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;
18 use base_db::ProcMacroKind;
21 pub use mbe::{ExpandError, ExpandResult, Origin};
23 use std::{hash::Hash, iter, sync::Arc};
25 use base_db::{impl_intern_key, salsa, CrateId, FileId, FileRange};
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},
38 proc_macro::ProcMacroExpander,
41 /// Input to the analyzer is a set of files, where each file is identified by
42 /// `FileId` and contains source code. However, another source of source code in
43 /// Rust are macros: each macro can be thought of as producing a "temporary
44 /// file". To assign an id to such a file, we use the id of the macro call that
45 /// produced the file. So, a `HirFileId` is either a `FileId` (source code
46 /// written by user), or a `MacroCallId` (source code produced by macro).
48 /// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
49 /// containing the call plus the offset of the macro call in the file. Note that
50 /// this is a recursive definition! However, the size_of of `HirFileId` is
51 /// finite (because everything bottoms out at the real `FileId`) and small
52 /// (`MacroCallId` uses the location interning. You can check details here:
53 /// <https://en.wikipedia.org/wiki/String_interning>).
54 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
55 pub struct HirFileId(HirFileIdRepr);
57 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
62 impl From<FileId> for HirFileId {
63 fn from(id: FileId) -> Self {
64 HirFileId(HirFileIdRepr::FileId(id))
67 impl From<MacroFile> for HirFileId {
68 fn from(id: MacroFile) -> Self {
69 HirFileId(HirFileIdRepr::MacroFile(id))
73 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
74 pub struct MacroFile {
75 pub macro_call_id: MacroCallId,
78 /// `MacroCallId` identifies a particular macro invocation, like
79 /// `println!("Hello, {}", world)`.
80 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
81 pub struct MacroCallId(salsa::InternId);
82 impl_intern_key!(MacroCallId);
84 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
85 pub struct MacroCallLoc {
87 pub(crate) krate: CrateId,
88 eager: Option<EagerCallInfo>,
89 pub kind: MacroCallKind,
92 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
93 pub struct MacroDefId {
95 pub kind: MacroDefKind,
96 pub local_inner: bool,
99 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
100 pub enum MacroDefKind {
101 Declarative(AstId<ast::Macro>),
102 BuiltIn(BuiltinFnLikeExpander, AstId<ast::Macro>),
103 // FIXME: maybe just Builtin and rename BuiltinFnLikeExpander to BuiltinExpander
104 BuiltInAttr(BuiltinAttrExpander, AstId<ast::Macro>),
105 BuiltInDerive(BuiltinDeriveExpander, AstId<ast::Macro>),
106 BuiltInEager(EagerExpander, AstId<ast::Macro>),
107 ProcMacro(ProcMacroExpander, ProcMacroKind, AstId<ast::Fn>),
110 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
111 struct EagerCallInfo {
112 /// NOTE: This can be *either* the expansion result, *or* the argument to the eager macro!
113 arg_or_expansion: Arc<tt::Subtree>,
114 included_file: Option<FileId>,
117 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
118 pub enum MacroCallKind {
120 ast_id: AstId<ast::MacroCall>,
124 ast_id: AstId<ast::Adt>,
125 derive_name: Box<str>,
126 /// Syntactical index of the invoking `#[derive]` attribute.
128 /// Outer attributes are counted first, then inner attributes. This does not support
129 /// out-of-line modules, which may have attributes spread across 2 files!
130 derive_attr_index: u32,
133 ast_id: AstId<ast::Item>,
135 attr_args: (tt::Subtree, mbe::TokenMap),
136 /// Syntactical index of the invoking `#[attribute]`.
138 /// Outer attributes are counted first, then inner attributes. This does not support
139 /// out-of-line modules, which may have attributes spread across 2 files!
140 invoc_attr_index: u32,
145 /// For macro-expansion files, returns the file original source file the
146 /// expansion originated from.
147 pub fn original_file(self, db: &dyn db::AstDatabase) -> FileId {
149 HirFileIdRepr::FileId(file_id) => file_id,
150 HirFileIdRepr::MacroFile(macro_file) => {
151 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
152 let file_id = match &loc.eager {
153 Some(EagerCallInfo { included_file: Some(file), .. }) => (*file).into(),
154 _ => loc.kind.file_id(),
156 file_id.original_file(db)
161 pub fn expansion_level(self, db: &dyn db::AstDatabase) -> u32 {
164 while let HirFileIdRepr::MacroFile(macro_file) = curr.0 {
165 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
168 curr = loc.kind.file_id();
173 /// If this is a macro call, returns the syntax node of the call.
