From f942d10e8010918c677b40f821e504d87f057ead Mon Sep 17 00:00:00 2001
From: Edwin Cheng <edwin0cheng@gmail.com>
Date: Sun, 20 Dec 2020 17:13:40 +0800
Subject: [PATCH] Use pattern_single instead of pattern in mbe pat

---
 crates/mbe/src/tests.rs      | 12 ++++++++++++
 crates/parser/src/grammar.rs |  2 +-
 crates/parser/src/lib.rs     |  2 +-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/crates/mbe/src/tests.rs b/crates/mbe/src/tests.rs
index f10e7a9b69..451fa1456a 100644
--- a/crates/mbe/src/tests.rs
+++ b/crates/mbe/src/tests.rs
@@ -1003,6 +1003,18 @@ fn test_underscore() {
     .assert_expand_items(r#"foo! { => }"#, r#"0"#);
 }
 
+#[test]
+fn test_vertical_bar_with_pat() {
+    parse_macro(
+        r#"
+            macro_rules! foo {
+                 (| $pat:pat | ) => { 0 }
+            }
+    "#,
+    )
+    .assert_expand_items(r#"foo! { | x | }"#, r#"0"#);
+}
+
 #[test]
 fn test_lifetime() {
     parse_macro(
diff --git a/crates/parser/src/grammar.rs b/crates/parser/src/grammar.rs
index 1a078f6b4c..f08c8bab74 100644
--- a/crates/parser/src/grammar.rs
+++ b/crates/parser/src/grammar.rs
@@ -55,7 +55,7 @@ pub(crate) mod fragments {
     use super::*;
 
     pub(crate) use super::{
-        expressions::block_expr, paths::type_path as path, patterns::pattern, types::type_,
+        expressions::block_expr, paths::type_path as path, patterns::pattern_single, types::type_,
     };
 
     pub(crate) fn expr(p: &mut Parser) {
diff --git a/crates/parser/src/lib.rs b/crates/parser/src/lib.rs
index ab8e4c70e8..811e740f98 100644
--- a/crates/parser/src/lib.rs
+++ b/crates/parser/src/lib.rs
@@ -112,7 +112,7 @@ pub fn parse_fragment(
         FragmentKind::Path => grammar::fragments::path,
         FragmentKind::Expr => grammar::fragments::expr,
         FragmentKind::Type => grammar::fragments::type_,
-        FragmentKind::Pattern => grammar::fragments::pattern,
+        FragmentKind::Pattern => grammar::fragments::pattern_single,
         FragmentKind::Item => grammar::fragments::item,
         FragmentKind::Block => grammar::fragments::block_expr,
         FragmentKind::Visibility => grammar::fragments::opt_visibility,