diff --git a/src/radix.h b/src/radix.h
index 0467874ee..585555ef4 100644
--- a/src/radix.h
+++ b/src/radix.h
@@ -1,362 +1,362 @@
 // Copyright (c) 2019 The Bitcoin developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_RADIX_H
 #define BITCOIN_RADIX_H
 
 #include <rcu.h>
 #include <util/system.h>
 
 #include <array>
 #include <atomic>
 #include <cstdint>
 #include <memory>
 #include <type_traits>
 
 /**
  * This is a radix tree storing values identified by a unique key.
  *
  * The tree is composed of nodes (RadixNode) containing an array of
  * RadixElement. The key is split into chunks of a few bits that serve as an
  * index into that array. RadixElement is a discriminated union of either a
  * RadixNode* representing the next level in the tree, or a T* representing a
  * leaf. New RadixNode are added lazily when two leaves would go in the same
  * slot.
  *
  * Reads walk the tree using sequential atomic loads, and insertions are done
  * using CAS, which ensures both can be executed lock free. Removing any
  * elements from the tree can also be done using CAS, but requires waiting for
  * other readers before being destroyed. The tree uses RCU to track which thread
  * is reading the tree, which allows deletion to wait for other readers to be up
  * to speed before destroying anything. It is therefore crucial that the lock be
  * taken before reading anything in the tree.
  */
 template <typename T> struct RadixTree {
 private:
     static const int BITS = 4;
     static const int MASK = (1 << BITS) - 1;
     static const size_t CHILD_PER_LEVEL = 1 << BITS;
 
-    using K = typename std::remove_reference<decltype(
+    using KeyType = typename std::remove_reference<decltype(
         std::declval<T &>().getId())>::type;
-    static const size_t KEY_BITS = 8 * sizeof(K);
+    static const size_t KEY_BITS = 8 * sizeof(KeyType);
     static const uint32_t TOP_LEVEL = (KEY_BITS - 1) / BITS;
 
     struct RadixElement;
     struct RadixNode;
 
     std::atomic<RadixElement> root;
 
 public:
     RadixTree() : root(RadixElement()) {}
     ~RadixTree() { root.load().decrementRefCount(); }
 
     /**
      * Copy semantic.
      */
     RadixTree(const RadixTree &src) : RadixTree() {
         {
             RCULock lock;
             RadixElement e = src.root.load();
             e.incrementRefCount();
             root = e;
         }
 
         // Make sure we the writes in the tree are behind us so
         // this copy won't mutate behind our back.
         RCULock::synchronize();
     }
 
     RadixTree &operator=(const RadixTree &rhs) {
         {
             RCULock lock;
             RadixElement e = rhs.root.load();
             e.incrementRefCount();
             root.load().decrementRefCount();
             root = e;
         }
 
         // Make sure we the writes in the tree are behind us so
         // this copy won't mutate behind our back.
         RCULock::synchronize();
 
         return *this;
     }
 
     /**
      * Move semantic.
      */
     RadixTree(RadixTree &&src) : RadixTree() { *this = std::move(src); }
     RadixTree &operator=(RadixTree &&rhs) {
         {
             RCULock lock;
             RadixElement e = rhs.root.load();
             rhs.root = root.load();
             root = e;
         }
 
         return *this;
     }
 
     /**
      * Insert a value into the tree.
      * Returns true if the value was inserted, false if it was already present.
      */
     bool insert(const RCUPtr<T> &value) {
         return insert(value->getId(), value);
     }
 
     /**
      * Get the value corresponding to a key.
      * Returns the value if found, nullptr if not.
      */
-    RCUPtr<T> get(const K &key) {
+    RCUPtr<T> get(const KeyType &key) {
         uint32_t level = TOP_LEVEL;
 
         RCULock lock;
         RadixElement e = root.load();
 
         // Find a leaf.
         while (e.isNode()) {
             e = e.getNode()->get(level--, key)->load();
         }
 
