement"),
205 pub fn expect_expr(self) -> P<ast::Expr> {
207 Annotatable::Expr(expr) => expr,
208 _ => panic!("expected expression"),
212 pub fn expect_arm(self) -> ast::Arm {
214 Annotatable::Arm(arm) => arm,
215 _ => panic!("expected match arm"),
219 pub fn expect_expr_field(self) -> ast::ExprField {
221 Annotatable::ExprField(field) => field,
222 _ => panic!("expected field"),
226 pub fn expect_pat_field(self) -> ast::PatField {
228 Annotatable::PatField(fp) => fp,
229 _ => panic!("expected field pattern"),
233 pub fn expect_generic_param(self) -> ast::GenericParam {
235 Annotatable::GenericParam(gp) => gp,
236 _ => panic!("expected generic parameter"),
240 pub fn expect_param(self) -> ast::Param {
242 Annotatable::Param(param) => param,
243 _ => panic!("expected parameter"),
247 pub fn expect_field_def(self) -> ast::FieldDef {
249 Annotatable::FieldDef(sf) => sf,
250 _ => panic!("expected struct field"),
254 pub fn expect_variant(self) -> ast::Variant {
256 Annotatable::Variant(v) => v,
257 _ => panic!("expected variant"),
262 /// Result of an expansion that may need to be retried.
263 /// Consider using this for non-`MultiItemModifier` expanders as well.
264 pub enum ExpandResult<T, U> {
265 /// Expansion produced a result (possibly dummy).
267 /// Expansion could not produce a result and needs to be retried.
271 // `meta_item` is the attribute, and `item` is the item being modified.
272 pub trait MultiItemModifier {
275 ecx: &mut ExtCtxt<'_>,
277 meta_item: &ast::MetaItem,
279 ) -> ExpandResult<Vec<Annotatable>, Annotatable>;
282 impl<F> MultiItemModifier for F
284 F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
288 ecx: &mut ExtCtxt<'_>,
290 meta_item: &ast::MetaItem,
292 ) -> ExpandResult<Vec<Annotatable>, Annotatable> {
293 ExpandResult::Ready(self(ecx, span, meta_item, item))
297 pub trait ProcMacro {
300 ecx: &'cx mut ExtCtxt<'_>,
303 ) -> Result<TokenStream, ErrorReported>;
306 impl<F> ProcMacro for F
308 F: Fn(TokenStream) -> TokenStream,
312 _ecx: &'cx mut ExtCtxt<'_>,
315 ) -> Result<TokenStream, ErrorReported> {
316 // FIXME setup implicit context in TLS before calling self.
321 pub trait AttrProcMacro {
324 ecx: &'cx mut ExtCtxt<'_>,
326 annotation: TokenStream,
327 annotated: TokenStream,
328 ) -> Result<TokenStream, ErrorReported>;
331 impl<F> AttrProcMacro for F
333 F: Fn(TokenStream, TokenStream) -> TokenStream,
337 _ecx: &'cx mut ExtCtxt<'_>,
339 annotation: TokenStream,
340 annotated: TokenStream,
341 ) -> Result<TokenStream, ErrorReported> {
342 // FIXME setup implicit context in TLS before calling self.
343 Ok(self(annotation, annotated))
347 /// Represents a thing that maps token trees to Macro Results
348 pub trait TTMacroExpander {
351 ecx: &'cx mut ExtCtxt<'_>,
354 ) -> Box<dyn MacResult + 'cx>;
357 pub type MacroExpanderFn =
358 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>;
360 impl<F> TTMacroExpander for F
362 F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>,
366 ecx: &'cx mut ExtCtxt<'_>,
369 ) -> Box<dyn MacResult + 'cx> {
370 self(ecx, span, input)
374 // Use a macro because forwarding to a simple function has type system issues
375 macro_rules! make_stmts_default {
377 $me.make_expr().map(|e| {
378 smallvec![ast::Stmt {
379 id: ast::DUMMY_NODE_ID,
381 kind: ast::StmtKind::Expr(e),
387 /// The result of a macro expansion. The return values of the various
388 /// methods are spliced into the AST at the callsite of the macro.
389 pub trait MacResult {
390 /// Creates an expression.
391 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
394 /// Creates zero or more items.