174 pub fn call_node(self, db: &dyn db::AstDatabase) -> Option<InFile<SyntaxNode>> {
176 HirFileIdRepr::FileId(_) => None,
177 HirFileIdRepr::MacroFile(macro_file) => {
178 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
179 Some(loc.kind.to_node(db))
184 /// Return expansion information if it is a macro-expansion file
185 pub fn expansion_info(self, db: &dyn db::AstDatabase) -> Option<ExpansionInfo> {
187 HirFileIdRepr::FileId(_) => None,
188 HirFileIdRepr::MacroFile(macro_file) => {
189 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
191 let arg_tt = loc.kind.arg(db)?;
193 let def = loc.def.ast_id().left().and_then(|id| {
194 let def_tt = match id.to_node(db) {
195 ast::Macro::MacroRules(mac) => mac.token_tree()?,
196 ast::Macro::MacroDef(mac) => mac.body()?,
198 Some(InFile::new(id.file_id, def_tt))
200 let attr_input_or_mac_def = def.or_else(|| match loc.kind {
201 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => {
204 .doc_comments_and_attrs()
205 .nth(invoc_attr_index as usize)
206 .and_then(Either::right)?
208 Some(InFile::new(ast_id.file_id, tt))
213 let macro_def = db.macro_def(loc.def).ok()?;
214 let (parse, exp_map) = db.parse_macro_expansion(macro_file).value?;
215 let macro_arg = db.macro_arg(macro_file.macro_call_id)?;
218 expanded: InFile::new(self, parse.syntax_node()),
219 arg: InFile::new(loc.kind.file_id(), arg_tt),
220 attr_input_or_mac_def,
221 macro_arg_shift: mbe::Shift::new(¯o_arg.0),
230 /// Indicate it is macro file generated for builtin derive
231 pub fn is_builtin_derive(&self, db: &dyn db::AstDatabase) -> Option<InFile<ast::Item>> {
233 HirFileIdRepr::FileId(_) => None,
234 HirFileIdRepr::MacroFile(macro_file) => {
235 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
236 let item = match loc.def.kind {
237 MacroDefKind::BuiltInDerive(..) => loc.kind.to_node(db),
240 Some(item.with_value(ast::Item::cast(item.value.clone())?))
245 pub fn is_custom_derive(&self, db: &dyn db::AstDatabase) -> bool {
247 HirFileIdRepr::FileId(_) => false,
248 HirFileIdRepr::MacroFile(macro_file) => {
249 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
251 MacroDefKind::ProcMacro(_, ProcMacroKind::CustomDerive, _) => true,
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 fn arg(&self, db: &dyn db::AstDatabase) -> Option<SyntaxNode> {
355 MacroCallKind::FnLike { ast_id, .. } => {
356 Some(ast_id.to_node(db).token_tree()?.syntax().clone())
358 MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
359 MacroCallKind::Attr { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
363 fn expand_to(&self) -> ExpandTo {
365 MacroCallKind::FnLike { expand_to, .. } => *expand_to,
366 MacroCallKind::Derive { .. } => ExpandTo::Items,
367 MacroCallKind::Attr { .. } => ExpandTo::Items, // is this always correct?
373 pub fn as_file(self) -> HirFileId {
374 MacroFile { macro_call_id: self }.into()
378 /// ExpansionInfo mainly describes how to map text range between src and expanded macro
379 #[derive(Debug, Clone, PartialEq, Eq)]
380 pub struct ExpansionInfo {
381 expanded: InFile<SyntaxNode>,
382 /// The argument TokenTree or item for attributes
383 arg: InFile<SyntaxNode>,
384 /// The `macro_rules!` or attribute input.
385 attr_input_or_mac_def: Option<InFile<ast::TokenTree>>,
387 macro_def: Arc<TokenExpander>,
388 macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
389 /// A shift built from `macro_arg`'s subtree, relevant for attributes as the item is the macro arg
390 /// and as such we need to shift tokens if they are part of an attributes input instead of their item.
391 macro_arg_shift: mbe::Shift,
392 exp_map: Arc<mbe::TokenMap>,
396 pub fn expanded(&self) -> InFile<SyntaxNode> {
397 self.expanded.clone()
400 pub fn call_node(&self) -> Option<InFile<SyntaxNode>> {
401 Some(self.arg.with_value(self.arg.value.parent()?))
404 /// Map a token down from macro input into the macro expansion.
