Update QL doc for allowParameterReturnInSelf

Author: hvitved

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowPrivate.qll

@@ -289,7 +289,10 @@ predicate lambdaCall(DataFlowCall call, LambdaCallKind kind, Node receiver) { no
 predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preservesValue) { none() }
 
 /**
- * Holds if flow is allowed to pass from parameter `p`, to a return
- * node, and back out to `p`.
+ * Holds if flow is allowed to pass from parameter `p` and back to itself as a
+ * side-effect, resulting in a summary from `p` to itself.
+ *
+ * One example would be to allow flow like `p.foo = p.bar;`, which is disallowed
+ * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) { none() }

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll

@@ -509,7 +509,10 @@ predicate lambdaCall(DataFlowCall call, LambdaCallKind kind, Node receiver) { no
 predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preservesValue) { none() }
 
 /**
- * Holds if flow is allowed to pass from parameter `p`, to a return
- * node, and back out to `p`.
+ * Holds if flow is allowed to pass from parameter `p` and back to itself as a
+ * side-effect, resulting in a summary from `p` to itself.
+ *
+ * One example would be to allow flow like `p.foo = p.bar;`, which is disallowed
+ * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) { none() }

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll

@@ -2015,8 +2015,11 @@ predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preserves
 }
 
 /**
- * Holds if flow is allowed to pass from parameter `p`, to a return
- * node, and back out to `p`.
+ * Holds if flow is allowed to pass from parameter `p` and back to itself as a
+ * side-effect, resulting in a summary from `p` to itself.
+ *
+ * One example would be to allow flow like `p.foo = p.bar;`, which is disallowed
+ * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) {
   FlowSummaryImpl::Private::summaryAllowParameterReturnInSelf(p)

java/ql/lib/semmle/code/java/dataflow/internal/DataFlowPrivate.qll

@@ -367,8 +367,11 @@ predicate lambdaCall(DataFlowCall call, LambdaCallKind kind, Node receiver) {
 predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preservesValue) { none() }
 
 /**
- * Holds if flow is allowed to pass from parameter `p`, to a return
- * node, and back out to `p`.
+ * Holds if flow is allowed to pass from parameter `p` and back to itself as a
+ * side-effect, resulting in a summary from `p` to itself.
+ *
+ * One example would be to allow flow like `p.foo = p.bar;`, which is disallowed
+ * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) {
   FlowSummaryImpl::Private::summaryAllowParameterReturnInSelf(p)

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll

@@ -1666,7 +1666,10 @@ predicate lambdaCall(DataFlowCall call, LambdaCallKind kind, Node receiver) { no
 predicate additionalLambdaFlowStep(Node nodeFrom, Node nodeTo, boolean preservesValue) { none() }
 
 /**
- * Holds if flow is allowed to pass from parameter `p`, to a return
- * node, and back out to `p`.
+ * Holds if flow is allowed to pass from parameter `p` and back to itself as a
+ * side-effect, resulting in a summary from `p` to itself.
+ *
+ * One example would be to allow flow like `p.foo = p.bar;`, which is disallowed
+ * by default as a heuristic.
  */
 predicate allowParameterReturnInSelf(ParameterNode p) { none() }