diff --git a/src/ai/ai_gui.cpp b/src/ai/ai_gui.cpp
index 3cfee3f6a5..bf03a47600 100644
--- a/src/ai/ai_gui.cpp
+++ b/src/ai/ai_gui.cpp
@@ -318,7 +318,7 @@ struct AISettingsWindow : public Window {
 				SetDParam(idx++, current_value == 0 ? STR_CONFIG_SETTING_OFF : STR_CONFIG_SETTING_ON);
 			} else {
 				DrawArrowButtons(buttons_left, y + 2, COLOUR_YELLOW, (this->clicked_button == i) ? 1 + (this->clicked_increase != rtl) : 0, editable && current_value > (*it).min_value, editable && current_value < (*it).max_value);
-				if (it->labels != NULL && it->labels->Find(current_value) != it->labels->End()) {
+				if (it->labels != NULL && it->labels->Contains(current_value)) {
 					SetDParam(idx++, STR_JUST_RAW_STRING);
 					SetDParamStr(idx++, it->labels->Find(current_value)->second);
 				} else {
diff --git a/src/ai/ai_info.cpp b/src/ai/ai_info.cpp
index ff5dca946b..54725cd487 100644
--- a/src/ai/ai_info.cpp
+++ b/src/ai/ai_info.cpp
@@ -307,7 +307,8 @@ SQInteger AIInfo::AddLabels(HSQUIRRELVM vm)
 		int key = atoi(key_string + 1);
 		const char *label = SQ2OTTD(sq_label);
 
-		if (config->labels->Find(key) == config->labels->End()) config->labels->Insert(key, strdup(label));
+		/* !Contains() prevents strdup from leaking. */
+		if (!config->labels->Contains(key)) config->labels->Insert(key, strdup(label));
 
 		sq_pop(vm, 2);
 	}
diff --git a/src/core/smallmap_type.hpp b/src/core/smallmap_type.hpp
index 8689447c14..7c01866894 100644
--- a/src/core/smallmap_type.hpp
+++ b/src/core/smallmap_type.hpp
@@ -54,6 +54,16 @@ struct SmallMap : SmallVector<SmallPair<T, U>, S> {
 		return this->End();
 	}
 
+	/**
+	 * Tests whether a key is assigned in this map.
+	 * @param key key to test
+	 * @return true iff the item is present
+	 */
+	FORCEINLINE bool Contains(const T &key)
+	{
+		return this->Find(key) != this->End();
+	}
+
 	/**
 	 * Removes given pair from this map
 	 * @param pair pair to remove
@@ -90,7 +100,7 @@ struct SmallMap : SmallVector<SmallPair<T, U>, S> {
 	 */
 	FORCEINLINE bool Insert(const T &key, const U &data)
 	{
-		if (this->Find(key) != this->End()) return false;
+		if (this->Contains(key)) return false;
 		Pair *n = this->Append();
 		n->first = key;
 		n->second = data;
diff --git a/src/network/core/address.cpp b/src/network/core/address.cpp
index 586ee863a9..57edf50cb5 100644
--- a/src/network/core/address.cpp
+++ b/src/network/core/address.cpp
@@ -212,7 +212,7 @@ SOCKET NetworkAddress::Resolve(int family, int socktype, int flags, SocketList *
 		 * ofcourse totally unneeded ;) */
 		if (sockets != NULL) {
 			NetworkAddress address(runp->ai_addr, (int)runp->ai_addrlen);
-			if (sockets->Find(address) != sockets->End()) continue;
+			if (sockets->Contains(address)) continue;
 		}
 		sock = func(runp);
 		if (sock == INVALID_SOCKET) continue;
diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
index 2ec921d085..0e7934b68b 100644
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -258,7 +258,7 @@ struct NewGRFParametersWindow : public Window {
 				DrawArrowButtons(buttons_left, y + 2, COLOUR_YELLOW, (this->clicked_button == i) ? 1 + (this->clicked_increase != rtl) : 0, current_value > par_info->min_value, current_value < par_info->max_value);
 				SetDParam(2, STR_JUST_INT);
 				SetDParam(3, current_value);
-				if (par_info->value_names.Find(current_value) != par_info->value_names.End()) {
+				if (par_info->value_names.Contains(current_value)) {
 					const char *label = GetGRFStringFromGRFText(par_info->value_names.Find(current_value)->second);
 					if (label != NULL) {
 						SetDParam(2, STR_JUST_RAW_STRING);