1 files changed, 105 insertions, 0 deletions

diff --git a/crates/ra_ide/src/goto_type_definition.rs b/crates/ra_ide/src/goto_type_definition.rs
new file mode 100644
index 000000000..992a08809
--- /dev/null
+++ b/crates/ra_ide/src/goto_type_definition.rs
@@ -0,0 +1,105 @@
+//! FIXME: write short doc here
+
+use hir::db::AstDatabase;
+use ra_syntax::{ast, AstNode};
+
+use crate::{
+    db::RootDatabase, display::ToNav, expand::descend_into_macros, FilePosition, NavigationTarget,
+    RangeInfo,
+};
+
+pub(crate) fn goto_type_definition(
+    db: &RootDatabase,
+    position: FilePosition,
+) -> Option<RangeInfo<Vec<NavigationTarget>>> {
+    let file = db.parse_or_expand(position.file_id.into())?;
+    let token = file.token_at_offset(position.offset).filter(|it| !it.kind().is_trivia()).next()?;
+    let token = descend_into_macros(db, position.file_id, token);
+
+    let node = token.value.ancestors().find_map(|token| {
+        token
+            .ancestors()
+            .find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())
+    })?;
+
+    let analyzer = hir::SourceAnalyzer::new(db, token.with_value(&node), None);
+
+    let ty: hir::Type = if let Some(ty) =
+        ast::Expr::cast(node.clone()).and_then(|e| analyzer.type_of(db, &e))
+    {
+        ty
+    } else if let Some(ty) = ast::Pat::cast(node.clone()).and_then(|p| analyzer.type_of_pat(db, &p))
+    {
+        ty
+    } else {
+        return None;
+    };
+
+    let adt_def = ty.autoderef(db).find_map(|ty| ty.as_adt())?;
+
+    let nav = adt_def.to_nav(db);
+    Some(RangeInfo::new(node.text_range(), vec![nav]))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mock_analysis::analysis_and_position;
+
+    fn check_goto(fixture: &str, expected: &str) {
+        let (analysis, pos) = analysis_and_position(fixture);
+
+        let mut navs = analysis.goto_type_definition(pos).unwrap().unwrap().info;
+        assert_eq!(navs.len(), 1);
+        let nav = navs.pop().unwrap();
+        nav.assert_match(expected);
+    }
+
+    #[test]
+    fn goto_type_definition_works_simple() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo;
+            fn foo() {
+                let f: Foo;
+                f<|>
+            }
+            ",
+            "Foo STRUCT_DEF FileId(1) [0; 11) [7; 10)",
+        );
+    }
+
+    #[test]
+    fn goto_type_definition_works_simple_ref() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo;
+            fn foo() {
+                let f: &Foo;
+                f<|>
+            }
+            ",
+            "Foo STRUCT_DEF FileId(1) [0; 11) [7; 10)",
+        );
+    }
+
+    #[test]
+    fn goto_type_definition_works_through_macro() {
+        check_goto(
+            "
+            //- /lib.rs
+            macro_rules! id {
+                ($($tt:tt)*) => { $($tt)* }
+            }
+            struct Foo {}
+            id! {
+                fn bar() {
+                    let f<|> = Foo {};
+                }
+            }
+            ",
+            "Foo STRUCT_DEF FileId(1) [52; 65) [59; 62)",
+        );
+    }
+}