395 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
399 /// Creates zero or more impl items.
400 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
404 /// Creates zero or more trait items.
405 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
409 /// Creates zero or more items in an `extern {}` block
410 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
414 /// Creates a pattern.
415 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
419 /// Creates zero or more statements.
421 /// By default this attempts to create an expression statement,
422 /// returning None if that fails.
423 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
424 make_stmts_default!(self)
427 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
431 fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
435 fn make_expr_fields(self: Box<Self>) -> Option<SmallVec<[ast::ExprField; 1]>> {
439 fn make_pat_fields(self: Box<Self>) -> Option<SmallVec<[ast::PatField; 1]>> {
443 fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
447 fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
451 fn make_field_defs(self: Box<Self>) -> Option<SmallVec<[ast::FieldDef; 1]>> {
455 fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
460 macro_rules! make_MacEager {
461 ( $( $fld:ident: $t:ty, )* ) => {
462 /// `MacResult` implementation for the common case where you've already
463 /// built each form of AST that you might return.
465 pub struct MacEager {
467 pub $fld: Option<$t>,
473 pub fn $fld(v: $t) -> Box<dyn MacResult> {
487 items: SmallVec<[P<ast::Item>; 1]>,
488 impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
489 trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
490 foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
491 stmts: SmallVec<[ast::Stmt; 1]>,
495 impl MacResult for MacEager {
496 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
500 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
504 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
508 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
512 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
516 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
517 match self.stmts.as_ref().map_or(0, |s| s.len()) {
518 0 => make_stmts_default!(self),
523 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
524 if let Some(p) = self.pat {
527 if let Some(e) = self.expr {
528 if let ast::ExprKind::Lit(_) = e.kind {
529 return Some(P(ast::Pat {
530 id: ast::DUMMY_NODE_ID,
532 kind: PatKind::Lit(e),
540 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
545 /// Fill-in macro expansion result, to allow compilation to continue
546 /// after hitting errors.
547 #[derive(Copy, Clone)]
548 pub struct DummyResult {
554 /// Creates a default MacResult that can be anything.
556 /// Use this as a return value after hitting any errors and
557 /// calling `span_err`.
558 pub fn any(span: Span) -> Box<dyn MacResult + 'static> {
559 Box::new(DummyResult { is_error: true, span })
562 /// Same as `any`, but must be a valid fragment, not error.
563 pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
564 Box::new(DummyResult { is_error: false, span })
567 /// A plain dummy expression.
568 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
570 id: ast::DUMMY_NODE_ID,
571 kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
573 attrs: ast::AttrVec::new(),
578 /// A plain dummy pattern.
579 pub fn raw_pat(sp: Span) -> ast::Pat {
580 ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp, tokens: None }
583 /// A plain dummy type.
584 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
586 id: ast::DUMMY_NODE_ID,
587 kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
594 impl MacResult for DummyResult {
595 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
596 Some(DummyResult::raw_expr(self.span, self.is_error))
599 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
600 Some(P(DummyResult::raw_pat(self.span)))
603 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
604 Some(SmallVec::new())
607 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
608 Some(SmallVec::new())
611 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
612 Some(SmallVec::new())
615 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
616 Some(SmallVec::new())
619 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
620 Some(smallvec![ast::Stmt {
621 id: ast::DUMMY_NODE_ID,
622 kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
627 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
628 Some(DummyResult::raw_ty(self.span, self.is_error))
631 fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
632 Some(SmallVec::new())
635 fn make_expr_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::ExprField; 1]>> {
636 Some(SmallVec::new())
639 fn make_pat_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::PatField; 1]>> {
640 Some(SmallVec::new())
643 fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
644 Some(SmallVec::new())
647 fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
648 Some(SmallVec::new())
651 fn make_field_defs(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldDef; 1]>> {
652 Some(SmallVec::new())
655 fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
656 Some(SmallVec::new())
660 /// A syntax extension kind.
661 pub enum SyntaxExtensionKind {
662 /// A token-based function-like macro.
664 /// An expander with signature TokenStream -> TokenStream.
665 Box<dyn ProcMacro + sync::Sync + sync::Send>,
668 /// An AST-based function-like macro.
670 /// An expander with signature TokenStream -> AST.
671 Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
674 /// A token-based attribute macro.