         T *leaf = e.getLeaf();
         if (leaf == nullptr || leaf->getId() != key) {
             // We failed to find the proper element.
             return RCUPtr<T>();
         }
 
         // The leaf is non-null and the keys match. We have our guy.
         return RCUPtr<T>::copy(leaf);
     }
 
-    RCUPtr<const T> get(const K &key) const {
+    RCUPtr<const T> get(const KeyType &key) const {
         T const *ptr = const_cast<RadixTree *>(this)->get(key).release();
         return RCUPtr<const T>::acquire(ptr);
     }
 
 #define SEEK_LEAF_LOOP()                                                       \
     RadixElement e = eptr->load();                                             \
                                                                                \
     /* Walk down the tree until we find a leaf for our node. */                \
     do {                                                                       \
         while (e.isNode()) {                                                   \
         Node:                                                                  \
             auto nptr = e.getNode();                                           \
             if (!nptr->isShared()) {                                           \
                 eptr = nptr->get(level--, key);                                \
                 e = eptr->load();                                              \
                 continue;                                                      \
             }                                                                  \
                                                                                \
             auto copy = std::make_unique<RadixNode>(*nptr);                    \
             if (!eptr->compare_exchange_strong(e, RadixElement(copy.get()))) { \
                 /* We failed to insert our subtree, just try again. */         \
                 continue;                                                      \
             }                                                                  \
                                                                                \
             /* We have a subtree, resume normal operations from there. */      \
             e.decrementRefCount();                                             \
             eptr = copy->get(level--, key);                                    \
             e = eptr->load();                                                  \
             copy.release();                                                    \
         }                                                                      \
     } while (0)
 
     /**
      * Remove an element from the tree.
      * Returns the removed element, or nullptr if there isn't one.
      */
-    RCUPtr<T> remove(const K &key) {
+    RCUPtr<T> remove(const KeyType &key) {
         uint32_t level = TOP_LEVEL;
 
         RCULock lock;
         std::atomic<RadixElement> *eptr = &root;
 
         SEEK_LEAF_LOOP();
 
         T *leaf = e.getLeaf();
         if (leaf == nullptr || leaf->getId() != key) {
             // We failed to find the proper element.
             return RCUPtr<T>();
         }
 
         // We have the proper element, try to delete it.
         if (eptr->compare_exchange_strong(e, RadixElement())) {
             return RCUPtr<T>::acquire(leaf);
         }
 
         // The element was replaced, either by a subtree or another element.
         if (e.isNode()) {
             goto Node;
         }
 
         // The element in the slot is not the one we are looking for.
         return RCUPtr<T>();
     }
 
 private:
-    bool insert(const K &key, RCUPtr<T> value) {
+    bool insert(const KeyType &key, RCUPtr<T> value) {
         uint32_t level = TOP_LEVEL;
 
         RCULock lock;
         std::atomic<RadixElement> *eptr = &root;
 
         while (true) {
             SEEK_LEAF_LOOP();
 
             // If the slot is empty, try to insert right there.
             if (e.getLeaf() == nullptr) {
                 if (eptr->compare_exchange_strong(e,
                                                   RadixElement(value.get()))) {
                     value.release();
                     return true;
                 }
 
                 // CAS failed, we may have a node in there now.
                 if (e.isNode()) {
                     goto Node;
                 }
             }
 
             // The element was already in the tree.
-            const K &leafKey = e.getLeaf()->getId();
+            const KeyType &leafKey = e.getLeaf()->getId();
             if (key == leafKey) {
                 return false;
             }
 
             // There is an element there, but it isn't a subtree. We need to
             // convert it into a subtree and resume insertion into that subtree.
             auto newChild = std::make_unique<RadixNode>(level, leafKey, e);
             if (eptr->compare_exchange_strong(e,
                                               RadixElement(newChild.get()))) {
                 // We have a subtree, resume normal operations from there.
                 newChild.release();
             } else {
                 // We failed to insert our subtree, clean it before it is freed.
                 newChild->get(level, leafKey)->store(RadixElement());
             }
         }
     }
 
