1 use crate::expand::{self, AstFragment, Invocation};
2 use crate::module::DirectoryOwnership;
6 use rustc_ast::tokenstream::TokenStream;
7 use rustc_ast::visit::{AssocCtxt, Visitor};
8 use rustc_ast::{self as ast, Attribute, NodeId, PatKind};
9 use rustc_attr::{self as attr, Deprecation, HasAttrs, 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_parse::{self, nt_to_tokenstream, parser, MACRO_ARGUMENTS};
14 use rustc_session::{parse::ParseSess, Limit, Session};
15 use rustc_span::def_id::{DefId, LOCAL_CRATE};
16 use rustc_span::edition::Edition;
17 use rustc_span::hygiene::{AstPass, ExpnData, ExpnId, ExpnKind};
18 use rustc_span::source_map::SourceMap;
19 use rustc_span::symbol::{kw, sym, Ident, Symbol};
20 use rustc_span::{FileName, MultiSpan, Span, DUMMY_SP};
21 use smallvec::{smallvec, SmallVec};
23 use std::default::Default;
25 use std::path::PathBuf;
28 crate use rustc_span::hygiene::MacroKind;
30 #[derive(Debug, Clone)]
31 pub enum Annotatable {
33 TraitItem(P<ast::AssocItem>),
34 ImplItem(P<ast::AssocItem>),
35 ForeignItem(P<ast::ForeignItem>),
40 FieldPat(ast::FieldPat),
41 GenericParam(ast::GenericParam),
43 StructField(ast::StructField),
44 Variant(ast::Variant),
47 impl HasAttrs for Annotatable {
48 fn attrs(&self) -> &[Attribute] {
50 Annotatable::Item(ref item) => &item.attrs,
51 Annotatable::TraitItem(ref trait_item) => &trait_item.attrs,
52 Annotatable::ImplItem(ref impl_item) => &impl_item.attrs,
53 Annotatable::ForeignItem(ref foreign_item) => &foreign_item.attrs,
54 Annotatable::Stmt(ref stmt) => stmt.attrs(),
55 Annotatable::Expr(ref expr) => &expr.attrs,
56 Annotatable::Arm(ref arm) => &arm.attrs,
57 Annotatable::Field(ref field) => &field.attrs,
58 Annotatable::FieldPat(ref fp) => &fp.attrs,
59 Annotatable::GenericParam(ref gp) => &gp.attrs,
60 Annotatable::Param(ref p) => &p.attrs,
61 Annotatable::StructField(ref sf) => &sf.attrs,
62 Annotatable::Variant(ref v) => &v.attrs(),
66 fn visit_attrs(&mut self, f: impl FnOnce(&mut Vec<Attribute>)) {
68 Annotatable::Item(item) => item.visit_attrs(f),
69 Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f),
70 Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f),
71 Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f),
72 Annotatable::Stmt(stmt) => stmt.visit_attrs(f),
73 Annotatable::Expr(expr) => expr.visit_attrs(f),
74 Annotatable::Arm(arm) => arm.visit_attrs(f),
75 Annotatable::Field(field) => field.visit_attrs(f),
76 Annotatable::FieldPat(fp) => fp.visit_attrs(f),
77 Annotatable::GenericParam(gp) => gp.visit_attrs(f),
78 Annotatable::Param(p) => p.visit_attrs(f),
79 Annotatable::StructField(sf) => sf.visit_attrs(f),
80 Annotatable::Variant(v) => v.visit_attrs(f),
86 pub fn span(&self) -> Span {
88 Annotatable::Item(ref item) => item.span,
89 Annotatable::TraitItem(ref trait_item) => trait_item.span,
90 Annotatable::ImplItem(ref impl_item) => impl_item.span,
91 Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
92 Annotatable::Stmt(ref stmt) => stmt.span,
93 Annotatable::Expr(ref expr) => expr.span,
94 Annotatable::Arm(ref arm) => arm.span,
95 Annotatable::Field(ref field) => field.span,
96 Annotatable::FieldPat(ref fp) => fp.pat.span,
97 Annotatable::GenericParam(ref gp) => gp.ident.span,
98 Annotatable::Param(ref p) => p.span,
99 Annotatable::StructField(ref sf) => sf.span,
100 Annotatable::Variant(ref v) => v.span,
104 pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
106 Annotatable::Item(item) => visitor.visit_item(item),