676 /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
677 /// The first TokenSteam is the attribute itself, the second is the annotated item.
678 /// The produced TokenSteam replaces the input TokenSteam.
679 Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
682 /// An AST-based attribute macro.
684 /// An expander with signature (AST, AST) -> AST.
685 /// The first AST fragment is the attribute itself, the second is the annotated item.
686 /// The produced AST fragment replaces the input AST fragment.
687 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
690 /// A trivial attribute "macro" that does nothing,
691 /// only keeps the attribute and marks it as inert,
692 /// thus making it ineligible for further expansion.
694 /// Suppresses the `unused_attributes` lint for this attribute.
698 /// A token-based derive macro.
700 /// An expander with signature TokenStream -> TokenStream (not yet).
701 /// The produced TokenSteam is appended to the input TokenSteam.
702 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
705 /// An AST-based derive macro.
707 /// An expander with signature AST -> AST.
708 /// The produced AST fragment is appended to the input AST fragment.
709 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
713 /// A struct representing a macro definition in "lowered" form ready for expansion.
714 pub struct SyntaxExtension {
715 /// A syntax extension kind.
716 pub kind: SyntaxExtensionKind,
717 /// Span of the macro definition.
719 /// List of unstable features that are treated as stable inside this macro.
720 pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
721 /// Suppresses the `unsafe_code` lint for code produced by this macro.
722 pub allow_internal_unsafe: bool,
723 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
724 pub local_inner_macros: bool,
725 /// The macro's stability info.
726 pub stability: Option<Stability>,
727 /// The macro's deprecation info.
728 pub deprecation: Option<Deprecation>,
729 /// Names of helper attributes registered by this macro.
730 pub helper_attrs: Vec<Symbol>,
731 /// Edition of the crate in which this macro is defined.
732 pub edition: Edition,
733 /// Built-in macros have a couple of special properties like availability
734 /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
735 pub builtin_name: Option<Symbol>,
738 impl SyntaxExtension {
739 /// Returns which kind of macro calls this syntax extension.
740 pub fn macro_kind(&self) -> MacroKind {
742 SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
743 SyntaxExtensionKind::Attr(..)
744 | SyntaxExtensionKind::LegacyAttr(..)
745 | SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr,
746 SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
752 /// Constructs a syntax extension with default properties.
753 pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
756 allow_internal_unstable: None,
757 allow_internal_unsafe: false,
758 local_inner_macros: false,
761 helper_attrs: Vec::new(),
768 /// Constructs a syntax extension with the given properties
769 /// and other properties converted from attributes.
772 kind: SyntaxExtensionKind,
774 helper_attrs: Vec<Symbol>,
777 attrs: &[ast::Attribute],
778 ) -> SyntaxExtension {
779 let allow_internal_unstable =
780 attr::allow_internal_unstable(sess, &attrs).collect::<Vec<Symbol>>();
782 let mut local_inner_macros = false;
783 if let Some(macro_export) = sess.find_by_name(attrs, sym::macro_export) {
784 if let Some(l) = macro_export.meta_item_list() {
785 local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
789 let builtin_name = sess
790 .find_by_name(attrs, sym::rustc_builtin_macro)
791 .map(|a| a.value_str().unwrap_or(name));
792 let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
793 if let Some((_, sp)) = const_stability {
796 .struct_span_err(sp, "macros cannot have const stability attributes")
797 .span_label(sp, "invalid const stability attribute")
799 sess.source_map().guess_head_span(span),
800 "const stability attribute affects this macro",
808 allow_internal_unstable: (!allow_internal_unstable.is_empty())
809 .then(|| allow_internal_unstable.into()),
810 allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe),
812 stability: stability.map(|(s, _)| s),
813 deprecation: attr::find_deprecation(&sess, attrs).map(|(d, _)| d),
820 pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
822 _: &'cx mut ExtCtxt<'_>,
825 ) -> Box<dyn MacResult + 'cx> {
826 DummyResult::any(span)
828 SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
831 pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
837 ) -> Vec<Annotatable> {
840 SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
843 pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension {
844 SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
852 macro_def_id: Option<DefId>,
855 ExpnKind::Macro(self.macro_kind(), descr),
859 self.allow_internal_unstable.clone(),
860 self.allow_internal_unsafe,
861 self.local_inner_macros,
868 /// Error type that denotes indeterminacy.
