C++: Add upgrade and downgrade scripts

cpp/downgrades/e594389175c098d7225683d0fd8cefcc47d84bc1/upgrade.properties

@@ -0,0 +1,4 @@
+description: Mix typedefs and usings
+compatibility: full
+usertypes.rel: run usertypes.qlo
+usertype_alias_kind.rel: delete

cpp/downgrades/e594389175c098d7225683d0fd8cefcc47d84bc1/usertypes.ql

@@ -0,0 +1,20 @@
+class UserType extends @usertype {
+  string toString() { none() }
+}
+
+int getTyperefKind(UserType usertype) {
+  usertype_alias_kind(usertype, 0) and
+  result = 5
+  or
+  usertype_alias_kind(usertype, 1) and
+  result = 14
+}
+
+bindingset[kind]
+int getKind(UserType usertype, int kind) {
+  if kind = 18 then result = getTyperefKind(usertype) else result = kind
+}
+
+from UserType usertype, string name, int kind
+where usertypes(usertype, name, kind)
+select usertype, name, getKind(usertype, kind)

cpp/ql/lib/upgrades/59cb96ca699929b63941e81905f9b8de7eed59a6/upgrade.properties

@@ -0,0 +1,4 @@
+description: Mix typedefs and usings
+compatibility: full
+usertypes.rel: run usertypes.qlo
+usertype_alias_kind.rel: run usertype_alias_kind.qlo

cpp/ql/lib/upgrades/59cb96ca699929b63941e81905f9b8de7eed59a6/usertype_alias_kind.ql

@@ -0,0 +1,14 @@
+class UserType extends @usertype {
+  string toString() { none() }
+}
+
+bindingset[kind]
+int getKind(int kind) {
+  kind = 5 and result = 0
+  or
+  kind = 14 and result = 1
+}
+
+from UserType usertype, int kind
+where usertypes(usertype, _, kind)
+select usertype, getKind(kind)

cpp/ql/lib/upgrades/59cb96ca699929b63941e81905f9b8de7eed59a6/usertypes.ql

@@ -0,0 +1,10 @@
+class UserType extends @usertype {
+  string toString() { none() }
+}
+
+bindingset[kind]
+int getKind(int kind) { if kind = [5, 14] then result = 18 else result = kind }
+
+from UserType usertype, string name, int kind
+where usertypes(usertype, name, kind)
+select usertype, name, getKind(kind)