Squashed 'subprojects/thiserror/' content from commit 247eab5

git-subtree-dir: subprojects/thiserror
git-subtree-split: 247eab5d79e27ad28859afdf8bc600a4242829b7

tests/ui/concat-display.rs

@@ -0,0 +1,15 @@
+use thiserror::Error;
+
+macro_rules! error_type {
+    ($name:ident, $what:expr) => {
+        // Use #[error("invalid {}", $what)] instead.
+
+        #[derive(Error, Debug)]
+        #[error(concat!("invalid ", $what))]
+        pub struct $name;
+    };
+}
+
+error_type!(Error, "foo");
+
+fn main() {}