1 files changed, 72 insertions, 0 deletions
diff --git a/vendor/static_assertions/src/assert_fields.rs b/vendor/static_assertions/src/assert_fields.rs
new file mode 100644
index 000000000..00f624277
--- /dev/null
+++ b/vendor/static_assertions/src/assert_fields.rs
@@ -0,0 +1,72 @@
+/// Asserts that the type has the given fields.
+///
+/// # Examples
+///
+/// One common use case is when types have fields defined multiple times as a
+/// result of `#[cfg]`. This can be an issue when exposing a public API.
+///
+/// ```
+/// # #[macro_use] extern crate static_assertions;
+/// pub struct Ty {
+///     #[cfg(windows)]
+///     pub val1: u8,
+///     #[cfg(not(windows))]
+///     pub val1: usize,
+///
+///     #[cfg(unix)]
+///     pub val2: u32,
+///     #[cfg(not(unix))]
+///     pub val2: usize,
+/// }
+///
+/// // Always have `val2` regardless of OS
+/// assert_fields!(Ty: val2);
+/// ```
+///
+/// This macro even works with `enum` variants:
+///
+/// ```
+/// # #[macro_use] extern crate static_assertions; fn main() {}
+/// enum Data {
+///     Val {
+///         id: i32,
+///         name: String,
+///         bytes: [u8; 128],
+///     },
+///     Ptr(*const u8),
+/// }
+///
+/// assert_fields!(Data::Val: id, bytes);
+/// ```
+///
+/// The following example fails to compile because [`Range`] does not have a field named `middle`:
+///
+/// ```compile_fail
+/// # #[macro_use] extern crate static_assertions; fn main() {}
+/// use std::ops::Range;
+///
+/// assert_fields!(Range<u32>: middle);
+/// ```
+///
+/// [`Range`]: https://doc.rust-lang.org/std/ops/struct.Range.html
+#[macro_export]
+macro_rules! assert_fields {
+    ($t:ident::$v:ident: $($f:ident),+) => {
+        #[allow(unknown_lints, unneeded_field_pattern)]
+        const _: fn() = || {
+            #[allow(dead_code, unreachable_patterns)]
+            fn assert(value: $t) {
+                match value {
+                    $($t::$v { $f: _, .. } => {},)+
+                    _ => {}
+                }
+            }
+        };
+    };
+    ($t:path: $($f:ident),+) => {
+        #[allow(unknown_lints, unneeded_field_pattern)]
+        const _: fn() = || {
+            $(let $t { $f: _, .. };)+
+        };
+    };
+}