406 /// The inner workings of this function differ slightly depending on the type of macro we are dealing with:
408 /// For declarative macros, we need to accommodate for the macro definition site(which acts as a second unchanging input)
409 /// , as tokens can mapped in and out of it.
410 /// To do this we shift all ids in the expansion by the maximum id of the definition site giving us an easy
411 /// way to map all the tokens.
413 /// Attributes have two different inputs, the input tokentree in the attribute node and the item
414 /// the attribute is annotating. Similarly as for declarative macros we need to do a shift here
415 /// as well. Currently this is done by shifting the attribute input by the maximum id of the item.
416 /// - function-like and derives:
417 /// Both of these only have one simple call site input so no special handling is required here.
418 pub fn map_token_down(
420 db: &dyn db::AstDatabase,
421 item: Option<ast::Item>,
422 token: InFile<&SyntaxToken>,
423 ) -> Option<impl Iterator<Item = InFile<SyntaxToken>> + '_> {
424 assert_eq!(token.file_id, self.arg.file_id);
425 let token_id_in_attr_input = if let Some(item) = item {
426 // check if we are mapping down in an attribute input
427 // this is a special case as attributes can have two inputs
428 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
429 let loc = db.lookup_intern_macro_call(call_id);
431 let token_range = token.value.text_range();
433 MacroCallKind::Attr { attr_args: (_, map), invoc_attr_index, .. } => {
435 .doc_comments_and_attrs()
436 .nth(*invoc_attr_index as usize)
437 .and_then(Either::right)?;
438 match attr.token_tree() {
440 if token_tree.syntax().text_range().contains_range(token_range) =>
442 let attr_input_start =
443 token_tree.left_delimiter_token()?.text_range().start();
445 token.value.text_range().checked_sub(attr_input_start)?;
446 // shift by the item's tree's max id
448 self.macro_arg_shift.shift(map.token_by_range(relative_range)?);
460 let token_id = match token_id_in_attr_input {
461 Some(token_id) => token_id,
462 // the token is not inside an attribute's input so do the lookup in the macro_arg as ususal
465 token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
466 let token_id = self.macro_arg.1.token_by_range(relative_range)?;
467 // conditionally shift the id by a declaratives macro definition
468 self.macro_def.map_id_down(token_id)
474 .ranges_by_token(token_id, token.value.kind())
475 .flat_map(move |range| self.expanded.value.covering_element(range).into_token());
477 Some(tokens.map(move |token| self.expanded.with_value(token)))
480 /// Map a token up out of the expansion it resides in into the arguments of the macro call of the expansion.
483 db: &dyn db::AstDatabase,
484 token: InFile<&SyntaxToken>,
485 ) -> Option<(InFile<SyntaxToken>, Origin)> {
486 // Fetch the id through its text range,
487 let token_id = self.exp_map.token_by_range(token.value.text_range())?;
488 // conditionally unshifting the id to accommodate for macro-rules def site
489 let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
491 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
492 let loc = db.lookup_intern_macro_call(call_id);
494 // Attributes are a bit special for us, they have two inputs, the input tokentree and the annotated item.
495 let (token_map, tt) = match &loc.kind {
496 MacroCallKind::Attr { attr_args: (_, arg_token_map), .. } => {
497 // try unshifting the the token id, if unshifting fails, the token resides in the non-item attribute input
498 // note that the `TokenExpander::map_id_up` earlier only unshifts for declarative macros, so we don't double unshift with this
499 match self.macro_arg_shift.unshift(token_id) {
501 token_id = unshifted;
502 (arg_token_map, self.attr_input_or_mac_def.clone()?.syntax().cloned())
504 None => (&self.macro_arg.1, self.arg.clone()),
508 mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
509 mbe::Origin::Def => match (&*self.macro_def, &self.attr_input_or_mac_def) {
510 (TokenExpander::DeclarativeMacro { def_site_token_map, .. }, Some(tt)) => {
511 (def_site_token_map, tt.syntax().cloned())
513 _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
518 let range = token_map.first_range_by_token(token_id, token.value.kind())?;
520 tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
521 Some((tt.with_value(token), origin))
525 /// `AstId` points to an AST node in any file.
527 /// It is stable across reparses, and can be used as salsa key/value.
528 // FIXME: isn't this just a `Source<FileAstId<N>>` ?
