diff --git a/src/coins.h b/src/coins.h
--- a/src/coins.h
+++ b/src/coins.h
@@ -170,12 +170,12 @@
 
 public:
     CCoinsViewBacked(CCoinsView *viewIn);
-    bool GetCoin(const COutPoint &outpoint, Coin &coin) const;
-    bool HaveCoin(const COutPoint &outpoint) const;
-    uint256 GetBestBlock() const;
+    bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
+    bool HaveCoin(const COutPoint &outpoint) const override;
+    uint256 GetBestBlock() const override;
     void SetBackend(CCoinsView &viewIn);
-    bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
-    CCoinsViewCursor *Cursor() const;
+    bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override;
+    CCoinsViewCursor *Cursor() const override;
     size_t EstimateSize() const override;
 };
 
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -48,7 +48,7 @@
         return true;
     }
 
-    bool HaveCoin(const COutPoint outpoint) const {
+    bool HaveCoin(const COutPoint &outpoint) const {
         Coin coin;
         return GetCoin(outpoint, coin);
     }
@@ -96,7 +96,7 @@
     CCoinsMap &map() { return cacheCoins; }
     size_t &usage() { return cachedCoinsUsage; }
 };
-}
+} // namespace
 
 BOOST_FIXTURE_TEST_SUITE(coins_tests, BasicTestingSetup)
 
diff --git a/src/txdb.h b/src/txdb.h
--- a/src/txdb.h
+++ b/src/txdb.h
@@ -71,11 +71,11 @@
 public:
     CCoinsViewDB(size_t nCacheSize, bool fMemory = false, bool fWipe = false);
 
-    bool GetCoin(const COutPoint &outpoint, Coin &coin) const;
-    bool HaveCoin(const COutPoint &outpoint) const;
-    uint256 GetBestBlock() const;
-    bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
-    CCoinsViewCursor *Cursor() const;
+    bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
+    bool HaveCoin(const COutPoint &outpoint) const override;
+    uint256 GetBestBlock() const override;
+    bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override;
+    CCoinsViewCursor *Cursor() const override;
 
     //! Attempt to update from an older database format.
     //! Returns whether an error occurred.