Add incremental-fulldeps test suite and regression test for #47290.

Author: michaelwoerister

src/bootstrap/check.rs

@@ -568,6 +568,11 @@ static HOST_COMPILETESTS: &[Test] = &[
         mode: "compile-fail",
         suite: "compile-fail-fulldeps",
     },
+    Test {
+        path: "src/test/incremental-fulldeps",
+        mode: "incremental",
+        suite: "incremental-fulldeps",
+    },
     Test { path: "src/test/run-make", mode: "run-make", suite: "run-make" },
     Test { path: "src/test/rustdoc", mode: "rustdoc", suite: "rustdoc" },
 

src/test/incremental-fulldeps/auxiliary/incremental_proc_macro_aux.rs

@@ -0,0 +1,31 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+
+// Add a function to shift DefIndex of registrar function
+#[cfg(cfail2)]
+fn foo() {}
+
+#[proc_macro_derive(IncrementalMacro)]
+pub fn derive(input: TokenStream) -> TokenStream {
+    #[cfg(cfail2)]
+    {
+        foo();
+    }
+
+    "".parse().unwrap()
+}

src/test/incremental-fulldeps/incremental_proc_macro.rs

@@ -0,0 +1,27 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// aux-build:incremental_proc_macro_aux.rs
+// ignore-stage1
+// revisions: cfail1 cfail2
+// must-compile-successfully
+
+// This test makes sure that we still find the proc-macro registrar function
+// when we compile proc-macros incrementally (see #47292).
+
+#![crate_type = "rlib"]
+
+#[macro_use]
+extern crate incremental_proc_macro_aux;
+
+#[derive(IncrementalMacro)]
+pub struct Foo {
+    x: u32
+}