529 pub type AstId<N> = InFile<FileAstId<N>>;
531 impl<N: AstNode> AstId<N> {
532 pub fn to_node(&self, db: &dyn db::AstDatabase) -> N {
533 let root = db.parse_or_expand(self.file_id).unwrap();
534 db.ast_id_map(self.file_id).get(self.value).to_node(&root)
538 /// `InFile<T>` stores a value of `T` inside a particular file/syntax tree.
540 /// Typical usages are:
542 /// * `InFile<SyntaxNode>` -- syntax node in a file
543 /// * `InFile<ast::FnDef>` -- ast node in a file
544 /// * `InFile<TextSize>` -- offset in a file
545 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
546 pub struct InFile<T> {
547 pub file_id: HirFileId,
552 pub fn new(file_id: HirFileId, value: T) -> InFile<T> {
553 InFile { file_id, value }
556 // Similarly, naming here is stupid...
557 pub fn with_value<U>(&self, value: U) -> InFile<U> {
558 InFile::new(self.file_id, value)
561 pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> InFile<U> {
562 InFile::new(self.file_id, f(self.value))
564 pub fn as_ref(&self) -> InFile<&T> {
565 self.with_value(&self.value)
567 pub fn file_syntax(&self, db: &dyn db::AstDatabase) -> SyntaxNode {
568 db.parse_or_expand(self.file_id).expect("source created from invalid file")
572 impl<T: Clone> InFile<&T> {
573 pub fn cloned(&self) -> InFile<T> {
574 self.with_value(self.value.clone())
578 impl<T> InFile<Option<T>> {
579 pub fn transpose(self) -> Option<InFile<T>> {
580 let value = self.value?;
581 Some(InFile::new(self.file_id, value))
585 impl<'a> InFile<&'a SyntaxNode> {
586 pub fn ancestors_with_macros(
588 db: &dyn db::AstDatabase,
589 ) -> impl Iterator<Item = InFile<SyntaxNode>> + Clone + '_ {
590 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
591 Some(parent) => Some(node.with_value(parent)),
593 let parent_node = node.file_id.call_node(db)?;
599 /// Skips the attributed item that caused the macro invocation we are climbing up
600 pub fn ancestors_with_macros_skip_attr_item(
602 db: &dyn db::AstDatabase,
603 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
604 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
605 Some(parent) => Some(node.with_value(parent)),
607 let parent_node = node.file_id.call_node(db)?;
608 if node.file_id.is_attr_macro(db) {
609 // macro call was an attributed item, skip it
610 // FIXME: does this fail if this is a direct expansion of another macro?
611 parent_node.map(|node| node.parent()).transpose()
619 /// Falls back to the macro call range if the node cannot be mapped up fully.
620 pub fn original_file_range(self, db: &dyn db::AstDatabase) -> FileRange {
621 if let Some(res) = self.original_file_range_opt(db) {
625 // Fall back to whole macro call.
626 let mut node = self.cloned();
627 while let Some(call_node) = node.file_id.call_node(db) {
631 let orig_file = node.file_id.original_file(db);
632 assert_eq!(node.file_id, orig_file.into());
634 FileRange { file_id: orig_file, range: node.value.text_range() }
637 /// Attempts to map the syntax node back up its macro calls.
638 pub fn original_file_range_opt(self, db: &dyn db::AstDatabase) -> Option<FileRange> {
639 match ascend_node_border_tokens(db, self) {
640 Some(InFile { file_id, value: (first, last) }) => {
641 let original_file = file_id.original_file(db);
642 let range = first.text_range().cover(last.text_range());
643 if file_id != original_file.into() {
644 tracing::error!("Failed mapping up more for {:?}", range);
647 Some(FileRange { file_id: original_file, range })
649 _ if !self.file_id.is_macro() => Some(FileRange {
650 file_id: self.file_id.original_file(db),
651 range: self.value.text_range(),
658 fn ascend_node_border_tokens(
659 db: &dyn db::AstDatabase,
660 InFile { file_id, value: node }: InFile<&SyntaxNode>,
661 ) -> Option<InFile<(SyntaxToken, SyntaxToken)>> {
662 let expansion = file_id.expansion_info(db)?;
664 // the input node has only one token ?
