Swift: add database migration scripts for move semantics

swift/downgrades/556e495d498c9c01286088785b590a7e80f0bb0b/downgrade.ql

@@ -0,0 +1,30 @@
+class Element extends @element {
+  string toString() { none() }
+}
+
+query predicate new_unspecified_elements(Element e, string property, string error) {
+  unspecified_elements(e, property, error)
+  or
+  error =
+    "Move semantics support removed during database downgrade. Please update your CodeQL code." and
+  property = "" and
+  (
+    copy_exprs(e, _) or
+    consume_exprs(e, _) or
+    borrow_exprs(e)
+  )
+}
+
+query predicate new_unspecified_element_children(Element e, int index, Element child) {
+  unspecified_element_children(e, index, child)
+  or
+  copy_exprs(e, child) and index = 0
+  or
+  consume_exprs(e, child) and index = 0
+  or
+  borrow_exprs(e) and identity_exprs(e, child) and index = 0
+}
+
+query predicate new_identity_exprs(Element e, Element child) {
+  identity_exprs(e, child) and not borrow_exprs(e)
+}

swift/downgrades/556e495d498c9c01286088785b590a7e80f0bb0b/upgrade.properties

@@ -0,0 +1,10 @@
+description: Removes elements related to move semantics
+compatibility: partial
+
+unspecified_elements.rel: run downgrade.ql new_unspecified_elements
+unspecified_element_children.rel: run downgrade.ql new_unspecified_element_children
+identity_exprs.rel: run downgrade.ql new_identity_exprs
+
+copy_exprs.rel: delete
+consume_exprs.rel: delete
+borrow_exprs.rel: delete

swift/ql/lib/upgrades/04ef9ecaa9e06a587f252f147462861e3d32846a/upgrade.properties

@@ -0,0 +1,2 @@
+description: Added AST nodes related to move semantics
+compatibility: partial