Swift: add BraceStmt.getVariable(_) child with logic in QL.

swift/ql/lib/codeql/swift/elements/stmt/BraceStmt.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
+      )
+  }
 }

swift/schema.py

@@ -935,6 +935,7 @@ class StmtCondition(AstNode):
     elements: list[ConditionElement] | child
 
 class BraceStmt(Stmt):
+    variables: list[VarDecl] | child | doc("variable declared in the scope of this brace statement")
     elements: list[AstNode] | child
 
 class BreakStmt(Stmt):