665 let first = skip_trivia_token(node.first_token()?, Direction::Next)?;
666 let last = skip_trivia_token(node.last_token()?, Direction::Prev)?;
667 let is_single_token = first == last;
669 node.descendants().find_map(|it| {
670 let first = skip_trivia_token(it.first_token()?, Direction::Next)?;
671 let first = ascend_call_token(db, &expansion, InFile::new(file_id, first))?;
673 let last = skip_trivia_token(it.last_token()?, Direction::Prev)?;
674 let last = ascend_call_token(db, &expansion, InFile::new(file_id, last))?;
676 if (!is_single_token && first == last) || (first.file_id != last.file_id) {
680 Some(InFile::new(first.file_id, (first.value, last.value)))
684 fn ascend_call_token(
685 db: &dyn db::AstDatabase,
686 expansion: &ExpansionInfo,
687 token: InFile<SyntaxToken>,
688 ) -> Option<InFile<SyntaxToken>> {
689 let (mapped, origin) = expansion.map_token_up(db, token.as_ref())?;
690 if origin != Origin::Call {
693 if let Some(info) = mapped.file_id.expansion_info(db) {
694 return ascend_call_token(db, &info, mapped);
699 impl InFile<SyntaxToken> {
700 pub fn ancestors_with_macros(
702 db: &dyn db::AstDatabase,
703 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
704 self.value.parent().into_iter().flat_map({
705 let file_id = self.file_id;
706 move |parent| InFile::new(file_id, &parent).ancestors_with_macros(db)
711 impl<N: AstNode> InFile<N> {
712 pub fn descendants<T: AstNode>(self) -> impl Iterator<Item = InFile<T>> {
713 self.value.syntax().descendants().filter_map(T::cast).map(move |n| self.with_value(n))
716 pub fn original_ast_node(self, db: &dyn db::AstDatabase) -> Option<InFile<N>> {
717 match ascend_node_border_tokens(db, self.syntax()) {
718 Some(InFile { file_id, value: (first, last) }) => {
719 let original_file = file_id.original_file(db);
720 if file_id != original_file.into() {
721 let range = first.text_range().cover(last.text_range());
722 tracing::error!("Failed mapping up more for {:?}", range);
725 let anc = algo::least_common_ancestor(&first.parent()?, &last.parent()?)?;
726 Some(InFile::new(file_id, anc.ancestors().find_map(N::cast)?))
728 _ if !self.file_id.is_macro() => Some(self),
733 pub fn syntax(&self) -> InFile<&SyntaxNode> {
734 self.with_value(self.value.syntax())
738 /// In Rust, macros expand token trees to token trees. When we want to turn a
739 /// token tree into an AST node, we need to figure out what kind of AST node we
740 /// want: something like `foo` can be a type, an expression, or a pattern.
742 /// Naively, one would think that "what this expands to" is a property of a
743 /// particular macro: macro `m1` returns an item, while macro `m2` returns an
744 /// expression, etc. That's not the case -- macros are polymorphic in the
745 /// result, and can expand to any type of the AST node.
747 /// What defines the actual AST node is the syntactic context of the macro
748 /// invocation. As a contrived example, in `let T![*] = T![*];` the first `T`
749 /// expands to a pattern, while the second one expands to an expression.
751 /// `ExpandTo` captures this bit of information about a particular macro call
753 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
763 pub fn from_call_site(call: &ast::MacroCall) -> ExpandTo {
764 use syntax::SyntaxKind::*;
766 let syn = call.syntax();
768 let parent = match syn.parent() {
770 None => return ExpandTo::Statements,
773 match parent.kind() {
774 MACRO_ITEMS | SOURCE_FILE | ITEM_LIST => ExpandTo::Items,
775 MACRO_STMTS | EXPR_STMT | STMT_LIST => ExpandTo::Statements,
776 MACRO_PAT => ExpandTo::Pattern,
777 MACRO_TYPE => ExpandTo::Type,
779 ARG_LIST | TRY_EXPR | TUPLE_EXPR | PAREN_EXPR | ARRAY_EXPR | FOR_EXPR | PATH_EXPR
780 | CLOSURE_EXPR | CONDITION | BREAK_EXPR | RETURN_EXPR | MATCH_EXPR | MATCH_ARM
781 | MATCH_GUARD | RECORD_EXPR_FIELD | CALL_EXPR | INDEX_EXPR | METHOD_CALL_EXPR
782 | FIELD_EXPR | AWAIT_EXPR | CAST_EXPR | REF_EXPR | PREFIX_EXPR | RANGE_EXPR
783 | BIN_EXPR => ExpandTo::Expr,
785 // FIXME: Handle LHS Pattern
790 // Unknown , Just guess it is `Items`