8 files changed, 10 insertions, 10 deletions
diff --git a/src/qt/callback.h b/src/qt/callback.h
index a8b593a652..da6b0c4c2e 100644
--- a/src/qt/callback.h
+++ b/src/qt/callback.h
@@ -16,7 +16,7 @@ class FunctionCallback : public Callback
     F f;
 
 public:
-    FunctionCallback(F f_) : f(std::move(f_)) {}
+    explicit FunctionCallback(F f_) : f(std::move(f_)) {}
     ~FunctionCallback() override {}
     void call() override { f(this); }
 };
diff --git a/src/qt/coincontroldialog.h b/src/qt/coincontroldialog.h
index 99a9f893ff..4949c91771 100644
--- a/src/qt/coincontroldialog.h
+++ b/src/qt/coincontroldialog.h
@@ -30,9 +30,9 @@ namespace Ui {
 class CCoinControlWidgetItem : public QTreeWidgetItem
 {
 public:
-    CCoinControlWidgetItem(QTreeWidget *parent, int type = Type) : QTreeWidgetItem(parent, type) {}
-    CCoinControlWidgetItem(int type = Type) : QTreeWidgetItem(type) {}
-    CCoinControlWidgetItem(QTreeWidgetItem *parent, int type = Type) : QTreeWidgetItem(parent, type) {}
+    explicit CCoinControlWidgetItem(QTreeWidget *parent, int type = Type) : QTreeWidgetItem(parent, type) {}
+    explicit CCoinControlWidgetItem(int type = Type) : QTreeWidgetItem(type) {}
+    explicit CCoinControlWidgetItem(QTreeWidgetItem *parent, int type = Type) : QTreeWidgetItem(parent, type) {}
 
     bool operator<(const QTreeWidgetItem &other) const;
 };
diff --git a/src/qt/intro.cpp b/src/qt/intro.cpp
index 72809942f1..0ff95d8502 100644
--- a/src/qt/intro.cpp
+++ b/src/qt/intro.cpp
@@ -43,7 +43,7 @@ class FreespaceChecker : public QObject
     Q_OBJECT
 
 public:
-    FreespaceChecker(Intro *intro);
+    explicit FreespaceChecker(Intro *intro);
 
     enum Status {
         ST_OK,
diff --git a/src/qt/notificator.cpp b/src/qt/notificator.cpp
index 8718929c6a..a7a7a4ce11 100644
--- a/src/qt/notificator.cpp
+++ b/src/qt/notificator.cpp
@@ -93,7 +93,7 @@ class FreedesktopImage
 {
 public:
     FreedesktopImage() {}
-    FreedesktopImage(const QImage &img);
+    explicit FreedesktopImage(const QImage &img);
 
     static int metaType();
 
diff --git a/src/qt/overviewpage.cpp b/src/qt/overviewpage.cpp
index ba344f4dbf..ba1839e7b4 100644
--- a/src/qt/overviewpage.cpp
+++ b/src/qt/overviewpage.cpp
@@ -25,7 +25,7 @@ class TxViewDelegate : public QAbstractItemDelegate
 {
     Q_OBJECT
 public:
-    TxViewDelegate(const PlatformStyle *_platformStyle, QObject *parent=nullptr):
+    explicit TxViewDelegate(const PlatformStyle *_platformStyle, QObject *parent=nullptr):
         QAbstractItemDelegate(parent), unit(BitcoinUnits::BTC),
         platformStyle(_platformStyle)
     {
diff --git a/src/qt/paymentrequestplus.cpp b/src/qt/paymentrequestplus.cpp
index 0a5cb98668..d3799f59ab 100644
--- a/src/qt/paymentrequestplus.cpp
+++ b/src/qt/paymentrequestplus.cpp
@@ -22,7 +22,7 @@
 class SSLVerifyError : public std::runtime_error
 {
 public:
-    SSLVerifyError(std::string err) : std::runtime_error(err) { }
+    explicit SSLVerifyError(std::string err) : std::runtime_error(err) { }
 };
 
 bool PaymentRequestPlus::parse(const QByteArray& data)
diff --git a/src/qt/paymentserver.h b/src/qt/paymentserver.h
index f845c4c7c8..98b2364b92 100644
--- a/src/qt/paymentserver.h
+++ b/src/qt/paymentserver.h
@@ -72,7 +72,7 @@ public:
     static bool ipcSendCommandLine();
 
     // parent should be QApplication object
-    PaymentServer(QObject* parent, bool startLocalServer = true);
+    explicit PaymentServer(QObject* parent, bool startLocalServer = true);
     ~PaymentServer();
 
     // Load root certificate authorities. Pass nullptr (default)
diff --git a/src/qt/utilitydialog.h b/src/qt/utilitydialog.h
index acaa864148..738eeed136 100644
--- a/src/qt/utilitydialog.h
+++ b/src/qt/utilitydialog.h
@@ -41,7 +41,7 @@ class ShutdownWindow : public QWidget
     Q_OBJECT
 
 public:
-    ShutdownWindow(QWidget *parent=0, Qt::WindowFlags f=0);
+    explicit ShutdownWindow(QWidget *parent=0, Qt::WindowFlags f=0);
     static QWidget *showShutdownWindow(BitcoinGUI *window);
 
 protected: