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;
19 use base_db::ProcMacroKind;
22 pub use mbe::{ExpandError, ExpandResult, Origin};
23 use mod_path::ModPath;
25 use std::{hash::Hash, iter, sync::Arc};
27 use base_db::{impl_intern_key, salsa, CrateId, FileId, FileRange};
29 algo::{self, skip_trivia_token},
30 ast::{self, AstNode, HasDocComments},
31 Direction, SyntaxNode, SyntaxToken,
35 ast_id_map::FileAstId,
36 builtin_attr_macro::BuiltinAttrExpander,
37 builtin_derive_macro::BuiltinDeriveExpander,
38 builtin_fn_macro::{BuiltinFnLikeExpander, EagerExpander},
40 proc_macro::ProcMacroExpander,
43 /// Input to the analyzer is a set of files, where each file is identified by
44 /// `FileId` and contains source code. However, another source of source code in
45 /// Rust are macros: each macro can be thought of as producing a "temporary
46 /// file". To assign an id to such a file, we use the id of the macro call that
47 /// produced the file. So, a `HirFileId` is either a `FileId` (source code
48 /// written by user), or a `MacroCallId` (source code produced by macro).
50 /// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
51 /// containing the call plus the offset of the macro call in the file. Note that
52 /// this is a recursive definition! However, the size_of of `HirFileId` is
53 /// finite (because everything bottoms out at the real `FileId`) and small
54 /// (`MacroCallId` uses the location interning. You can check details here:
55 /// <https://en.wikipedia.org/wiki/String_interning>).
56 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
57 pub struct HirFileId(HirFileIdRepr);
59 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
64 impl From<FileId> for HirFileId {
65 fn from(id: FileId) -> Self {
66 HirFileId(HirFileIdRepr::FileId(id))
69 impl From<MacroFile> for HirFileId {
70 fn from(id: MacroFile) -> Self {
71 HirFileId(HirFileIdRepr::MacroFile(id))
75 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
76 pub struct MacroFile {
77 pub macro_call_id: MacroCallId,
80 /// `MacroCallId` identifies a particular macro invocation, like
81 /// `println!("Hello, {}", world)`.
82 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
83 pub struct MacroCallId(salsa::InternId);
84 impl_intern_key!(MacroCallId);
86 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
87 pub struct MacroCallLoc {
89 pub(crate) krate: CrateId,
90 eager: Option<EagerCallInfo>,
91 pub kind: MacroCallKind,
94 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
95 pub struct MacroDefId {
97 pub kind: MacroDefKind,
98 pub local_inner: bool,
101 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
102 pub enum MacroDefKind {
103 Declarative(AstId<ast::Macro>),
104 BuiltIn(BuiltinFnLikeExpander, AstId<ast::Macro>),
105 // FIXME: maybe just Builtin and rename BuiltinFnLikeExpander to BuiltinExpander
106 BuiltInAttr(BuiltinAttrExpander, AstId<ast::Macro>),
107 BuiltInDerive(BuiltinDeriveExpander, AstId<ast::Macro>),
108 BuiltInEager(EagerExpander, AstId<ast::Macro>),
109 ProcMacro(ProcMacroExpander, ProcMacroKind, AstId<ast::Fn>),
112 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
113 struct EagerCallInfo {
114 /// NOTE: This can be *either* the expansion result, *or* the argument to the eager macro!
115 arg_or_expansion: Arc<tt::Subtree>,
116 included_file: Option<FileId>,
119 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
120 pub enum MacroCallKind {
122 ast_id: AstId<ast::MacroCall>,
126 ast_id: AstId<ast::Adt>,
127 derive_name: Box<str>,
128 /// Syntactical index of the invoking `#[derive]` attribute.
130 /// Outer attributes are counted first, then inner attributes. This does not support
131 /// out-of-line modules, which may have attributes spread across 2 files!
