Merge pull request github#13240 from d10c/swift/brace-stmt-variables

Swift: reorganize `VarDecl` instances within `BraceStmt`

Author: d10c

swift/ql/.generated.list

@@ -0,0 +1,4 @@
+---
+category: breaking
+---
+* The `BraceStmt` AST node's `AstNode getElement(index)` member predicate no longer returns `VarDecl`s after the `PatternBindingDecl` that declares them. Instead, a new `VarDecl getVariable(index)` predicate has been introduced for accessing the variables declared in a `BraceStmt`. This change only affects query writers.

swift/ql/lib/change-notes/2023-06-06-brace-stmt-variables.md

@@ -19,8 +19,8 @@ class NamedPattern extends Generated::NamedPattern {
    * This will be the case as long as the variable is subsequently used.
    */
   VarDecl getVarDecl() {
-    this.getImmediateEnclosingPattern*() = result.getParentPattern().getFullyUnresolved() and
-    result.getName() = this.getName()
+    this.getImmediateEnclosingPattern*() = result.getImmediateParentPattern() and
+    pragma[only_bind_out](result.getName()) = pragma[only_bind_out](this.getName())
   }
 
   override string toString() { result = this.getName() }

swift/ql/lib/codeql/swift/elements/pattern/NamedPattern.qll

@@ -11,4 +11,23 @@ class BraceStmt extends Generated::BraceStmt {
   }
 
   override string toString() { result = "{ ... }" }
+
+  override AstNode getImmediateElement(int index) {
+    result =
+      rank[index + 1](AstNode element, int i |
+        element = super.getImmediateElement(i) and
+        not element instanceof VarDecl
+      |
+        element order by i
+      )
+  }
+
+  override VarDecl getVariable(int index) {
+    result =
+      rank[index + 1](VarDecl variable, int i |
+        variable = super.getImmediateElement(i)
+      |
+        variable order by i
+      )
+  }
 }