diff --git a/Telegram/SourceFiles/_other/updater.cpp b/Telegram/SourceFiles/_other/updater.cpp
index dbcce31379..35dd767b44 100644
--- a/Telegram/SourceFiles/_other/updater.cpp
+++ b/Telegram/SourceFiles/_other/updater.cpp
@@ -30,18 +30,26 @@ bool equal(const wstring &a, const wstring &b) {
 
 void updateError(const WCHAR *msg, DWORD errorCode) {
 	WCHAR errMsg[2048];
-	LPWSTR errorText = NULL, errorTextDefault = L"(Unknown error)";
-	FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, errorCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPWSTR)&errorText, 0, 0);
-	if (!errorText) {
-		errorText = errorTextDefault;
-	}
+	LPWSTR errorTextFormatted = nullptr;
+	auto formatFlags = FORMAT_MESSAGE_FROM_SYSTEM
+		| FORMAT_MESSAGE_ALLOCATE_BUFFER
+		| FORMAT_MESSAGE_IGNORE_INSERTS;
+	FormatMessage(
+		formatFlags,
+		NULL,
+		errorCode,
+		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+		(LPWSTR)&errorTextFormatted,
+		0,
+		0);
+	auto errorText = errorTextFormatted
+		? errorTextFormatted
+		: L"(Unknown error)";
 	wsprintf(errMsg, L"%s, error code: %d\nError message: %s", msg, errorCode, errorText);
 
 	MessageBox(0, errMsg, L"Update error!", MB_ICONERROR);
 
-	if (errorText != errorTextDefault) {
-		LocalFree(errorText);
-	}
+	LocalFree(errorTextFormatted);
 }
 
 HANDLE _logFile = 0;
@@ -309,20 +317,20 @@ void updateRegistry() {
 								WCHAR nameStr[bufSize], dateStr[bufSize], publisherStr[bufSize], icongroupStr[bufSize];
 								SYSTEMTIME stLocalTime;
 								GetLocalTime(&stLocalTime);
-								RegSetValueEx(rkey, L"DisplayVersion", 0, REG_SZ, (BYTE*)versionStr, ((versionLen / 2) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"DisplayVersion", 0, REG_SZ, (const BYTE*)versionStr, ((versionLen / 2) + 1) * sizeof(WCHAR));
 								wsprintf(nameStr, L"Telegram Desktop version %s", versionStr);
-								RegSetValueEx(rkey, L"DisplayName", 0, REG_SZ, (BYTE*)nameStr, (wcslen(nameStr) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"DisplayName", 0, REG_SZ, (const BYTE*)nameStr, (wcslen(nameStr) + 1) * sizeof(WCHAR));
 								wsprintf(publisherStr, L"Telegram Messenger LLP");
-								RegSetValueEx(rkey, L"Publisher", 0, REG_SZ, (BYTE*)publisherStr, (wcslen(publisherStr) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"Publisher", 0, REG_SZ, (const BYTE*)publisherStr, (wcslen(publisherStr) + 1) * sizeof(WCHAR));
 								wsprintf(icongroupStr, L"Telegram Desktop");
-								RegSetValueEx(rkey, L"Inno Setup: Icon Group", 0, REG_SZ, (BYTE*)icongroupStr, (wcslen(icongroupStr) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"Inno Setup: Icon Group", 0, REG_SZ, (const BYTE*)icongroupStr, (wcslen(icongroupStr) + 1) * sizeof(WCHAR));
 								wsprintf(dateStr, L"%04d%02d%02d", stLocalTime.wYear, stLocalTime.wMonth, stLocalTime.wDay);
-								RegSetValueEx(rkey, L"InstallDate", 0, REG_SZ, (BYTE*)dateStr, (wcslen(dateStr) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"InstallDate", 0, REG_SZ, (const BYTE*)dateStr, (wcslen(dateStr) + 1) * sizeof(WCHAR));
 
