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::{Origin, ValueResult};
22 use std::{fmt, 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 pub type ExpandResult<T> = ValueResult<T, ExpandError>;
44 #[derive(Debug, PartialEq, Eq, Clone)]
45 pub enum ExpandError {
47 Mbe(mbe::ExpandError),
51 impl From<mbe::ExpandError> for ExpandError {
52 fn from(mbe: mbe::ExpandError) -> Self {
57 impl fmt::Display for ExpandError {
58 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
60 ExpandError::UnresolvedProcMacro => f.write_str("unresolved proc-macro"),
61 ExpandError::Mbe(it) => it.fmt(f),
62 ExpandError::Other(it) => f.write_str(it),
67 /// Input to the analyzer is a set of files, where each file is identified by
68 /// `FileId` and contains source code. However, another source of source code in
69 /// Rust are macros: each macro can be thought of as producing a "temporary
70 /// file". To assign an id to such a file, we use the id of the macro call that
71 /// produced the file. So, a `HirFileId` is either a `FileId` (source code
72 /// written by user), or a `MacroCallId` (source code produced by macro).
74 /// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
75 /// containing the call plus the offset of the macro call in the file. Note that
76 /// this is a recursive definition! However, the size_of of `HirFileId` is
77 /// finite (because everything bottoms out at the real `FileId`) and small
78 /// (`MacroCallId` uses the location interning. You can check details here:
79 /// <https://en.wikipedia.org/wiki/String_interning>).
80 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
81 pub struct HirFileId(HirFileIdRepr);
83 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
89 impl From<FileId> for HirFileId {
90 fn from(id: FileId) -> Self {
91 HirFileId(HirFileIdRepr::FileId(id))
95 impl From<MacroFile> for HirFileId {
96 fn from(id: MacroFile) -> Self {
97 HirFileId(HirFileIdRepr::MacroFile(id))
101 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
102 pub struct MacroFile {
103 pub macro_call_id: MacroCallId,
106 /// `MacroCallId` identifies a particular macro invocation, like
107 /// `println!("Hello, {}", world)`.
108 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
109 pub struct MacroCallId(salsa::InternId);
110 impl_intern_key!(MacroCallId);
112 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
113 pub struct MacroCallLoc {
115 pub(crate) krate: CrateId,
116 eager: Option<EagerCallInfo>,
117 pub kind: MacroCallKind,
120 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
121 pub struct MacroDefId {
123 pub kind: MacroDefKind,
124 pub local_inner: bool,
127 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
128 pub enum MacroDefKind {
129 Declarative(AstId<ast::Macro>),
130 BuiltIn(BuiltinFnLikeExpander, AstId<ast::Macro>),
131 // FIXME: maybe just Builtin and rename BuiltinFnLikeExpander to BuiltinExpander
132 BuiltInAttr(BuiltinAttrExpander, AstId<ast::Macro>),
133 BuiltInDerive(BuiltinDeriveExpander, AstId<ast::Macro>),
134 BuiltInEager(EagerExpander, AstId<ast::Macro>),
135 ProcMacro(ProcMacroExpander, ProcMacroKind, AstId<ast::Fn>),
138 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
139 struct EagerCallInfo {
140 /// NOTE: This can be *either* the expansion result, *or* the argument to the eager macro!
141 arg_or_expansion: Arc<tt::Subtree>,
142 included_file: Option<FileId>,
145 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
146 pub enum MacroCallKind {
148 ast_id: AstId<ast::MacroCall>,
152 ast_id: AstId<ast::Adt>,
153 /// Syntactical index of the invoking `#[derive]` attribute.
155 /// Outer attributes are counted first, then inner attributes. This does not support
156 /// out-of-line modules, which may have attributes spread across 2 files!
157 derive_attr_index: u32,
158 /// Index of the derive macro in the derive attribute
162 ast_id: AstId<ast::Item>,
163 attr_args: Arc<(tt::Subtree, mbe::TokenMap)>,
164 /// Syntactical index of the invoking `#[attribute]`.