107 Annotatable::TraitItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Trait),
108 Annotatable::ImplItem(item) => visitor.visit_assoc_item(item, AssocCtxt::Impl),
109 Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item),
110 Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt),
111 Annotatable::Expr(expr) => visitor.visit_expr(expr),
112 Annotatable::Arm(arm) => visitor.visit_arm(arm),
113 Annotatable::Field(field) => visitor.visit_field(field),
114 Annotatable::FieldPat(fp) => visitor.visit_field_pattern(fp),
115 Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp),
116 Annotatable::Param(p) => visitor.visit_param(p),
117 Annotatable::StructField(sf) => visitor.visit_struct_field(sf),
118 Annotatable::Variant(v) => visitor.visit_variant(v),
122 crate fn into_tokens(self, sess: &ParseSess) -> TokenStream {
123 let nt = match self {
124 Annotatable::Item(item) => token::NtItem(item),
125 Annotatable::TraitItem(item) | Annotatable::ImplItem(item) => {
126 token::NtItem(P(item.and_then(ast::AssocItem::into_item)))
128 Annotatable::ForeignItem(item) => {
129 token::NtItem(P(item.and_then(ast::ForeignItem::into_item)))
131 Annotatable::Stmt(stmt) => token::NtStmt(stmt.into_inner()),
132 Annotatable::Expr(expr) => token::NtExpr(expr),
134 | Annotatable::Field(..)
135 | Annotatable::FieldPat(..)
136 | Annotatable::GenericParam(..)
137 | Annotatable::Param(..)
138 | Annotatable::StructField(..)
139 | Annotatable::Variant(..) => panic!("unexpected annotatable"),
141 nt_to_tokenstream(&nt, sess, DUMMY_SP)
144 pub fn expect_item(self) -> P<ast::Item> {
146 Annotatable::Item(i) => i,
147 _ => panic!("expected Item"),
151 pub fn expect_trait_item(self) -> P<ast::AssocItem> {
153 Annotatable::TraitItem(i) => i,
154 _ => panic!("expected Item"),
158 pub fn expect_impl_item(self) -> P<ast::AssocItem> {
160 Annotatable::ImplItem(i) => i,
161 _ => panic!("expected Item"),
165 pub fn expect_foreign_item(self) -> P<ast::ForeignItem> {
167 Annotatable::ForeignItem(i) => i,
168 _ => panic!("expected foreign item"),
172 pub fn expect_stmt(self) -> ast::Stmt {
174 Annotatable::Stmt(stmt) => stmt.into_inner(),
175 _ => panic!("expected statement"),
179 pub fn expect_expr(self) -> P<ast::Expr> {
181 Annotatable::Expr(expr) => expr,
182 _ => panic!("expected expression"),
186 pub fn expect_arm(self) -> ast::Arm {
188 Annotatable::Arm(arm) => arm,
189 _ => panic!("expected match arm"),
193 pub fn expect_field(self) -> ast::Field {
195 Annotatable::Field(field) => field,
196 _ => panic!("expected field"),
200 pub fn expect_field_pattern(self) -> ast::FieldPat {
202 Annotatable::FieldPat(fp) => fp,
203 _ => panic!("expected field pattern"),
207 pub fn expect_generic_param(self) -> ast::GenericParam {
209 Annotatable::GenericParam(gp) => gp,
210 _ => panic!("expected generic parameter"),
214 pub fn expect_param(self) -> ast::Param {
216 Annotatable::Param(param) => param,
217 _ => panic!("expected parameter"),
221 pub fn expect_struct_field(self) -> ast::StructField {
223 Annotatable::StructField(sf) => sf,
224 _ => panic!("expected struct field"),
228 pub fn expect_variant(self) -> ast::Variant {
230 Annotatable::Variant(v) => v,
231 _ => panic!("expected variant"),
235 pub fn derive_allowed(&self) -> bool {
237 Annotatable::Item(ref item) => match item.kind {
238 ast::ItemKind::Struct(..) | ast::ItemKind::Enum(..) | ast::ItemKind::Union(..) => {
248 /// Result of an expansion that may need to be retried.
