From ad17ba12d1a9985a7b8bc52060942149ffb18b69 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Fri, 16 Sep 2022 16:11:58 +0200
Subject: [PATCH] Complete variants and assoc items in path pattern through
 type aliases

---
 .../ide-completion/src/completions/pattern.rs |  1 +
 crates/ide-completion/src/tests/pattern.rs    | 27 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/crates/ide-completion/src/completions/pattern.rs b/crates/ide-completion/src/completions/pattern.rs
index 71d2d9d434..58d5bf114c 100644
--- a/crates/ide-completion/src/completions/pattern.rs
+++ b/crates/ide-completion/src/completions/pattern.rs
@@ -145,6 +145,7 @@ pub(crate) fn complete_pattern_path(
                             u.ty(ctx.db)
                         }
                         hir::PathResolution::Def(hir::ModuleDef::BuiltinType(ty)) => ty.ty(ctx.db),
+                        hir::PathResolution::Def(hir::ModuleDef::TypeAlias(ty)) => ty.ty(ctx.db),
                         _ => return,
                     };
 
diff --git a/crates/ide-completion/src/tests/pattern.rs b/crates/ide-completion/src/tests/pattern.rs
index 85c4dbd662..db8bef6640 100644
--- a/crates/ide-completion/src/tests/pattern.rs
+++ b/crates/ide-completion/src/tests/pattern.rs
@@ -714,3 +714,30 @@ impl Ty {
         "#]],
     );
 }
+
+#[test]
+fn through_alias() {
+    check_empty(
+        r#"
+enum Enum<T> {
+    Unit,
+    Tuple(T),
+}
+
+type EnumAlias<T> = Enum<T>;
+
+fn f(x: EnumAlias<u8>) {
+    match x {
+        EnumAlias::$0 => (),
+        _ => (),
+    }
+
+}
+
+"#,
+        expect![[r#"
+            bn Tuple(…) Tuple($1)$0
+            bn Unit     Unit$0
+        "#]],
+    );
+}