166 /// Outer attributes are counted first, then inner attributes. This does not support
167 /// out-of-line modules, which may have attributes spread across 2 files!
168 invoc_attr_index: u32,
173 /// For macro-expansion files, returns the file original source file the
174 /// expansion originated from.
175 pub fn original_file(self, db: &dyn db::AstDatabase) -> FileId {
177 HirFileIdRepr::FileId(file_id) => file_id,
178 HirFileIdRepr::MacroFile(macro_file) => {
179 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
180 let file_id = match loc.eager {
181 Some(EagerCallInfo { included_file: Some(file), .. }) => file.into(),
182 _ => loc.kind.file_id(),
184 file_id.original_file(db)
189 pub fn expansion_level(self, db: &dyn db::AstDatabase) -> u32 {
192 while let HirFileIdRepr::MacroFile(macro_file) = curr.0 {
193 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
196 curr = loc.kind.file_id();
201 /// If this is a macro call, returns the syntax node of the call.
202 pub fn call_node(self, db: &dyn db::AstDatabase) -> Option<InFile<SyntaxNode>> {
204 HirFileIdRepr::FileId(_) => None,
205 HirFileIdRepr::MacroFile(macro_file) => {
206 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
207 Some(loc.kind.to_node(db))
212 /// Return expansion information if it is a macro-expansion file
213 pub fn expansion_info(self, db: &dyn db::AstDatabase) -> Option<ExpansionInfo> {
215 HirFileIdRepr::FileId(_) => None,
216 HirFileIdRepr::MacroFile(macro_file) => {
217 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
219 let arg_tt = loc.kind.arg(db)?;
221 let def = loc.def.ast_id().left().and_then(|id| {
222 let def_tt = match id.to_node(db) {
223 ast::Macro::MacroRules(mac) => mac.token_tree()?,
224 ast::Macro::MacroDef(mac) => mac.body()?,
226 Some(InFile::new(id.file_id, def_tt))
228 let attr_input_or_mac_def = def.or_else(|| match loc.kind {
229 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => {
232 .doc_comments_and_attrs()
233 .nth(invoc_attr_index as usize)
234 .and_then(Either::left)?
236 Some(InFile::new(ast_id.file_id, tt))
241 let macro_def = db.macro_def(loc.def).ok()?;
242 let (parse, exp_map) = db.parse_macro_expansion(macro_file).value?;
243 let macro_arg = db.macro_arg(macro_file.macro_call_id)?;
246 expanded: InFile::new(self, parse.syntax_node()),
247 arg: InFile::new(loc.kind.file_id(), arg_tt),
248 attr_input_or_mac_def,
249 macro_arg_shift: mbe::Shift::new(¯o_arg.0),
258 /// Indicate it is macro file generated for builtin derive
259 pub fn is_builtin_derive(&self, db: &dyn db::AstDatabase) -> Option<InFile<ast::Item>> {
