wip(test): Run with -- --nocapture --verbose and invoked should not appear in 2nd output

Author: futile

tests/incremental/derive_macro_expansion/auxiliary/derive_nothing.rs

@@ -0,0 +1,24 @@
+//@ force-host
+//@ no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+use proc_macro::TokenStream;
+
+#[proc_macro_derive(Nothing)]
+pub fn derive(input: TokenStream) -> TokenStream {
+    eprintln!("invoked");
+
+    r#"
+        pub mod nothing_mod {
+            // #[cfg(cfail1)]
+            pub fn nothing() {
+                eprintln!("nothing");
+            }
+
+            // #[cfg(cfail2)]
+            // fn nothingx() {}
+        }
+    "#.parse().unwrap()
+}

tests/incremental/derive_macro_expansion/item_changed.rs

@@ -0,0 +1,48 @@
+//@ aux-build:derive_nothing.rs
+//@ revisions:cfail1 cfail2
+//@ compile-flags: -Z query-dep-graph
+//@ check-pass (FIXME(62277): could be check-pass?)
+
+// TODO(pr-time): do these revisions make sense? only "check" required?
+
+#![feature(rustc_attrs)]
+#![feature(stmt_expr_attributes)]
+#![allow(dead_code)]
+#![crate_type = "rlib"]
+
+#![rustc_partition_codegened(module="item_changed-foo", cfg="cfail1")]
+// #![rustc_partition_reused(module="item_changed-foo", cfg="cfail2")]
+#![rustc_partition_reused(module="item_changed-foo-nothing_mod", cfg="cfail2")]
+
+ #[macro_use]
+ extern crate derive_nothing;
+
+pub mod foo {
+    // #[rustc_clean(cfg="cfail2")]
+     #[derive(Nothing)]
+    pub struct Foo;
+
+    #[cfg(cfail2)]
+    pub fn second_fn() {
+        eprintln!("just forcing codegen");
+    }
+
+    pub fn use_foo(_f: Foo) {
+        // #[cfg(cfail1)]
+        nothing_mod::nothing();
+
+        // #[cfg(cfail2)]
+        // nothingx();
+
+        eprintln!("foo used");
+    }
+}
+
+// fn main() {
+//     Foo;
+//
+//     nothing();
+//
+//     #[cfg(rpass2)]
+//     Bar;
+// }