Merge #1924

1924: Support inferring&completing `Self` type in enum/struct/union definitions r=ice1000 a=ice1000

Signed-off-by: ice1000 <[email protected]>

An attempt to fix #1908.
This code works, but I believe the implementation is ugly. Please give me suggestions!

Co-authored-by: ice1000 <[email protected]>

3 files changed, 21 insertions, 0 deletions

diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index ca9aefc42..a69f04ff1 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -559,6 +559,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             match resolver.resolve_path_in_type_ns_fully(self.db, &path) {
                 Some(TypeNs::Adt(Adt::Struct(it))) => it.into(),
                 Some(TypeNs::Adt(Adt::Union(it))) => it.into(),
+                Some(TypeNs::AdtSelfType(adt)) => adt.into(),
                 Some(TypeNs::EnumVariant(it)) => it.into(),
                 Some(TypeNs::TypeAlias(it)) => it.into(),
 
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index 4b67c82e7..a604c02e2 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -175,6 +175,7 @@ impl Ty {
                 Ty::Param { idx, name }
             }
             TypeNs::SelfType(impl_block) => impl_block.target_ty(db),
+            TypeNs::AdtSelfType(adt) => adt.ty(db),
 
             TypeNs::Adt(it) => Ty::from_hir_path_inner(db, resolver, resolved_segment, it.into()),
             TypeNs::BuiltinType(it) => {
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index 25dad81eb..03b30adcd 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -135,6 +135,25 @@ mod boxed {
 }
 
 #[test]
+fn infer_adt_self() {
+    let (db, pos) = MockDatabase::with_position(
+        r#"
+//- /main.rs
+enum Nat { Succ(Self), Demo(Nat), Zero }
+
+fn test() {
+    let foo: Nat = Nat::Zero;
+    if let Nat::Succ(x) = foo {
+        x<|>
+    }
+}
+
+"#,
+    );
+    assert_eq!("Nat", type_at_pos(&db, pos));
+}
+
+#[test]
 fn infer_try() {
     let (mut db, pos) = MockDatabase::with_position(
         r#"