Rust: Clean up and change note.

Author: geoffw0

rust/ql/lib/change-notes/2026-02-05-neutral-models.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Added support for neutral models (`extensible: neutralModel`) to control where generated source, sink and flow summary models apply.

rust/ql/lib/codeql/rust/dataflow/internal/ModelsAsData.qll

@@ -90,9 +90,9 @@ extensible predicate summaryModel(
 );
 
 /**
- * Holds if a neutral model of kind `kind` exists for the function with canonical path `path`.  The
- * only effect of a neutral model is to prevent generated and inherited models of the corresponding
- * `kind` (`source`, `sink` or `summary`) from being applied.
+ * Holds if a neutral model exists for the function with canonical path `path`.  The only
+ * effect of a neutral model is to prevent generated and inherited models of the corresponding
+ * `kind` (`source`, `sink` or `summary`) from being applied to that function.
  */
 extensible predicate neutralModel(
   string path, string kind, string provenance, QlBuiltins::ExtensionId madId
@@ -148,18 +148,16 @@ private predicate summaryModelRelevant(
   summaryModel(f, input, output, kind, provenance, isInherited, madId) and
   // Only apply generated or inherited models to functions in library code and
   // when no strictly better model (or neutral model) exists
-  (
-    if provenance.isGenerated() or isInherited = true
-    then
-      not f.fromSource() and
-      not exists(Provenance other | summaryModel(f, _, _, _, other, false, _) |
-        provenance.isGenerated() and other.isManual()
-        or
-        provenance = other and isInherited = true
-      ) and
-      not neutralModel(f.getCanonicalPath(), "summary", _, _)
-    else any()
-  )
+  if provenance.isGenerated() or isInherited = true
+  then
+    not f.fromSource() and
+    not exists(Provenance other | summaryModel(f, _, _, _, other, false, _) |
+      provenance.isGenerated() and other.isManual()
+      or
+      provenance = other and isInherited = true
+    ) and
+    not neutralModel(f.getCanonicalPath(), "summary", _, _)
+  else any()
 }
 
 private class SummarizedCallableFromModel extends SummarizedCallable::Range {

rust/ql/test/library-tests/dataflow/models/main.rs

@@ -430,8 +430,8 @@ pub fn neutral_manual_sink(i: i64) {}
 
 fn test_neutrals() {
     // neutral models should cause corresponding generated models to be ignored.
-    // Thus, the `neutral_generated_*` source/sink, which have both a
-    // generated and a neutral model, should not have flow.
+    // Thus, the `neutral_generated_source` and `neutral_generated_sink`, which
+    // have both a generated and a neutral model, should not have flow.
 
     sink(generated_source(1)); // $ hasValueFlow=1
     sink(neutral_generated_source(2));