1 //! `hir_expand` deals with macro expansion.
3 //! Specifically, it implements a concept of `MacroFile` -- a file whose syntax
4 //! tree originates not from the text of some `FileId`, but from some macro
11 pub mod builtin_attr_macro;
12 pub mod builtin_derive_macro;
13 pub mod builtin_fn_macro;
20 pub use mbe::{ExpandError, ExpandResult, Origin};
22 use std::{hash::Hash, iter, sync::Arc};
24 use base_db::{impl_intern_key, salsa, CrateId, FileId, FileRange, ProcMacroKind};
27 algo::{self, skip_trivia_token},
28 ast::{self, AstNode, HasDocComments},
29 Direction, SyntaxNode, SyntaxToken,
33 ast_id_map::FileAstId,
34 builtin_attr_macro::BuiltinAttrExpander,
35 builtin_derive_macro::BuiltinDeriveExpander,
36 builtin_fn_macro::{BuiltinFnLikeExpander, EagerExpander},
39 proc_macro::ProcMacroExpander,
42 /// Input to the analyzer is a set of files, where each file is identified by
43 /// `FileId` and contains source code. However, another source of source code in
44 /// Rust are macros: each macro can be thought of as producing a "temporary
45 /// file". To assign an id to such a file, we use the id of the macro call that
46 /// produced the file. So, a `HirFileId` is either a `FileId` (source code
47 /// written by user), or a `MacroCallId` (source code produced by macro).
49 /// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
50 /// containing the call plus the offset of the macro call in the file. Note that
51 /// this is a recursive definition! However, the size_of of `HirFileId` is
52 /// finite (because everything bottoms out at the real `FileId`) and small
53 /// (`MacroCallId` uses the location interning. You can check details here:
54 /// <https://en.wikipedia.org/wiki/String_interning>).
55 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
56 pub struct HirFileId(HirFileIdRepr);
58 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
64 impl From<FileId> for HirFileId {
65 fn from(id: FileId) -> Self {
66 HirFileId(HirFileIdRepr::FileId(id))
70 impl From<MacroFile> for HirFileId {
71 fn from(id: MacroFile) -> Self {
72 HirFileId(HirFileIdRepr::MacroFile(id))
76 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
77 pub struct MacroFile {
78 pub macro_call_id: MacroCallId,
81 /// `MacroCallId` identifies a particular macro invocation, like
82 /// `println!("Hello, {}", world)`.
83 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
84 pub struct MacroCallId(salsa::InternId);
85 impl_intern_key!(MacroCallId);
87 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
88 pub struct MacroCallLoc {
90 pub(crate) krate: CrateId,
91 eager: Option<EagerCallInfo>,
92 pub kind: MacroCallKind,
95 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
96 pub struct MacroDefId {
98 pub kind: MacroDefKind,
99 pub local_inner: bool,
102 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
103 pub enum MacroDefKind {
104 Declarative(AstId<ast::Macro>),
105 BuiltIn(BuiltinFnLikeExpander, AstId<ast::Macro>),
106 // FIXME: maybe just Builtin and rename BuiltinFnLikeExpander to BuiltinExpander
107 BuiltInAttr(BuiltinAttrExpander, AstId<ast::Macro>),
108 BuiltInDerive(BuiltinDeriveExpander, AstId<ast::Macro>),
109 BuiltInEager(EagerExpander, AstId<ast::Macro>),
110 ProcMacro(ProcMacroExpander, ProcMacroKind, AstId<ast::Fn>),
113 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
114 struct EagerCallInfo {
115 /// NOTE: This can be *either* the expansion result, *or* the argument to the eager macro!
116 arg_or_expansion: Arc<tt::Subtree>,
117 included_file: Option<FileId>,
120 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
121 pub enum MacroCallKind {
123 ast_id: AstId<ast::MacroCall>,
127 ast_id: AstId<ast::Adt>,
128 derive_name: Box<str>,
129 /// Syntactical index of the invoking `#[derive]` attribute.