261 HirFileIdRepr::FileId(_) => None,
262 HirFileIdRepr::MacroFile(macro_file) => {
263 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
264 let item = match loc.def.kind {
265 MacroDefKind::BuiltInDerive(..) => loc.kind.to_node(db),
268 Some(item.with_value(ast::Item::cast(item.value.clone())?))
273 pub fn is_custom_derive(&self, db: &dyn db::AstDatabase) -> bool {
275 HirFileIdRepr::FileId(_) => false,
276 HirFileIdRepr::MacroFile(macro_file) => {
277 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
278 matches!(loc.def.kind, MacroDefKind::ProcMacro(_, ProcMacroKind::CustomDerive, _))
283 /// Return whether this file is an include macro
284 pub fn is_include_macro(&self, db: &dyn db::AstDatabase) -> bool {
286 HirFileIdRepr::MacroFile(macro_file) => {
287 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
288 matches!(loc.eager, Some(EagerCallInfo { included_file: Some(_), .. }))
294 /// Return whether this file is an include macro
295 pub fn is_attr_macro(&self, db: &dyn db::AstDatabase) -> bool {
297 HirFileIdRepr::MacroFile(macro_file) => {
298 let loc: MacroCallLoc = db.lookup_intern_macro_call(macro_file.macro_call_id);
299 matches!(loc.kind, MacroCallKind::Attr { .. })
305 pub fn is_macro(self) -> bool {
306 matches!(self.0, HirFileIdRepr::MacroFile(_))
309 pub fn macro_file(self) -> Option<MacroFile> {
311 HirFileIdRepr::FileId(_) => None,
312 HirFileIdRepr::MacroFile(m) => Some(m),
318 pub fn as_lazy_macro(
320 db: &dyn db::AstDatabase,
324 db.intern_macro_call(MacroCallLoc { def: self, krate, eager: None, kind })
327 pub fn ast_id(&self) -> Either<AstId<ast::Macro>, AstId<ast::Fn>> {
328 let id = match self.kind {
329 MacroDefKind::ProcMacro(.., id) => return Either::Right(id),
330 MacroDefKind::Declarative(id)
331 | MacroDefKind::BuiltIn(_, id)
332 | MacroDefKind::BuiltInAttr(_, id)
333 | MacroDefKind::BuiltInDerive(_, id)
334 | MacroDefKind::BuiltInEager(_, id) => id,
339 pub fn is_proc_macro(&self) -> bool {
340 matches!(self.kind, MacroDefKind::ProcMacro(..))
343 pub fn is_attribute(&self) -> bool {
346 MacroDefKind::BuiltInAttr(..) | MacroDefKind::ProcMacro(_, ProcMacroKind::Attr, _)
351 // FIXME: attribute indices do not account for `cfg_attr`, which means that we'll strip the whole
352 // `cfg_attr` instead of just one of the attributes it expands to
355 /// Returns the file containing the macro invocation.
356 fn file_id(&self) -> HirFileId {
358 MacroCallKind::FnLike { ast_id: InFile { file_id, .. }, .. }
359 | MacroCallKind::Derive { ast_id: InFile { file_id, .. }, .. }
360 | MacroCallKind::Attr { ast_id: InFile { file_id, .. }, .. } => file_id,
364 pub fn to_node(&self, db: &dyn db::AstDatabase) -> InFile<SyntaxNode> {
366 MacroCallKind::FnLike { ast_id, .. } => {
367 ast_id.with_value(ast_id.to_node(db).syntax().clone())
369 MacroCallKind::Derive { ast_id, .. } => {
370 ast_id.with_value(ast_id.to_node(db).syntax().clone())
372 MacroCallKind::Attr { ast_id, .. } => {
373 ast_id.with_value(ast_id.to_node(db).syntax().clone())
378 /// Returns the original file range that best describes the location of this macro call.
380 /// Here we try to roughly match what rustc does to improve diagnostics: fn-like macros
381 /// get the whole `ast::MacroCall`, attribute macros get the attribute's range, and derives
382 /// get only the specific derive that is being referred to.
383 pub fn original_call_range(self, db: &dyn db::AstDatabase) -> FileRange {
386 match kind.file_id().0 {
387 HirFileIdRepr::MacroFile(file) => {
388 kind = db.lookup_intern_macro_call(file.macro_call_id).kind;
390 HirFileIdRepr::FileId(file_id) => break file_id,
394 let range = match kind {
395 MacroCallKind::FnLike { ast_id, .. } => ast_id.to_node(db).syntax().text_range(),
396 MacroCallKind::Derive { ast_id, derive_attr_index, .. } => {
397 // FIXME: should be the range of the macro name, not the whole derive
400 .doc_comments_and_attrs()
401 .nth(derive_attr_index as usize)
402 .expect("missing derive")
403 .expect_left("derive is a doc comment?")
407 MacroCallKind::Attr { ast_id, invoc_attr_index, .. } => ast_id
409 .doc_comments_and_attrs()
410 .nth(invoc_attr_index as usize)
411 .expect("missing attribute")
412 .expect_left("attribute macro is a doc comment?")
