WIP expose SuccessorType on CFG edges

Author: owen-mc

go/ql/lib/semmle/go/controlflow/ControlFlowGraph.qll

@@ -4,6 +4,7 @@
 
 import go
 private import ControlFlowGraphImpl
+private import codeql.controlflow.SuccessorType
 
 /** Provides helper predicates for mapping btween CFG nodes and the AST. */
 module ControlFlow {
@@ -40,6 +41,9 @@ module ControlFlow {
     /** Gets a node that directly follows this one in the control-flow graph. */
     Node getASuccessor() { result = CFG::succ(this) }
 
+    /** Gets a node that directly follows this one in the control-flow graph. */
+    Node getASuccessor(SuccessorType t) { result = CFG::succ(this, t) }
+
     /** Gets a node that directly precedes this one in the control-flow graph. */
     Node getAPredecessor() { this = result.getASuccessor() }
 
@@ -350,4 +354,6 @@ module ControlFlow {
   }
 }
 
+class ControlFlowNode = ControlFlow::Node;
+
 class Write = ControlFlow::WriteNode;