132 derive_attr_index: u32,
135 ast_id: AstId<ast::Item>,
137 attr_args: (tt::Subtree, mbe::TokenMap),
138 /// Syntactical index of the invoking `#[attribute]`.
140 /// Outer attributes are counted first, then inner attributes. This does not support
141 /// out-of-line modules, which may have attributes spread across 2 files!
142 invoc_attr_index: u32,
147 /// For macro-expansion files, returns the file original source file the
148 /// expansion originated from.
149 pub fn original_file(self, db: &dyn db::AstDatabase) -> FileId {
151 HirFileIdRepr::FileId(file_id) => file_id,
152 HirFileIdRepr::MacroFile(macro_file) => {
153 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
154 let file_id = match &loc.eager {
155 Some(EagerCallInfo { included_file: Some(file), .. }) => (*file).into(),
156 _ => loc.kind.file_id(),
158 file_id.original_file(db)
163 pub fn expansion_level(self, db: &dyn db::AstDatabase) -> u32 {
166 while let HirFileIdRepr::MacroFile(macro_file) = curr.0 {
167 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
170 curr = loc.kind.file_id();
175 /// If this is a macro call, returns the syntax node of the call.
176 pub fn call_node(self, db: &dyn db::AstDatabase) -> Option<InFile<SyntaxNode>> {
178 HirFileIdRepr::FileId(_) => None,
179 HirFileIdRepr::MacroFile(macro_file) => {
180 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
181 Some(loc.kind.to_node(db))
186 /// Return expansion information if it is a macro-expansion file
187 pub fn expansion_info(self, db: &dyn db::AstDatabase) -> Option<ExpansionInfo> {
189 HirFileIdRepr::FileId(_) => None,
190 HirFileIdRepr::MacroFile(macro_file) => {
191 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
193 let arg_tt = loc.kind.arg(db)?;
195 let def = loc.def.ast_id().left().and_then(|id| {
196 let def_tt = match id.to_node(db) {
197 ast::Macro::MacroRules(mac) => mac.token_tree()?,
198 ast::Macro::MacroDef(mac) => mac.body()?,
200 Some(InFile::new(id.file_id, def_tt))
202 let attr_input_or_mac_def = def.or_else(|| match loc.kind {
203 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => {
206 .doc_comments_and_attrs()
207 .nth(invoc_attr_index as usize)
208 .and_then(Either::left)?
210 Some(InFile::new(ast_id.file_id, tt))
215 let macro_def = db.macro_def(loc.def).ok()?;
216 let (parse, exp_map) = db.parse_macro_expansion(macro_file).value?;
217 let macro_arg = db.macro_arg(macro_file.macro_call_id)?;
220 expanded: InFile::new(self, parse.syntax_node()),
221 arg: InFile::new(loc.kind.file_id(), arg_tt),
222 attr_input_or_mac_def,
223 macro_arg_shift: mbe::Shift::new(¯o_arg.0),
232 /// Indicate it is macro file generated for builtin derive
233 pub fn is_builtin_derive(&self, db: &dyn db::AstDatabase) -> Option<InFile<ast::Item>> {
