test-macros: Avoid always producing errors in #[derive(Print)]

Author: petrochenkov

src/test/ui/proc-macro/auxiliary/test-macros.rs

@@ -108,5 +108,6 @@ pub fn print_attr(_: TokenStream, input: TokenStream) -> TokenStream {
 
 #[proc_macro_derive(Print, attributes(print_helper))]
 pub fn print_derive(input: TokenStream) -> TokenStream {
-    print_helper(input, "DERIVE")
+    print_helper(input, "DERIVE");
+    TokenStream::new()
 }

src/test/ui/proc-macro/dollar-crate.rs

@@ -1,3 +1,4 @@
+// check-pass
 // edition:2018
 // aux-build:test-macros.rs
 // aux-build:dollar-crate-external.rs
@@ -23,7 +24,7 @@ mod local {
             struct A($crate::S);
 
             #[derive(Print)]
-            struct D($crate::S); //~ ERROR the name `D` is defined multiple times
+            struct D($crate::S);
         };
     }
 
@@ -33,7 +34,7 @@ mod local {
 mod external {
     use crate::dollar_crate_external;
 
-    dollar_crate_external::external!(); //~ ERROR the name `D` is defined multiple times
+    dollar_crate_external::external!();
 }
 
 fn main() {}