249 /// Consider using this for non-`MultiItemModifier` expanders as well.
250 pub enum ExpandResult<T, U> {
251 /// Expansion produced a result (possibly dummy).
253 /// Expansion could not produce a result and needs to be retried.
254 /// The string is an explanation that will be printed if we are stuck in an infinite retry loop.
258 // `meta_item` is the attribute, and `item` is the item being modified.
259 pub trait MultiItemModifier {
262 ecx: &mut ExtCtxt<'_>,
264 meta_item: &ast::MetaItem,
266 ) -> ExpandResult<Vec<Annotatable>, Annotatable>;
269 impl<F> MultiItemModifier for F
271 F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> Vec<Annotatable>,
275 ecx: &mut ExtCtxt<'_>,
277 meta_item: &ast::MetaItem,
279 ) -> ExpandResult<Vec<Annotatable>, Annotatable> {
280 ExpandResult::Ready(self(ecx, span, meta_item, item))
284 pub trait ProcMacro {
287 ecx: &'cx mut ExtCtxt<'_>,
290 ) -> Result<TokenStream, ErrorReported>;
293 impl<F> ProcMacro for F
295 F: Fn(TokenStream) -> TokenStream,
299 _ecx: &'cx mut ExtCtxt<'_>,
302 ) -> Result<TokenStream, ErrorReported> {
303 // FIXME setup implicit context in TLS before calling self.
308 pub trait AttrProcMacro {
311 ecx: &'cx mut ExtCtxt<'_>,
313 annotation: TokenStream,
314 annotated: TokenStream,
315 ) -> Result<TokenStream, ErrorReported>;
318 impl<F> AttrProcMacro for F
320 F: Fn(TokenStream, TokenStream) -> TokenStream,
324 _ecx: &'cx mut ExtCtxt<'_>,
326 annotation: TokenStream,
327 annotated: TokenStream,
328 ) -> Result<TokenStream, ErrorReported> {
329 // FIXME setup implicit context in TLS before calling self.
330 Ok(self(annotation, annotated))
334 /// Represents a thing that maps token trees to Macro Results
335 pub trait TTMacroExpander {
338 ecx: &'cx mut ExtCtxt<'_>,
341 ) -> Box<dyn MacResult + 'cx>;
344 pub type MacroExpanderFn =
345 for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>;
347 impl<F> TTMacroExpander for F
349 F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) -> Box<dyn MacResult + 'cx>,
353 ecx: &'cx mut ExtCtxt<'_>,
356 ) -> Box<dyn MacResult + 'cx> {
357 self(ecx, span, input)
361 // Use a macro because forwarding to a simple function has type system issues
362 macro_rules! make_stmts_default {
364 $me.make_expr().map(|e| {
365 smallvec![ast::Stmt {
366 id: ast::DUMMY_NODE_ID,
368 kind: ast::StmtKind::Expr(e),
375 /// The result of a macro expansion. The return values of the various
376 /// methods are spliced into the AST at the callsite of the macro.
377 pub trait MacResult {
378 /// Creates an expression.
379 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
382 /// Creates zero or more items.
383 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
387 /// Creates zero or more impl items.
388 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
392 /// Creates zero or more trait items.
393 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
397 /// Creates zero or more items in an `extern {}` block
398 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
402 /// Creates a pattern.
403 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
407 /// Creates zero or more statements.
409 /// By default this attempts to create an expression statement,
410 /// returning None if that fails.