235 HirFileIdRepr::FileId(_) => None,
236 HirFileIdRepr::MacroFile(macro_file) => {
237 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
238 let item = match loc.def.kind {
239 MacroDefKind::BuiltInDerive(..) => loc.kind.to_node(db),
242 Some(item.with_value(ast::Item::cast(item.value.clone())?))
247 pub fn is_custom_derive(&self, db: &dyn db::AstDatabase) -> bool {
249 HirFileIdRepr::FileId(_) => false,
250 HirFileIdRepr::MacroFile(macro_file) => {
251 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
253 MacroDefKind::ProcMacro(_, ProcMacroKind::CustomDerive, _) => true,
260 /// Return whether this file is an include macro
261 pub fn is_include_macro(&self, db: &dyn db::AstDatabase) -> bool {
263 HirFileIdRepr::MacroFile(macro_file) => {
264 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
265 matches!(loc.eager, Some(EagerCallInfo { included_file: Some(_), .. }))
271 /// Return whether this file is an include macro
272 pub fn is_attr_macro(&self, db: &dyn db::AstDatabase) -> bool {
274 HirFileIdRepr::MacroFile(macro_file) => {
275 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
276 matches!(loc.kind, MacroCallKind::Attr { .. })
282 pub fn is_macro(self) -> bool {
283 matches!(self.0, HirFileIdRepr::MacroFile(_))
286 pub fn macro_file(self) -> Option<MacroFile> {
288 HirFileIdRepr::FileId(_) => None,
289 HirFileIdRepr::MacroFile(m) => Some(m),
295 pub fn as_lazy_macro(
297 db: &dyn db::AstDatabase,
301 db.intern_macro_call(MacroCallLoc { def: self, krate, eager: None, kind })
304 pub fn ast_id(&self) -> Either<AstId<ast::Macro>, AstId<ast::Fn>> {
305 let id = match &self.kind {
306 MacroDefKind::ProcMacro(.., id) => return Either::Right(*id),
307 MacroDefKind::Declarative(id)
308 | MacroDefKind::BuiltIn(_, id)
309 | MacroDefKind::BuiltInAttr(_, id)
310 | MacroDefKind::BuiltInDerive(_, id)
311 | MacroDefKind::BuiltInEager(_, id) => id,
316 pub fn is_proc_macro(&self) -> bool {
317 matches!(self.kind, MacroDefKind::ProcMacro(..))
320 pub fn is_attribute(&self) -> bool {
323 MacroDefKind::BuiltInAttr(..) | MacroDefKind::ProcMacro(_, ProcMacroKind::Attr, _)
328 // FIXME: attribute indices do not account for `cfg_attr`, which means that we'll strip the whole
329 // `cfg_attr` instead of just one of the attributes it expands to
332 /// Returns the file containing the macro invocation.
333 fn file_id(&self) -> HirFileId {
335 MacroCallKind::FnLike { ast_id: InFile { file_id, .. }, .. }
336 | MacroCallKind::Derive { ast_id: InFile { file_id, .. }, .. }
337 | MacroCallKind::Attr { ast_id: InFile { file_id, .. }, .. } => file_id,
341 pub fn to_node(&self, db: &dyn db::AstDatabase) -> InFile<SyntaxNode> {
343 MacroCallKind::FnLike { ast_id, .. } => {
344 ast_id.with_value(ast_id.to_node(db).syntax().clone())
346 MacroCallKind::Derive { ast_id, .. } => {
347 ast_id.with_value(ast_id.to_node(db).syntax().clone())
349 MacroCallKind::Attr { ast_id, .. } => {
350 ast_id.with_value(ast_id.to_node(db).syntax().clone())
355 /// Returns the original file range that best describes the location of this macro call.
357 /// Here we try to roughly match what rustc does to improve diagnostics: fn-like macros
358 /// get the whole `ast::MacroCall`, attribute macros get the attribute's range, and derives
359 /// get only the specific derive that is being referred to.
360 pub fn original_call_range(self, db: &dyn db::AstDatabase) -> FileRange {
363 match kind.file_id().0 {
364 HirFileIdRepr::MacroFile(file) => {
365 kind = db.lookup_intern_macro_call(file.macro_call_id).kind;
371 // `call_id` is now the outermost macro call, so its location is in a real file.
372 let file_id = match kind.file_id().0 {
373 HirFileIdRepr::FileId(it) => it,
374 HirFileIdRepr::MacroFile(_) => unreachable!("encountered unexpected macro file"),
376 let range = match kind {
377 MacroCallKind::FnLike { ast_id, .. } => ast_id.to_node(db).syntax().text_range(),
378 MacroCallKind::Derive { ast_id, derive_attr_index, .. } => {
379 // FIXME: should be the range of the macro name, not the whole derive
382 .doc_comments_and_attrs()
383 .nth(derive_attr_index as usize)
384 .expect("missing derive")
385 .expect_left("derive is a doc comment?")