869 pub struct Indeterminate;
871 pub trait ResolverExpand {
872 fn next_node_id(&mut self) -> NodeId;
874 fn resolve_dollar_crates(&mut self);
875 fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment);
876 fn register_builtin_macro(&mut self, name: Symbol, ext: SyntaxExtensionKind);
878 fn expansion_for_ast_pass(
883 parent_module_id: Option<NodeId>,
886 fn resolve_imports(&mut self);
888 fn resolve_macro_invocation(
891 eager_expansion_root: ExpnId,
893 ) -> Result<Lrc<SyntaxExtension>, Indeterminate>;
895 fn check_unused_macros(&mut self);
897 /// Some parent node that is close enough to the given macro call.
898 fn lint_node_id(&self, expn_id: ExpnId) -> NodeId;
900 // Resolver interfaces for specific built-in macros.
901 /// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
902 fn has_derive_copy(&self, expn_id: ExpnId) -> bool;
903 /// Resolve paths inside the `#[derive(...)]` attribute with the given `ExpnId`.
907 derives: Vec<ast::Path>,
909 ) -> Result<(), Indeterminate>;
910 /// Take resolutions for paths inside the `#[derive(...)]` attribute with the given `ExpnId`
911 /// back from resolver.
912 fn take_derive_resolutions(
915 ) -> Option<Vec<(Lrc<SyntaxExtension>, ast::Path)>>;
916 /// Path resolution logic for `#[cfg_accessible(path)]`.
917 fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result<bool, Indeterminate>;
920 #[derive(Clone, Default)]
921 pub struct ModuleData {
922 /// Path to the module starting from the crate name, like `my_crate::foo::bar`.
923 pub mod_path: Vec<Ident>,
924 /// Stack of paths to files loaded by out-of-line module items,
925 /// used to detect and report recursive module inclusions.
926 pub file_path_stack: Vec<PathBuf>,
927 /// Directory to search child module files in,
928 /// often (but not necessarily) the parent of the top file path on the `file_path_stack`.
929 pub dir_path: PathBuf,
933 pub fn with_dir_path(&self, dir_path: PathBuf) -> ModuleData {
935 mod_path: self.mod_path.clone(),
936 file_path_stack: self.file_path_stack.clone(),
943 pub struct ExpansionData {
946 pub module: Rc<ModuleData>,
947 pub dir_ownership: DirOwnership,
948 pub prior_type_ascription: Option<(Span, bool)>,
951 type OnExternModLoaded<'a> =
952 Option<&'a dyn Fn(Ident, Vec<Attribute>, Vec<P<Item>>, Span) -> (Vec<Attribute>, Vec<P<Item>>)>;
954 /// One of these is made during expansion and incrementally updated as we go;
955 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
956 /// -> expn_data` of their expansion context stored into their span.
957 pub struct ExtCtxt<'a> {
958 pub sess: &'a Session,
959 pub ecfg: expand::ExpansionConfig<'a>,
960 pub reduced_recursion_limit: Option<Limit>,
961 pub root_path: PathBuf,
962 pub resolver: &'a mut dyn ResolverExpand,
963 pub current_expansion: ExpansionData,
964 /// Error recovery mode entered when expansion is stuck
965 /// (or during eager expansion, but that's a hack).
966 pub force_mode: bool,
967 pub expansions: FxHashMap<Span, Vec<String>>,
968 /// Called directly after having parsed an external `mod foo;` in expansion.
970 /// `Ident` is the module name.
971 pub(super) extern_mod_loaded: OnExternModLoaded<'a>,
974 impl<'a> ExtCtxt<'a> {
977 ecfg: expand::ExpansionConfig<'a>,
978 resolver: &'a mut dyn ResolverExpand,
979 extern_mod_loaded: OnExternModLoaded<'a>,
984 reduced_recursion_limit: None,
987 root_path: PathBuf::new(),
988 current_expansion: ExpansionData {
991 module: Default::default(),
992 dir_ownership: DirOwnership::Owned { relative: None },
993 prior_type_ascription: None,
996 expansions: FxHashMap::default(),
1000 /// Returns a `Folder` for deeply expanding all macros in an AST node.