411 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
412 make_stmts_default!(self)
415 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
419 fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> {
423 fn make_fields(self: Box<Self>) -> Option<SmallVec<[ast::Field; 1]>> {
427 fn make_field_patterns(self: Box<Self>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
431 fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
435 fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> {
439 fn make_struct_fields(self: Box<Self>) -> Option<SmallVec<[ast::StructField; 1]>> {
443 fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> {
448 macro_rules! make_MacEager {
449 ( $( $fld:ident: $t:ty, )* ) => {
450 /// `MacResult` implementation for the common case where you've already
451 /// built each form of AST that you might return.
453 pub struct MacEager {
455 pub $fld: Option<$t>,
461 pub fn $fld(v: $t) -> Box<dyn MacResult> {
475 items: SmallVec<[P<ast::Item>; 1]>,
476 impl_items: SmallVec<[P<ast::AssocItem>; 1]>,
477 trait_items: SmallVec<[P<ast::AssocItem>; 1]>,
478 foreign_items: SmallVec<[P<ast::ForeignItem>; 1]>,
479 stmts: SmallVec<[ast::Stmt; 1]>,
483 impl MacResult for MacEager {
484 fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
488 fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
492 fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
496 fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
500 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
504 fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> {
505 match self.stmts.as_ref().map_or(0, |s| s.len()) {
506 0 => make_stmts_default!(self),
511 fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
512 if let Some(p) = self.pat {
515 if let Some(e) = self.expr {
516 if let ast::ExprKind::Lit(_) = e.kind {
517 return Some(P(ast::Pat {
518 id: ast::DUMMY_NODE_ID,
520 kind: PatKind::Lit(e),
528 fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
533 /// Fill-in macro expansion result, to allow compilation to continue
534 /// after hitting errors.
535 #[derive(Copy, Clone)]
536 pub struct DummyResult {
542 /// Creates a default MacResult that can be anything.
544 /// Use this as a return value after hitting any errors and
545 /// calling `span_err`.
546 pub fn any(span: Span) -> Box<dyn MacResult + 'static> {
547 Box::new(DummyResult { is_error: true, span })
550 /// Same as `any`, but must be a valid fragment, not error.
551 pub fn any_valid(span: Span) -> Box<dyn MacResult + 'static> {
552 Box::new(DummyResult { is_error: false, span })
555 /// A plain dummy expression.
556 pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> {
558 id: ast::DUMMY_NODE_ID,
559 kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) },
561 attrs: ast::AttrVec::new(),
566 /// A plain dummy pattern.
567 pub fn raw_pat(sp: Span) -> ast::Pat {
568 ast::Pat { id: ast::DUMMY_NODE_ID, kind: PatKind::Wild, span: sp, tokens: None }
571 /// A plain dummy type.
572 pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> {
574 id: ast::DUMMY_NODE_ID,
575 kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) },
582 impl MacResult for DummyResult {
583 fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
584 Some(DummyResult::raw_expr(self.span, self.is_error))
587 fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
588 Some(P(DummyResult::raw_pat(self.span)))
591 fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
592 Some(SmallVec::new())
595 fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
596 Some(SmallVec::new())
599 fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::AssocItem>; 1]>> {
600 Some(SmallVec::new())
603 fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[P<ast::ForeignItem>; 1]>> {
604 Some(SmallVec::new())
607 fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> {
608 Some(smallvec![ast::Stmt {
609 id: ast::DUMMY_NODE_ID,
610 kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)),
616 fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
617 Some(DummyResult::raw_ty(self.span, self.is_error))
620 fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> {
621 Some(SmallVec::new())
624 fn make_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::Field; 1]>> {
625 Some(SmallVec::new())
628 fn make_field_patterns(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldPat; 1]>> {
629 Some(SmallVec::new())
632 fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> {
633 Some(SmallVec::new())
636 fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> {
637 Some(SmallVec::new())
640 fn make_struct_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::StructField; 1]>> {
641 Some(SmallVec::new())
644 fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> {
645 Some(SmallVec::new())
649 /// A syntax extension kind.
