1 files changed, 229 insertions, 0 deletions

diff --git a/crates/ide/src/goto_implementation.rs b/crates/ide/src/goto_implementation.rs
new file mode 100644
index 000000000..f503f4ec5
--- /dev/null
+++ b/crates/ide/src/goto_implementation.rs
@@ -0,0 +1,229 @@
+use hir::{Crate, ImplDef, Semantics};
+use ide_db::RootDatabase;
+use syntax::{algo::find_node_at_offset, ast, AstNode};
+
+use crate::{display::ToNav, FilePosition, NavigationTarget, RangeInfo};
+
+// Feature: Go to Implementation
+//
+// Navigates to the impl block of structs, enums or traits. Also implemented as a code lens.
+//
+// |===
+// | Editor  | Shortcut
+//
+// | VS Code | kbd:[Ctrl+F12]
+// |===
+pub(crate) fn goto_implementation(
+    db: &RootDatabase,
+    position: FilePosition,
+) -> Option<RangeInfo<Vec<NavigationTarget>>> {
+    let sema = Semantics::new(db);
+    let source_file = sema.parse(position.file_id);
+    let syntax = source_file.syntax().clone();
+
+    let krate = sema.to_module_def(position.file_id)?.krate();
+
+    if let Some(nominal_def) = find_node_at_offset::<ast::AdtDef>(&syntax, position.offset) {
+        return Some(RangeInfo::new(
+            nominal_def.syntax().text_range(),
+            impls_for_def(&sema, &nominal_def, krate)?,
+        ));
+    } else if let Some(trait_def) = find_node_at_offset::<ast::Trait>(&syntax, position.offset) {
+        return Some(RangeInfo::new(
+            trait_def.syntax().text_range(),
+            impls_for_trait(&sema, &trait_def, krate)?,
+        ));
+    }
+
+    None
+}
+
+fn impls_for_def(
+    sema: &Semantics<RootDatabase>,
+    node: &ast::AdtDef,
+    krate: Crate,
+) -> Option<Vec<NavigationTarget>> {
+    let ty = match node {
+        ast::AdtDef::Struct(def) => sema.to_def(def)?.ty(sema.db),
+        ast::AdtDef::Enum(def) => sema.to_def(def)?.ty(sema.db),
+        ast::AdtDef::Union(def) => sema.to_def(def)?.ty(sema.db),
+    };
+
+    let impls = ImplDef::all_in_crate(sema.db, krate);
+
+    Some(
+        impls
+            .into_iter()
+            .filter(|impl_def| ty.is_equal_for_find_impls(&impl_def.target_ty(sema.db)))
+            .map(|imp| imp.to_nav(sema.db))
+            .collect(),
+    )
+}
+
+fn impls_for_trait(
+    sema: &Semantics<RootDatabase>,
+    node: &ast::Trait,
+    krate: Crate,
+) -> Option<Vec<NavigationTarget>> {
+    let tr = sema.to_def(node)?;
+
+    let impls = ImplDef::for_trait(sema.db, krate, tr);
+
+    Some(impls.into_iter().map(|imp| imp.to_nav(sema.db)).collect())
+}
+
+#[cfg(test)]
+mod tests {
+    use base_db::FileRange;
+
+    use crate::mock_analysis::MockAnalysis;
+
+    fn check(ra_fixture: &str) {
+        let (mock, position) = MockAnalysis::with_files_and_position(ra_fixture);
+        let annotations = mock.annotations();
+        let analysis = mock.analysis();
+
+        let navs = analysis.goto_implementation(position).unwrap().unwrap().info;
+
+        let key = |frange: &FileRange| (frange.file_id, frange.range.start());
+
+        let mut expected = annotations
+            .into_iter()
+            .map(|(range, data)| {
+                assert!(data.is_empty());
+                range
+            })
+            .collect::<Vec<_>>();
+        expected.sort_by_key(key);
+
+        let mut actual = navs
+            .into_iter()
+            .map(|nav| FileRange { file_id: nav.file_id, range: nav.focus_or_full_range() })
+            .collect::<Vec<_>>();
+        actual.sort_by_key(key);
+
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn goto_implementation_works() {
+        check(
+            r#"
+struct Foo<|>;
+impl Foo {}
+   //^^^
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_works_multiple_blocks() {
+        check(
+            r#"
+struct Foo<|>;
+impl Foo {}
+   //^^^
+impl Foo {}
+   //^^^
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_works_multiple_mods() {
+        check(
+            r#"
+struct Foo<|>;
+mod a {
+    impl super::Foo {}
+       //^^^^^^^^^^
+}
+mod b {
+    impl super::Foo {}
+       //^^^^^^^^^^
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_works_multiple_files() {
+        check(
+            r#"
+//- /lib.rs
+struct Foo<|>;
+mod a;
+mod b;
+//- /a.rs
+impl crate::Foo {}
+   //^^^^^^^^^^
+//- /b.rs
+impl crate::Foo {}
+   //^^^^^^^^^^
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_for_trait() {
+        check(
+            r#"
+trait T<|> {}
+struct Foo;
+impl T for Foo {}
+         //^^^
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_for_trait_multiple_files() {
+        check(
+            r#"
+//- /lib.rs
+trait T<|> {};
+struct Foo;
+mod a;
+mod b;
+//- /a.rs
+impl crate::T for crate::Foo {}
+                //^^^^^^^^^^
+//- /b.rs
+impl crate::T for crate::Foo {}
+                //^^^^^^^^^^
+            "#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_all_impls() {
+        check(
+            r#"
+//- /lib.rs
+trait T {}
+struct Foo<|>;
+impl Foo {}
+   //^^^
+impl T for Foo {}
+         //^^^
+impl T for &Foo {}
+         //^^^^
+"#,
+        );
+    }
+
+    #[test]
+    fn goto_implementation_to_builtin_derive() {
+        check(
+            r#"
+  #[derive(Copy)]
+//^^^^^^^^^^^^^^^
+struct Foo<|>;
+
+mod marker {
+    trait Copy {}
+}
+"#,
+        );
+    }
+}