diff --git a/src/daemon/daemon.h b/src/daemon/daemon.h
index 561cb4d9d..655ca8a3d 100644
--- a/src/daemon/daemon.h
+++ b/src/daemon/daemon.h
@@ -31,7 +31,7 @@
 
 namespace daemonize {
 
-class t_internals;
+struct t_internals;
 
 class t_daemon final {
 public:
diff --git a/src/wallet/api/address_book.h b/src/wallet/api/address_book.h
index 33d06a078..5f72c5860 100644
--- a/src/wallet/api/address_book.h
+++ b/src/wallet/api/address_book.h
@@ -32,8 +32,7 @@
 #include "wallet/wallet2.h"
 
 namespace Monero {
-    
-class AddressBookRow;
+
 class WalletImpl;
 
 class AddressBookImpl : public AddressBook
diff --git a/src/wallet/api/transaction_history.h b/src/wallet/api/transaction_history.h
index bd18e9440..37c9ea0e4 100644
--- a/src/wallet/api/transaction_history.h
+++ b/src/wallet/api/transaction_history.h
@@ -33,7 +33,6 @@
 
 namespace Monero {
 
-class TransactionInfo;
 class WalletImpl;
 
 class TransactionHistoryImpl : public TransactionHistory
diff --git a/src/wallet/api/wallet.h b/src/wallet/api/wallet.h
index 6c0b8ef23..4520f2565 100644
--- a/src/wallet/api/wallet.h
+++ b/src/wallet/api/wallet.h
@@ -123,7 +123,7 @@ private:
 private:
     friend class PendingTransactionImpl;
     friend class TransactionHistoryImpl;
-    friend class Wallet2CallbackImpl;
+    friend struct Wallet2CallbackImpl;
     friend class AddressBookImpl;
 
     tools::wallet2 * m_wallet;