compile to noop if tuple is empty

Author: BobTheBuidler

mypyc/irbuild/specialize.py

@@ -654,7 +654,11 @@ def translate_isinstance(builder: IRBuilder, expr: CallExpr, callee: RefExpr) ->
             obj = builder.accept(obj_expr, can_borrow=can_borrow)
             return builder.builder.isinstance_helper(obj, irs, expr.line)
 
-    if isinstance(type_expr, TupleExpr) and type_expr.items:
+    if isinstance(type_expr, TupleExpr):
+        if not type_expr.items:
+            # we can compile this case to a noop
+            return builder.false()
+    
         nodes: list[SymbolNode | None] = []
         for item in type_expr.items:
             if not isinstance(item, RefExpr):