389 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => ast_id
391 .doc_comments_and_attrs()
392 .nth(invoc_attr_index as usize)
393 .expect("missing attribute")
394 .expect_left("attribute macro is a doc comment?")
399 FileRange { range, file_id }
402 fn arg(&self, db: &dyn db::AstDatabase) -> Option<SyntaxNode> {
404 MacroCallKind::FnLike { ast_id, .. } => {
405 Some(ast_id.to_node(db).token_tree()?.syntax().clone())
407 MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
408 MacroCallKind::Attr { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
412 fn expand_to(&self) -> ExpandTo {
414 MacroCallKind::FnLike { expand_to, .. } => *expand_to,
415 MacroCallKind::Derive { .. } => ExpandTo::Items,
416 MacroCallKind::Attr { .. } => ExpandTo::Items, // is this always correct?
422 pub fn as_file(self) -> HirFileId {
423 MacroFile { macro_call_id: self }.into()
427 /// ExpansionInfo mainly describes how to map text range between src and expanded macro
428 #[derive(Debug, Clone, PartialEq, Eq)]
429 pub struct ExpansionInfo {
430 expanded: InFile<SyntaxNode>,
431 /// The argument TokenTree or item for attributes
432 arg: InFile<SyntaxNode>,
433 /// The `macro_rules!` or attribute input.
434 attr_input_or_mac_def: Option<InFile<ast::TokenTree>>,
436 macro_def: Arc<TokenExpander>,
437 macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
438 /// A shift built from `macro_arg`'s subtree, relevant for attributes as the item is the macro arg
439 /// and as such we need to shift tokens if they are part of an attributes input instead of their item.
440 macro_arg_shift: mbe::Shift,
441 exp_map: Arc<mbe::TokenMap>,
445 pub fn expanded(&self) -> InFile<SyntaxNode> {
446 self.expanded.clone()
449 pub fn call_node(&self) -> Option<InFile<SyntaxNode>> {
450 Some(self.arg.with_value(self.arg.value.parent()?))
453 /// Map a token down from macro input into the macro expansion.
455 /// The inner workings of this function differ slightly depending on the type of macro we are dealing with:
457 /// For declarative macros, we need to accommodate for the macro definition site(which acts as a second unchanging input)
458 /// , as tokens can mapped in and out of it.
459 /// To do this we shift all ids in the expansion by the maximum id of the definition site giving us an easy
460 /// way to map all the tokens.
462 /// Attributes have two different inputs, the input tokentree in the attribute node and the item
463 /// the attribute is annotating. Similarly as for declarative macros we need to do a shift here
464 /// as well. Currently this is done by shifting the attribute input by the maximum id of the item.
465 /// - function-like and derives:
466 /// Both of these only have one simple call site input so no special handling is required here.
467 pub fn map_token_down(
469 db: &dyn db::AstDatabase,
470 item: Option<ast::Item>,
471 token: InFile<&SyntaxToken>,
472 ) -> Option<impl Iterator<Item = InFile<SyntaxToken>> + '_> {
473 assert_eq!(token.file_id, self.arg.file_id);
474 let token_id_in_attr_input = if let Some(item) = item {
475 // check if we are mapping down in an attribute input
476 // this is a special case as attributes can have two inputs
477 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
478 let loc = db.lookup_intern_macro_call(call_id);
480 let token_range = token.value.text_range();
482 MacroCallKind::Attr { attr_args: (_, map), invoc_attr_index, .. } => {
484 .doc_comments_and_attrs()
485 .nth(*invoc_attr_index as usize)
486 .and_then(Either::left)?;
487 match attr.token_tree() {
489 if token_tree.syntax().text_range().contains_range(token_range) =>
491 let attr_input_start =
492 token_tree.left_delimiter_token()?.text_range().start();
494 token.value.text_range().checked_sub(attr_input_start)?;
495 // shift by the item's tree's max id
497 self.macro_arg_shift.shift(map.token_by_range(relative_range)?);
509 let token_id = match token_id_in_attr_input {
510 Some(token_id) => token_id,
511 // the token is not inside an attribute's input so do the lookup in the macro_arg as ususal
514 token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
515 let token_id = self.macro_arg.1.token_by_range(relative_range)?;
516 // conditionally shift the id by a declaratives macro definition
517 self.macro_def.map_id_down(token_id)
523 .ranges_by_token(token_id, token.value.kind())
524 .flat_map(move |range| self.expanded.value.covering_element(range).into_token());
526 Some(tokens.map(move |token| self.expanded.with_value(token)))
529 /// Map a token up out of the expansion it resides in into the arguments of the macro call of the expansion.
