Merge pull request #1785 from jbj/dataflow-recursion-prevention-shared

C++/C#/Java: Pyrameterize ConfigurationRecursionPrevention

change-notes/1.22/analysis-cpp.md

@@ -29,3 +29,4 @@
 - Fixed the `LocalScopeVariableReachability.qll` library's handling of loops with an entry condition is both always true upon first entry, and where there is more than one control flow path through the loop condition.  This change increases the accuracy of the `LocalScopeVariableReachability.qll` library and queries which depend on it.
 - The `semmle.code.cpp.models` library now models data flow through `std::swap`.
 - There is a new `Variable.isThreadLocal()` predicate. It can be used to tell whether a variable is `thread_local`.
+- Recursion through the `DataFlow` library is now always a compile error. Such recursion has been deprecated since release 1.16. If one `DataFlow::Configuration` needs to depend on the results of another, switch one of them to use one of the `DataFlow2` through `DataFlow4` libraries.

cpp/ql/src/semmle/code/cpp/dataflow/DataFlow2.qll

@@ -12,27 +12,4 @@ import cpp
 
 module DataFlow2 {
   import semmle.code.cpp.dataflow.internal.DataFlowImpl2
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  private abstract
-  class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0
-      or
-      strictcount(Node n | this.isSink(n)) < 0
-      or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-      or
-      super.hasFlow(source, sink)
-    }
-  }
 }

cpp/ql/src/semmle/code/cpp/dataflow/DataFlow3.qll

@@ -12,27 +12,4 @@ import cpp
 
 module DataFlow3 {
   import semmle.code.cpp.dataflow.internal.DataFlowImpl3
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  private abstract
-  class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0
-      or
-      strictcount(Node n | this.isSink(n)) < 0
-      or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-      or
-      super.hasFlow(source, sink)
-    }
-  }
 }

cpp/ql/src/semmle/code/cpp/dataflow/DataFlow4.qll

@@ -12,27 +12,4 @@ import cpp
 
 module DataFlow4 {
   import semmle.code.cpp.dataflow.internal.DataFlowImpl4
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  private abstract
-  class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0
-      or
-      strictcount(Node n | this.isSink(n)) < 0
-      or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-      or
-      super.hasFlow(source, sink)
-    }
-  }
 }

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl2.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl3.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl4.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/ir/dataflow/DataFlow2.qll

@@ -12,27 +12,4 @@ import cpp
 
 module DataFlow2 {
   import semmle.code.cpp.ir.dataflow.internal.DataFlowImpl2
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  private abstract
-  class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0
-      or
-      strictcount(Node n | this.isSink(n)) < 0
-      or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-      or
-      super.hasFlow(source, sink)
-    }
-  }
 }

cpp/ql/src/semmle/code/cpp/ir/dataflow/DataFlow3.qll

@@ -12,27 +12,4 @@ import cpp
 
 module DataFlow3 {
   import semmle.code.cpp.ir.dataflow.internal.DataFlowImpl3
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  private abstract
-  class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0
-      or
-      strictcount(Node n | this.isSink(n)) < 0
-      or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-      or
-      super.hasFlow(source, sink)
-    }
-  }
 }

cpp/ql/src/semmle/code/cpp/ir/dataflow/DataFlow4.qll

@@ -12,27 +12,4 @@ import cpp
 
 module DataFlow4 {
   import semmle.code.cpp.ir.dataflow.internal.DataFlowImpl4
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  private abstract
-  class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0
-      or
-      strictcount(Node n | this.isSink(n)) < 0
-      or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
-      or
-      super.hasFlow(source, sink)
-    }
-  }
 }

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl2.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl3.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl4.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

csharp/ql/src/semmle/code/csharp/dataflow/DataFlow.qll

@@ -7,23 +7,4 @@ import csharp
 
 module DataFlow {
   import semmle.code.csharp.dataflow.internal.DataFlowImpl
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Five copies are available: `DataFlow` through `DataFlow5`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

csharp/ql/src/semmle/code/csharp/dataflow/DataFlow2.qll

@@ -7,23 +7,4 @@ import csharp
 
 module DataFlow2 {
   import semmle.code.csharp.dataflow.internal.DataFlowImpl2
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Five copies are available: `DataFlow` through `DataFlow5`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

csharp/ql/src/semmle/code/csharp/dataflow/DataFlow3.qll

@@ -7,23 +7,4 @@ import csharp
 
 module DataFlow3 {
   import semmle.code.csharp.dataflow.internal.DataFlowImpl3
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Five copies are available: `DataFlow` through `DataFlow5`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

