Merge pull request github#9404 from MathiasVP/swift-get-enclosing-function

Swift: Add `getEnclosingFunction` to `AstNode`

Author: rdmarsh2

swift/ql/lib/codeql/swift/elements/AstNode.qll

@@ -1,4 +1,17 @@
-// generated by codegen/codegen.py, remove this comment if you wish to edit this file
 private import codeql.swift.generated.AstNode
+private import codeql.swift.elements.decl.AbstractFunctionDecl
+private import codeql.swift.generated.GetImmediateParent
 
-class AstNode extends AstNodeBase { }
+private Element getEnclosingFunctionStep(Element e) {
+  not e instanceof AbstractFunctionDecl and
+  result = getImmediateParent(e)
+}
+
+cached
+private AbstractFunctionDecl getEnclosingFunctionCached(AstNode ast) {
+  result = getEnclosingFunctionStep*(getImmediateParent(ast))
+}
+
+class AstNode extends AstNodeBase {
+  final AbstractFunctionDecl getEnclosingFunction() { result = getEnclosingFunctionCached(this) }
+}