diff --git a/ncd/NCDEvaluator.c b/ncd/NCDEvaluator.c
index 43978ec89..1e5ead090 100644
--- a/ncd/NCDEvaluator.c
+++ b/ncd/NCDEvaluator.c
@@ -200,22 +200,32 @@ static int add_expr_recurser (NCDEvaluator *o, NCDValue *value, NCDValMem *mem,
             
             if (!ncd_make_name_indices(o->string_index, NCDValue_VarName(value), &var.varnames, &var.num_names)) {
                 BLog(BLOG_ERROR, "ncd_make_name_indices failed");
-                goto fail;
+                goto fail_var0;
             }
             
             size_t index;
-            if (!NCDEvaluator__VarVec_AppendValue(&o->vars, var, &index)) {
-                BLog(BLOG_ERROR, "failed to grow var array");
-                BFree(var.varnames);
-                goto fail;
+            struct NCDEvaluator__Var *varptr = NCDEvaluator__VarVec_Push(&o->vars, &index);
+            if (!varptr) {
+                BLog(BLOG_ERROR, "NCDEvaluator__VarVec_Push failed");
+                goto fail_var1;
             }
             
             if (index >= MAX_LOCAL_IDS) {
                 BLog(BLOG_ERROR, "too many variables");
-                goto fail;
+                goto fail_var2;
             }
             
+            *varptr = var;
+            
             *out = NCDVal_NewPlaceholder(mem, ((int)index << 1) | 0);
+            break;
+            
+        fail_var2:
+            NCDEvaluator__VarVec_Pop(&o->vars, NULL);
+        fail_var1:
+            BFree(var.varnames);
+        fail_var0:
+            goto fail;
         } break;
         
         case NCDVALUE_INVOC: {
@@ -253,19 +263,24 @@ static int add_expr_recurser (NCDEvaluator *o, NCDValue *value, NCDValMem *mem,
             }
             
             size_t index;
-            if (!NCDEvaluator__CallVec_AppendValue(&o->calls, call, &index)) {
-                BLog(BLOG_ERROR, "failed to grow call array");
+            struct NCDEvaluator__Call *callptr = NCDEvaluator__CallVec_Push(&o->calls, &index);
+            if (!callptr) {
+                BLog(BLOG_ERROR, "NCDEvaluator__CallVec_Push failed");
                 goto fail_invoc1;
             }
             
             if (index >= MAX_LOCAL_IDS) {
                 BLog(BLOG_ERROR, "too many variables");
-                goto fail;
+                goto fail_invoc2;
             }
             
+            *callptr = call;
+            
             *out = NCDVal_NewPlaceholder(mem, ((int)index << 1) | 1);
             break;
             
+        fail_invoc2:
+            NCDEvaluator__CallVec_Pop(&o->calls, NULL);
         fail_invoc1:
             while (call.num_args-- > 0) {
                 expr_free(&call.args[call.num_args]);
diff --git a/structure/Vector_decl.h b/structure/Vector_decl.h
index c29be0b60..8e36c9dd8 100644
--- a/structure/Vector_decl.h
+++ b/structure/Vector_decl.h
@@ -39,9 +39,7 @@ static int Vector_Init (Vector *o, size_t capacity) WARN_UNUSED;
 static void Vector_Free (Vector *o);
 static size_t Vector_Count (Vector *o);
 static VectorElem * Vector_Get (Vector *o, size_t index);
-static int Vector_AllocAppend (Vector *o, size_t count, VectorElem **out_ptr) WARN_UNUSED;
-static void Vector_DoAppend (Vector *o, size_t count);
-static int Vector_AppendValue (Vector *o, VectorElem value, size_t *out_index) WARN_UNUSED;
+static int Vector_Reserve (Vector *o, size_t capacity) WARN_UNUSED;
 static VectorElem * Vector_Push (Vector *o, size_t *out_index) WARN_UNUSED;
 static VectorElem * Vector_Pop (Vector *o, size_t *out_index);
 