532 db: &dyn db::AstDatabase,
533 token: InFile<&SyntaxToken>,
534 ) -> Option<(InFile<SyntaxToken>, Origin)> {
535 // Fetch the id through its text range,
536 let token_id = self.exp_map.token_by_range(token.value.text_range())?;
537 // conditionally unshifting the id to accommodate for macro-rules def site
538 let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
540 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
541 let loc = db.lookup_intern_macro_call(call_id);
543 // Attributes are a bit special for us, they have two inputs, the input tokentree and the annotated item.
544 let (token_map, tt) = match &loc.kind {
545 MacroCallKind::Attr { attr_args: (_, arg_token_map), .. } => {
546 // try unshifting the the token id, if unshifting fails, the token resides in the non-item attribute input
547 // note that the `TokenExpander::map_id_up` earlier only unshifts for declarative macros, so we don't double unshift with this
548 match self.macro_arg_shift.unshift(token_id) {
550 token_id = unshifted;
551 (arg_token_map, self.attr_input_or_mac_def.clone()?.syntax().cloned())
553 None => (&self.macro_arg.1, self.arg.clone()),
557 mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
558 mbe::Origin::Def => match (&*self.macro_def, &self.attr_input_or_mac_def) {
559 (TokenExpander::DeclarativeMacro { def_site_token_map, .. }, Some(tt)) => {
560 (def_site_token_map, tt.syntax().cloned())
562 _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
567 let range = token_map.first_range_by_token(token_id, token.value.kind())?;
569 tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
570 Some((tt.with_value(token), origin))
574 /// `AstId` points to an AST node in any file.
576 /// It is stable across reparses, and can be used as salsa key/value.
577 // FIXME: isn't this just a `Source<FileAstId<N>>` ?
578 pub type AstId<N> = InFile<FileAstId<N>>;
580 impl<N: AstNode> AstId<N> {
581 pub fn to_node(&self, db: &dyn db::AstDatabase) -> N {
582 let root = db.parse_or_expand(self.file_id).unwrap();
583 db.ast_id_map(self.file_id).get(self.value).to_node(&root)
587 /// `InFile<T>` stores a value of `T` inside a particular file/syntax tree.
589 /// Typical usages are:
591 /// * `InFile<SyntaxNode>` -- syntax node in a file
592 /// * `InFile<ast::FnDef>` -- ast node in a file
593 /// * `InFile<TextSize>` -- offset in a file
594 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
595 pub struct InFile<T> {
596 pub file_id: HirFileId,
601 pub fn new(file_id: HirFileId, value: T) -> InFile<T> {
602 InFile { file_id, value }
605 // Similarly, naming here is stupid...
