Check for eprintln on CI

crates/ra_hir_ty/src/lib.rs

@@ -1,6 +1,11 @@
 //! The type system. We currently use this to infer types for completion, hover
 //! information and various assists.
 
+#[allow(unused)]
+macro_rules! eprintln {
+    ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
+}
+
 macro_rules! impl_froms {
     ($e:ident: $($v:ident $(($($sv:ident),*))?),*) => {
         $(