650 pub enum SyntaxExtensionKind {
651 /// A token-based function-like macro.
653 /// An expander with signature TokenStream -> TokenStream.
654 Box<dyn ProcMacro + sync::Sync + sync::Send>,
657 /// An AST-based function-like macro.
659 /// An expander with signature TokenStream -> AST.
660 Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
663 /// A token-based attribute macro.
665 /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
666 /// The first TokenSteam is the attribute itself, the second is the annotated item.
667 /// The produced TokenSteam replaces the input TokenSteam.
668 Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
671 /// An AST-based attribute macro.
673 /// An expander with signature (AST, AST) -> AST.
674 /// The first AST fragment is the attribute itself, the second is the annotated item.
675 /// The produced AST fragment replaces the input AST fragment.
676 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
679 /// A trivial attribute "macro" that does nothing,
680 /// only keeps the attribute and marks it as inert,
681 /// thus making it ineligible for further expansion.
683 /// Suppresses the `unused_attributes` lint for this attribute.
687 /// A token-based derive macro.
689 /// An expander with signature TokenStream -> TokenStream (not yet).
690 /// The produced TokenSteam is appended to the input TokenSteam.
691 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
694 /// An AST-based derive macro.
696 /// An expander with signature AST -> AST.
697 /// The produced AST fragment is appended to the input AST fragment.
698 Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
702 /// A struct representing a macro definition in "lowered" form ready for expansion.
703 pub struct SyntaxExtension {
704 /// A syntax extension kind.
705 pub kind: SyntaxExtensionKind,
706 /// Span of the macro definition.
708 /// List of unstable features that are treated as stable inside this macro.
709 pub allow_internal_unstable: Option<Lrc<[Symbol]>>,
710 /// Suppresses the `unsafe_code` lint for code produced by this macro.
711 pub allow_internal_unsafe: bool,
712 /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
713 pub local_inner_macros: bool,
714 /// The macro's stability info.
715 pub stability: Option<Stability>,
716 /// The macro's deprecation info.
717 pub deprecation: Option<Deprecation>,
718 /// Names of helper attributes registered by this macro.
719 pub helper_attrs: Vec<Symbol>,
720 /// Edition of the crate in which this macro is defined.
721 pub edition: Edition,
722 /// Built-in macros have a couple of special properties like availability
723 /// in `#[no_implicit_prelude]` modules, so we have to keep this flag.
724 pub is_builtin: bool,
725 /// We have to identify macros providing a `Copy` impl early for compatibility reasons.
726 pub is_derive_copy: bool,
729 impl SyntaxExtension {
730 /// Returns which kind of macro calls this syntax extension.
731 pub fn macro_kind(&self) -> MacroKind {
733 SyntaxExtensionKind::Bang(..) | SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang,
734 SyntaxExtensionKind::Attr(..)
735 | SyntaxExtensionKind::LegacyAttr(..)
736 | SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr,
737 SyntaxExtensionKind::Derive(..) | SyntaxExtensionKind::LegacyDerive(..) => {
743 /// Constructs a syntax extension with default properties.
744 pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension {
747 allow_internal_unstable: None,
748 allow_internal_unsafe: false,
749 local_inner_macros: false,
752 helper_attrs: Vec::new(),
755 is_derive_copy: false,
760 /// Constructs a syntax extension with the given properties
761 /// and other properties converted from attributes.
