Fix namespace renaming

Author: AJenbo

docs/CHANGELOG.md

@@ -52,6 +52,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **Renaming a namespace no longer corrupts group `use` statements.** Renaming a namespace segment that is imported with a group `use` (e.g. `use App\Old\{Foo, Bar};`) previously rewrote the group's shared prefix and then also spliced the new prefix into each member name, producing invalid PHP like `use App\New\{App\New\Foo, Bar};`. The member names are left untouched now, since the prefix rewrite alone already updates the whole statement correctly.
 - **Parameter name inlay hints no longer shift to the wrong parameter when only part of a multi-line call is visible.** Editors request inlay hints only for the currently visible viewport, and when a call's arguments were split across the viewport boundary, every hint after the first excluded argument was labelled with the previous parameter's name instead of its own. This was most noticeable on multi-line constructor calls with several arguments, such as those using constructor property promotion.
 - **Linked editing no longer types into unrelated parts of the file.** Adding a line above a variable (for example inserting a `/** */` docblock) and then typing could insert the typed characters at two arbitrary places further down, such as in the middle of a method name and in front of a trailing comment. PHPantom is re-reading the file in the background while you type, and linked editing was handing the editor positions measured against the previous version of the file, which the editor then edited on trust. Linked editing now verifies that the positions it reports still point at the variable, and offers nothing at all if they do not, so a keystroke can never land somewhere unexpected. It also becomes available in Blade templates, where the reported positions are checked against the template itself rather than the generated PHP.
 - **Rename no longer rewrites unrelated code when a file has just been edited.** PHPantom re-reads a file in the background after every keystroke, and rename could hand the editor positions measured against the previous version of that file, so confirming the rename edited whatever now sat at those positions. Rename and the rename preview now check that every position they report still points at the symbol, in each file the rename touches, and offer nothing at all when one does not. Retrying a moment later, once the background re-read has caught up, renames normally.

docs/todo.md

@@ -112,8 +112,7 @@ unlikely to move the needle for most users.
 | D3  | [Deprecated rendering — chain subject resolution](todo/diagnostics.md#d3-deprecated-rendering-chain-subject-resolution)                                                    | Low-Medium  | Medium      |
 | D5  | [External tool diagnostic suppression actions](todo/diagnostics.md#d5-external-tool-diagnostic-suppression-actions)                                                         | Low         | Low         |
 | D15 | [Unused parameter diagnostic](todo/diagnostics.md#d15-unused-parameter-diagnostic)                                                                                          | Low         | Low         |
-|     | **[Bug Fixes](todo/bugs.md)**                                                                                                                                               |             |             |
-| B2  | [Namespace rename writes an FQN into every name of a group `use`](todo/bugs.md#b2-namespace-rename-writes-an-fqn-into-every-name-of-a-group-use)                             | Medium      | Low         |
+|     | **[Bug Fixes](todo/bugs.md)** (no outstanding items)                                                                                                                        |             |             |
 |     | **[Code Actions](todo/actions.md)**                                                                                                                                         |             |             |
 | A40 | [Generate method from call](todo/actions.md#a40-generate-method-from-call)                                                                                                  | Medium-High | Medium      |
 | A41 | [Create class from non-existing name](todo/actions.md#a41-create-class-from-non-existing-name)                                                                              | Medium      | Medium      |

docs/todo/bugs.md

@@ -7,41 +7,4 @@ pipeline so it produces correct data. Downstream consumers
 (diagnostics, hover, completion, definition) should never need
 to second-guess upstream output.
 