131 /// Outer attributes are counted first, then inner attributes. This does not support
132 /// out-of-line modules, which may have attributes spread across 2 files!
133 derive_attr_index: u32,
136 ast_id: AstId<ast::Item>,
138 attr_args: (tt::Subtree, mbe::TokenMap),
139 /// Syntactical index of the invoking `#[attribute]`.
141 /// Outer attributes are counted first, then inner attributes. This does not support
142 /// out-of-line modules, which may have attributes spread across 2 files!
143 invoc_attr_index: u32,
148 /// For macro-expansion files, returns the file original source file the
149 /// expansion originated from.
150 pub fn original_file(self, db: &dyn db::AstDatabase) -> FileId {
152 HirFileIdRepr::FileId(file_id) => file_id,
153 HirFileIdRepr::MacroFile(macro_file) => {
154 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
155 let file_id = match loc.eager {
156 Some(EagerCallInfo { included_file: Some(file), .. }) => file.into(),
157 _ => loc.kind.file_id(),
159 file_id.original_file(db)
164 pub fn expansion_level(self, db: &dyn db::AstDatabase) -> u32 {
167 while let HirFileIdRepr::MacroFile(macro_file) = curr.0 {
168 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
171 curr = loc.kind.file_id();
176 /// If this is a macro call, returns the syntax node of the call.
177 pub fn call_node(self, db: &dyn db::AstDatabase) -> Option<InFile<SyntaxNode>> {
179 HirFileIdRepr::FileId(_) => None,
180 HirFileIdRepr::MacroFile(macro_file) => {
181 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
182 Some(loc.kind.to_node(db))
187 /// Return expansion information if it is a macro-expansion file
188 pub fn expansion_info(self, db: &dyn db::AstDatabase) -> Option<ExpansionInfo> {
190 HirFileIdRepr::FileId(_) => None,
191 HirFileIdRepr::MacroFile(macro_file) => {
192 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
194 let arg_tt = loc.kind.arg(db)?;
196 let def = loc.def.ast_id().left().and_then(|id| {
197 let def_tt = match id.to_node(db) {
198 ast::Macro::MacroRules(mac) => mac.token_tree()?,
199 ast::Macro::MacroDef(mac) => mac.body()?,
201 Some(InFile::new(id.file_id, def_tt))
203 let attr_input_or_mac_def = def.or_else(|| match loc.kind {
204 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => {
207 .doc_comments_and_attrs()
208 .nth(invoc_attr_index as usize)
209 .and_then(Either::left)?
211 Some(InFile::new(ast_id.file_id, tt))
216 let macro_def = db.macro_def(loc.def).ok()?;
217 let (parse, exp_map) = db.parse_macro_expansion(macro_file).value?;
218 let macro_arg = db.macro_arg(macro_file.macro_call_id)?;
221 expanded: InFile::new(self, parse.syntax_node()),
222 arg: InFile::new(loc.kind.file_id(), arg_tt),
223 attr_input_or_mac_def,
224 macro_arg_shift: mbe::Shift::new(¯o_arg.0),
233 /// Indicate it is macro file generated for builtin derive
234 pub fn is_builtin_derive(&self, db: &dyn db::AstDatabase) -> Option<InFile<ast::Item>> {