-								WCHAR *appURL = L"https://desktop.telegram.org";
-								RegSetValueEx(rkey, L"HelpLink", 0, REG_SZ, (BYTE*)appURL, (wcslen(appURL) + 1) * sizeof(WCHAR));
-								RegSetValueEx(rkey, L"URLInfoAbout", 0, REG_SZ, (BYTE*)appURL, (wcslen(appURL) + 1) * sizeof(WCHAR));
-								RegSetValueEx(rkey, L"URLUpdateInfo", 0, REG_SZ, (BYTE*)appURL, (wcslen(appURL) + 1) * sizeof(WCHAR));
+								const WCHAR *appURL = L"https://desktop.telegram.org";
+								RegSetValueEx(rkey, L"HelpLink", 0, REG_SZ, (const BYTE*)appURL, (wcslen(appURL) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"URLInfoAbout", 0, REG_SZ, (const BYTE*)appURL, (wcslen(appURL) + 1) * sizeof(WCHAR));
+								RegSetValueEx(rkey, L"URLUpdateInfo", 0, REG_SZ, (const BYTE*)appURL, (wcslen(appURL) + 1) * sizeof(WCHAR));
 							}
 						}
 					}
diff --git a/Telegram/SourceFiles/platform/win/main_window_win.cpp b/Telegram/SourceFiles/platform/win/main_window_win.cpp
index 33f6b5ae63..02ef443571 100644
--- a/Telegram/SourceFiles/platform/win/main_window_win.cpp
+++ b/Telegram/SourceFiles/platform/win/main_window_win.cpp
@@ -526,7 +526,7 @@ private:
 	BYTE r = 0, g = 0, b = 0;
 	COLORREF noKeyColor;
 
-	static LRESULT CALLBACK _PsShadowWindows::wndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
+	static LRESULT CALLBACK wndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
 
 };
 _PsShadowWindows _psShadowWindows;
diff --git a/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp b/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp
index 1c67bf2997..bf0525682e 100644
--- a/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp
+++ b/Telegram/SourceFiles/platform/win/notifications_manager_win.cpp
@@ -209,10 +209,16 @@ typedef ABI::Windows::Foundation::ITypedEventHandler<ToastNotification*, ::IInsp
 typedef ABI::Windows::Foundation::ITypedEventHandler<ToastNotification*, ToastDismissedEventArgs*> DesktopToastDismissedEventHandler;
 typedef ABI::Windows::Foundation::ITypedEventHandler<ToastNotification*, ToastFailedEventArgs*> DesktopToastFailedEventHandler;
 
-class ToastEventHandler : public Implements<DesktopToastActivatedEventHandler, DesktopToastDismissedEventHandler, DesktopToastFailedEventHandler> {
+class ToastEventHandler : public Implements<
+	DesktopToastActivatedEventHandler,
+	DesktopToastDismissedEventHandler,
+	DesktopToastFailedEventHandler> {
 public:
 	// We keep a weak pointer to a member field of native notifications manager.
-	ToastEventHandler::ToastEventHandler(const std::shared_ptr<Manager*> &guarded, const PeerId &peer, MsgId msg)
+	ToastEventHandler(
+		const std::shared_ptr<Manager*> &guarded,
+		const PeerId &peer,
+		MsgId msg)
 	: _peerId(peer)
 	, _msgId(msg)
 	, _weak(guarded) {
@@ -607,8 +613,8 @@ void queryQuietHours() {
 		return;
 	}
 
-	LPTSTR lpKeyName = L"Software\\Microsoft\\Windows\\CurrentVersion\\Notifications\\Settings";
-	LPTSTR lpValueName = L"NOC_GLOBAL_SETTING_TOASTS_ENABLED";
+	LPCWSTR lpKeyName = L"Software\\Microsoft\\Windows\\CurrentVersion\\Notifications\\Settings";
+	LPCWSTR lpValueName = L"NOC_GLOBAL_SETTING_TOASTS_ENABLED";
 	HKEY key;
 	auto result = RegOpenKeyEx(HKEY_CURRENT_USER, lpKeyName, 0, KEY_READ, &key);
 	if (result != ERROR_SUCCESS) {
diff --git a/Telegram/SourceFiles/platform/win/specific_win.cpp b/Telegram/SourceFiles/platform/win/specific_win.cpp
index 9d04deaafe..eef41923bb 100644
--- a/Telegram/SourceFiles/platform/win/specific_win.cpp
+++ b/Telegram/SourceFiles/platform/win/specific_win.cpp
@@ -532,15 +532,23 @@ QString SystemLanguage() {
 
 namespace {
 	void _psLogError(const char *str, LSTATUS code) {
-		LPTSTR errorText = NULL, errorTextDefault = L"(Unknown error)";
-		FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&errorText, 0, 0);
-		if (!errorText) {
-			errorText = errorTextDefault;
-		}
+		LPWSTR errorTextFormatted = nullptr;
+		auto formatFlags = FORMAT_MESSAGE_FROM_SYSTEM
+			| FORMAT_MESSAGE_ALLOCATE_BUFFER
+			| FORMAT_MESSAGE_IGNORE_INSERTS;
+		FormatMessage(
+			formatFlags,
+			NULL,
+			code,
+			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+			(LPTSTR)&errorTextFormatted,
+			0,
+			0);
+		auto errorText = errorTextFormatted
+			? errorTextFormatted
+			: L"(Unknown error)";
 		LOG((str).arg(code).arg(QString::fromStdWString(errorText)));
-		if (errorText != errorTextDefault) {
-			LocalFree(errorText);
-		}
+		LocalFree(errorTextFormatted);
 	}
 
