Use shimmed std::as_const instead of qAsConst

include/stdshims.h

@@ -5,11 +5,12 @@
 #define STDSHIMS_H
 
 #include <memory>
+#include <type_traits>
 #include <utility>
 
 #if (__cplusplus >= 201402L || _MSC_VER)
 #ifndef _MSC_VER
-#warning "This file should now be removed! The functions it provides are part of the C++14 standard."
+#warning "This part of this file should now be removed! The functions it provides are part of the C++14 standard."
 #endif
 using std::make_unique;
 
@@ -30,5 +31,24 @@ std::unique_ptr<T, Deleter> make_unique(Args&&... args)
 }
 #endif
 
+#if (__cplusplus >= 201703L || _MSC_VER >= 1914)
+#ifndef _MSC_VER
+#warning "This part of this file should now be removed! The functions it provides are part of the C++17 standard."
+#endif
+using std::as_const;
+
+#else
+
+/// Shim for http://en.cppreference.com/w/cpp/utility/as_const
+template <typename T>
+constexpr typename std::add_const<T>::type& as_const(T& t) noexcept
+{
+    return t;
+}
+
+template <typename T>
+void as_const(const T&&) = delete;
+#endif
+
 #endif // include guard
 

src/gui/widgets/ControlLayout.cpp

@@ -73,6 +73,8 @@
 
 #include "ControlLayout.h"
 
+#include "stdshims.h"
+
 #include <QWidget>
 #include <QLayoutItem>
 #include <QLineEdit>
@@ -208,7 +210,7 @@ QSize ControlLayout::minimumSize() const
 	// get maximum height and width for all children.
 	// as Qt will later call heightForWidth, only the width here really matters
 	QSize size;
-	for (const QLayoutItem *item : qAsConst(m_itemMap))
+	for (const QLayoutItem *item : as_const(m_itemMap))
 	{
 		size = size.expandedTo(item->minimumSize());
 	}