Replace as *... raw pointer-type changes with more explicit `.cast(…

…)` (#685)

`.cast()` allows changing the pointer type without hiding (accidental)
mutability changes (noting that `*mut` still coerces to `*.const`).

For mutability changes Rust 1.65 included `cast_mut()` and
`cast_const()`, but those would bump our MSRV too eagerly for now.

ash-window/src/lib.rs

@@ -51,7 +51,7 @@ pub unsafe fn create_surface(
 
         (RawDisplayHandle::Xlib(display), RawWindowHandle::Xlib(window)) => {
             let surface_desc = vk::XlibSurfaceCreateInfoKHR::builder()
-                .dpy(display.display as *mut _)
+                .dpy(display.display.cast())
                 .window(window.window);
             let surface_fn = khr::XlibSurface::new(entry, instance);
             surface_fn.create_xlib_surface(&surface_desc, allocation_callbacks)
@@ -77,7 +77,7 @@ pub unsafe fn create_surface(
             use raw_window_metal::{appkit, Layer};
 
             let layer = match appkit::metal_layer_from_handle(window) {
-                Layer::Existing(layer) | Layer::Allocated(layer) => layer as *mut _,
+                Layer::Existing(layer) | Layer::Allocated(layer) => layer.cast(),
                 Layer::None => return Err(vk::Result::ERROR_INITIALIZATION_FAILED),
             };
 
@@ -91,7 +91,7 @@ pub unsafe fn create_surface(
             use raw_window_metal::{uikit, Layer};
 
             let layer = match uikit::metal_layer_from_handle(window) {
-                Layer::Existing(layer) | Layer::Allocated(layer) => layer as *mut _,
+                Layer::Existing(layer) | Layer::Allocated(layer) => layer.cast(),
                 Layer::None => return Err(vk::Result::ERROR_INITIALIZATION_FAILED),
             };
 

ash/src/device.rs

@@ -2032,7 +2032,7 @@ impl Device {
             first_query,
             query_count,
             data_size,
-            data.as_mut_ptr() as *mut _,
+            data.as_mut_ptr().cast(),
             mem::size_of::<T>() as _,
             flags,
         )

ash/src/extensions/khr/acceleration_structure.rs

@@ -200,7 +200,7 @@ impl AccelerationStructure {
             acceleration_structures.as_ptr(),
             query_type,
             data.len(),
-            data.as_mut_ptr() as *mut std::ffi::c_void,
+            data.as_mut_ptr().cast(),
             stride,
         )
         .result()

ash/src/extensions/nv/ray_tracing.rs

@@ -206,7 +206,7 @@ impl RayTracing {
             first_group,
             group_count,
             data.len(),
-            data.as_mut_ptr() as *mut std::ffi::c_void,
+            data.as_mut_ptr().cast(),
         )
         .result()
     }
@@ -223,7 +223,7 @@ impl RayTracing {
             self.handle,
             accel_struct,
             std::mem::size_of::<u64>(),
-            handle_ptr as *mut std::ffi::c_void,
+            handle_ptr.cast(),
         )
         .result_with_success(handle)
     }

ash/src/util.rs

@@ -31,7 +31,7 @@ impl<T: Copy> Align<T> {
         use std::slice::from_raw_parts_mut;
         if self.elem_size == size_of::<T>() as u64 {
             unsafe {
-                let mapped_slice = from_raw_parts_mut(self.ptr as *mut T, slice.len());
+                let mapped_slice = from_raw_parts_mut(self.ptr.cast(), slice.len());
                 mapped_slice.copy_from_slice(slice);
             }
         } else {
@@ -75,7 +75,9 @@ impl<'a, T: Copy + 'a> Iterator for AlignIter<'a, T> {
         }
         unsafe {
             // Need to cast to *mut u8 because () has size 0
-            let ptr = (self.align.ptr as *mut u8).offset(self.current as isize) as *mut T;
+            let ptr = (self.align.ptr.cast::<u8>())
+                .offset(self.current as isize)
+                .cast();
             self.current += self.align.elem_size;
             Some(&mut *ptr)
         }
@@ -118,7 +120,9 @@ pub fn read_spv<R: io::Read + io::Seek>(x: &mut R) -> io::Result<Vec<u32>> {
     // reading uninitialized memory.
     let mut result = vec![0u32; words];
     x.seek(io::SeekFrom::Start(0))?;
-    x.read_exact(unsafe { slice::from_raw_parts_mut(result.as_mut_ptr() as *mut u8, words * 4) })?;
+    x.read_exact(unsafe {
+        slice::from_raw_parts_mut(result.as_mut_ptr().cast::<u8>(), words * 4)
+    })?;
     const MAGIC_NUMBER: u32 = 0x0723_0203;
     if !result.is_empty() && result[0] == MAGIC_NUMBER.swap_bytes() {
         for word in &mut result {

