fix: bad parsing for module select type annotations closes #550

crates/aiken-lang/src/parser.rs

@@ -1519,7 +1519,7 @@ pub fn type_parser() -> impl Parser<Token, ast::Annotation, Error = ParseError>
                         .then(
                             r.separated_by(just(Token::Comma))
                                 .allow_trailing()
-                                .delimited_by(just(Token::LeftParen), just(Token::RightParen))
+                                .delimited_by(just(Token::Less), just(Token::Greater))
                                 .or_not(),
                         )
                         .or_not(),

crates/aiken-lang/src/tests/parser.rs

@@ -38,6 +38,55 @@ fn windows_newline() {
     )
 }
 
+#[test]
+fn type_annotation_with_module_prefix() {
+    let code = indoc! {r#"
+       use aiken
+
+       pub fn go() -> aiken.Option<Int> {
+         False
+       }
+    "#};
+
+    assert_definitions(
+        code,
+        vec![
+            ast::UntypedDefinition::Use(ast::Use {
+                as_name: None,
+                location: Span::new((), 0..9),
+                module: vec!["aiken".to_string()],
+                package: (),
+                unqualified: vec![],
+            }),
+            ast::UntypedDefinition::Fn(ast::Function {
+                arguments: vec![],
+                body: expr::UntypedExpr::Var {
+                    location: Span::new((), 48..53),
+                    name: "False".to_string(),
+                },
+                doc: None,
+                location: Span::new((), 11..43),
+                name: "go".to_string(),
+                public: true,
+                return_annotation: Some(ast::Annotation::Constructor {
+                    location: Span::new((), 26..43),
+                    module: Some("aiken".to_string()),
+                    name: "Option".to_string(),
+                    arguments: vec![ast::Annotation::Constructor {
+                        location: Span::new((), 39..42),
+                        module: None,
+                        name: "Int".to_string(),
+                        arguments: vec![],
+                    }],
+                }),
+                return_type: (),
+                end_position: 54,
+                can_error: true,
+            }),
+        ],
+    )
+}
+
 #[test]
 fn test_fail() {
     let code = indoc! {r#"