417 FileRange { range, file_id }
420 fn arg(&self, db: &dyn db::AstDatabase) -> Option<SyntaxNode> {
422 MacroCallKind::FnLike { ast_id, .. } => {
423 Some(ast_id.to_node(db).token_tree()?.syntax().clone())
425 MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
426 MacroCallKind::Attr { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
430 fn expand_to(&self) -> ExpandTo {
432 MacroCallKind::FnLike { expand_to, .. } => *expand_to,
433 MacroCallKind::Derive { .. } => ExpandTo::Items,
434 MacroCallKind::Attr { .. } => ExpandTo::Items, // is this always correct?
440 pub fn as_file(self) -> HirFileId {
441 MacroFile { macro_call_id: self }.into()
445 /// ExpansionInfo mainly describes how to map text range between src and expanded macro
446 #[derive(Debug, Clone, PartialEq, Eq)]
447 pub struct ExpansionInfo {
448 expanded: InFile<SyntaxNode>,
449 /// The argument TokenTree or item for attributes
450 arg: InFile<SyntaxNode>,
451 /// The `macro_rules!` or attribute input.
452 attr_input_or_mac_def: Option<InFile<ast::TokenTree>>,
454 macro_def: Arc<TokenExpander>,
455 macro_arg: Arc<(tt::Subtree, mbe::TokenMap, fixup::SyntaxFixupUndoInfo)>,
456 /// A shift built from `macro_arg`'s subtree, relevant for attributes as the item is the macro arg
457 /// and as such we need to shift tokens if they are part of an attributes input instead of their item.
458 macro_arg_shift: mbe::Shift,
459 exp_map: Arc<mbe::TokenMap>,
463 pub fn expanded(&self) -> InFile<SyntaxNode> {
464 self.expanded.clone()
467 pub fn call_node(&self) -> Option<InFile<SyntaxNode>> {
468 Some(self.arg.with_value(self.arg.value.parent()?))
471 /// Map a token down from macro input into the macro expansion.
473 /// The inner workings of this function differ slightly depending on the type of macro we are dealing with:
475 /// For declarative macros, we need to accommodate for the macro definition site(which acts as a second unchanging input)
476 /// , as tokens can mapped in and out of it.
477 /// To do this we shift all ids in the expansion by the maximum id of the definition site giving us an easy
478 /// way to map all the tokens.
480 /// Attributes have two different inputs, the input tokentree in the attribute node and the item
481 /// the attribute is annotating. Similarly as for declarative macros we need to do a shift here
482 /// as well. Currently this is done by shifting the attribute input by the maximum id of the item.
483 /// - function-like and derives:
484 /// Both of these only have one simple call site input so no special handling is required here.
485 pub fn map_token_down(
487 db: &dyn db::AstDatabase,
488 item: Option<ast::Item>,
489 token: InFile<&SyntaxToken>,
490 ) -> Option<impl Iterator<Item = InFile<SyntaxToken>> + '_> {
491 assert_eq!(token.file_id, self.arg.file_id);
492 let token_id_in_attr_input = if let Some(item) = item {
493 // check if we are mapping down in an attribute input
494 // this is a special case as attributes can have two inputs
495 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
496 let loc = db.lookup_intern_macro_call(call_id);
498 let token_range = token.value.text_range();
500 MacroCallKind::Attr { attr_args, invoc_attr_index, .. } => {
502 .doc_comments_and_attrs()
503 .nth(*invoc_attr_index as usize)
504 .and_then(Either::left)?;
505 match attr.token_tree() {
507 if token_tree.syntax().text_range().contains_range(token_range) =>
509 let attr_input_start =
510 token_tree.left_delimiter_token()?.text_range().start();
512 token.value.text_range().checked_sub(attr_input_start)?;
513 // shift by the item's tree's max id
516 .shift(attr_args.1.token_by_range(relative_range)?);
528 let token_id = match token_id_in_attr_input {
529 Some(token_id) => token_id,
530 // the token is not inside an attribute's input so do the lookup in the macro_arg as ususal
533 token.value.text_range().checked_sub(self.arg.value.text_range().start())?;
534 let token_id = self.macro_arg.1.token_by_range(relative_range)?;
535 // conditionally shift the id by a declaratives macro definition
536 self.macro_def.map_id_down(token_id)
542 .ranges_by_token(token_id, token.value.kind())
543 .flat_map(move |range| self.expanded.value.covering_element(range).into_token());
545 Some(tokens.map(move |token| self.expanded.with_value(token)))
548 /// Map a token up out of the expansion it resides in into the arguments of the macro call of the expansion.
