Swift: add CFG and PrintAst consistency queries, enabling them in CI

Author: redsun82

swift/actions/run-ql-tests/action.yml

@@ -26,6 +26,7 @@ runs:
           --check-repeated-labels \
           --check-redefined-labels \
           --check-use-before-definition \
+          --consistency-queries "${{ github.workspace }}/swift/ql/src/consistency" \
           --compilation-cache "${{ steps.query-cache.outputs.cache-dir }}" \
           ${{ inputs.flags }} \
           swift/ql/test

swift/ql/lib/codeql/swift/printast/Consistency.qll

@@ -0,0 +1,29 @@
+private import codeql.swift.printast.PrintAstNode
+
+query predicate doubleChildren(
+  PrintAstNode parent, int index, PrintAstNode child1, PrintAstNode child2
+) {
+  child1 != child2 and
+  parent.hasChild(child1, index, _) and
+  parent.hasChild(child2, index, _)
+}
+
+query predicate doubleIndexes(PrintAstNode parent, int index1, int index2, PrintAstNode child) {
+  index1 != index2 and
+  parent.hasChild(child, index1, _) and
+  parent.hasChild(child, index2, _)
+}
+
+query predicate doubleParents(PrintAstNode parent1, PrintAstNode parent2, PrintAstNode child) {
+  parent1 != parent2 and
+  parent1.hasChild(child, _, _) and
+  parent2.hasChild(child, _, _)
+}
+
+private predicate isChildOf(PrintAstNode parent, PrintAstNode child) {
+  parent.hasChild(child, _, _)
+}
+
+query predicate parentChildLoops(PrintAstNode parent, PrintAstNode child) {
+  isChildOf(parent, child) and isChildOf*(child, parent)
+}

swift/ql/test/library-tests/controlflow/graph/consistency.ql renamed to swift/ql/src/consistency/CfgConsistency.ql

@@ -0,0 +1 @@
+import codeql.swift.printast.Consistency