diff --git a/loopy/check.py b/loopy/check.py
index 0ef1f163aaed071d5dc4d219017b1164342be651..d3040ac90ad10a4fa9ebd2292a5d109ff36002a9 100644
--- a/loopy/check.py
+++ b/loopy/check.py
@@ -82,8 +82,9 @@ def check_for_inactive_iname_access(kernel):
         if not expression_inames <= kernel.insn_inames(insn):
             raise LoopyError(
                     "instruction '%s' references "
-                    "inames that the instruction does not depend on"
-                    % insn.id)
+                    "inames '%s' that the instruction does not depend on"
+                    % (insn.id,
+                        ", ".join(expression_inames - kernel.insn_inames(insn))))
 
 
 def _is_racing_iname_tag(tv, tag):