Goto definition works inside macros

crates/ra_hir/src/source_binder.rs

@@ -11,7 +11,7 @@
     expr::{ExprId, PatId},
     path::known,
 };
-use hir_expand::{name::AsName, Source};
+use hir_expand::{name::AsName, AstId, MacroCallId, MacroCallLoc, MacroFileKind, Source};
 use ra_syntax::{
     ast::{self, AstNode},
     match_ast, AstPtr,
@@ -126,6 +126,20 @@ pub struct ReferenceDescriptor {
     pub name: String,
 }
 
+pub struct Expansion {
+    macro_call_id: MacroCallId,
+}
+
+impl Expansion {
+    pub fn translate_offset(&self, db: &impl HirDatabase, offset: TextUnit) -> Option<TextUnit> {
+        let exp_info = self.file_id().expansion_info(db)?;
+        exp_info.translate_offset(offset)
+    }
+    pub fn file_id(&self) -> HirFileId {
+        self.macro_call_id.as_file(MacroFileKind::Items)
+    }
+}
+
 impl SourceAnalyzer {
     pub fn new(
         db: &impl HirDatabase,
@@ -386,6 +400,13 @@ pub fn impls_future(&self, db: &impl HirDatabase, ty: Ty) -> bool {
         implements_trait(&canonical_ty, db, &self.resolver, krate, std_future_trait)
     }
 
+    pub fn expand(&self, db: &impl HirDatabase, macro_call: &ast::MacroCall) -> Option<Expansion> {
+        let def = self.resolve_macro_call(db, macro_call)?.id;
+        let ast_id = AstId::new(self.file_id, db.ast_id_map(self.file_id).ast_id(macro_call));
+        let macro_call_loc = MacroCallLoc { def, ast_id };
+        Some(Expansion { macro_call_id: db.intern_macro(macro_call_loc) })
+    }
+
     #[cfg(test)]
     pub(crate) fn body_source_map(&self) -> Arc<BodySourceMap> {
         self.body_source_map.clone().unwrap()

crates/ra_hir_expand/src/lib.rs

@@ -160,6 +160,15 @@ pub struct ExpansionInfo {
 }
 
 impl ExpansionInfo {
+    pub fn translate_offset(&self, offset: TextUnit) -> Option<TextUnit> {
+        let offset = offset.checked_sub(self.arg_start.1)?;
+        let token_id = self.macro_arg.1.token_by_offset(offset)?;
+        let token_id = tt::TokenId(token_id.0 + self.shift);
+
+        let (r, _) = self.exp_map.ranges.iter().find(|(_, tid)| *tid == token_id)?;
+        Some(r.start())
+    }
+
     pub fn find_range(&self, from: TextRange) -> Option<(HirFileId, TextRange)> {
         let token_id = look_in_rev_map(&self.exp_map, from)?;
 

crates/ra_ide_api/src/goto_definition.rs

@@ -1,11 +1,10 @@
 //! FIXME: write short doc here
 
-use hir::Source;
-use ra_db::SourceDatabase;
+use hir::{db::AstDatabase, Source};
 use ra_syntax::{
     algo::find_node_at_offset,
     ast::{self, DocCommentsOwner},
-    match_ast, AstNode, SyntaxNode,
+    match_ast, AstNode, SyntaxNode, TextUnit,
 };
 
 use crate::{
@@ -19,17 +18,29 @@ pub(crate) fn goto_definition(
     db: &RootDatabase,
     position: FilePosition,
 ) -> Option<RangeInfo<Vec<NavigationTarget>>> {
-    let parse = db.parse(position.file_id);
-    let syntax = parse.tree().syntax().clone();
-    if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(&syntax, position.offset) {
-        let navs =
-            reference_definition(db, Source::new(position.file_id.into(), &name_ref)).to_vec();
+    go(db, Source::new(position.file_id.into(), position.offset))
+}
+
+fn go(db: &RootDatabase, offset: Source<TextUnit>) -> Option<RangeInfo<Vec<NavigationTarget>>> {
+    let syntax = db.parse_or_expand(offset.file_id)?;
+
+    if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(&syntax, offset.ast) {
+        let navs = reference_definition(db, offset.with_ast(&name_ref)).to_vec();
         return Some(RangeInfo::new(name_ref.syntax().text_range(), navs.to_vec()));
     }
-    if let Some(name) = find_node_at_offset::<ast::Name>(&syntax, position.offset) {
-        let navs = name_definition(db, Source::new(position.file_id.into(), &name))?;
+    if let Some(name) = find_node_at_offset::<ast::Name>(&syntax, offset.ast) {
+        let navs = name_definition(db, offset.with_ast(&name))?;
         return Some(RangeInfo::new(name.syntax().text_range(), navs));
     }
+    if let Some(macro_call) = find_node_at_offset::<ast::MacroCall>(&syntax, offset.ast) {
+        let source_analyzer =
+            hir::SourceAnalyzer::new(db, offset.with_ast(macro_call.syntax()), None);
+        if let Some(exp) = source_analyzer.expand(db, &macro_call) {
+            if let Some(offset) = exp.translate_offset(db, offset.ast) {
+                return go(db, Source::new(exp.file_id(), offset));
+            }
+        }
+    }
     None
 }
 
@@ -677,4 +688,23 @@ mod bar<|> {
             "bar MODULE FileId(1) [0; 11) [4; 7)",
         );
     }
+
+    #[test]
+    fn goto_from_macro() {
+        check_goto(
+            "
+            //- /lib.rs
+            macro_rules! id {
+                ($($tt:tt)*) => { $($tt)* }
+            }
+            fn foo() {}
+            id! {
+                fn bar() {
+                    fo<|>o();
+                }
+            }
+            ",
+            "foo FN_DEF FileId(1) [52; 63) [55; 58)",
+        );
+    }
 }

crates/ra_mbe/src/syntax_bridge.rs

@@ -77,6 +77,12 @@ pub fn token_tree_to_syntax_node(
 }
 
 impl TokenMap {
+    pub fn token_by_offset(&self, relative_offset: TextUnit) -> Option<tt::TokenId> {
+        let (idx, _) =
+            self.tokens.iter().enumerate().find(|(_, range)| range.contains(relative_offset))?;
+        Some(tt::TokenId(idx as u32))
+    }
+
     pub fn relative_range_of(&self, tt: tt::TokenId) -> Option<TextRange> {
         let idx = tt.0 as usize;
         self.tokens.get(idx).copied()