diff --git a/structure/Vector_footer.h b/structure/Vector_footer.h
index df438af62..3e561d9aa 100644
--- a/structure/Vector_footer.h
+++ b/structure/Vector_footer.h
@@ -36,8 +36,6 @@
 #undef Vector_Free
 #undef Vector_Count
 #undef Vector_Get
-#undef Vector_AllocAppend
-#undef Vector_DoAppend
-#undef Vector_AppendValue
+#undef Vector_Reserve
 #undef Vector_Push
 #undef Vector_Pop
diff --git a/structure/Vector_header.h b/structure/Vector_header.h
index da9d18879..61be2294a 100644
--- a/structure/Vector_header.h
+++ b/structure/Vector_header.h
@@ -37,8 +37,6 @@
 #define Vector_Free MERGE(VECTOR_NAME, _Free)
 #define Vector_Count MERGE(VECTOR_NAME, _Count)
 #define Vector_Get MERGE(VECTOR_NAME, _Get)
-#define Vector_AllocAppend MERGE(VECTOR_NAME, _AllocAppend)
-#define Vector_DoAppend MERGE(VECTOR_NAME, _DoAppend)
-#define Vector_AppendValue MERGE(VECTOR_NAME, _AppendValue)
+#define Vector_Reserve MERGE(VECTOR_NAME, _Reserve)
 #define Vector_Push MERGE(VECTOR_NAME, _Push)
 #define Vector_Pop MERGE(VECTOR_NAME, _Pop)
diff --git a/structure/Vector_impl.h b/structure/Vector_impl.h
index 84652cd71..b71d515b5 100644
--- a/structure/Vector_impl.h
+++ b/structure/Vector_impl.h
@@ -61,18 +61,16 @@ static VectorElem * Vector_Get (Vector *o, size_t index)
     return &o->elems[index];
 }
 
-static int Vector_AllocAppend (Vector *o, size_t count, VectorElem **out_ptr)
+static int Vector_Reserve (Vector *o, size_t capacity)
 {
-    ASSERT(count > 0)
-    
-    if (count > o->capacity - o->count) {
+    if (capacity > o->capacity) {
         size_t new_capacity = o->capacity;
         do {
             if (new_capacity > SIZE_MAX / 2) {
                 return 0;
             }
             new_capacity = (new_capacity == 0) ? 1 : (2 * new_capacity);
-        } while (count > new_capacity - o->count);
+        } while (capacity > new_capacity);
         
         VectorElem *new_elems = BAllocArray(new_capacity, sizeof(VectorElem));
         if (!new_elems) {
@@ -89,43 +87,19 @@ static int Vector_AllocAppend (Vector *o, size_t count, VectorElem **out_ptr)
         o->capacity = new_capacity;
     }
     
-    if (out_ptr) {
-        *out_ptr = &o->elems[o->count];
-    }
-    return 1;
-}
-
-static void Vector_DoAppend (Vector *o, size_t count)
-{
-    ASSERT(count <= o->capacity - o->count)
-    
-    o->count += count;
-}
-
-static int Vector_AppendValue (Vector *o, VectorElem value, size_t *out_index)
-{
-    VectorElem *ptr;
-    if (!Vector_AllocAppend(o, 1, &ptr)) {
-        return 0;
-    }
-    *ptr = value;
-    if (out_index) {
-        *out_index = o->count;
-    }
-    Vector_DoAppend(o, 1);
     return 1;
 }
 
 static VectorElem * Vector_Push (Vector *o, size_t *out_index)
 {
-    VectorElem *ptr;
-    if (!Vector_AllocAppend(o, 1, &ptr)) {
+    if (o->count == SIZE_MAX || !Vector_Reserve(o, o->count + 1)) {
         return NULL;
     }
     if (out_index) {
         *out_index = o->count;
     }
-    Vector_DoAppend(o, 1);
+    VectorElem *ptr = &o->elems[o->count];
+    o->count++;
     return ptr;
 }