From d5eb43f246236b18646d9090ac2c4b6b04aee5b3 Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Sat, 25 Apr 2020 23:09:20 +0800
Subject: Checks no repetition for an empty token

---
 crates/ra_mbe/src/tests.rs | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

(limited to 'crates/ra_mbe/src/tests.rs')

diff --git a/crates/ra_mbe/src/tests.rs b/crates/ra_mbe/src/tests.rs
index 100ed41f2..6b139fb12 100644
--- a/crates/ra_mbe/src/tests.rs
+++ b/crates/ra_mbe/src/tests.rs
@@ -1657,7 +1657,7 @@ impl MacroFixture {
     }
 }
 
-pub(crate) fn parse_macro(ra_fixture: &str) -> MacroFixture {
+fn parse_macro_to_tt(ra_fixture: &str) -> tt::Subtree {
     let source_file = ast::SourceFile::parse(ra_fixture).ok().unwrap();
     let macro_definition =
         source_file.syntax().descendants().find_map(ast::MacroCall::cast).unwrap();
@@ -1671,10 +1671,24 @@ pub(crate) fn parse_macro(ra_fixture: &str) -> MacroFixture {
     .0;
     assert_eq!(definition_tt, parsed);
 
+    definition_tt
+}
+
+pub(crate) fn parse_macro(ra_fixture: &str) -> MacroFixture {
+    let definition_tt = parse_macro_to_tt(ra_fixture);
     let rules = MacroRules::parse(&definition_tt).unwrap();
     MacroFixture { rules }
 }
 
+pub(crate) fn parse_macro_error(ra_fixture: &str) -> ParseError {
+    let definition_tt = parse_macro_to_tt(ra_fixture);
+
+    match MacroRules::parse(&definition_tt) {
+        Ok(_) => panic!("Expect error"),
+        Err(err) => err,
+    }
+}
+
 pub(crate) fn parse_to_token_tree_by_syntax(ra_fixture: &str) -> tt::Subtree {
     let source_file = ast::SourceFile::parse(ra_fixture).ok().unwrap();
     let tt = syntax_node_to_token_tree(source_file.syntax()).unwrap().0;
@@ -1840,6 +1854,27 @@ fn test_no_space_after_semi_colon() {
     );
 }
 
+// https://github.com/rust-lang/rust/blob/master/src/test/ui/issues/issue-57597.rs
+#[test]
+fn test_rustc_issue_57597() {
+    fn test_error(fixture: &str) {
+        assert_eq!(parse_macro_error(fixture), ParseError::RepetitionEmtpyTokenTree);
+    }
+
+    test_error("macro_rules! foo { ($($($i:ident)?)+) => {}; }");
+    test_error("macro_rules! foo { ($($($i:ident)?)*) => {}; }");
+    test_error("macro_rules! foo { ($($($i:ident)?)?) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)?)?)?) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)*)?)?) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)?)*)?) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)?)?)*) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)*)*)?) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)?)*)*) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)?)*)+) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)+)?)*) => {}; }");
+    test_error("macro_rules! foo { ($($($($i:ident)+)*)?) => {}; }");
+}
+
 #[test]
 fn test_expand_bad_literal() {
     parse_macro(
-- 
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