test: Add test for async-move in 2015 Rust proc macro

Author: CohenArthur

tests/ui/proc-macro/auxiliary/async-move.rs

@@ -0,0 +1,36 @@
+// force-host
+// no-prefer-dynamic
+
+#![crate_type = "proc-macro"]
+
+extern crate proc_macro;
+use proc_macro::*;
+
+#[proc_macro_attribute]
+pub fn foo(_attr: TokenStream, item: TokenStream) -> TokenStream {
+    let tt = item.into_iter().next().unwrap();
+    let sp = tt.span();
+    let mut arg = TokenStream::new();
+    let mut g = Group::new(Delimiter::Brace, TokenStream::new());
+    g.set_span(sp);
+    arg.extend([
+        TokenTree::Ident(Ident::new("async", sp)),
+        TokenTree::Ident(Ident::new("move", sp)),
+        TokenTree::Group(g),
+    ]);
+    let mut body = TokenStream::new();
+    body.extend([
+        TokenTree::Ident(Ident::new("async_main", sp)),
+        TokenTree::Group(Group::new(Delimiter::Parenthesis, arg)),
+    ]);
+
+    let mut ret = TokenStream::new();
+    ret.extend([
+        TokenTree::Ident(Ident::new("fn", sp)),
+        TokenTree::Ident(Ident::new("main", sp)),
+        TokenTree::Group(Group::new(Delimiter::Parenthesis, TokenStream::new())),
+        TokenTree::Group(Group::new(Delimiter::Brace, body)),
+    ]);
+    eprintln!("{:?}", ret);
+    ret
+}

tests/ui/proc-macro/issue-89699.rs

@@ -0,0 +1,6 @@
+// aux-build:async-move.rs
+
+extern crate async_move;
+
+#[async_move::foo]
+fn foo() {} //~ ERROR `async move` blocks are only allowed in Rust 2018 or later

tests/ui/proc-macro/issue-89699.stderr

@@ -0,0 +1,9 @@
+TokenStream [Ident { ident: "fn", span: #0 bytes(73..75) }, Ident { ident: "main", span: #0 bytes(73..75) }, Group { delimiter: Parenthesis, stream: TokenStream [], span: #5 bytes(54..72) }, Group { delimiter: Brace, stream: TokenStream [Ident { ident: "async_main", span: #0 bytes(73..75) }, Group { delimiter: Parenthesis, stream: TokenStream [Ident { ident: "async", span: #0 bytes(73..75) }, Ident { ident: "move", span: #0 bytes(73..75) }, Group { delimiter: Brace, stream: TokenStream [], span: #0 bytes(73..75) }], span: #5 bytes(54..72) }], span: #5 bytes(54..72) }]
+error: `async move` blocks are only allowed in Rust 2018 or later
+  --> $DIR/issue-89699.rs:6:1
+   |
+LL | fn foo() {}
+   | ^^
+
+error: aborting due to previous error
+