236 HirFileIdRepr::FileId(_) => None,
237 HirFileIdRepr::MacroFile(macro_file) => {
238 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
239 let item = match loc.def.kind {
240 MacroDefKind::BuiltInDerive(..) => loc.kind.to_node(db),
243 Some(item.with_value(ast::Item::cast(item.value.clone())?))
248 pub fn is_custom_derive(&self, db: &dyn db::AstDatabase) -> bool {
250 HirFileIdRepr::FileId(_) => false,
251 HirFileIdRepr::MacroFile(macro_file) => {
252 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
253 matches!(loc.def.kind, MacroDefKind::ProcMacro(_, ProcMacroKind::CustomDerive, _))
258 /// Return whether this file is an include macro
259 pub fn is_include_macro(&self, db: &dyn db::AstDatabase) -> bool {
261 HirFileIdRepr::MacroFile(macro_file) => {
262 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
263 matches!(loc.eager, Some(EagerCallInfo { included_file: Some(_), .. }))
269 /// Return whether this file is an include macro
270 pub fn is_attr_macro(&self, db: &dyn db::AstDatabase) -> bool {
272 HirFileIdRepr::MacroFile(macro_file) => {
273 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
274 matches!(loc.kind, MacroCallKind::Attr { .. })
280 pub fn is_macro(self) -> bool {
281 matches!(self.0, HirFileIdRepr::MacroFile(_))
284 pub fn macro_file(self) -> Option<MacroFile> {
286 HirFileIdRepr::FileId(_) => None,
287 HirFileIdRepr::MacroFile(m) => Some(m),
293 pub fn as_lazy_macro(
295 db: &dyn db::AstDatabase,
299 db.intern_macro_call(MacroCallLoc { def: self, krate, eager: None, kind })
302 pub fn ast_id(&self) -> Either<AstId<ast::Macro>, AstId<ast::Fn>> {
303 let id = match self.kind {
304 MacroDefKind::ProcMacro(.., id) => return Either::Right(id),
305 MacroDefKind::Declarative(id)
306 | MacroDefKind::BuiltIn(_, id)
307 | MacroDefKind::BuiltInAttr(_, id)
308 | MacroDefKind::BuiltInDerive(_, id)
309 | MacroDefKind::BuiltInEager(_, id) => id,
314 pub fn is_proc_macro(&self) -> bool {
315 matches!(self.kind, MacroDefKind::ProcMacro(..))
318 pub fn is_attribute(&self) -> bool {
321 MacroDefKind::BuiltInAttr(..) | MacroDefKind::ProcMacro(_, ProcMacroKind::Attr, _)
326 // FIXME: attribute indices do not account for `cfg_attr`, which means that we'll strip the whole
327 // `cfg_attr` instead of just one of the attributes it expands to
330 /// Returns the file containing the macro invocation.
331 fn file_id(&self) -> HirFileId {
333 MacroCallKind::FnLike { ast_id: InFile { file_id, .. }, .. }
334 | MacroCallKind::Derive { ast_id: InFile { file_id, .. }, .. }
335 | MacroCallKind::Attr { ast_id: InFile { file_id, .. }, .. } => file_id,
339 pub fn to_node(&self, db: &dyn db::AstDatabase) -> InFile<SyntaxNode> {
341 MacroCallKind::FnLike { ast_id, .. } => {
342 ast_id.with_value(ast_id.to_node(db).syntax().clone())
344 MacroCallKind::Derive { ast_id, .. } => {
345 ast_id.with_value(ast_id.to_node(db).syntax().clone())
347 MacroCallKind::Attr { ast_id, .. } => {
348 ast_id.with_value(ast_id.to_node(db).syntax().clone())
353 /// Returns the original file range that best describes the location of this macro call.
355 /// Here we try to roughly match what rustc does to improve diagnostics: fn-like macros
356 /// get the whole `ast::MacroCall`, attribute macros get the attribute's range, and derives
357 /// get only the specific derive that is being referred to.
358 pub fn original_call_range(self, db: &dyn db::AstDatabase) -> FileRange {
361 match kind.file_id().0 {
362 HirFileIdRepr::MacroFile(file) => {
363 kind = db.lookup_intern_macro_call(file.macro_call_id).kind;
365 HirFileIdRepr::FileId(file_id) => break file_id,
369 let range = match kind {
370 MacroCallKind::FnLike { ast_id, .. } => ast_id.to_node(db).syntax().text_range(),
371 MacroCallKind::Derive { ast_id, derive_attr_index, .. } => {
372 // FIXME: should be the range of the macro name, not the whole derive
375 .doc_comments_and_attrs()
376 .nth(derive_attr_index as usize)
377 .expect("missing derive")
378 .expect_left("derive is a doc comment?")
