refactor: let wgpu-core impl. OOB as valid. err.

This does not, in fact, remove any bounds checks in practice. It is now
a validation error, implemented by the previous commit.

wgpu/src/api/buffer.rs

@@ -234,7 +234,6 @@ impl Buffer {
     /// end of the buffer.
     pub fn slice<S: RangeBounds<BufferAddress>>(&self, bounds: S) -> BufferSlice<'_> {
         let (offset, size) = range_to_offset_size(bounds);
-        check_buffer_bounds(self.size, offset, size);
         BufferSlice {
             buffer: self,
             offset,
@@ -645,31 +644,6 @@ impl Drop for BufferViewMut<'_> {
     }
 }
 
-fn check_buffer_bounds(
-    buffer_size: BufferAddress,
-    offset: BufferAddress,
-    size: Option<BufferSize>,
-) {
-    // A slice of length 0 is invalid, so the offset must not be equal to or greater than the buffer size.
-    if offset >= buffer_size {
-        panic!(
-            "slice offset {} is out of range for buffer of size {}",
-            offset, buffer_size
-        );
-    }
-
-    if let Some(size) = size {
-        // Detect integer overflow.
-        let end = offset.checked_add(size.get());
-        if end.map_or(true, |end| end > buffer_size) {
-            panic!(
-                "slice offset {} size {} is out of range for buffer of size {}",
-                offset, size, buffer_size
-            );
-        }
-    }
-}
-
 fn range_to_offset_size<S: RangeBounds<BufferAddress>>(
     bounds: S,
 ) -> (BufferAddress, Option<BufferSize>) {
@@ -690,7 +664,7 @@ fn range_to_offset_size<S: RangeBounds<BufferAddress>>(
 
 #[cfg(test)]
 mod tests {
-    use super::{check_buffer_bounds, range_to_offset_size, BufferSize};
+    use super::{range_to_offset_size, BufferSize};
 
     #[test]
     fn range_to_offset_size_works() {
@@ -713,31 +687,4 @@ mod tests {
     fn range_to_offset_size_panics_for_unbounded_empty_range() {
         range_to_offset_size(..0);
     }
-
-    #[test]
-    #[should_panic]
-    fn check_buffer_bounds_panics_for_offset_at_size() {
-        check_buffer_bounds(100, 100, None);
-    }
-
-    #[test]
-    fn check_buffer_bounds_works_for_end_in_range() {
-        check_buffer_bounds(200, 100, BufferSize::new(50));
-        check_buffer_bounds(200, 100, BufferSize::new(100));
-        check_buffer_bounds(u64::MAX, u64::MAX - 100, BufferSize::new(100));
-        check_buffer_bounds(u64::MAX, 0, BufferSize::new(u64::MAX));
-        check_buffer_bounds(u64::MAX, 1, BufferSize::new(u64::MAX - 1));
-    }
-
-    #[test]
-    #[should_panic]
-    fn check_buffer_bounds_panics_for_end_over_size() {
-        check_buffer_bounds(200, 100, BufferSize::new(101));
-    }
-
-    #[test]
-    #[should_panic]
-    fn check_buffer_bounds_panics_for_end_wraparound() {
-        check_buffer_bounds(u64::MAX, 1, BufferSize::new(u64::MAX));
-    }
 }