diff --git a/command_buffer.cpp b/command_buffer.cpp
index ae21a5f..60bed16 100644
--- a/command_buffer.cpp
+++ b/command_buffer.cpp
@@ -20,6 +20,8 @@
 #include "./event.hpp"
 #include "./pipeline.hpp"
 
+#include <cruft/util/cast.hpp>
+
 using vk::command_buffer;
 
 
@@ -117,9 +119,9 @@ command_buffer::wait (util::view<const event*> events,
                       util::view<const VkImageMemoryBarrier*> VkImageMemoryBarriers)
 {
     vkCmdWaitEvents (id (),
-                     events.size (), &events.cbegin ()->id (),
+                     trunc_cast<uint32_t> (events.size ()), &events.cbegin ()->id (),
                      src_mask, dst_mask,
-                     VkMemoryBarriers.size (), VkMemoryBarriers.cbegin (),
-                     VkBufferMemoryBarriers.size (), VkBufferMemoryBarriers.cbegin (),
-                     VkImageMemoryBarriers.size (), VkImageMemoryBarriers.cbegin ());
+                     trunc_cast<uint32_t> (VkMemoryBarriers.size ()), VkMemoryBarriers.cbegin (),
+                     trunc_cast<uint32_t> (VkBufferMemoryBarriers.size ()), VkBufferMemoryBarriers.cbegin (),
+                     trunc_cast<uint32_t> (VkImageMemoryBarriers.size ()), VkImageMemoryBarriers.cbegin ());
 }
diff --git a/device.cpp b/device.cpp
index 3911ef9..6e7e331 100644
--- a/device.cpp
+++ b/device.cpp
@@ -19,6 +19,9 @@
 
 #include "./physical_device.hpp"
 
+#include <cruft/util/cast.hpp>
+#include <cruft/util/debug.hpp>
+
 using vk::device;
 
 
@@ -44,7 +47,9 @@ void
 device::flush (const VkMappedMemoryRange *first,
                const VkMappedMemoryRange *last)
 {
-    auto err = vkFlushMappedMemoryRanges (id (), last - first, first);
+    CHECK_LE (first, last);
+
+    auto err = vkFlushMappedMemoryRanges (id (), trunc_cast<uint32_t> (last - first), first);
     error::try_code (err);
 }
 
@@ -54,7 +59,9 @@ void
 device::invalidate (const VkMappedMemoryRange *first,
                     const VkMappedMemoryRange *last)
 {
-    auto err = vkInvalidateMappedMemoryRanges (id (), last - first, first);
+    CHECK_LE (first, last);
+
+    auto err = vkInvalidateMappedMemoryRanges (id (), trunc_cast<uint32_t> (last - first), first);
     error::try_code (err);
 }
 
diff --git a/fence.cpp b/fence.cpp
index 152a4a6..23d60ed 100644
--- a/fence.cpp
+++ b/fence.cpp
@@ -19,6 +19,9 @@
 
 #include "./device.hpp"
 
+#include <cruft/util/cast.hpp>
+#include <cruft/util/debug.hpp>
+
 using vk::fence;
 
 
@@ -36,7 +39,9 @@ fence::is_ready (const device &dev)
 void
 fence::reset (const device &dev, fence *first, fence *last)
 {
-    vkResetFences (dev.id (), last - first, &first->id ());
+    CHECK_LE (first, last);
+
+    vkResetFences (dev.id (), trunc_cast<uint32_t> (last - first), &first->id ());
 }
 
 
@@ -44,7 +49,9 @@ fence::reset (const device &dev, fence *first, fence *last)
 void
 fence::wait (const device &d, fence *first, fence *last, uint64_t timeout)
 {
-    vkWaitForFences (d.id (), last - first, &first->id (), VK_FALSE, timeout);
+    CHECK_LE (first, last);
+
+    vkWaitForFences (d.id (), trunc_cast<uint32_t> (last - first), &first->id (), VK_FALSE, timeout);
 }
 
 
@@ -52,5 +59,7 @@ fence::wait (const device &d, fence *first, fence *last, uint64_t timeout)
 void
 fence::wait_all (const device &d, fence *first, fence *last, uint64_t timeout)
 {
-    vkWaitForFences (d.id (), last - first, &first->id (), VK_TRUE, timeout);
+    CHECK_LE (first, last);
+
+    vkWaitForFences (d.id (), trunc_cast<uint32_t> (last - first), &first->id (), VK_TRUE, timeout);
 }