Represent lifetimes as two joint tokens in proc macros

src/test/run-pass-fulldeps/proc-macro/auxiliary/lifetimes.rs

@@ -0,0 +1,36 @@
+// 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
+
+#![feature(proc_macro)]
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::*;
+
+#[proc_macro]
+pub fn lifetimes_bang(input: TokenStream) -> TokenStream {
+    // Roundtrip through token trees
+    input.into_iter().collect()
+}
+
+#[proc_macro_attribute]
+pub fn lifetimes_attr(_: TokenStream, input: TokenStream) -> TokenStream {
+    // Roundtrip through AST
+    input
+}
+
+#[proc_macro_derive(Lifetimes)]
+pub fn lifetimes_derive(input: TokenStream) -> TokenStream {
+    // Roundtrip through a string
+    format!("mod m {{ {} }}", input).parse().unwrap()
+}

src/test/run-pass-fulldeps/proc-macro/lifetimes.rs

@@ -0,0 +1,36 @@
+// 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:lifetimes.rs
+// ignore-stage1
+
+#![feature(proc_macro)]
+
+extern crate lifetimes;
+use lifetimes::*;
+
+lifetimes_bang! {
+    fn bang<'a>() -> &'a u8 { &0 }
+}
+
+#[lifetimes_attr]
+fn attr<'a>() -> &'a u8 { &1 }
+
+#[derive(Lifetimes)]
+pub struct Lifetimes<'a> {
+    pub field: &'a u8,
+}
+
+fn main() {
+    assert_eq!(bang::<'static>(), &0);
+    assert_eq!(attr::<'static>(), &1);
+    let l1 = Lifetimes { field: &0 };
+    let l2 = m::Lifetimes { field: &1 };
+}

src/test/ui-fulldeps/auxiliary/lifetimes.rs

@@ -0,0 +1,30 @@
+// 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
+
+#![feature(proc_macro)]
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+
+use proc_macro::*;
+
+#[proc_macro]
+pub fn single_quote_alone(_: TokenStream) -> TokenStream {
+    // `&'a u8`, but the `'` token is not joint
+    let trees: Vec<TokenTree> = vec![
+        Punct::new('&', Spacing::Alone).into(),
+        Punct::new('\'', Spacing::Alone).into(),
+        Ident::new("a", Span::call_site()).into(),
+        Ident::new("u8", Span::call_site()).into(),
+    ];
+    trees.into_iter().collect()
+}

src/test/ui-fulldeps/lifetimes.rs

@@ -0,0 +1,19 @@
+// 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:lifetimes.rs
+
+#![feature(proc_macro, proc_macro_non_items)]
+
+extern crate lifetimes;
+
+use lifetimes::*;
+
+type A = single_quote_alone!(); //~ ERROR expected type, found `'`

src/test/ui-fulldeps/lifetimes.stderr

@@ -0,0 +1,8 @@
+error: expected type, found `'`
+  --> $DIR/lifetimes.rs:19:10
+   |
+LL | type A = single_quote_alone!(); //~ ERROR expected type, found `'`
+   |          ^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+