1001 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
1002 expand::MacroExpander::new(self, false)
1005 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
1006 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
1007 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
1008 expand::MacroExpander::new(self, true)
1010 pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
1011 rustc_parse::stream_to_parser(&self.sess.parse_sess, stream, MACRO_ARGUMENTS)
1013 pub fn source_map(&self) -> &'a SourceMap {
1014 self.sess.parse_sess.source_map()
1016 pub fn parse_sess(&self) -> &'a ParseSess {
1017 &self.sess.parse_sess
1019 pub fn call_site(&self) -> Span {
1020 self.current_expansion.id.expn_data().call_site
1023 /// Equivalent of `Span::def_site` from the proc macro API,
1024 /// except that the location is taken from the span passed as an argument.
1025 pub fn with_def_site_ctxt(&self, span: Span) -> Span {
1026 span.with_def_site_ctxt(self.current_expansion.id)
1029 /// Equivalent of `Span::call_site` from the proc macro API,
1030 /// except that the location is taken from the span passed as an argument.
1031 pub fn with_call_site_ctxt(&self, span: Span) -> Span {
1032 span.with_call_site_ctxt(self.current_expansion.id)
1035 /// Equivalent of `Span::mixed_site` from the proc macro API,
1036 /// except that the location is taken from the span passed as an argument.
1037 pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
1038 span.with_mixed_site_ctxt(self.current_expansion.id)
1041 /// Returns span for the macro which originally caused the current expansion to happen.
1043 /// Stops backtracing at include! boundary.
1044 pub fn expansion_cause(&self) -> Option<Span> {
1045 self.current_expansion.id.expansion_cause()
1048 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1049 self.sess.parse_sess.span_diagnostic.struct_span_err(sp, msg)
1052 /// Emit `msg` attached to `sp`, without immediately stopping
1055 /// Compilation will be stopped in the near future (at the end of
1056 /// the macro expansion phase).
1057 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1058 self.sess.parse_sess.span_diagnostic.span_err(sp, msg);
1060 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1061 self.sess.parse_sess.span_diagnostic.span_warn(sp, msg);
1063 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1064 self.sess.parse_sess.span_diagnostic.span_bug(sp, msg);
1066 pub fn trace_macros_diag(&mut self) {
1067 for (sp, notes) in self.expansions.iter() {
1068 let mut db = self.sess.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
1074 // Fixme: does this result in errors?
1075 self.expansions.clear();
1077 pub fn bug(&self, msg: &str) -> ! {
1078 self.sess.parse_sess.span_diagnostic.bug(msg);
1080 pub fn trace_macros(&self) -> bool {
1083 pub fn set_trace_macros(&mut self, x: bool) {
1084 self.ecfg.trace_mac = x
1086 pub fn std_path(&self, components: &[Symbol]) -> Vec<Ident> {
1087 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1088 iter::once(Ident::new(kw::DollarCrate, def_site))
1089 .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
1092 pub fn def_site_path(&self, components: &[Symbol]) -> Vec<Ident> {
1093 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1094 components.iter().map(|&s| Ident::new(s, def_site)).collect()
1097 pub fn check_unused_macros(&mut self) {
1098 self.resolver.check_unused_macros();
1101 /// Resolves a path mentioned inside Rust code.
1103 /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths.
1105 /// Returns an absolute path to the file that `path` refers to.
1106 pub fn resolve_path(
1108 path: impl Into<PathBuf>,
1110 ) -> Result<PathBuf, DiagnosticBuilder<'a>> {
1111 let path = path.into();
1113 // Relative paths are resolved relative to the file in which they are found
1114 // after macro expansion (that is, they are unhygienic).
1115 if !path.is_absolute() {
1116 let callsite = span.source_callsite();
1117 let mut result = match self.source_map().span_to_unmapped_path(callsite) {
1118 FileName::Real(name) => name.into_local_path(),
1119 FileName::DocTest(path, _) => path,
1121 return Err(self.struct_span_err(
1123 &format!("cannot resolve relative path in non-file source `{}`", other),
1136 /// Extracts a string literal from the macro expanded version of `expr`,
1137 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
1138 /// compilation on error, merely emits a non-fatal error and returns `None`.
