Update roadmap

Author: AJenbo

docs/todo.md

@@ -140,11 +140,8 @@ unlikely to move the needle for most users.
 | X4  | Full background indexing (`strategy = "full"`)                           | Medium     | High        |
 | X6  | Disk cache (evaluate later)                                              | Medium     | High        |
 |     | **[Bug Fixes](todo/bugs.md)**                                            |            |             |
-| B2  | Orphan PHPStan processes on server shutdown                              | High       | Low         |
-| B5  | Implementation error diagnostic skips enums                              | Medium     | Low         |
-| B7  | Inlay hints: wrong parameter name with mixed named/positional args       | Medium     | Medium      |
-| B10 | PHPStan cache written after file close causes stale diagnostics          | Low-Medium | Low         |
-| B1  | Native type hints not considered in virtual property specificity ranking | Low-Medium | Medium      |
+| B11 | [Diagnostic deduplication drops distinct diagnostics on same range](todo/bugs.md#b11--diagnostic-deduplication-drops-distinct-diagnostics-on-the-same-range) | Medium | Low |
+| B12 | [PHPStan cache pruning uses length-only comparison](todo/bugs.md#b12--phpstan-cache-pruning-uses-length-only-comparison) | Low | Low |
 |     | **[Inline Completion](todo/inline-completion.md)**                       |            |             |
 | N1  | Template engine (type-aware snippets)                                    | Medium     | High        |
 | N2  | N-gram prediction from PHP corpus                                        | Medium     | Very High   |

docs/todo/bugs.md

@@ -14,3 +14,44 @@ within the same impact tier.
 | **Effort** | **Low** (≤ 1 day), **Medium** (2-5 days), **Medium-High** (1-2 weeks), **High** (2-4 weeks), **Very High** (> 1 month) |
 
 ---
+
+## B11 — Diagnostic deduplication drops distinct diagnostics on the same range
+
+| Impact     | Effort |
+| ---------- | ------ |
+| Medium     | Low    |
+
+`deduplicate_diagnostics` in `src/diagnostics/mod.rs` calls
+`dedup_by(|a, b| a.range == b.range)` after sorting by range. This
+removes **all** diagnostics that share the exact same span, regardless
+of their diagnostic code, message, or severity. If two genuinely
+different native diagnostics land on the same range (e.g. an
+`argument_count` error and an `unknown_member` warning on the same
+expression), the second one is silently dropped.
+
+**Fix:** Change the dedup key from `a.range == b.range` to
+`a.range == b.range && a.code == b.code`. This preserves distinct
+diagnostic codes on the same span while still collapsing true
+duplicates produced by different analysis phases.
+
+---
+
+## B12 — PHPStan cache pruning uses length-only comparison
+
+| Impact     | Effort |
+| ---------- | ------ |
+| Low        | Low    |
+
+In `publish_diagnostics_for_file` (`src/diagnostics/mod.rs`), the
+PHPStan cache pruning step only updates the cache when
+`pruned.len() != cached.len()`. If deduplication replaces one PHPStan
+diagnostic with a different one at the same count (same number of
+entries but different content), the cache is not updated. On the next
+Phase 1 merge the stale entry would reappear.
+
+In practice this is unlikely because pruning only ever removes entries
+(never replaces them), but the check is technically incorrect.
+
+**Fix:** Replace the length comparison with a content comparison, or
+unconditionally write the pruned set back into the cache (the extra
+write is negligible).