382 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => ast_id
384 .doc_comments_and_attrs()
385 .nth(invoc_attr_index as usize)
386 .expect("missing attribute")
387 .expect_left("attribute macro is a doc comment?")
392 FileRange { range, file_id }
395 fn arg(&self, db: &dyn db::AstDatabase) -> Option<SyntaxNode> {
397 MacroCallKind::FnLike { ast_id, .. } => {
398 Some(ast_id.to_node(db).token_tree()?.syntax().clone())
400 MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
401 MacroCallKind::Attr { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
405 fn expand_to(&self) -> ExpandTo {
407 MacroCallKind::FnLike { expand_to, .. } => *expand_to,
408 MacroCallKind::Derive { .. } => ExpandTo::Items,
409 MacroCallKind::Attr { .. } => ExpandTo::Items, // is this always correct?
415 pub fn as_file(self) -> HirFileId {
416 MacroFile { macro_call_id: self }.into()
420 /// ExpansionInfo mainly describes how to map text range between src and expanded macro
421 #[derive(Debug, Clone, PartialEq, Eq)]
422 pub struct ExpansionInfo {
423 expanded: InFile<SyntaxNode>,
424 /// The argument TokenTree or item for attributes
425 arg: InFile<SyntaxNode>,
426 /// The `macro_rules!` or attribute input.
427 attr_input_or_mac_def: Option<InFile<ast::TokenTree>>,
429 macro_def: Arc<TokenExpander>,
430 macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
431 /// A shift built from `macro_arg`'s subtree, relevant for attributes as the item is the macro arg
432 /// and as such we need to shift tokens if they are part of an attributes input instead of their item.
433 macro_arg_shift: mbe::Shift,
434 exp_map: Arc<mbe::TokenMap>,
438 pub fn expanded(&self) -> InFile<SyntaxNode> {
439 self.expanded.clone()
442 pub fn call_node(&self) -> Option<InFile<SyntaxNode>> {
443 Some(self.arg.with_value(self.arg.value.parent()?))
446 /// Map a token down from macro input into the macro expansion.
448 /// The inner workings of this function differ slightly depending on the type of macro we are dealing with:
450 /// For declarative macros, we need to accommodate for the macro definition site(which acts as a second unchanging input)
451 /// , as tokens can mapped in and out of it.
452 /// To do this we shift all ids in the expansion by the maximum id of the definition site giving us an easy
453 /// way to map all the tokens.
455 /// Attributes have two different inputs, the input tokentree in the attribute node and the item
456 /// the attribute is annotating. Similarly as for declarative macros we need to do a shift here
457 /// as well. Currently this is done by shifting the attribute input by the maximum id of the item.
458 /// - function-like and derives:
459 /// Both of these only have one simple call site input so no special handling is required here.
