Merge pull request #121 from dtolnay/assert

Move element size check into private_new

Author: dtolnay

impl/src/declaration.rs

@@ -229,10 +229,6 @@ pub fn expand(input: TokenStream) -> TokenStream {
             )))]
             #unsupported_platform
 
-            #linkme_path::__private::assert!(
-                #linkme_path::__private::mem::size_of::<<#ty as #linkme_path::__private::Slice>::Element>() > 0,
-            );
-
             unsafe {
                 #linkme_path::DistributedSlice::private_new(
                     #name,

src/distributed_slice.rs

@@ -155,13 +155,16 @@ impl<T> Clone for StaticPtr<T> {
 
 impl<T> DistributedSlice<[T]> {
     #[doc(hidden)]
+    #[track_caller]
     pub const unsafe fn private_new(
         name: &'static str,
         section_start: *const [T; 0],
         section_stop: *const [T; 0],
         dupcheck_start: *const (),
         dupcheck_stop: *const (),
     ) -> Self {
+        assert!(mem::size_of::<T>() > 0);
+
         DistributedSlice {
             name,
             section_start: StaticPtr {

src/private.rs

@@ -1,6 +1,4 @@
 #[doc(hidden)]
-pub use core::assert;
-#[doc(hidden)]
 pub use core::mem;
 #[doc(hidden)]
 pub use core::primitive::isize;

tests/ui/zerosized.stderr

@@ -1,6 +1,7 @@
-error[E0080]: evaluation panicked: assertion failed: ::linkme::__private::mem::size_of::<<[Unit] as
-                          ::linkme::__private::Slice>::Element>() > 0
+error[E0080]: evaluation panicked: assertion failed: mem::size_of::<T>() > 0
  --> tests/ui/zerosized.rs:7:1
   |
 7 | #[distributed_slice]
   | ^^^^^^^^^^^^^^^^^^^^ evaluation of `ZEROSIZED` failed here
+  |
+  = note: this error originates in the attribute macro `distributed_slice` (in Nightly builds, run with -Z macro-backtrace for more info)