Assert that Vulkan array-getters return the same length

Originally introduced in [#489] this inserts the array-length equality
check everywhere else: in the supposedly invalid and inexistant event
where Vulkan suddenly returns less items (`count` has been modified)
than were originally queried through respective `_len()` functions (or
more likely: a slice of invalid length passed by the user) and some
elements at the end of the slice are left uninitialized, panic.

Wherever there is valid concern or possibility for this to happen - or
to circumvent assertions and panics altogether - mutable references to
mutable slices should be passed allowing the length to be promptly
updated.

[#489]: #489 (comment)

ash/src/device.rs

@@ -328,6 +328,7 @@ impl Device {
             &mut count,
             out.as_mut_ptr(),
         );
+        assert_eq!(count, out.len() as u32);
     }
 
     #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/vkTrimCommandPool.html>"]

ash/src/extensions/khr/get_memory_requirements2.rs

@@ -70,6 +70,7 @@ impl GetMemoryRequirements2 {
             &mut count,
             out.as_mut_ptr(),
         );
+        assert_eq!(count, out.len() as u32);
     }
 
     pub fn name() -> &'static CStr {

ash/src/extensions/khr/get_physical_device_properties2.rs

@@ -107,6 +107,7 @@ impl GetPhysicalDeviceProperties2 {
             &mut count,
             out.as_mut_ptr(),
         );
+        assert_eq!(count, out.len() as u32);
     }
 
     /// Retrieve the number of elements to pass to [`Self::get_physical_device_sparse_image_format_properties2()`]
@@ -144,6 +145,7 @@ impl GetPhysicalDeviceProperties2 {
                 &mut count,
                 out.as_mut_ptr(),
             );
+        assert_eq!(count, out.len() as u32);
     }
 
     pub fn name() -> &'static CStr {

ash/src/instance.rs

@@ -67,10 +67,12 @@ impl Instance {
         &self,
         out: &mut [vk::PhysicalDeviceGroupProperties],
     ) -> VkResult<()> {
-        let mut group_count = out.len() as u32;
+        let mut count = out.len() as u32;
         self.instance_fn_1_1
-            .enumerate_physical_device_groups(self.handle(), &mut group_count, out.as_mut_ptr())
-            .result()
+            .enumerate_physical_device_groups(self.handle(), &mut count, out.as_mut_ptr())
+            .result()?;
+        assert_eq!(count, out.len() as u32);
+        Ok(())
     }
 
     #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/vkGetPhysicalDeviceFeatures2.html>"]
@@ -144,13 +146,14 @@ impl Instance {
         physical_device: vk::PhysicalDevice,
         out: &mut [vk::QueueFamilyProperties2],
     ) {
-        let mut queue_count = out.len() as u32;
+        let mut count = out.len() as u32;
         self.instance_fn_1_1
             .get_physical_device_queue_family_properties2(
                 physical_device,
-                &mut queue_count,
+                &mut count,
                 out.as_mut_ptr(),
             );
+        assert_eq!(count, out.len() as u32);
     }
 
     #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/vkGetPhysicalDeviceMemoryProperties2.html>"]
@@ -190,14 +193,15 @@ impl Instance {
         format_info: &vk::PhysicalDeviceSparseImageFormatInfo2,
         out: &mut [vk::SparseImageFormatProperties2],
     ) {
-        let mut format_count = out.len() as u32;
+        let mut count = out.len() as u32;
         self.instance_fn_1_1
             .get_physical_device_sparse_image_format_properties2(
                 physical_device,
                 format_info,
-                &mut format_count,
+                &mut count,
                 out.as_mut_ptr(),
             );
+        assert_eq!(count, out.len() as u32);
     }
 
     #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/vkGetPhysicalDeviceExternalBufferProperties.html>"]