551 db: &dyn db::AstDatabase,
552 token: InFile<&SyntaxToken>,
553 ) -> Option<(InFile<SyntaxToken>, Origin)> {
554 // Fetch the id through its text range,
555 let token_id = self.exp_map.token_by_range(token.value.text_range())?;
556 // conditionally unshifting the id to accommodate for macro-rules def site
557 let (mut token_id, origin) = self.macro_def.map_id_up(token_id);
559 let call_id = self.expanded.file_id.macro_file()?.macro_call_id;
560 let loc = db.lookup_intern_macro_call(call_id);
562 // Attributes are a bit special for us, they have two inputs, the input tokentree and the annotated item.
563 let (token_map, tt) = match &loc.kind {
564 MacroCallKind::Attr { attr_args, .. } => {
565 // try unshifting the the token id, if unshifting fails, the token resides in the non-item attribute input
566 // note that the `TokenExpander::map_id_up` earlier only unshifts for declarative macros, so we don't double unshift with this
567 match self.macro_arg_shift.unshift(token_id) {
569 token_id = unshifted;
570 (&attr_args.1, self.attr_input_or_mac_def.clone()?.syntax().cloned())
572 None => (&self.macro_arg.1, self.arg.clone()),
576 mbe::Origin::Call => (&self.macro_arg.1, self.arg.clone()),
577 mbe::Origin::Def => match (&*self.macro_def, &self.attr_input_or_mac_def) {
578 (TokenExpander::DeclarativeMacro { def_site_token_map, .. }, Some(tt)) => {
579 (def_site_token_map, tt.syntax().cloned())
581 _ => panic!("`Origin::Def` used with non-`macro_rules!` macro"),
586 let range = token_map.first_range_by_token(token_id, token.value.kind())?;
588 tt.value.covering_element(range + tt.value.text_range().start()).into_token()?;
589 Some((tt.with_value(token), origin))
593 /// `AstId` points to an AST node in any file.
595 /// It is stable across reparses, and can be used as salsa key/value.
596 pub type AstId<N> = InFile<FileAstId<N>>;
598 impl<N: AstNode> AstId<N> {
599 pub fn to_node(&self, db: &dyn db::AstDatabase) -> N {
600 let root = db.parse_or_expand(self.file_id).unwrap();
601 db.ast_id_map(self.file_id).get(self.value).to_node(&root)
605 /// `InFile<T>` stores a value of `T` inside a particular file/syntax tree.
