Fix assert during cfg generation when encountering 'while: return 1 else:'

src/core/cfg.cpp

@@ -1837,9 +1837,14 @@ public:
             jend->target = end;
             curblock->connectTo(end);
         }
-        curblock = end;
 
+        if (end->predecessors.size() == 0) {
+            delete end;
+            curblock = NULL;
+        } else {
+            curblock = end;
             cfg->placeBlock(end);
+        }
 
         return true;
     }

test/tests/loops.py

@@ -5,3 +5,11 @@ def f():
             break
         break
 f()
+
+def f2(x):
+    while x:
+        return 1
+    else:
+        return 2
+print f2(1)
+