Trade: actually, do it like this.

src/Magnum/Trade/MeshData.cpp

@@ -133,30 +133,27 @@ MeshData::MeshData(const MeshPrimitive primitive, Containers::Array<char>&& inde
             "Trade::MeshData: attribute" << i << "has" << attribute._vertexCount << "vertices but" << expectedAttributeVertexCount << "expected", );
         /* Check that the view fits into the provided vertex data array. For
            implementation-specific formats we don't know the size so use 0 to
-           check at least partially. */
+           check at least partially. If the mesh has zero vertices, we don't
+           check anything -- accessing the memory would be invalid anyway and
+           enforcing this would lead to unnecessary friction with interleaved
+           attributes of empty meshes. */
+        if(_vertexCount) {
             const UnsignedInt typeSize =
                 isVertexFormatImplementationSpecific(attribute._format) ? 0 :
                 (vertexFormatSize(attribute._format)*
                 (attribute._arraySize ? attribute._arraySize : 1));
             if(attribute._isOffsetOnly) {
                 const std::size_t size = attribute._data.offset + (_vertexCount - 1)*attribute._stride + typeSize;
-            /* For meshes with zero vertices we don't check the pointer, since
+                CORRADE_ASSERT(size <= _vertexData.size(),
-               accessing the memory is invalid anyway and enforcing this would
-               lead to unnecessary friction with interleaved attributes of
-               empty meshes. */
-            CORRADE_ASSERT(!_vertexCount || size <= _vertexData.size(),
                     "Trade::MeshData: offset-only attribute" << i << "spans" << size << "bytes but passed vertexData array has only" << _vertexData.size(), );
             } else {
                 const void* const begin = static_cast<const char*>(attribute._data.pointer);
                 const void* const end = static_cast<const char*>(attribute._data.pointer) + (_vertexCount - 1)*attribute._stride + typeSize;
-            /* For meshes with zero vertices we don't check the pointer, since
+                CORRADE_ASSERT(begin >= _vertexData.begin() && end <= _vertexData.end(),
-               accessing the memory is invalid anyway and enforcing this would
-               lead to unnecessary friction with interleaved attributes of
-               empty meshes. */
-            CORRADE_ASSERT(!_vertexCount || (begin >= _vertexData.begin() && end <= _vertexData.end()),
                     "Trade::MeshData: attribute" << i << "[" << Debug::nospace << begin << Debug::nospace << ":" << Debug::nospace << end << Debug::nospace << "] is not contained in passed vertexData array [" << Debug::nospace << static_cast<const void*>(_vertexData.begin()) << Debug::nospace << ":" << Debug::nospace << static_cast<const void*>(_vertexData.end()) << Debug::nospace << "]", );
             }
         }
+    }
     #endif
 }