Python: Separate callable for lambdas

Since lambdas are split, but their children are not,
we use the Function as the callable.

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

@@ -498,10 +498,13 @@ import ArgumentPassing
  */
 newtype TDataFlowCallable =
   TCallableValue(CallableValue callable) {
-    callable instanceof FunctionValue
+    callable instanceof FunctionValue and
+    // TODO: push into FunctionValue
+    not callable.(FunctionValue).getOrigin().getNode() instanceof Lambda
     or
     callable instanceof ClassValue
   } or
+  TLambda(Function lambda) { lambda.getName() = "lambda" } or
   TModule(Module m)
 
 /** Represents a callable. */
@@ -544,6 +547,27 @@ class DataFlowCallableValue extends DataFlowCallable, TCallableValue {
   override CallableValue getCallableValue() { result = callable }
 }
 
+/** A class representing a callable lambda. */
+class DataFlowLambda extends DataFlowCallable, TLambda {
+  Function lambda;
+
+  DataFlowLambda() { this = TLambda(lambda) }
+
+  override string toString() { result = lambda.toString() }
+
+  override CallNode getACall() { result = getCallableValue().getACall() }
+
+  override Scope getScope() { result = lambda.getEvaluatingScope() }
+
+  override NameNode getParameter(int n) { result = getParameter(getCallableValue(), n) }
+
+  override string getName() { result = "Lambda callable" }
+
+  override CallableValue getCallableValue() {
+    result.(FunctionValue).getOrigin().getNode() = lambda.getDefinition()
+  }
+}
+
 /** A class representing the scope in which a `ModuleVariableNode` appears. */
 class DataFlowModuleScope extends DataFlowCallable, TModule {
   Module mod;