feat(resolver): add error for super outside of subclass

src/interpreter/resolver.py

@@ -31,6 +31,7 @@ class LoopType(Enum):
 class ClassType(Enum):
     NONE = auto()
     CLASS = auto()
+    SUBCLASS = auto()
 
 
 class Resolver(Expr.Visitor[None], Stmt.Visitor[None]):
@@ -124,6 +125,10 @@ class Resolver(Expr.Visitor[None], Stmt.Visitor[None]):
         self.resolve_local(expr, expr.keyword)
 
     def visit_super_expr(self, expr: SuperExpr) -> None:
+        if self.current_class == ClassType.NONE:
+            Pebble.token_error(expr.keyword, "Cannot use 'super' outside of a class.")
+        elif self.current_class != ClassType.SUBCLASS:
+            Pebble.token_error(expr.keyword, "Cannot use 'super' in a class with no superclass.")
         self.resolve_local(expr, expr.keyword)
 
     def visit_block_stmt(self, stmt: BlockStmt) -> None:
@@ -140,6 +145,7 @@ class Resolver(Expr.Visitor[None], Stmt.Visitor[None]):
         if stmt.superclass is not None:
             if stmt.name.lexeme == stmt.superclass.name.lexeme:
                 Pebble.token_error(stmt.superclass.name, "A class cannot inherit from itself.")
+            self.current_class = ClassType.SUBCLASS
             self.resolve(stmt.superclass)
 
             self.begin_scope()