-## B2 Namespace rename writes an FQN into every name of a group `use`
-
-Renaming namespace `App\Old` to `App\New` turns
-
-```php
-use App\Old\{Foo, Bar};
-```
-
-into
-
-```php
-use App\New\{App\New\Foo, App\New\Bar};
-```
-
-which is a parse error. This is covered by
-`rename_namespace_updates_group_use` in `src/rename/tests.rs`, but the
-assertion only checks that `App\New` appears somewhere in the result, so
-it passes on the broken output.
-
-Two paths in `rename/namespace.rs` edit the same line:
-
-- `collect_use_statement_edits` scans the source and rewrites the group
-  prefix (`App\Old` → `App\New`), which is the correct and complete edit.
-- `collect_fqn_reference_edits` walks the symbol map, where each name
-  inside the braces is a `ClassReference` span whose recorded `name` is
-  the *composed* FQN (`App\Old\Foo`) while the span itself covers only
-  the trailing `Foo`. It therefore emits a second edit replacing `Foo`
-  with the full `App\New\Foo`.
-
-The two edits do not overlap, so the `dedup_by(ranges_overlap)` pass that
-resolves the ordinary `use App\Old\Foo;` case does not catch them.
-
-The fix belongs in `collect_fqn_reference_edits`: a span whose source
-text is only a segment-aligned tail of its recorded name is a group-use
-member, and the group prefix edit already covers it, so it should be
-skipped. `source_spells_reference` in the same file already
-distinguishes the two shapes. Extend the test to assert the full
-expected line rather than a substring.
+No outstanding items.

src/rename/namespace.rs

@@ -434,10 +434,17 @@ impl Backend {
                 return false;
             }
 
-            // Skip use-statement references (they don't have `\` in span
-            // unless they are inline FQN like `\App\Foo` in code).
-            // Actually, use-statement spans DO contain the full FQN.
-            // We rely on deduplication to handle overlaps.
+            // A group-use member (`use App\Old\{Foo, Bar};`) records the
+            // composed FQN (`App\Old\Foo`) on a span that covers only the
+            // trailing segment (`Foo`). `collect_use_statement_edits`
+            // already rewrites the group's shared prefix, so emitting a
+            // second edit here would duplicate that rewrite onto the
+            // trailing segment, turning `App\New\{Foo, Bar}` into
+            // `App\New\{App\New\Foo, Bar}`. Skip it: only a span that
+            // spells the reference in full needs its own edit.
+            if !source_spells_reference_fully(source, name) {
+                continue;
+            }
 
             let new_name = if name_normalized.len() == old_prefix.len() {
                 if name.starts_with('\\') {
@@ -550,16 +557,23 @@ impl Backend {
 /// counts too.  Anything else means the offsets no longer describe the
 /// buffer.
 fn source_spells_reference(source: &str, name: &str) -> bool {
+    source_spells_reference_fully(source, name) || source_spells_reference_as_tail(source, name)
+}
+
+/// Whether `source` spells the entirety of `name` (case-insensitively).
+fn source_spells_reference_fully(source: &str, name: &str) -> bool {
+    strip_fqn_prefix(source).eq_ignore_ascii_case(strip_fqn_prefix(name))
+}
+
+/// Whether `source` spells only a segment-aligned tail of `name`, as a
+/// group-use member's span does (see [`source_spells_reference`]).
+fn source_spells_reference_as_tail(source: &str, name: &str) -> bool {
     let source = strip_fqn_prefix(source);
     let name = strip_fqn_prefix(name);
-    source.eq_ignore_ascii_case(name)
-        || name
-            .len()
-            .checked_sub(source.len())
-            .and_then(|split| name.split_at_checked(split))
-            .is_some_and(|(prefix, tail)| {
-                prefix.ends_with('\\') && tail.eq_ignore_ascii_case(source)
-            })
+    name.len()
+        .checked_sub(source.len())
+        .and_then(|split| name.split_at_checked(split))
+        .is_some_and(|(prefix, tail)| prefix.ends_with('\\') && tail.eq_ignore_ascii_case(source))
 }
 
 // ─── Namespace segment helpers ──────────────────────────────────────────────

src/rename/tests.rs

@@ -3535,10 +3535,14 @@ async fn rename_namespace_updates_group_use() {
     let edits_b = edits_for_uri(&edit, &uri_b);
     let result_b = apply_edits(text_b, &edits_b);
 
-    assert!(
-        result_b.contains("App\\New"),
-        "Group use prefix should be updated: {}",
-        result_b
+    assert_eq!(
+        result_b,
+        concat!(
+            "<?php\n",
+            "use App\\New\\{Foo, Bar};\n",
+            "function demo(Foo $f, Bar $b): void {}\n",
+        ),
+        "Group use prefix should be updated without touching member names"
     );
 }