4 files changed, 25 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);
diff --git a/crates/ra_parser/src/syntax_kind/generated.rs b/crates/ra_parser/src/syntax_kind/generated.rs
index 036415eac..374fd5aec 100644
--- a/crates/ra_parser/src/syntax_kind/generated.rs
+++ b/crates/ra_parser/src/syntax_kind/generated.rs
@@ -104,6 +104,7 @@ pub enum SyntaxKind {
     MOVE_KW,
     RETURN_KW,
     TRY_KW,
+    BOX_KW,
     AUTO_KW,
     DEFAULT_KW,
     EXISTENTIAL_KW,
@@ -187,6 +188,7 @@ pub enum SyntaxKind {
     NAMED_FIELD_LIST,
     NAMED_FIELD,
     TRY_BLOCK_EXPR,
+    BOX_EXPR,
     CALL_EXPR,
     INDEX_EXPR,
     METHOD_CALL_EXPR,
@@ -335,6 +337,7 @@ macro_rules! T {
     (move) => { $crate::SyntaxKind::MOVE_KW };
     (return) => { $crate::SyntaxKind::RETURN_KW };
     (try) => { $crate::SyntaxKind::TRY_KW };
+    (box) => { $crate::SyntaxKind::BOX_KW };
     (auto) => { $crate::SyntaxKind::AUTO_KW };
     (default) => { $crate::SyntaxKind::DEFAULT_KW };
     (existential) => { $crate::SyntaxKind::EXISTENTIAL_KW };
@@ -394,6 +397,7 @@ impl SyntaxKind {
             | MOVE_KW
             | RETURN_KW
             | TRY_KW
+            | BOX_KW
             | AUTO_KW
             | DEFAULT_KW
             | EXISTENTIAL_KW
@@ -567,6 +571,7 @@ impl SyntaxKind {
             MOVE_KW => &SyntaxInfo { name: "MOVE_KW" },
             RETURN_KW => &SyntaxInfo { name: "RETURN_KW" },
             TRY_KW => &SyntaxInfo { name: "TRY_KW" },
+            BOX_KW => &SyntaxInfo { name: "BOX_KW" },
             AUTO_KW => &SyntaxInfo { name: "AUTO_KW" },
             DEFAULT_KW => &SyntaxInfo { name: "DEFAULT_KW" },
             EXISTENTIAL_KW => &SyntaxInfo { name: "EXISTENTIAL_KW" },
@@ -650,6 +655,7 @@ impl SyntaxKind {
             NAMED_FIELD_LIST => &SyntaxInfo { name: "NAMED_FIELD_LIST" },
             NAMED_FIELD => &SyntaxInfo { name: "NAMED_FIELD" },
             TRY_BLOCK_EXPR => &SyntaxInfo { name: "TRY_BLOCK_EXPR" },
+            BOX_EXPR => &SyntaxInfo { name: "BOX_EXPR" },
             CALL_EXPR => &SyntaxInfo { name: "CALL_EXPR" },
             INDEX_EXPR => &SyntaxInfo { name: "INDEX_EXPR" },
             METHOD_CALL_EXPR => &SyntaxInfo { name: "METHOD_CALL_EXPR" },
@@ -745,6 +751,7 @@ impl SyntaxKind {
             "move" => MOVE_KW,
             "return" => RETURN_KW,
             "try" => TRY_KW,
+            "box" => BOX_KW,
             _ => return None,
         };
         Some(kw)