 #undef SEEK_LEAF_LOOP
 
     struct RadixElement {
     private:
         union {
             RadixNode *node;
             T *leaf;
             uintptr_t raw;
         };
 
         static const uintptr_t DISCRIMINANT = 0x01;
         bool getDiscriminant() const { return (raw & DISCRIMINANT) != 0; }
 
     public:
         explicit RadixElement() noexcept : raw(DISCRIMINANT) {}
         explicit RadixElement(RadixNode *nodeIn) noexcept : node(nodeIn) {}
         explicit RadixElement(T *leafIn) noexcept : leaf(leafIn) {
             raw |= DISCRIMINANT;
         }
 
         /**
          * RadixElement is designed to be a dumb wrapper. This allows any
          * container to release what is held by the RadixElement.
          */
         void incrementRefCount() {
             if (isNode()) {
                 RCUPtr<RadixNode>::copy(getNode()).release();
             } else {
                 RCUPtr<T>::copy(getLeaf()).release();
             }
         }
 
         void decrementRefCount() {
             if (isNode()) {
                 RadixNode *ptr = getNode();
                 RCUPtr<RadixNode>::acquire(ptr);
             } else {
                 T *ptr = getLeaf();
                 RCUPtr<T>::acquire(ptr);
             }
         }
 
         /**
          * Node features.
          */
         bool isNode() const { return !getDiscriminant(); }
 
         RadixNode *getNode() {
             assert(isNode());
             return node;
         }
 
         const RadixNode *getNode() const {
             assert(isNode());
             return node;
         }
 
         /**
          * Leaf features.
          */
         bool isLeaf() const { return getDiscriminant(); }
 
         T *getLeaf() {
             assert(isLeaf());
             return reinterpret_cast<T *>(raw & ~DISCRIMINANT);
         }
 
         const T *getLeaf() const {
             assert(isLeaf());
             return const_cast<RadixElement *>(this)->getLeaf();
         }
     };
 
     struct RadixNode {
         IMPLEMENT_RCU_REFCOUNT(uint64_t);
 
     private:
         union {
             std::array<std::atomic<RadixElement>, CHILD_PER_LEVEL> children;
             std::array<RadixElement, CHILD_PER_LEVEL>
                 non_atomic_children_DO_NOT_USE;
         };
 
     public:
-        RadixNode(uint32_t level, const K &key, RadixElement e)
+        RadixNode(uint32_t level, const KeyType &key, RadixElement e)
             : non_atomic_children_DO_NOT_USE() {
             get(level, key)->store(e);
         }
 
         ~RadixNode() {
             for (RadixElement e : non_atomic_children_DO_NOT_USE) {
                 e.decrementRefCount();
             }
         }
 
         RadixNode(const RadixNode &rhs) : non_atomic_children_DO_NOT_USE() {
             for (size_t i = 0; i < CHILD_PER_LEVEL; i++) {
                 auto e = rhs.children[i].load();
                 e.incrementRefCount();
                 non_atomic_children_DO_NOT_USE[i] = e;
             }
         }
 
         RadixNode &operator=(const RadixNode &) = delete;
 
-        std::atomic<RadixElement> *get(uint32_t level, const K &key) {
+        std::atomic<RadixElement> *get(uint32_t level, const KeyType &key) {
             return &children[(key >> (level * BITS)) & MASK];
         }
 
         bool isShared() const { return refcount > 0; }
     };
 
     // Make sure the alignment works for T and RadixElement.
     static_assert(alignof(T) > 1, "T's alignment must be 2 or more.");
     static_assert(alignof(RadixNode) > 1,
                   "RadixNode alignment must be 2 or more.");
 };
 
 #endif // BITCOIN_RADIX_H