24     Current = Current->Next;
71     for (T *I = First;; I = I->Next) {  in checkConsistency()
77     CHECK_EQ(Last->Next, nullptr);  in checkConsistency()
88     X->Next = nullptr;  in push_back()
92       Last->Next = X;  in push_back()
100     X->Next = First;  in push_front()
107     First = First->Next;  in pop_front()
113   // Insert X next to Prev
118     X->Next = Prev->Next;  in insert()
119     Prev->Next = X;  in insert()
129     DCHECK_EQ(Prev->Next, X);  in extract()
130     Prev->Next = X->Next;  in extract()
143       Last->Next = L->First;  in append_back()
165     X->Next = First;  in push_front()
177     CHECK_EQ(Prev->Next, Y);  in insert()
178     Prev->Next = X;  in insert()
180     X->Next = Y;  in insert()
186     X->Next = nullptr;  in push_back()
190       DCHECK_EQ(Last->Next, nullptr);  in push_back()
191       Last->Next = X;  in push_back()
200     First = First->Next;  in pop_front()
213     T *Next = X->Next;  in remove()  local
215       CHECK_EQ(Prev->Next, X);  in remove()
216       Prev->Next = Next;  in remove()
218     if (Next) {  in remove()
219       CHECK_EQ(Next->Prev, X);  in remove()
220       Next->Prev = Prev;  in remove()
224       First = Next;  in remove()
229       DCHECK_EQ(Next, nullptr);  in remove()
232       DCHECK_NE(Next, nullptr);  in remove()