3 files changed, 18 insertions, 5 deletions

diff --git a/crates/ra_parser/src/grammar/expressions.rs b/crates/ra_parser/src/grammar/expressions.rs
index 2ae05521c..795dccea1 100644
--- a/crates/ra_parser/src/grammar/expressions.rs
+++ b/crates/ra_parser/src/grammar/expressions.rs
@@ -583,8 +583,3 @@ pub(crate) fn named_field_list(p: &mut Parser) {
     p.expect(T!['}']);
     m.complete(p, NAMED_FIELD_LIST);
 }
-
-// test box_syntax
-// fn foo() {
-//     let x = box 1i32;
-// }
diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index 725fb99f6..41be283d0 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -74,6 +74,7 @@ pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMar
         T![if] => if_expr(p),
 
         T![loop] => loop_expr(p, None),
+        T![box] => box_expr(p, None),
         T![for] => for_expr(p, None),
         T![while] => while_expr(p, None),
         T![try] => try_block_expr(p, None),
@@ -507,3 +508,17 @@ fn try_block_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
     block(p);
     m.complete(p, TRY_EXPR)
 }
+
+// test box_expr
+// fn foo() {
+//     let x = box 1i32;
+// }
+fn box_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
+    assert!(p.at(T![box]));
+    let m = m.unwrap_or_else(|| p.start());
+    p.bump();
+    if p.at_ts(EXPR_FIRST) {
+        expr(p);
+    }
+    m.complete(p, BOX_EXPR)
+}
diff --git a/crates/ra_parser/src/grammar/patterns.rs b/crates/ra_parser/src/grammar/patterns.rs
index 16ae9da63..46034942a 100644
--- a/crates/ra_parser/src/grammar/patterns.rs
+++ b/crates/ra_parser/src/grammar/patterns.rs
@@ -60,6 +60,7 @@ fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option<CompletedMarker> {
     let la1 = p.nth(1);
     if la0 == T![ref]
         || la0 == T![mut]
+        || la0 == T![box]
         || (la0 == IDENT && !(la1 == T![::] || la1 == T!['('] || la1 == T!['{'] || la1 == T![!]))
     {
         return Some(bind_pat(p, true));
@@ -260,9 +261,11 @@ fn pat_list(p: &mut Parser, ket: SyntaxKind) {
 //     let ref mut d = ();
 //     let e @ _ = ();
 //     let ref mut f @ g @ _ = ();
+//     let box i = Box::new(1i32);
 // }
 fn bind_pat(p: &mut Parser, with_at: bool) -> CompletedMarker {
     let m = p.start();
+    p.eat(T![box]);
     p.eat(T![ref]);
     p.eat(T![mut]);
     name(p);