Update for_helpers.py

Author: BobTheBuidler

mypyc/irbuild/for_helpers.py

@@ -171,7 +171,7 @@ def for_loop_helper_with_index(
         body_insts: a function that generates the body of the loop.
                     It needs a index as parameter.
     """
-    assert is_sequence_rprimitive(expr_reg.type), expr_reg
+    assert is_sequence_rprimitive(expr_reg.type), (expr_reg, expr_reg.type)
     target_type = builder.get_sequence_type(expr)
 
     body_block = BasicBlock()
@@ -808,7 +808,7 @@ class ForSequence(ForGenerator):
     def init(
         self, expr_reg: Value, target_type: RType, reverse: bool, length: Value | None = None
     ) -> None:
-        assert is_sequence_rprimitive(expr_reg.type), expr_reg
+        assert is_sequence_rprimitive(expr_reg.type), (expr_reg, expr_reg.type)
         builder = self.builder
         # Record a Value indicating the length of the sequence, if known at compile time.
         self.length = length