diff --git a/mlir/lib/IR/Operation.cpp b/mlir/lib/IR/Operation.cpp
--- a/mlir/lib/IR/Operation.cpp
+++ b/mlir/lib/IR/Operation.cpp
@@ -727,7 +727,8 @@
                                                     unsigned numOperands) {
   if (op->getNumOperands() < numOperands)
     return op->emitOpError()
-           << "expected " << numOperands << " or more operands";
+           << "expected " << numOperands << " or more operands, but found "
+           << op->getNumOperands();
   return success();
 }