Remove another aspect of ImageView that was deprecated in 2019.10.

This got deprecated in 069c81b9cb but
without any visible documentation bit, so it was almost impossible to
trace back to a particular version. Or know about it when using the API.

doc/changelog.dox

@@ -1751,6 +1751,9 @@ See also:
     -   Templated @cpp Image*::data() @ce APIs returning a pointer which
         allowed for dangerous data access without any bounds, type or layout
         checks, use @ref Image::pixels() instead
+    -   Passing empty data with a non-zero size to @ref ImageView constructors,
+        which caused a runtime deprecation warning, is not allowed anymore. Use
+        a constructor without the data parameter instead.
     -   @cpp GL::TextureFormat::R3B3G2 @ce containing a typo, use
         @ref GL::TextureFormat::R3G3B2 instead
     -   @cpp Platform::GlfwApplication::Key::Smicolon @ce containing a typo,

src/Magnum/ImageView.cpp

@@ -36,15 +36,7 @@ template<UnsignedInt dimensions, class T> ImageView<dimensions, T>::ImageView(co
 template<UnsignedInt dimensions, class T> ImageView<dimensions, T>::ImageView(const PixelStorage storage, const UnsignedInt format, const UnsignedInt formatExtra, const UnsignedInt pixelSize, const VectorTypeFor<dimensions, Int>& size, const Containers::ArrayView<ErasedType> data, const ImageFlags<dimensions> flags) noexcept: ImageView{storage, pixelFormatWrap(format), formatExtra, pixelSize, size, data, flags} {}
 
 template<UnsignedInt dimensions, class T> ImageView<dimensions, T>::ImageView(const PixelStorage storage, const PixelFormat format, const UnsignedInt formatExtra, const UnsignedInt pixelSize, const VectorTypeFor<dimensions, Int>& size, const Containers::ArrayView<ErasedType> data, const ImageFlags<dimensions> flags) noexcept: _storage{storage}, _format{format}, _formatExtra{formatExtra}, _pixelSize{pixelSize}, _flags{flags}, _size{size}, _data{reinterpret_cast<Type*>(data.data()), data.size()} {
-    #ifdef MAGNUM_BUILD_DEPRECATED
-    #ifndef CORRADE_NO_ASSERT
-    if(size.product() && !_data && !_data.size())
-        Warning{} << "ImageView: passing empty data to a non-empty view is deprecated, use a constructor without the data parameter instead";
-    #endif
-    CORRADE_ASSERT(!_data || Implementation::imageDataSize(*this) <= _data.size(), "ImageView: data too small, got" << _data.size() << "but expected at least" << Implementation::imageDataSize(*this) << "bytes", );
-    #else
     CORRADE_ASSERT(Implementation::imageDataSize(*this) <= _data.size(), "ImageView: data too small, got" << _data.size() << "but expected at least" << Implementation::imageDataSize(*this) << "bytes", );
-    #endif
     #ifndef CORRADE_NO_ASSERT
     Implementation::checkImageFlagsForSize("ImageView:", flags, size);
     #endif

src/Magnum/Test/ImageViewTest.cpp

@@ -657,16 +657,12 @@ void ImageViewTest::constructCompressedFromMutable() {
 }
 
 void ImageViewTest::constructNullptr() {
-    #ifdef MAGNUM_BUILD_DEPRECATED
-    CORRADE_SKIP("This is still allowed on a deprecated build, can't test.");
-    #elif defined(CORRADE_NO_ASSERT)
-    CORRADE_SKIP("CORRADE_NO_ASSERT defined, can't test assertions");
-    #else
+    CORRADE_SKIP_IF_NO_ASSERT();
+
     Containers::String out;
     Error redirectError{&out};
     ImageView2D{PixelFormat::RGB8Unorm, {1, 3},  nullptr};
     CORRADE_COMPARE(out, "ImageView: data too small, got 0 but expected at least 12 bytes\n");
-    #endif
 }
 
 void ImageViewTest::constructInvalidSize() {