764 kind: SyntaxExtensionKind,
766 helper_attrs: Vec<Symbol>,
769 attrs: &[ast::Attribute],
770 ) -> SyntaxExtension {
771 let allow_internal_unstable = attr::allow_internal_unstable(sess, &attrs)
772 .map(|features| features.collect::<Vec<Symbol>>().into());
774 let mut local_inner_macros = false;
775 if let Some(macro_export) = sess.find_by_name(attrs, sym::macro_export) {
776 if let Some(l) = macro_export.meta_item_list() {
777 local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
781 let is_builtin = sess.contains_name(attrs, sym::rustc_builtin_macro);
782 let (stability, const_stability) = attr::find_stability(&sess, attrs, span);
783 if const_stability.is_some() {
786 .span_err(span, "macros cannot have const stability attributes");
792 allow_internal_unstable,
793 allow_internal_unsafe: sess.contains_name(attrs, sym::allow_internal_unsafe),
796 deprecation: attr::find_deprecation(&sess, attrs, span),
800 is_derive_copy: is_builtin && name == sym::Copy,
804 pub fn dummy_bang(edition: Edition) -> SyntaxExtension {
806 _: &'cx mut ExtCtxt<'_>,
809 ) -> Box<dyn MacResult + 'cx> {
810 DummyResult::any(span)
812 SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition)
815 pub fn dummy_derive(edition: Edition) -> SyntaxExtension {
821 ) -> Vec<Annotatable> {
824 SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition)
827 pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension {
828 SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition)
836 macro_def_id: Option<DefId>,
839 kind: ExpnKind::Macro(self.macro_kind(), descr),
843 allow_internal_unstable: self.allow_internal_unstable.clone(),
844 allow_internal_unsafe: self.allow_internal_unsafe,
845 local_inner_macros: self.local_inner_macros,
846 edition: self.edition,
854 /// Result of resolving a macro invocation.
855 pub enum InvocationRes {
856 Single(Lrc<SyntaxExtension>),
857 DeriveContainer(Vec<Lrc<SyntaxExtension>>),
860 /// Error type that denotes indeterminacy.
861 pub struct Indeterminate;
863 pub trait ResolverExpand {
864 fn next_node_id(&mut self) -> NodeId;
866 fn resolve_dollar_crates(&mut self);
867 fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment);
868 fn register_builtin_macro(&mut self, ident: Ident, ext: SyntaxExtension);
870 fn expansion_for_ast_pass(
875 parent_module_id: Option<NodeId>,
878 fn resolve_imports(&mut self);
880 fn resolve_macro_invocation(
883 eager_expansion_root: ExpnId,
885 ) -> Result<InvocationRes, Indeterminate>;
887 fn check_unused_macros(&mut self);
889 /// Some parent node that is close enough to the given macro call.
890 fn lint_node_id(&mut self, expn_id: ExpnId) -> NodeId;
892 fn has_derive_copy(&self, expn_id: ExpnId) -> bool;
893 fn add_derive_copy(&mut self, expn_id: ExpnId);
894 fn cfg_accessible(&mut self, expn_id: ExpnId, path: &ast::Path) -> Result<bool, Indeterminate>;
898 pub struct ModuleData {
899 pub mod_path: Vec<Ident>,
900 pub directory: PathBuf,
904 pub struct ExpansionData {
907 pub module: Rc<ModuleData>,
908 pub directory_ownership: DirectoryOwnership,
909 pub prior_type_ascription: Option<(Span, bool)>,
912 /// One of these is made during expansion and incrementally updated as we go;
913 /// when a macro expansion occurs, the resulting nodes have the `backtrace()
914 /// -> expn_data` of their expansion context stored into their span.
915 pub struct ExtCtxt<'a> {
916 pub sess: &'a Session,
917 pub ecfg: expand::ExpansionConfig<'a>,
918 pub reduced_recursion_limit: Option<Limit>,
919 pub root_path: PathBuf,
920 pub resolver: &'a mut dyn ResolverExpand,
921 pub current_expansion: ExpansionData,
922 pub expansions: FxHashMap<Span, Vec<String>>,
923 /// Called directly after having parsed an external `mod foo;` in expansion.
