Merge #1157

1157: Add mbe stmt matcher r=matklad a=edwin0cheng

Add `stmt` matcher in `ra_mbe` , and added corresponding `stmt()` parser in `ra_syntax`. 
This PR also help PR #1148 for `MarcoKind::Items` parsing.

Note: 
* According [the book](https://doc.rust-lang.org/reference/macros-by-example.html), mbe `stmt` matcher will only match statement without the trailing semicolon 
* `item` is a valid statement.





Co-authored-by: Edwin Cheng <[email protected]>

1 files changed, 15 insertions, 0 deletions

diff --git a/crates/ra_mbe/src/lib.rs b/crates/ra_mbe/src/lib.rs
index a530f3b03..a1f438906 100644
--- a/crates/ra_mbe/src/lib.rs
+++ b/crates/ra_mbe/src/lib.rs
@@ -582,4 +582,19 @@ SOURCE_FILE@[0; 40)
         );
         assert_expansion(&rules, "foo! { (a, b) }", "fn foo () {let (a , b) ;}");
     }
+
+    #[test]
+    fn test_stmt() {
+        let rules = create_rules(
+            r#"
+        macro_rules! foo {
+            ($ i:stmt) => (
+                fn bar() { $ i; }
+            )
+        }
+"#,
+        );
+        assert_expansion(&rules, "foo! { 2 }", "fn bar () {2 ;}");
+        assert_expansion(&rules, "foo! { let a = 0 }", "fn bar () {let a = 0 ;}");
+    }
 }