460 pub fn map_token_down(
462 db: &dyn db::AstDatabase,
463 item: Option<ast::Item>,
464 token: InFile<&SyntaxToken>,
465 ) -> Option<impl Iterator<Item = InFile<SyntaxToken>> + '_> {
466 assert_eq!(token.file_id, self.arg.file_id);
467 let token_id_in_attr_input = if let Some(item) = item {
468 // check if we are mapping down in an attribute input
469 // this is a special case as attributes can have two inputs
470 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
471 let loc = db.lookup_intern_macro_call(call_id);
473 let token_range = token.value.text_range();
475 MacroCallKind::Attr { attr_args: (_, map), invoc_attr_index, .. } => {
477 .doc_comments_and_attrs()
478 .nth(*invoc_attr_index as usize)
479 .and_then(Either::left)?;
480 match attr.token_tree() {
482 if token_tree.syntax().text_range().contains_range(token_range) =>
484 let attr_input_start =
485 token_tree.left_delimiter_token()?.text_range().start();
487 token.value.text_range().checked_sub(attr_input_start)?;
488 // shift by the item's tree's max id
490 self.macro_arg_shift.shift(map.token_by_range(relative_range)?);
502 let token_id = match token_id_in_attr_input {
503 Some(token_id) => token_id,
504 // the token is not inside an attribute's input so do the lookup in the macro_arg as ususal
507 token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
508 let token_id = self.macro_arg.1.token_by_range(relative_range)?;
509 // conditionally shift the id by a declaratives macro definition
510 self.macro_def.map_id_down(token_id)
516 .ranges_by_token(token_id, token.value.kind())
517 .flat_map(move |range| self.expanded.value.covering_element(range).into_token());
519 Some(tokens.map(move |token| self.expanded.with_value(token)))
522 /// Map a token up out of the expansion it resides in into the arguments of the macro call of the expansion.
525 db: &dyn db::AstDatabase,
526 token: InFile<&SyntaxToken>,
527 ) -> Option<(InFile<SyntaxToken>, Origin)> {
528 // Fetch the id through its text range,
529 let token_id = self.exp_map.token_by_range(token.value.text_range())?;
530 // conditionally unshifting the id to accommodate for macro-rules def site
531 let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
533 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
534 let loc = db.lookup_intern_macro_call(call_id);
536 // Attributes are a bit special for us, they have two inputs, the input tokentree and the annotated item.
537 let (token_map, tt) = match &loc.kind {
538 MacroCallKind::Attr { attr_args: (_, arg_token_map), .. } => {
539 // try unshifting the the token id, if unshifting fails, the token resides in the non-item attribute input
540 // note that the `TokenExpander::map_id_up` earlier only unshifts for declarative macros, so we don't double unshift with this
541 match self.macro_arg_shift.unshift(token_id) {
543 token_id = unshifted;
544 (arg_token_map, self.attr_input_or_mac_def.clone()?.syntax().cloned())
546 None => (&self.macro_arg.1, self.arg.clone()),
550 mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
551 mbe::Origin::Def => match (&*self.macro_def, &self.attr_input_or_mac_def) {
552 (TokenExpander::DeclarativeMacro { def_site_token_map, .. }, Some(tt)) => {
553 (def_site_token_map, tt.syntax().cloned())
555 _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
560 let range = token_map.first_range_by_token(token_id, token.value.kind())?;
562 tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
563 Some((tt.with_value(token), origin))
567 /// `AstId` points to an AST node in any file.
569 /// It is stable across reparses, and can be used as salsa key/value.
570 pub type AstId<N> = InFile<FileAstId<N>>;
572 impl<N: AstNode> AstId<N> {
573 pub fn to_node(&self, db: &dyn db::AstDatabase) -> N {
574 let root = db.parse_or_expand(self.file_id).unwrap();
575 db.ast_id_map(self.file_id).get(self.value).to_node(&root)
579 /// `InFile<T>` stores a value of `T` inside a particular file/syntax tree.
