Add tests for marker trait impls
diff --git a/tests/marker.rs b/tests/marker.rs
new file mode 100644
index 0000000..7bb5027
--- /dev/null
+++ b/tests/marker.rs
@@ -0,0 +1,61 @@
+extern crate proc_macro2;
+
+use proc_macro2::*;
+
+macro_rules! assert_impl {
+ ($ty:ident is $($marker:ident) and +) => {
+ #[test]
+ #[allow(non_snake_case)]
+ fn $ty() {
+ fn assert_implemented<T: $($marker +)+>() {}
+ assert_implemented::<$ty>();
+ }
+ };
+
+ ($ty:ident is not $($marker:ident) or +) => {
+ #[test]
+ #[allow(non_snake_case)]
+ fn $ty() {
+ $(
+ {
+ // Implemented for types that implement $marker.
+ trait IsNotImplemented {
+ fn assert_not_implemented() {}
+ }
+ impl<T: $marker> IsNotImplemented for T {}
+
+ // Implemented for the type being tested.
+ trait IsImplemented {
+ fn assert_not_implemented() {}
+ }
+ impl IsImplemented for $ty {}
+
+ // If $ty does not implement $marker, there is no ambiguity
+ // in the following trait method call.
+ <$ty>::assert_not_implemented();
+ }
+ )+
+ }
+ };
+}
+
+assert_impl!(Delimiter is Send and Sync);
+assert_impl!(Spacing is Send and Sync);
+
+assert_impl!(Group is not Send or Sync);
+assert_impl!(Ident is not Send or Sync);
+assert_impl!(LexError is not Send or Sync);
+assert_impl!(Literal is not Send or Sync);
+assert_impl!(Punct is not Send or Sync);
+assert_impl!(Span is not Send or Sync);
+assert_impl!(TokenStream is not Send or Sync);
+assert_impl!(TokenTree is not Send or Sync);
+
+#[cfg(procmacro2_semver_exempt)]
+mod semver_exempt {
+ use super::*;
+
+ assert_impl!(LineColumn is Send and Sync);
+
+ assert_impl!(SourceFile is not Send or Sync);
+}