C++: Add upgrade and downgrade script

cpp/downgrades/cf72c8898d19eb1b3374432cf79d8276cb07ad43/exprparents.ql

@@ -0,0 +1,21 @@
+class Element extends @element {
+  string toString() { none() }
+}
+
+class Expr extends @expr {
+  string toString() { none() }
+}
+
+class Stmt extends @stmt {
+  string toString() { none() }
+}
+
+predicate isStmtWithInitializer(Stmt stmt) {
+  exists(int kind | stmts(stmt, kind, _) | kind = 2 or kind = 11 or kind = 35)
+}
+
+from Expr child, int index, int index_new, Element parent
+where
+  exprparents(child, index, parent) and
+  if isStmtWithInitializer(parent) then index_new = index - 1 else index_new = index
+select child, index_new, parent

cpp/downgrades/cf72c8898d19eb1b3374432cf79d8276cb07ad43/stmtparents.ql

@@ -0,0 +1,22 @@
+class Element extends @element {
+  string toString() { none() }
+}
+
+class Stmt extends @stmt {
+  string toString() { none() }
+}
+
+predicate isStmtWithInitializer(Stmt stmt) {
+  exists(int kind | stmts(stmt, kind, _) | kind = 2 or kind = 11 or kind = 35)
+}
+
+from Stmt child, int index, int index_new, Element parent
+where
+  stmtparents(child, index, parent) and
+  (
+    not isStmtWithInitializer(parent)
+    or
+    index > 0
+  ) and
+  if isStmtWithInitializer(parent) then index_new = index - 1 else index_new = index
+select child, index_new, parent

cpp/downgrades/cf72c8898d19eb1b3374432cf79d8276cb07ad43/upgrade.properties

@@ -0,0 +1,6 @@
+description: Support C++17 if and switch initializers
+compatibility: partial
+if_initialization.rel: delete
+switch_initialization.rel: delete
+exprparents.rel: run exprparents.qlo
+stmtparents.rel: run stmtparents.qlo

cpp/ql/lib/upgrades/e9a518baf14f4322ac243578a8e1391386ff030f/exprparents.ql

@@ -0,0 +1,21 @@
+class Element extends @element {
+  string toString() { none() }
+}
+
+class Expr extends @expr {
+  string toString() { none() }
+}
+
+class Stmt extends @stmt {
+  string toString() { none() }
+}
+
+predicate isStmtWithInitializer(Stmt stmt) {
+  exists(int kind | stmts(stmt, kind, _) | kind = 2 or kind = 11 or kind = 35)
+}
+
+from Expr child, int index, int index_new, Element parent
+where
+  exprparents(child, index, parent) and
+  if isStmtWithInitializer(parent) then index_new = index + 1 else index_new = index
+select child, index_new, parent

cpp/ql/lib/upgrades/e9a518baf14f4322ac243578a8e1391386ff030f/stmtparents.ql

@@ -0,0 +1,17 @@
+class Element extends @element {
+  string toString() { none() }
+}
+
+class Stmt extends @stmt {
+  string toString() { none() }
+}
+
+predicate isStmtWithInitializer(Stmt stmt) {
+  exists(int kind | stmts(stmt, kind, _) | kind = 2 or kind = 11 or kind = 35)
+}
+
+from Stmt child, int index, int index_new, Element parent
+where
+  stmtparents(child, index, parent) and
+  if isStmtWithInitializer(parent) then index_new = index + 1 else index_new = index
+select child, index_new, parent

cpp/ql/lib/upgrades/e9a518baf14f4322ac243578a8e1391386ff030f/upgrade.properties

@@ -0,0 +1,4 @@
+description: Support C++17 if and switch initializers
+compatibility: partial
+exprparents.rel: run exprparents.qlo
+stmtparents.rel: run stmtparents.qlo