test: Add test for async-move in 2015 Rust proc macro

Add a test to ensure issue #89699 does not show up again. This test
emits an `async move` closure in a proc macro, which is used in a
test program compiled with edition 2015. We make sure the error message
is nice and shows up properly.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/ui/proc-macro/edition-gated-async-move-syntax-issue89699.rs b/tests/ui/proc-macro/edition-gated-async-move-syntax-issue89699.rs
new file mode 100644
index 00000000000..1a9d4601aca
--- /dev/null
+++ b/tests/ui/proc-macro/edition-gated-async-move-syntax-issue89699.rs
@@ -0,0 +1,10 @@
+// aux-build:edition-gated-async-move-syntax.rs
+// edition: 2015
+
+// Non-regression test for issue #89699, where a proc-macro emitting syntax only available in
+// edition 2018 and up (`async move`) is used on edition 2015
+
+extern crate edition_gated_async_move_syntax;
+
+#[edition_gated_async_move_syntax::foo]
+fn foo() {} //~ ERROR `async move` blocks are only allowed in Rust 2018 or later