607 /// Typical usages are:
609 /// * `InFile<SyntaxNode>` -- syntax node in a file
610 /// * `InFile<ast::FnDef>` -- ast node in a file
611 /// * `InFile<TextSize>` -- offset in a file
612 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
613 pub struct InFile<T> {
614 pub file_id: HirFileId,
619 pub fn new(file_id: HirFileId, value: T) -> InFile<T> {
620 InFile { file_id, value }
623 pub fn with_value<U>(&self, value: U) -> InFile<U> {
624 InFile::new(self.file_id, value)
627 pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> InFile<U> {
628 InFile::new(self.file_id, f(self.value))
630 pub fn as_ref(&self) -> InFile<&T> {
631 self.with_value(&self.value)
633 pub fn file_syntax(&self, db: &dyn db::AstDatabase) -> SyntaxNode {
634 db.parse_or_expand(self.file_id).expect("source created from invalid file")
638 impl<T: Clone> InFile<&T> {
639 pub fn cloned(&self) -> InFile<T> {
640 self.with_value(self.value.clone())
644 impl<T> InFile<Option<T>> {
645 pub fn transpose(self) -> Option<InFile<T>> {
646 let value = self.value?;
647 Some(InFile::new(self.file_id, value))
651 impl<'a> InFile<&'a SyntaxNode> {
652 pub fn ancestors_with_macros(
654 db: &dyn db::AstDatabase,
655 ) -> impl Iterator<Item = InFile<SyntaxNode>> + Clone + '_ {
656 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
657 Some(parent) => Some(node.with_value(parent)),
658 None => node.file_id.call_node(db),
662 /// Skips the attributed item that caused the macro invocation we are climbing up
663 pub fn ancestors_with_macros_skip_attr_item(
665 db: &dyn db::AstDatabase,
666 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
667 iter::successors(Some(self.cloned()), move |node| match node.value.parent() {
668 Some(parent) => Some(node.with_value(parent)),
670 let parent_node = node.file_id.call_node(db)?;
671 if node.file_id.is_attr_macro(db) {
672 // macro call was an attributed item, skip it
673 // FIXME: does this fail if this is a direct expansion of another macro?
674 parent_node.map(|node| node.parent()).transpose()
682 /// Falls back to the macro call range if the node cannot be mapped up fully.
683 pub fn original_file_range(self, db: &dyn db::AstDatabase) -> FileRange {
684 if let Some(res) = self.original_file_range_opt(db) {
688 // Fall back to whole macro call.
689 match self.file_id.0 {
690 HirFileIdRepr::FileId(file_id) => FileRange { file_id, range: self.value.text_range() },
691 HirFileIdRepr::MacroFile(mac_file) => {
692 let loc = db.lookup_intern_macro_call(mac_file.macro_call_id);
693 loc.kind.original_call_range(db)
698 /// Attempts to map the syntax node back up its macro calls.
699 pub fn original_file_range_opt(self, db: &dyn db::AstDatabase) -> Option<FileRange> {
700 match ascend_node_border_tokens(db, self) {
701 Some(InFile { file_id, value: (first, last) }) => {
702 let original_file = file_id.original_file(db);
703 let range = first.text_range().cover(last.text_range());
704 if file_id != original_file.into() {
705 tracing::error!("Failed mapping up more for {:?}", range);
708 Some(FileRange { file_id: original_file, range })
710 _ if !self.file_id.is_macro() => Some(FileRange {
711 file_id: self.file_id.original_file(db),
712 range: self.value.text_range(),
719 fn ascend_node_border_tokens(
720 db: &dyn db::AstDatabase,
721 InFile { file_id, value: node }: InFile<&SyntaxNode>,
722 ) -> Option<InFile<(SyntaxToken, SyntaxToken)>> {
723 let expansion = file_id.expansion_info(db)?;
725 let first_token = |node: &SyntaxNode| skip_trivia_token(node.first_token()?, Direction::Next);
726 let last_token = |node: &SyntaxNode| skip_trivia_token(node.last_token()?, Direction::Prev);
728 let first = first_token(node)?;
729 let last = last_token(node)?;
730 let first = ascend_call_token(db, &expansion, InFile::new(file_id, first))?;
731 let last = ascend_call_token(db, &expansion, InFile::new(file_id, last))?;