924 pub(super) extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
927 impl<'a> ExtCtxt<'a> {
930 ecfg: expand::ExpansionConfig<'a>,
931 resolver: &'a mut dyn ResolverExpand,
932 extern_mod_loaded: Option<&'a dyn Fn(&ast::Crate)>,
937 reduced_recursion_limit: None,
940 root_path: PathBuf::new(),
941 current_expansion: ExpansionData {
944 module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }),
945 directory_ownership: DirectoryOwnership::Owned { relative: None },
946 prior_type_ascription: None,
948 expansions: FxHashMap::default(),
952 /// Returns a `Folder` for deeply expanding all macros in an AST node.
953 pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
954 expand::MacroExpander::new(self, false)
957 /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node.
958 /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified.
959 pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
960 expand::MacroExpander::new(self, true)
962 pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> {
963 rustc_parse::stream_to_parser(&self.sess.parse_sess, stream, MACRO_ARGUMENTS)
965 pub fn source_map(&self) -> &'a SourceMap {
966 self.sess.parse_sess.source_map()
968 pub fn parse_sess(&self) -> &'a ParseSess {
969 &self.sess.parse_sess
971 pub fn call_site(&self) -> Span {
972 self.current_expansion.id.expn_data().call_site
975 /// Equivalent of `Span::def_site` from the proc macro API,
976 /// except that the location is taken from the span passed as an argument.
977 pub fn with_def_site_ctxt(&self, span: Span) -> Span {
978 span.with_def_site_ctxt(self.current_expansion.id)
981 /// Equivalent of `Span::call_site` from the proc macro API,
982 /// except that the location is taken from the span passed as an argument.
983 pub fn with_call_site_ctxt(&self, span: Span) -> Span {
984 span.with_call_site_ctxt(self.current_expansion.id)
987 /// Equivalent of `Span::mixed_site` from the proc macro API,
988 /// except that the location is taken from the span passed as an argument.
989 pub fn with_mixed_site_ctxt(&self, span: Span) -> Span {
990 span.with_mixed_site_ctxt(self.current_expansion.id)
993 /// Returns span for the macro which originally caused the current expansion to happen.
995 /// Stops backtracing at include! boundary.
996 pub fn expansion_cause(&self) -> Option<Span> {
997 self.current_expansion.id.expansion_cause()
1000 pub fn struct_span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> DiagnosticBuilder<'a> {
1001 self.sess.parse_sess.span_diagnostic.struct_span_err(sp, msg)
1004 /// Emit `msg` attached to `sp`, without immediately stopping
1007 /// Compilation will be stopped in the near future (at the end of
1008 /// the macro expansion phase).
1009 pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1010 self.sess.parse_sess.span_diagnostic.span_err(sp, msg);
1012 pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) {
1013 self.sess.parse_sess.span_diagnostic.span_warn(sp, msg);
1015 pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! {
1016 self.sess.parse_sess.span_diagnostic.span_bug(sp, msg);
1018 pub fn trace_macros_diag(&mut self) {
1019 for (sp, notes) in self.expansions.iter() {
1020 let mut db = self.sess.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro");
1026 // Fixme: does this result in errors?
1027 self.expansions.clear();
1029 pub fn bug(&self, msg: &str) -> ! {
1030 self.sess.parse_sess.span_diagnostic.bug(msg);
1032 pub fn trace_macros(&self) -> bool {
1035 pub fn set_trace_macros(&mut self, x: bool) {
1036 self.ecfg.trace_mac = x
1038 pub fn std_path(&self, components: &[Symbol]) -> Vec<Ident> {
1039 let def_site = self.with_def_site_ctxt(DUMMY_SP);
1040 iter::once(Ident::new(kw::DollarCrate, def_site))
1041 .chain(components.iter().map(|&s| Ident::with_dummy_span(s)))
1045 pub fn check_unused_macros(&mut self) {
1046 self.resolver.check_unused_macros();
1049 /// Resolves a path mentioned inside Rust code.
1051 /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths.
1053 /// Returns an absolute path to the file that `path` refers to.
