better parser errors

error_test/parser/top_level_errors.sui

@@ -0,0 +1,45 @@
+# Top-level declaration errors
+
+# Invalid top-level token
+invalid_token
+
+# Incomplete use statement
+use
+
+# Missing path in use
+use as alias
+
+# Invalid use syntax
+use "path" invalid
+
+# Incomplete load statement
+load
+
+# Missing alias in load
+load "lib"
+
+# Invalid load syntax
+load "lib" invalid alias
+
+# Incomplete extern declaration
+extern
+
+# Missing return type in extern
+extern add(x: int, y: int)
+
+# Invalid extern syntax
+extern add(x: int, y: int) -> int invalid
+
+# Incomplete impl declaration
+impl
+
+# Missing methods in impl
+impl MyType
+end
+
+# Incomplete trait declaration
+trait
+
+# Missing methods in trait
+trait MyTrait
+end