ash/src/vk/definitions.rs

@@ -5208,7 +5208,7 @@ impl<'a> SpecializationInfoBuilder<'a> {
     #[inline]
     pub fn data(mut self, data: &'a [u8]) -> Self {
         self.inner.data_size = data.len();
-        self.inner.p_data = data.as_ptr() as *const c_void;
+        self.inner.p_data = data.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -6906,7 +6906,7 @@ impl<'a> PipelineCacheCreateInfoBuilder<'a> {
     #[inline]
     pub fn initial_data(mut self, initial_data: &'a [u8]) -> Self {
         self.inner.initial_data_size = initial_data.len();
-        self.inner.p_initial_data = initial_data.as_ptr() as *const c_void;
+        self.inner.p_initial_data = initial_data.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -12726,7 +12726,7 @@ impl<'a> DebugMarkerObjectTagInfoEXTBuilder<'a> {
     #[inline]
     pub fn tag(mut self, tag: &'a [u8]) -> Self {
         self.inner.tag_size = tag.len();
-        self.inner.p_tag = tag.as_ptr() as *const c_void;
+        self.inner.p_tag = tag.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -26002,7 +26002,7 @@ impl<'a> WriteDescriptorSetInlineUniformBlockBuilder<'a> {
     #[inline]
     pub fn data(mut self, data: &'a [u8]) -> Self {
         self.inner.data_size = data.len() as _;
-        self.inner.p_data = data.as_ptr() as *const c_void;
+        self.inner.p_data = data.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -26305,7 +26305,7 @@ impl<'a> ValidationCacheCreateInfoEXTBuilder<'a> {
     #[inline]
     pub fn initial_data(mut self, initial_data: &'a [u8]) -> Self {
         self.inner.initial_data_size = initial_data.len();
-        self.inner.p_initial_data = initial_data.as_ptr() as *const c_void;
+        self.inner.p_initial_data = initial_data.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -27834,7 +27834,7 @@ impl<'a> DebugUtilsObjectTagInfoEXTBuilder<'a> {
     #[inline]
     pub fn tag(mut self, tag: &'a [u8]) -> Self {
         self.inner.tag_size = tag.len();
-        self.inner.p_tag = tag.as_ptr() as *const c_void;
+        self.inner.p_tag = tag.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -43328,7 +43328,7 @@ impl<'a> PipelineExecutableInternalRepresentationKHRBuilder<'a> {
     #[inline]
     pub fn data(mut self, data: &'a mut [u8]) -> Self {
         self.inner.data_size = data.len();
-        self.inner.p_data = data.as_mut_ptr() as *mut c_void;
+        self.inner.p_data = data.as_mut_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]
@@ -47840,7 +47840,7 @@ impl<'a> AccelerationStructureBuildGeometryInfoKHRBuilder<'a> {
         geometries_ptrs: &'a [&'a AccelerationStructureGeometryKHR],
     ) -> Self {
         self.inner.geometry_count = geometries_ptrs.len() as _;
-        self.inner.pp_geometries = geometries_ptrs.as_ptr() as *const *const _;
+        self.inner.pp_geometries = geometries_ptrs.as_ptr().cast();
         self
     }
     #[inline]
@@ -59999,7 +59999,7 @@ impl<'a> CuModuleCreateInfoNVXBuilder<'a> {
     #[inline]
     pub fn data(mut self, data: &'a [u8]) -> Self {
         self.inner.data_size = data.len();
-        self.inner.p_data = data.as_ptr() as *const c_void;
+        self.inner.p_data = data.as_ptr().cast();
         self
     }
     #[doc = r" Calling build will **discard** all the lifetime information. Only call this if"]

examples/src/lib.rs

@@ -34,7 +34,7 @@ macro_rules! offset_of {
         #[allow(unused_unsafe)]
         unsafe {
             let b: $base = mem::zeroed();
-            (&b.$field as *const _ as isize) - (&b as *const _ as isize)
+            std::ptr::addr_of!(b.$field) as isize - std::ptr::addr_of!(b) as isize
         }
     }};
 }

generator/src/lib.rs

@@ -1712,10 +1712,8 @@ pub fn derive_setters(
 
                     // Interpret void array as byte array
                     if field.basetype == "void" && matches!(field.reference, Some(vkxml::ReferenceType::Pointer)) {
-                        let mutable = if field.is_const { quote!(const) } else { quote!(mut) };
-
                         slice_param_ty_tokens = quote!([u8]);
-                        ptr = quote!(#ptr as *#mutable c_void);
+                        ptr = quote!(#ptr.cast());
                     };
 
                     let set_size_stmt = if field.is_pointer_to_static_sized_array() {
@@ -1733,7 +1731,7 @@ pub fn derive_setters(
                         let array_size = if let Some(array_size) = array_size.strip_suffix(",1") {
                             param_ident_short = format_ident!("{}_ptrs", param_ident_short);
                             slice_param_ty_tokens = field.safe_type_tokens(quote!('a), Some(1));
-                            ptr = quote!(#ptr as *const *const _);
+                            ptr = quote!(#ptr.cast());
                             array_size
                         } else {
                             array_size