Deprecated proc_macro doesn't trigger warning on build library

Change-Id: Ib3a396e7334d209fe6c6ef425bbfc7b2ae471378

src/libsyntax_ext/proc_macro_harness.rs

@@ -337,6 +337,7 @@ impl<'a> Visitor<'a> for CollectProcMacros<'a> {
 //          use proc_macro::bridge::client::ProcMacro;
 //
 //          #[rustc_proc_macro_decls]
+//          #[allow(deprecated)]
 //          static DECLS: &[ProcMacro] = &[
 //              ProcMacro::custom_derive($name_trait1, &[], ::$name1);
 //              ProcMacro::custom_derive($name_trait2, &["attribute_name"], ::$name2);

src/test/ui/proc-macro/proc-macro-deprecated-attr.rs

@@ -1,4 +1,6 @@
-// build-pass
+// check-pass
+
+#![deny(deprecated)]
 
 #![crate_type = "proc-macro"]
 
@@ -8,8 +10,5 @@ use proc_macro::*;
 #[proc_macro]
 #[deprecated(since = "1.0.0", note = "test")]
 pub fn test_compile_without_warning_with_deprecated(_: TokenStream) -> TokenStream {
-    "
-    extern crate proc_macro;
-    fn foo() { }
-    ".parse().unwrap()
+    TokenStream::new()
 }