1 files changed, 210 insertions, 0 deletions

diff --git a/crates/ra_ide/src/goto_implementation.rs b/crates/ra_ide/src/goto_implementation.rs
new file mode 100644
index 000000000..a5a296d22
--- /dev/null
+++ b/crates/ra_ide/src/goto_implementation.rs
@@ -0,0 +1,210 @@
+//! FIXME: write short doc here
+
+use hir::{Crate, ImplDef, Semantics};
+use ra_ide_db::RootDatabase;
+use ra_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::NominalDef>(&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::TraitDef>(&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::NominalDef,
+    krate: Crate,
+) -> Option<Vec<NavigationTarget>> {
+    let ty = match node {
+        ast::NominalDef::StructDef(def) => sema.to_def(def)?.ty(sema.db),
+        ast::NominalDef::EnumDef(def) => sema.to_def(def)?.ty(sema.db),
+        ast::NominalDef::UnionDef(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::TraitDef,
+    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 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_implementation(pos).unwrap().unwrap().info;
+        assert_eq!(navs.len(), expected.len());
+        navs.sort_by_key(|nav| (nav.file_id(), nav.full_range().start()));
+        navs.into_iter().enumerate().for_each(|(i, nav)| nav.assert_match(expected[i]));
+    }
+
+    #[test]
+    fn goto_implementation_works() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo<|>;
+            impl Foo {}
+            ",
+            &["impl IMPL_DEF FileId(1) 12..23"],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_works_multiple_blocks() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo<|>;
+            impl Foo {}
+            impl Foo {}
+            ",
+            &["impl IMPL_DEF FileId(1) 12..23", "impl IMPL_DEF FileId(1) 24..35"],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_works_multiple_mods() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo<|>;
+            mod a {
+                impl super::Foo {}
+            }
+            mod b {
+                impl super::Foo {}
+            }
+            ",
+            &["impl IMPL_DEF FileId(1) 24..42", "impl IMPL_DEF FileId(1) 57..75"],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_works_multiple_files() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo<|>;
+            mod a;
+            mod b;
+            //- /a.rs
+            impl crate::Foo {}
+            //- /b.rs
+            impl crate::Foo {}
+            ",
+            &["impl IMPL_DEF FileId(2) 0..18", "impl IMPL_DEF FileId(3) 0..18"],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_for_trait() {
+        check_goto(
+            "
+            //- /lib.rs
+            trait T<|> {}
+            struct Foo;
+            impl T for Foo {}
+            ",
+            &["impl IMPL_DEF FileId(1) 23..40"],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_for_trait_multiple_files() {
+        check_goto(
+            "
+            //- /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 {}
+            ",
+            &["impl IMPL_DEF FileId(2) 0..31", "impl IMPL_DEF FileId(3) 0..31"],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_all_impls() {
+        check_goto(
+            "
+            //- /lib.rs
+            trait T {}
+            struct Foo<|>;
+            impl Foo {}
+            impl T for Foo {}
+            impl T for &Foo {}
+            ",
+            &[
+                "impl IMPL_DEF FileId(1) 23..34",
+                "impl IMPL_DEF FileId(1) 35..52",
+                "impl IMPL_DEF FileId(1) 53..71",
+            ],
+        );
+    }
+
+    #[test]
+    fn goto_implementation_to_builtin_derive() {
+        check_goto(
+            "
+            //- /lib.rs
+            #[derive(Copy)]
+            struct Foo<|>;
+            ",
+            &["impl IMPL_DEF FileId(1) 0..15"],
+        );
+    }
+}