diff --git a/src/qt/clientmodel.cpp b/src/qt/clientmodel.cpp
--- a/src/qt/clientmodel.cpp
+++ b/src/qt/clientmodel.cpp
@@ -18,6 +18,7 @@
 #include "ui_interface.h"
 #include "util.h"
 #include "validation.h"
+#include "warnings.h"
 
 #include <cstdint>
 
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -26,6 +26,7 @@
 #include "utilstrencodings.h"
 #include "validation.h"
 #include "validationinterface.h"
+#include "warnings.h"
 
 #include <univalue.h>
 
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -22,6 +22,7 @@
 #include "wallet/wallet.h"
 #include "wallet/walletdb.h"
 #endif
+#include "warnings.h"
 
 #include <univalue.h>
 
diff --git a/src/rpc/net.cpp b/src/rpc/net.cpp
--- a/src/rpc/net.cpp
+++ b/src/rpc/net.cpp
@@ -19,6 +19,7 @@
 #include "utilstrencodings.h"
 #include "validation.h"
 #include "version.h"
+#include "warnings.h"
 
 #include <univalue.h>
 
diff --git a/src/validation.h b/src/validation.h
--- a/src/validation.h
+++ b/src/validation.h
@@ -388,19 +388,6 @@
  */
 bool IsInitialBlockDownload();
 
-/**
- * Format a string that describes several potential problems detected by the
- * core.
- * strFor can have three values:
- * - "rpc": get critical warnings, which should put the client in safe mode if
- * non-empty
- * - "statusbar": get all warnings
- * - "gui": get all warnings, translated (where possible) for GUI
- * This function only returns the highest priority warning of the set selected
- * by strFor.
- */
-std::string GetWarnings(const std::string &strFor);
-
 /**
  * Retrieve a transaction (from memory pool, or from disk, if possible).
  */
diff --git a/src/warnings.h b/src/warnings.h
--- a/src/warnings.h
+++ b/src/warnings.h
@@ -13,6 +13,17 @@
 void SetfLargeWorkForkFound(bool flag);
 bool GetfLargeWorkForkFound();
 void SetfLargeWorkInvalidChainFound(bool flag);
+/**
+ * Format a string that describes several potential problems detected by the
+ * core.
+ * strFor can have three values:
+ * - "rpc": get critical warnings, which should put the client in safe mode if
+ * non-empty
+ * - "statusbar": get all warnings
+ * - "gui": get all warnings, translated (where possible) for GUI
+ * This function only returns the highest priority warning of the set selected
+ * by strFor.
+ */
 std::string GetWarnings(const std::string &strFor);
 
 static const bool DEFAULT_TESTSAFEMODE = false;