581 /// Typical usages are:
583 /// * `InFile<SyntaxNode>` -- syntax node in a file
584 /// * `InFile<ast::FnDef>` -- ast node in a file
585 /// * `InFile<TextSize>` -- offset in a file
586 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
587 pub struct InFile<T> {
588 pub file_id: HirFileId,
593 pub fn new(file_id: HirFileId, value: T) -> InFile<T> {
594 InFile { file_id, value }
597 pub fn with_value<U>(&self, value: U) -> InFile<U> {
598 InFile::new(self.file_id, value)
601 pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> InFile<U> {
602 InFile::new(self.file_id, f(self.value))
604 pub fn as_ref(&self) -> InFile<&T> {
605 self.with_value(&self.value)
607 pub fn file_syntax(&self, db: &dyn db::AstDatabase) -> SyntaxNode {
608 db.parse_or_expand(self.file_id).expect("source created from invalid file")
612 impl<T: Clone> InFile<&T> {
613 pub fn cloned(&self) -> InFile<T> {
614 self.with_value(self.value.clone())
618 impl<T> InFile<Option<T>> {
619 pub fn transpose(self) -> Option<InFile<T>> {
620 let value = self.value?;
621 Some(InFile::new(self.file_id, value))
625 impl<'a> InFile<&'a SyntaxNode> {
626 pub fn ancestors_with_macros(
628 db: &dyn db::AstDatabase,
629 ) -> impl Iterator<Item = InFile<SyntaxNode>> + Clone + '_ {
630 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
631 Some(parent) => Some(node.with_value(parent)),
632 None => node.file_id.call_node(db),
636 /// Skips the attributed item that caused the macro invocation we are climbing up
637 pub fn ancestors_with_macros_skip_attr_item(
639 db: &dyn db::AstDatabase,
640 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
641 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
642 Some(parent) => Some(node.with_value(parent)),
644 let parent_node = node.file_id.call_node(db)?;
645 if node.file_id.is_attr_macro(db) {
646 // macro call was an attributed item, skip it
647 // FIXME: does this fail if this is a direct expansion of another macro?
648 parent_node.map(|node| node.parent()).transpose()
656 /// Falls back to the macro call range if the node cannot be mapped up fully.
657 pub fn original_file_range(self, db: &dyn db::AstDatabase) -> FileRange {
658 if let Some(res) = self.original_file_range_opt(db) {
662 // Fall back to whole macro call.
663 match self.file_id.0 {
664 HirFileIdRepr::FileId(file_id) => FileRange { file_id, range: self.value.text_range() },
665 HirFileIdRepr::MacroFile(mac_file) => {
666 let loc = db.lookup_intern_macro_call(mac_file.macro_call_id);
667 loc.kind.original_call_range(db)
672 /// Attempts to map the syntax node back up its macro calls.
673 pub fn original_file_range_opt(self, db: &dyn db::AstDatabase) -> Option<FileRange> {
674 match ascend_node_border_tokens(db, self) {
675 Some(InFile { file_id, value: (first, last) }) => {
676 let original_file = file_id.original_file(db);
677 let range = first.text_range().cover(last.text_range());
678 if file_id != original_file.into() {
679 tracing::error!("Failed mapping up more for {:?}", range);
682 Some(FileRange { file_id: original_file, range })
684 _ if !self.file_id.is_macro() => Some(FileRange {
685 file_id: self.file_id.original_file(db),
686 range: self.value.text_range(),
693 fn ascend_node_border_tokens(
694 db: &dyn db::AstDatabase,
695 InFile { file_id, value: node }: InFile<&SyntaxNode>,
696 ) -> Option<InFile<(SyntaxToken, SyntaxToken)>> {
697 let expansion = file_id.expansion_info(db)?;
699 let first_token = |node: &SyntaxNode| skip_trivia_token(node.first_token()?, Direction::Next);
700 let last_token = |node: &SyntaxNode| skip_trivia_token(node.last_token()?, Direction::Prev);
702 let first = first_token(node)?;
703 let last = last_token(node)?;
704 let first = ascend_call_token(db, &expansion, InFile::new(file_id, first))?;
705 let last = ascend_call_token(db, &expansion, InFile::new(file_id, last))?;
706 (first.file_id == last.file_id).then(|| InFile::new(first.file_id, (first.value, last.value)))
709 fn ascend_call_token(
710 db: &dyn db::AstDatabase,
711 expansion: &ExpansionInfo,
712 token: InFile<SyntaxToken>,
713 ) -> Option<InFile<SyntaxToken>> {
714 let (mapped, origin) = expansion.map_token_up(db, token.as_ref())?;
715 if origin != Origin::Call {
718 if let Some(info) = mapped.file_id.expansion_info(db) {
719 return ascend_call_token(db, &info, mapped);
724 impl InFile<SyntaxToken> {
725 pub fn ancestors_with_macros(
727 db: &dyn db::AstDatabase,
728 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
729 self.value.parent().into_iter().flat_map({
730 let file_id = self.file_id;
731 move |parent| InFile::new(file_id, &parent).ancestors_with_macros(db)
736 impl<N: AstNode> InFile<N> {
737 pub fn descendants<T: AstNode>(self) -> impl Iterator<Item = InFile<T>> {
738 self.value.syntax().descendants().filter_map(T::cast).map(move |n| self.with_value(n))
741 pub fn original_ast_node(self, db: &dyn db::AstDatabase) -> Option<InFile<N>> {
742 // This kind of upmapping can only be achieved in attribute expanded files,
743 // as we don't have node inputs otherwise and therefor can't find an `N` node in the input
744 if !self.file_id.is_macro() {
746 } else if !self.file_id.is_attr_macro(db) {
750 if let Some(InFile { file_id, value: (first, last) }) =
751 ascend_node_border_tokens(db, self.syntax())
753 if file_id.is_macro() {
754 let range = first.text_range().cover(last.text_range());
755 tracing::error!("Failed mapping out of macro file for {:?}", range);
758 // FIXME: This heuristic is brittle and with the right macro may select completely unrelated nodes
759 let anc = algo::least_common_ancestor(&first.parent()?, &last.parent()?)?;
760 let value = anc.ancestors().find_map(N::cast)?;
761 return Some(InFile::new(file_id, value));
766 pub fn syntax(&self) -> InFile<&SyntaxNode> {
767 self.with_value(self.value.syntax())
771 /// In Rust, macros expand token trees to token trees. When we want to turn a
772 /// token tree into an AST node, we need to figure out what kind of AST node we
773 /// want: something like `foo` can be a type, an expression, or a pattern.
775 /// Naively, one would think that "what this expands to" is a property of a
776 /// particular macro: macro `m1` returns an item, while macro `m2` returns an
777 /// expression, etc. That's not the case -- macros are polymorphic in the
778 /// result, and can expand to any type of the AST node.
780 /// What defines the actual AST node is the syntactic context of the macro
781 /// invocation. As a contrived example, in `let T![*] = T![*];` the first `T`
782 /// expands to a pattern, while the second one expands to an expression.
784 /// `ExpandTo` captures this bit of information about a particular macro call
786 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
796 pub fn from_call_site(call: &ast::MacroCall) -> ExpandTo {
797 use syntax::SyntaxKind::*;
799 let syn = call.syntax();
801 let parent = match syn.parent() {
803 None => return ExpandTo::Statements,
806 match parent.kind() {
807 MACRO_ITEMS | SOURCE_FILE | ITEM_LIST => ExpandTo::Items,
808 MACRO_STMTS | EXPR_STMT | STMT_LIST => ExpandTo::Statements,
809 MACRO_PAT => ExpandTo::Pattern,
810 MACRO_TYPE => ExpandTo::Type,
812 ARG_LIST | TRY_EXPR | TUPLE_EXPR | PAREN_EXPR | ARRAY_EXPR | FOR_EXPR | PATH_EXPR
813 | CLOSURE_EXPR | CONDITION | BREAK_EXPR | RETURN_EXPR | MATCH_EXPR | MATCH_ARM
814 | MATCH_GUARD | RECORD_EXPR_FIELD | CALL_EXPR | INDEX_EXPR | METHOD_CALL_EXPR
815 | FIELD_EXPR | AWAIT_EXPR | CAST_EXPR | REF_EXPR | PREFIX_EXPR | RANGE_EXPR
816 | BIN_EXPR => ExpandTo::Expr,
818 // FIXME: Handle LHS Pattern
823 // Unknown , Just guess it is `Items`
831 pub struct UnresolvedMacro {