From b71b15d3305e20d013433f9499717a62fa0c3fbd Mon Sep 17 00:00:00 2001
From: kek kek kek <andriy.n@obox.systems>
Date: Mon, 9 Oct 2023 09:36:57 -0700
Subject: [PATCH] chore: parse fieldless structures (#3021)

Co-authored-by: kevaundray <kevtheappdev@gmail.com>
---
 compiler/noirc_frontend/src/parser/parser.rs        | 13 ++++++++-----
 .../tests/execution_success/struct/src/main.nr      |  4 ++++
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/compiler/noirc_frontend/src/parser/parser.rs b/compiler/noirc_frontend/src/parser/parser.rs
index 7216dd9a924..702f056adcd 100644
--- a/compiler/noirc_frontend/src/parser/parser.rs
+++ b/compiler/noirc_frontend/src/parser/parser.rs
@@ -228,14 +228,15 @@ fn struct_definition() -> impl NoirParser<TopLevelStatement> {
     use self::Keyword::Struct;
     use Token::*;
 
-    let fields = struct_fields().delimited_by(just(LeftBrace), just(RightBrace)).recover_with(
-        nested_delimiters(
+    let fields = struct_fields()
+        .delimited_by(just(LeftBrace), just(RightBrace))
+        .recover_with(nested_delimiters(
             LeftBrace,
             RightBrace,
             [(LeftParen, RightParen), (LeftBracket, RightBracket)],
             |_| vec![],
-        ),
-    );
+        ))
+        .or(just(Semicolon).map(|_| Vec::new()));
 
     attributes()
         .or_not()
@@ -2281,6 +2282,7 @@ mod test {
     #[test]
     fn parse_structs() {
         let cases = vec![
+            "struct Foo;",
             "struct Foo { }",
             "struct Bar { ident: Field, }",
             "struct Baz { ident: Field, other: Field }",
@@ -2315,12 +2317,13 @@ mod test {
     #[test]
     fn parse_constructor() {
         let cases = vec![
+            "Baz",
             "Bar { ident: 32 }",
             "Baz { other: 2 + 42, ident: foo() + 1 }",
             "Baz { other, ident: foo() + 1, foo }",
         ];
-        parse_all(expression(), cases);
 
+        parse_all(expression(), cases);
         parse_with(expression(), "Foo { a + b }").unwrap_err();
     }
 
diff --git a/tooling/nargo_cli/tests/execution_success/struct/src/main.nr b/tooling/nargo_cli/tests/execution_success/struct/src/main.nr
index 5e3530e8364..2bd5a1aec28 100644
--- a/tooling/nargo_cli/tests/execution_success/struct/src/main.nr
+++ b/tooling/nargo_cli/tests/execution_success/struct/src/main.nr
@@ -52,7 +52,11 @@ fn get_dog() -> Animal {
     dog
 }
 
+struct Unit;
+
 fn main(x: Field, y: Field) {
+    let unit = Unit {};
+
     let first = Foo::default(x,y);
     let p = Pair { first, second: 1 };