fix: add fallback case in generated PartialEq impl

Author: rami3l

crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs

@@ -907,7 +907,7 @@ impl PartialEq for Foo {
     }
 
     #[test]
-    fn add_custom_impl_partial_eq_tuple_enum() {
+    fn add_custom_impl_partial_eq_partial_tuple_enum() {
         check_assist(
             replace_derive_with_manual_impl,
             r#"
@@ -936,6 +936,37 @@ impl PartialEq for Foo {
         )
     }
 
+    #[test]
+    fn add_custom_impl_partial_eq_tuple_enum() {
+        check_assist(
+            replace_derive_with_manual_impl,
+            r#"
+//- minicore: eq, derive
+#[derive(Partial$0Eq)]
+enum Foo {
+    Bar(String),
+    Baz(i32),
+}
+"#,
+            r#"
+enum Foo {
+    Bar(String),
+    Baz(i32),
+}
+
+impl PartialEq for Foo {
+    $0fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (Self::Bar(l0), Self::Bar(r0)) => l0 == r0,
+            (Self::Baz(l0), Self::Baz(r0)) => l0 == r0,
+            _ => core::mem::discriminant(self) == core::mem::discriminant(other),
+        }
+    }
+}
+"#,
+        )
+    }
+
     #[test]
     fn add_custom_impl_partial_eq_record_enum() {
         check_assist(

crates/ide-assists/src/utils/gen_trait_fn_body.rs

@@ -439,10 +439,8 @@ fn gen_partial_eq(adt: &ast::Adt, func: &ast::Fn) -> Option<()> {
             let eq_check =
                 make::expr_bin_op(lhs, BinaryOp::CmpOp(CmpOp::Eq { negated: false }), rhs);
 
-            let mut n_cases = 0;
             let mut arms = vec![];
             for variant in enum_.variant_list()?.variants() {
-                n_cases += 1;
                 match variant.field_list() {
                     // => (Self::Bar { bin: l_bin }, Self::Bar { bin: r_bin }) => l_bin == r_bin,
                     Some(ast::FieldList::RecordFieldList(list)) => {
@@ -517,10 +515,7 @@ fn gen_partial_eq(adt: &ast::Adt, func: &ast::Fn) -> Option<()> {
             let expr = match arms.len() {
                 0 => eq_check,
                 _ => {
-                    if n_cases > arms.len() {
-                        let lhs = make::wildcard_pat().into();
-                        arms.push(make::match_arm(Some(lhs), None, eq_check));
-                    }
+                    arms.push(make::match_arm(Some(make::wildcard_pat().into()), None, eq_check));
 
                     let match_target = make::expr_tuple(vec![lhs_name, rhs_name]);
                     let list = make::match_arm_list(arms).indent(ast::edit::IndentLevel(1));