606 pub fn with_value<U>(&self, value: U) -> InFile<U> {
607 InFile::new(self.file_id, value)
610 pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> InFile<U> {
611 InFile::new(self.file_id, f(self.value))
613 pub fn as_ref(&self) -> InFile<&T> {
614 self.with_value(&self.value)
616 pub fn file_syntax(&self, db: &dyn db::AstDatabase) -> SyntaxNode {
617 db.parse_or_expand(self.file_id).expect("source created from invalid file")
621 impl<T: Clone> InFile<&T> {
622 pub fn cloned(&self) -> InFile<T> {
623 self.with_value(self.value.clone())
627 impl<T> InFile<Option<T>> {
628 pub fn transpose(self) -> Option<InFile<T>> {
629 let value = self.value?;
630 Some(InFile::new(self.file_id, value))
634 impl<'a> InFile<&'a SyntaxNode> {
635 pub fn ancestors_with_macros(
637 db: &dyn db::AstDatabase,
638 ) -> impl Iterator<Item = InFile<SyntaxNode>> + Clone + '_ {
639 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
640 Some(parent) => Some(node.with_value(parent)),
641 None => node.file_id.call_node(db),
645 /// Skips the attributed item that caused the macro invocation we are climbing up
646 pub fn ancestors_with_macros_skip_attr_item(
648 db: &dyn db::AstDatabase,
649 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
650 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
651 Some(parent) => Some(node.with_value(parent)),
653 let parent_node = node.file_id.call_node(db)?;
654 if node.file_id.is_attr_macro(db) {
655 // macro call was an attributed item, skip it
656 // FIXME: does this fail if this is a direct expansion of another macro?
657 parent_node.map(|node| node.parent()).transpose()
665 /// Falls back to the macro call range if the node cannot be mapped up fully.
666 pub fn original_file_range(self, db: &dyn db::AstDatabase) -> FileRange {
667 if let Some(res) = self.original_file_range_opt(db) {
671 // Fall back to whole macro call.
672 match self.file_id.0 {
673 HirFileIdRepr::FileId(file_id) => FileRange { file_id, range: self.value.text_range() },
674 HirFileIdRepr::MacroFile(mac_file) => {
675 let loc = db.lookup_intern_macro_call(mac_file.macro_call_id);
676 loc.kind.original_call_range(db)
681 /// Attempts to map the syntax node back up its macro calls.
682 pub fn original_file_range_opt(self, db: &dyn db::AstDatabase) -> Option<FileRange> {
683 match ascend_node_border_tokens(db, self) {
684 Some(InFile { file_id, value: (first, last) }) => {
685 let original_file = file_id.original_file(db);
686 let range = first.text_range().cover(last.text_range());
687 if file_id != original_file.into() {
688 tracing::error!("Failed mapping up more for {:?}", range);
691 Some(FileRange { file_id: original_file, range })
693 _ if !self.file_id.is_macro() => Some(FileRange {
694 file_id: self.file_id.original_file(db),
695 range: self.value.text_range(),
702 fn ascend_node_border_tokens(
703 db: &dyn db::AstDatabase,
704 InFile { file_id, value: node }: InFile<&SyntaxNode>,
705 ) -> Option<InFile<(SyntaxToken, SyntaxToken)>> {
706 let expansion = file_id.expansion_info(db)?;
708 // the input node has only one token ?