 	bool _psOpenRegKey(LPCWSTR key, PHKEY rkey) {
diff --git a/Telegram/SourceFiles/rpl/variable.h b/Telegram/SourceFiles/rpl/variable.h
index 049a468798..f98a5a3d17 100644
--- a/Telegram/SourceFiles/rpl/variable.h
+++ b/Telegram/SourceFiles/rpl/variable.h
@@ -24,6 +24,26 @@ Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
 #include <rpl/event_stream.h>
 
 namespace rpl {
+namespace details {
+
+template <typename A, typename B>
+struct supports_equality_compare {
+	template <typename U, typename V>
+	static auto test(const U *u, const V *v)
+		-> decltype(*u == *v, details::true_t());
+	static details::false_t test(...);
+	static constexpr bool value
+		= (sizeof(test(
+		(std::decay_t<A>*)nullptr,
+			(std::decay_t<B>*)nullptr
+		)) == sizeof(details::true_t));
+};
+
+template <typename A, typename B>
+constexpr bool supports_equality_compare_v
+	= supports_equality_compare<A, B>::value;
+
+} // namespace details
 
 template <typename Type>
 class variable final {
@@ -86,30 +106,14 @@ public:
 	}
 
 private:
-	template <typename A, typename B>
-	struct supports_equality_compare {
-		template <typename U, typename V>
-		static auto test(const U *u, const V *v)
-			-> decltype(*u == *v, details::true_t());
-		static details::false_t test(...);
-		static constexpr bool value
-			= (sizeof(test(
-				(std::decay_t<A>*)nullptr,
-				(std::decay_t<B>*)nullptr
-			)) == sizeof(details::true_t));
-	};
-	template <typename A, typename B>
-	static constexpr bool supports_equality_compare_v
-		= supports_equality_compare<A, B>::value;
-
 	template <typename OtherType>
 	variable &assign(OtherType &&data) {
-		if constexpr (supports_equality_compare_v<Type, OtherType>) {
+		if constexpr (details::supports_equality_compare_v<Type, OtherType>) {
 			if (!(_data == data)) {
 				_data = std::forward<OtherType>(data);
 				_changes.fire_copy(_data);
 			}
-		} else if constexpr (supports_equality_compare_v<Type, Type>) {
+		} else if constexpr (details::supports_equality_compare_v<Type, Type>) {
 			auto old = std::move(_data);
 			_data = std::forward<OtherType>(data);
 			if (!(_data == old)) {
diff --git a/Telegram/SourceFiles/ui/text/text.cpp b/Telegram/SourceFiles/ui/text/text.cpp
index 10c7962b60..3b655aa029 100644
--- a/Telegram/SourceFiles/ui/text/text.cpp
+++ b/Telegram/SourceFiles/ui/text/text.cpp
@@ -663,8 +663,13 @@ private:
 	};
 
 	void computeLinkText(const QString &linkData, QString *outLinkText, LinkDisplayStatus *outDisplayStatus) {
-		QUrl url(linkData), good(url.isValid() ? url.toEncoded() : "");
-		QString readable = good.isValid() ? good.toDisplayString() : linkData;
+		auto url = QUrl(linkData);
+		auto good = QUrl(url.isValid()
+			? url.toEncoded()
+			: QByteArray());
+		auto readable = good.isValid()
+			? good.toDisplayString()
+			: linkData;
 		*outLinkText = _t->_st->font->elided(readable, st::linkCropLimit);
 		*outDisplayStatus = (*outLinkText == readable) ? LinkDisplayedFull : LinkDisplayedElided;
 	}
diff --git a/Telegram/gyp/settings_win.gypi b/Telegram/gyp/settings_win.gypi
index 247e3afd72..be93f25a66 100644
--- a/Telegram/gyp/settings_win.gypi
+++ b/Telegram/gyp/settings_win.gypi
@@ -37,6 +37,7 @@
           'DebugInformationFormat': '3',          # Program Database (/Zi)
           'AdditionalOptions': [
             '/std:c++latest',
+			'/permissive-',
             '/MP',     # Enable multi process build.
             '/EHsc',   # Catch C++ exceptions only, extern C functions never throw a C++ exception.
             '/WX',     # Treat warnings as errors.