732 (first.file_id == last.file_id).then(|| InFile::new(first.file_id, (first.value, last.value)))
735 fn ascend_call_token(
736 db: &dyn db::AstDatabase,
737 expansion: &ExpansionInfo,
738 token: InFile<SyntaxToken>,
739 ) -> Option<InFile<SyntaxToken>> {
740 let mut mapping = expansion.map_token_up(db, token.as_ref())?;
741 while let (mapped, Origin::Call) = mapping {
742 match mapped.file_id.expansion_info(db) {
743 Some(info) => mapping = info.map_token_up(db, mapped.as_ref())?,
744 None => return Some(mapped),
750 impl InFile<SyntaxToken> {
751 pub fn ancestors_with_macros(
753 db: &dyn db::AstDatabase,
754 ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
755 self.value.parent().into_iter().flat_map({
756 let file_id = self.file_id;
757 move |parent| InFile::new(file_id, &parent).ancestors_with_macros(db)
762 impl<N: AstNode> InFile<N> {
763 pub fn descendants<T: AstNode>(self) -> impl Iterator<Item = InFile<T>> {
764 self.value.syntax().descendants().filter_map(T::cast).map(move |n| self.with_value(n))
767 pub fn original_ast_node(self, db: &dyn db::AstDatabase) -> Option<InFile<N>> {
768 // This kind of upmapping can only be achieved in attribute expanded files,
769 // as we don't have node inputs otherwise and therefor can't find an `N` node in the input
770 if !self.file_id.is_macro() {
772 } else if !self.file_id.is_attr_macro(db) {
776 if let Some(InFile { file_id, value: (first, last) }) =
777 ascend_node_border_tokens(db, self.syntax())
779 if file_id.is_macro() {
780 let range = first.text_range().cover(last.text_range());
781 tracing::error!("Failed mapping out of macro file for {:?}", range);
784 // FIXME: This heuristic is brittle and with the right macro may select completely unrelated nodes
785 let anc = algo::least_common_ancestor(&first.parent()?, &last.parent()?)?;
786 let value = anc.ancestors().find_map(N::cast)?;
787 return Some(InFile::new(file_id, value));
792 pub fn syntax(&self) -> InFile<&SyntaxNode> {
793 self.with_value(self.value.syntax())
797 /// In Rust, macros expand token trees to token trees. When we want to turn a
798 /// token tree into an AST node, we need to figure out what kind of AST node we
799 /// want: something like `foo` can be a type, an expression, or a pattern.
801 /// Naively, one would think that "what this expands to" is a property of a
802 /// particular macro: macro `m1` returns an item, while macro `m2` returns an
803 /// expression, etc. That's not the case -- macros are polymorphic in the
804 /// result, and can expand to any type of the AST node.
806 /// What defines the actual AST node is the syntactic context of the macro
807 /// invocation. As a contrived example, in `let T![*] = T![*];` the first `T`
808 /// expands to a pattern, while the second one expands to an expression.
810 /// `ExpandTo` captures this bit of information about a particular macro call
812 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
822 pub fn from_call_site(call: &ast::MacroCall) -> ExpandTo {
823 use syntax::SyntaxKind::*;
825 let syn = call.syntax();
827 let parent = match syn.parent() {
829 None => return ExpandTo::Statements,
832 match parent.kind() {
833 MACRO_ITEMS | SOURCE_FILE | ITEM_LIST => ExpandTo::Items,
834 MACRO_STMTS | EXPR_STMT | STMT_LIST => ExpandTo::Statements,
835 MACRO_PAT => ExpandTo::Pattern,
836 MACRO_TYPE => ExpandTo::Type,
838 ARG_LIST | TRY_EXPR | TUPLE_EXPR | PAREN_EXPR | ARRAY_EXPR | FOR_EXPR | PATH_EXPR
839 | CLOSURE_EXPR | BREAK_EXPR | RETURN_EXPR | MATCH_EXPR | MATCH_ARM | MATCH_GUARD
840 | RECORD_EXPR_FIELD | CALL_EXPR | INDEX_EXPR | METHOD_CALL_EXPR | FIELD_EXPR
841 | AWAIT_EXPR | CAST_EXPR | REF_EXPR | PREFIX_EXPR | RANGE_EXPR | BIN_EXPR
842 | LET_EXPR => ExpandTo::Expr,
844 // FIXME: Handle LHS Pattern
849 // Unknown , Just guess it is `Items`
857 pub struct UnresolvedMacro {