fix [feature] treat deprecated functions differently in the IDE #716 (#1512)

Summary:
fix #716

Introduced a completion post-processing tweak so any item carrying CompletionItemTag::DEPRECATED now receives a heavier sort_text, which pushes deprecated suggestions beneath non-deprecated ones while still keeping existing prioritization rules for auto-imports and private symbols intact.

Pull Request resolved: #1512

Reviewed By: stroxler

Differential Revision: D86419461

Pulled By: kinto0

fbshipit-source-id: be60ab209b87791ebd612c8e6bf49f3943f797df

Author: asukaminato0721

pyrefly/lib/state/lsp.rs

@@ -2458,7 +2458,13 @@ impl<'a> Transaction<'a> {
             }
         }
         for item in &mut result {
-            let sort_text = if item.additional_text_edits.is_some() {
+            let sort_text = if item
+                .tags
+                .as_ref()
+                .is_some_and(|tags| tags.contains(&CompletionItemTag::DEPRECATED))
+            {
+                "9"
+            } else if item.additional_text_edits.is_some() {
                 "4"
             } else if item.label.starts_with("__") {
                 "3"

pyrefly/lib/test/lsp/completion.rs

@@ -172,9 +172,42 @@ foo.
 11 | foo.
          ^
 Completion Results:
+- (Field) x: int
 - (Field) [DEPRECATED] also_not_ok: int
 - (Method) [DEPRECATED] not_ok: def not_ok(self: Foo) -> None: ...
-- (Field) x: int
+"#
+        .trim(),
+        report.trim(),
+    );
+}
+
+#[test]
+fn completion_deprecated_top_level_function() {
+    let code = r#"
+from typing import *
+from warnings import deprecated
+
+@deprecated("this is deprecated")
+def test1() -> None:
+    ...
+
+def test2() -> None:
+    ...
+
+te
+# ^
+"#;
+    let report =
+        get_batched_lsp_operations_report_allow_error(&[("main", code)], get_default_test_report());
+    assert_eq!(
+        r#"
+# main.py
+12 | te
+       ^
+Completion Results:
+- (Class) deprecated: type[deprecated]
+- (Function) test2: () -> None
+- (Function) [DEPRECATED] test1: () -> None
 "#
         .trim(),
         report.trim(),
@@ -543,7 +576,6 @@ Completion Results:
                         ^
 Completion Results:
 - (Variable) deprecated
-- (Variable) [DEPRECATED] func_not_ok
 - (Variable) func_ok
 - (Variable) __annotations__
 - (Variable) __builtins__
@@ -557,6 +589,7 @@ Completion Results:
 - (Variable) __package__
 - (Variable) __path__
 - (Variable) __spec__
+- (Variable) [DEPRECATED] func_not_ok
 
 
 # foo.py