1054 pub fn resolve_path(
1056 path: impl Into<PathBuf>,
1058 ) -> Result<PathBuf, DiagnosticBuilder<'a>> {
1059 let path = path.into();
1061 // Relative paths are resolved relative to the file in which they are found
1062 // after macro expansion (that is, they are unhygienic).
1063 if !path.is_absolute() {
1064 let callsite = span.source_callsite();
1065 let mut result = match self.source_map().span_to_unmapped_path(callsite) {
1066 FileName::Real(name) => name.into_local_path(),
1067 FileName::DocTest(path, _) => path,
1069 return Err(self.struct_span_err(
1071 &format!("cannot resolve relative path in non-file source `{}`", other),
1084 /// Extracts a string literal from the macro expanded version of `expr`,
1085 /// emitting `err_msg` if `expr` is not a string literal. This does not stop
1086 /// compilation on error, merely emits a non-fatal error and returns `None`.
1087 pub fn expr_to_spanned_string<'a>(
1088 cx: &'a mut ExtCtxt<'_>,
1091 ) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> {
1092 // Perform eager expansion on the expression.
1093 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1094 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1096 Err(match expr.kind {
1097 ast::ExprKind::Lit(ref l) => match l.kind {
1098 ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)),
1099 ast::LitKind::Err(_) => None,
1100 _ => Some(cx.struct_span_err(l.span, err_msg)),
1102 ast::ExprKind::Err => None,
1103 _ => Some(cx.struct_span_err(expr.span, err_msg)),
1107 pub fn expr_to_string(
1108 cx: &mut ExtCtxt<'_>,
1111 ) -> Option<(Symbol, ast::StrStyle)> {
1112 expr_to_spanned_string(cx, expr, err_msg)
1119 .map(|(symbol, style, _)| (symbol, style))
1122 /// Non-fatally assert that `tts` is empty. Note that this function
1123 /// returns even when `tts` is non-empty, macros that *need* to stop
1124 /// compilation should call
1125 /// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
1126 /// done as rarely as possible).
1127 pub fn check_zero_tts(cx: &ExtCtxt<'_>, sp: Span, tts: TokenStream, name: &str) {
1128 if !tts.is_empty() {
1129 cx.span_err(sp, &format!("{} takes no arguments", name));
1133 /// Parse an expression. On error, emit it, advancing to `Eof`, and return `None`.
1134 pub fn parse_expr(p: &mut parser::Parser<'_>) -> Option<P<ast::Expr>> {
1135 match p.parse_expr() {
1136 Ok(e) => return Some(e),
1137 Err(mut err) => err.emit(),
1139 while p.token != token::Eof {
1145 /// Interpreting `tts` as a comma-separated sequence of expressions,
1146 /// expect exactly one string literal, or emit an error and return `None`.
1147 pub fn get_single_str_from_tts(
1148 cx: &mut ExtCtxt<'_>,
1152 ) -> Option<String> {
1153 let mut p = cx.new_parser_from_tts(tts);
1154 if p.token == token::Eof {
1155 cx.span_err(sp, &format!("{} takes 1 argument", name));
1158 let ret = parse_expr(&mut p)?;
1159 let _ = p.eat(&token::Comma);
1161 if p.token != token::Eof {
1162 cx.span_err(sp, &format!("{} takes 1 argument", name));
1164 expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
1167 /// Extracts comma-separated expressions from `tts`.
1168 /// On error, emit it, and return `None`.
1169 pub fn get_exprs_from_tts(
1170 cx: &mut ExtCtxt<'_>,
1173 ) -> Option<Vec<P<ast::Expr>>> {
1174 let mut p = cx.new_parser_from_tts(tts);
1175 let mut es = Vec::new();
1176 while p.token != token::Eof {
1177 let expr = parse_expr(&mut p)?;
1179 // Perform eager expansion on the expression.
1180 // We want to be able to handle e.g., `concat!("foo", "bar")`.
1181 let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr();
1184 if p.eat(&token::Comma) {
1187 if p.token != token::Eof {
1188 cx.span_err(sp, "expected token: `,`");