Convert DanglingCaptureWhenReturningLambdaObject to the new dataflow library

Note that this removes - what seems to be - a duplicated test result.

Author: jketema

cpp/common/src/codingstandards/cpp/rules/danglingcapturewhenreturninglambdaobject/DanglingCaptureWhenReturningLambdaObject.qll

@@ -5,7 +5,7 @@
  */
 
 import cpp
-import semmle.code.cpp.dataflow.DataFlow
+import semmle.code.cpp.dataflow.new.DataFlow
 import codingstandards.cpp.Customizations
 import codingstandards.cpp.Exclusions
 
@@ -48,7 +48,14 @@ query predicate problems(
   not isExcluded(returnStmt, getQuery()) and
   lambda.getACapture() = danglingCapture and
   (
-    DataFlow::localExprFlow(lambda, returnStmt.getExpr())
+    returnStmt.getExpr() = lambda
+    or
+    exists(DataFlow::Node lambdaNode, DataFlow::Node returnNode |
+      lambdaNode.asExpr() = lambda and
+      returnNode.asIndirectExpr() = returnStmt.getExpr()
+    |
+      DataFlow::localFlow(lambdaNode, returnNode)
+    )
     or
     // implement a rough heuristic to catch the results of constructors (such as std::function's)
     // which take an argument that has a dangling capture and flow to a return statement

cpp/common/test/rules/danglingcapturewhenreturninglambdaobject/DanglingCaptureWhenReturningLambdaObject.expected

@@ -1,7 +1,6 @@
 | test.cpp:6:3:6:12 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:5:12:5:27 | [...](...){...} | object | test.cpp:5:21:5:21 | l1 | l1 |
 | test.cpp:17:5:17:36 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:17:5:17:36 | [...](...){...} | object | test.cpp:17:27:17:27 | (captured this) | this |
 | test.cpp:27:5:27:17 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:26:17:26:42 | [...](...){...} | object | test.cpp:26:33:26:33 | val | val |
-| test.cpp:27:5:27:17 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:26:18:26:42 | [...](...){...} | object | test.cpp:26:33:26:33 | val | val |
 | test.cpp:33:3:33:33 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:33:3:33:33 | [...](...){...} | object | test.cpp:33:25:33:25 | i | i |
 | test.cpp:37:3:37:33 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:37:3:37:33 | [...](...){...} | object | test.cpp:37:25:37:25 | i | i |
 | test.cpp:46:3:46:45 | return ... | Returning lambda $@ with potentially dangling capture $@. | test.cpp:46:11:46:43 | [...](...){...} | object | test.cpp:46:13:46:16 | data | data |