Rollup merge of rust-lang#38607 - estebank:test-for-36935, r=petrochenkov

Test for appropriate span on second custom derive

Adds test for and closes rust-lang#36935.

Author: steveklabnik

src/test/ui/custom-derive/auxiliary/plugin.rs

@@ -0,0 +1,28 @@
+// Copyright 2016 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"]
+#![feature(proc_macro, proc_macro_lib)]
+
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+
+#[proc_macro_derive(Foo)]
+pub fn derive_foo(input: TokenStream) -> TokenStream {
+    input
+}
+
+#[proc_macro_derive(Bar)]
+pub fn derive_bar(input: TokenStream) -> TokenStream {
+    panic!("lolnope");
+}

src/test/ui/custom-derive/issue-36935.rs

@@ -0,0 +1,23 @@
+// Copyright 2016 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:plugin.rs
+
+#![feature(proc_macro)]
+
+#[macro_use] extern crate plugin;
+
+#[derive(Foo, Bar)]
+struct Baz {
+    a: i32,
+    b: i32,
+}
+
+fn main() {}

src/test/ui/custom-derive/issue-36935.stderr

@@ -0,0 +1,8 @@
+error: custom derive attribute panicked
+  --> $DIR/issue-36935.rs:17:15
+   |
+17 | #[derive(Foo, Bar)]
+   |               ^^^
+   |
+   = help: message: lolnope
+