709 let first = skip_trivia_token(node.first_token()?, Direction::Next)?;
710 let last = skip_trivia_token(node.last_token()?, Direction::Prev)?;
711 let is_single_token = first == last;
713 node.descendants().find_map(|it| {
714 let first = skip_trivia_token(it.first_token()?, Direction::Next)?;
715 let first = ascend_call_token(db, &expansion, InFile::new(file_id, first))?;
717 let last = skip_trivia_token(it.last_token()?, Direction::Prev)?;
718 let last = ascend_call_token(db, &expansion, InFile::new(file_id, last))?;
720 if (!is_single_token && first == last) || (first.file_id != last.file_id) {
724 Some(InFile::new(first.file_id, (first.value, last.value)))
728 fn ascend_call_token(
729 db: &dyn db::AstDatabase,
730 expansion: &ExpansionInfo,
731 token: InFile<SyntaxToken>,
732 ) -> Option<InFile<SyntaxToken>> {
733 let (mapped, origin) = expansion.map_token_up(db, token.as_ref())?;
734 if origin != Origin::Call {
737 if let Some(info) = mapped.file_id.expansion_info(db) {
738 return ascend_call_token(db, &info, mapped);
743 impl InFile<SyntaxToken> {
744 pub fn ancestors_with_macros(
746 db: &dyn db::AstDatabase,
747 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
748 self.value.parent().into_iter().flat_map({
749 let file_id = self.file_id;
750 move |parent| InFile::new(file_id, &parent).ancestors_with_macros(db)
755 impl<N: AstNode> InFile<N> {
756 pub fn descendants<T: AstNode>(self) -> impl Iterator<Item = InFile<T>> {
757 self.value.syntax().descendants().filter_map(T::cast).map(move |n| self.with_value(n))
760 pub fn original_ast_node(self, db: &dyn db::AstDatabase) -> Option<InFile<N>> {
761 match ascend_node_border_tokens(db, self.syntax()) {
762 Some(InFile { file_id, value: (first, last) }) => {
763 let original_file = file_id.original_file(db);
764 if file_id != original_file.into() {
765 let range = first.text_range().cover(last.text_range());
766 tracing::error!("Failed mapping up more for {:?}", range);
769 let anc = algo::least_common_ancestor(&first.parent()?, &last.parent()?)?;
770 Some(InFile::new(file_id, anc.ancestors().find_map(N::cast)?))
772 _ if !self.file_id.is_macro() => Some(self),
777 pub fn syntax(&self) -> InFile<&SyntaxNode> {
778 self.with_value(self.value.syntax())
782 /// In Rust, macros expand token trees to token trees. When we want to turn a
783 /// token tree into an AST node, we need to figure out what kind of AST node we
784 /// want: something like `foo` can be a type, an expression, or a pattern.
786 /// Naively, one would think that "what this expands to" is a property of a
787 /// particular macro: macro `m1` returns an item, while macro `m2` returns an
788 /// expression, etc. That's not the case -- macros are polymorphic in the
789 /// result, and can expand to any type of the AST node.
791 /// What defines the actual AST node is the syntactic context of the macro
792 /// invocation. As a contrived example, in `let T![*] = T![*];` the first `T`
793 /// expands to a pattern, while the second one expands to an expression.
795 /// `ExpandTo` captures this bit of information about a particular macro call
797 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
807 pub fn from_call_site(call: &ast::MacroCall) -> ExpandTo {
808 use syntax::SyntaxKind::*;
810 let syn = call.syntax();
812 let parent = match syn.parent() {
814 None => return ExpandTo::Statements,
817 match parent.kind() {
818 MACRO_ITEMS | SOURCE_FILE | ITEM_LIST => ExpandTo::Items,
819 MACRO_STMTS | EXPR_STMT | STMT_LIST => ExpandTo::Statements,
820 MACRO_PAT => ExpandTo::Pattern,
821 MACRO_TYPE => ExpandTo::Type,
823 ARG_LIST | TRY_EXPR | TUPLE_EXPR | PAREN_EXPR | ARRAY_EXPR | FOR_EXPR | PATH_EXPR
824 | CLOSURE_EXPR | CONDITION | BREAK_EXPR | RETURN_EXPR | MATCH_EXPR | MATCH_ARM
825 | MATCH_GUARD | RECORD_EXPR_FIELD | CALL_EXPR | INDEX_EXPR | METHOD_CALL_EXPR
826 | FIELD_EXPR | AWAIT_EXPR | CAST_EXPR | REF_EXPR | PREFIX_EXPR | RANGE_EXPR
827 | BIN_EXPR => ExpandTo::Expr,
829 // FIXME: Handle LHS Pattern
834 // Unknown , Just guess it is `Items`
842 pub struct UnresolvedMacro {