csharp/ql/src/semmle/code/csharp/dataflow/DataFlow4.qll

@@ -7,23 +7,4 @@ import csharp
 
 module DataFlow4 {
   import semmle.code.csharp.dataflow.internal.DataFlowImpl4
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Five copies are available: `DataFlow` through `DataFlow5`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

csharp/ql/src/semmle/code/csharp/dataflow/DataFlow5.qll

@@ -7,23 +7,4 @@ import csharp
 
 module DataFlow5 {
   import semmle.code.csharp.dataflow.internal.DataFlowImpl5
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Five copies are available: `DataFlow` through `DataFlow5`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowImpl2.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowImpl3.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowImpl4.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

csharp/ql/src/semmle/code/csharp/dataflow/internal/DataFlowImpl5.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

java/ql/src/semmle/code/java/dataflow/DataFlow.qll

@@ -7,23 +7,4 @@ import java
 
 module DataFlow {
   import semmle.code.java.dataflow.internal.DataFlowImpl
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

java/ql/src/semmle/code/java/dataflow/DataFlow2.qll

@@ -7,23 +7,4 @@ import java
 
 module DataFlow2 {
   import semmle.code.java.dataflow.internal.DataFlowImpl2
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

java/ql/src/semmle/code/java/dataflow/DataFlow3.qll

@@ -7,23 +7,4 @@ import java
 
 module DataFlow3 {
   import semmle.code.java.dataflow.internal.DataFlowImpl3
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

java/ql/src/semmle/code/java/dataflow/DataFlow4.qll

@@ -7,23 +7,4 @@ import java
 
 module DataFlow4 {
   import semmle.code.java.dataflow.internal.DataFlowImpl4
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

java/ql/src/semmle/code/java/dataflow/DataFlow5.qll

@@ -7,23 +7,4 @@ import java
 
 module DataFlow5 {
   import semmle.code.java.dataflow.internal.DataFlowImpl5
-
-  /**
-   * This class exists to prevent mutual recursion between the user-overridden
-   * member predicates of `Configuration` and the rest of the data-flow library.
-   * Good performance cannot be guaranteed in the presence of such recursion, so
-   * it should be replaced by using more than one copy of the data flow library.
-   * Four copies are available: `DataFlow` through `DataFlow4`.
-   */
-  abstract private class ConfigurationRecursionPrevention extends Configuration {
-    bindingset[this]
-    ConfigurationRecursionPrevention() { any() }
-
-    override predicate hasFlow(Node source, Node sink) {
-      strictcount(Node n | this.isSource(n)) < 0 or
-      strictcount(Node n | this.isSink(n)) < 0 or
-      strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0 or
-      super.hasFlow(source, sink)
-    }
-  }
 }

java/ql/src/semmle/code/java/dataflow/internal/DataFlowImpl.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

java/ql/src/semmle/code/java/dataflow/internal/DataFlowImpl2.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

java/ql/src/semmle/code/java/dataflow/internal/DataFlowImpl3.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

java/ql/src/semmle/code/java/dataflow/internal/DataFlowImpl4.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)

java/ql/src/semmle/code/java/dataflow/internal/DataFlowImpl5.qll

@@ -121,6 +121,27 @@ abstract class Configuration extends string {
   deprecated predicate hasFlowBackward(Node source, Node sink) { hasFlow(source, sink) }
 }
 
+/**
+ * This class exists to prevent mutual recursion between the user-overridden
+ * member predicates of `Configuration` and the rest of the data-flow library.
+ * Good performance cannot be guaranteed in the presence of such recursion, so
+ * it should be replaced by using more than one copy of the data flow library.
+ */
+abstract private class ConfigurationRecursionPrevention extends Configuration {
+  bindingset[this]
+  ConfigurationRecursionPrevention() { any() }
+
+  override predicate hasFlow(Node source, Node sink) {
+    strictcount(Node n | this.isSource(n)) < 0
+    or
+    strictcount(Node n | this.isSink(n)) < 0
+    or
+    strictcount(Node n1, Node n2 | this.isAdditionalFlowStep(n1, n2)) < 0
+    or
+    super.hasFlow(source, sink)
+  }
+}
+
 private predicate inBarrier(Node node, Configuration config) {
   config.isBarrierIn(node) and
   config.isSource(node)