fix hover on case _ show the remaining cases #3334

pyrefly/lib/lsp/wasm/hover.rs

@@ -640,6 +640,38 @@ fn in_keyword_in_iteration_at(
     None
 }
 
+fn match_wildcard_type_at(
+    transaction: &Transaction<'_>,
+    handle: &Handle,
+    position: TextSize,
+) -> Option<Type> {
+    let module = transaction.get_ast(handle)?;
+    let covering_nodes = Ast::locate_node(&module, position);
+    let is_wildcard = covering_nodes
+        .iter()
+        .any(|node| matches!(node, AnyNodeRef::PatternMatchAs(pattern) if pattern.name.is_none() && pattern.pattern.is_none()));
+    if !is_wildcard {
+        return None;
+    }
+    let case_range = covering_nodes.iter().find_map(|node| match node {
+        AnyNodeRef::MatchCase(case) => Some(case.range),
+        _ => None,
+    })?;
+    let subject_start = covering_nodes.iter().find_map(|node| match node {
+        AnyNodeRef::StmtMatch(stmt_match) => Some(stmt_match.subject.range().start()),
+        _ => None,
+    })?;
+    let key = Key::PatternNarrow(case_range);
+    if transaction
+        .get_bindings(handle)
+        .is_some_and(|bindings| bindings.is_valid_key(&key))
+    {
+        transaction.get_type_for_display(handle, &key)
+    } else {
+        transaction.get_type_at_for_display(handle, subject_start)
+    }
+}
+
 pub fn get_hover(
     transaction: &Transaction<'_>,
     handle: &Handle,
@@ -698,8 +730,8 @@ pub fn get_hover(
         });
     }
 
-    let mut type_ = transaction
-        .subscript_operator_type_at(handle, position)
+    let mut type_ = match_wildcard_type_at(transaction, handle, position)
+        .or_else(|| transaction.subscript_operator_type_at(handle, position))
         .or_else(|| transaction.get_type_at_for_display(handle, position))?;
 
     // Helper function to check if we're hovering over a callee and get its range

pyrefly/lib/test/lsp/hover.rs

@@ -378,6 +378,38 @@ def f() -> None:
     );
 }
 
+#[test]
+fn hover_on_match_wildcard_shows_remaining_type() {
+    let code = r#"
+from enum import StrEnum
+
+class E(StrEnum):
+    x = "1"
+    y = "2"
+
+def f(x: E) -> None:
+    match x:
+        case E.x:
+            pass
+        case _:
+#            ^
+            pass
+"#;
+    let report = get_batched_lsp_operations_report(&[("main", code)], |state, handle, position| {
+        match get_hover(&state.transaction(), handle, position, false) {
+            Some(Hover {
+                contents: HoverContents::Markup(markup),
+                ..
+            }) => markup.value,
+            _ => "None".to_owned(),
+        }
+    });
+    assert!(
+        report.contains("Literal[E.y]"),
+        "Expected hover to show remaining match type, got: {report}"
+    );
+}
+
 #[test]
 fn hover_over_string_with_hash_character() {
     let code = r#"