1139 pub fn expr_to_spanned_string<'a>(
1140 cx: &'a mut ExtCtxt<'_>,
1143 ) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> {
1144 // Perform eager expansion on the expression.
1145 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1146 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1148 Err(match expr.kind {
1149 ast::ExprKind::Lit(ref l) => match l.kind {
1150 ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
1151 ast::LitKind::Err(_) => None,
1152 _ => Some(cx.struct_span_err(l.span, err_msg)),
1154 ast::ExprKind::Err => None,
1155 _ => Some(cx.struct_span_err(expr.span, err_msg)),
1159 pub fn expr_to_string(
1160 cx: &mut ExtCtxt<'_>,
1163 ) -> Option<(Symbol, ast::StrStyle)> {
1164 expr_to_spanned_string(cx, expr, err_msg)
1171 .map(|(symbol, style, _)| (symbol, style))
1174 /// Non-fatally assert that `tts` is empty. Note that this function
1175 /// returns even when `tts` is non-empty, macros that *need* to stop
1176 /// compilation should call
1177 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1178 /// done as rarely as possible).
1179 pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) {
1180 if !tts.is_empty() {
1181 cx.span_err(sp, &format!("{} takes no arguments", name));
1185 /// Parse an expression. On error, emit it, advancing to `Eof`, and return `None`.
1186 pub fn parse_expr(p: &mut parser::Parser<'_>) -> Option<P<ast::Expr>> {
1187 match p.parse_expr() {
1188 Ok(e) => return Some(e),
1189 Err(mut err) => err.emit(),
1191 while p.token != token::Eof {
1197 /// Interpreting `tts` as a comma-separated sequence of expressions,
1198 /// expect exactly one string literal, or emit an error and return `None`.
1199 pub fn get_single_str_from_tts(
1200 cx: &mut ExtCtxt<'_>,
1204 ) -> Option<String> {
1205 let mut p = cx.new_parser_from_tts(tts);
1206 if p.token == token::Eof {
1207 cx.span_err(sp, &format!("{} takes 1 argument", name));
1210 let ret = parse_expr(&mut p)?;
1211 let _ = p.eat(&token::Comma);
1213 if p.token != token::Eof {
1214 cx.span_err(sp, &format!("{} takes 1 argument", name));
1216 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
1219 /// Extracts comma-separated expressions from `tts`.
1220 /// On error, emit it, and return `None`.
1221 pub fn get_exprs_from_tts(
1222 cx: &mut ExtCtxt<'_>,
1225 ) -> Option<Vec<P<ast::Expr>>> {
1226 let mut p = cx.new_parser_from_tts(tts);
1227 let mut es = Vec::new();
1228 while p.token != token::Eof {
1229 let expr = parse_expr(&mut p)?;
1231 // Perform eager expansion on the expression.
1232 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1233 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1236 if p.eat(&token::Comma) {
1239 if p.token != token::Eof {
1240 cx.span_err(sp, "expected token: `,`");
1247 /// This nonterminal looks like some specific enums from
1248 /// `proc-macro-hack` and `procedural-masquerade` crates.
1249 /// We need to maintain some special pretty-printing behavior for them due to incorrect
1250 /// asserts in old versions of those crates and their wide use in the ecosystem.
1251 /// See issue #73345 for more details.
1252 /// FIXME(#73933): Remove this eventually.
1253 pub(crate) fn pretty_printing_compatibility_hack(nt: &Nonterminal, sess: &ParseSess) -> bool {
1254 let item = match nt {
1255 Nonterminal::NtItem(item) => item,
1256 Nonterminal::NtStmt(stmt) => match &stmt.kind {
1257 ast::StmtKind::Item(item) => item,
1263 let name = item.ident.name;
1264 if name == sym::ProceduralMasqueradeDummyType {
1265 if let ast::ItemKind::Enum(enum_def, _) = &item.kind {
1266 if let [variant] = &*enum_def.variants {
1267 if variant.ident.name == sym::Input {
1268 sess.buffer_lint_with_diagnostic(
1269 &PROC_MACRO_BACK_COMPAT,
1272 "using `procedural-masquerade` crate",
1273 BuiltinLintDiagnostics::ProcMacroBackCompat(
1274 "The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. \
1275 Versions of this crate below 0.1.7 will eventually stop compiling.".to_string())