diff --git a/lib/Conversion/MooreToCore/MooreToCore.cpp b/lib/Conversion/MooreToCore/MooreToCore.cpp
index 02853b166773..198329739d54 100644
--- a/lib/Conversion/MooreToCore/MooreToCore.cpp
+++ b/lib/Conversion/MooreToCore/MooreToCore.cpp
@@ -181,7 +181,7 @@ struct NamedConstantOpConv : public OpConversionPattern<NamedConstantOp> {
       break;
     }
     auto symAttr =
-        rewriter.getStringAttr(symStr + Twine(":") + adaptor.getName());
+        rewriter.getStringAttr(symStr + Twine("_") + adaptor.getName());
     rewriter.replaceOpWithNewOp<hw::WireOp>(op, resultType, adaptor.getValue(),
                                             op.getNameAttr(),
                                             hw::InnerSymAttr::get(symAttr));
diff --git a/test/Conversion/MooreToCore/basic.mlir b/test/Conversion/MooreToCore/basic.mlir
index 9aff21a335b9..a572c9223980 100644
--- a/test/Conversion/MooreToCore/basic.mlir
+++ b/test/Conversion/MooreToCore/basic.mlir
@@ -240,17 +240,17 @@ moore.module @SubModule_0(in %a : !moore.l1, in %b : !moore.l1, out c : !moore.l
 moore.module @ParamTest(){
 
   // CHECK-NEXT: [[Pa:%.+]] = hw.constant 1 : i32
-  // CHECK-NEXT: %p1 = hw.wire [[Pa]] sym @parameter:p1 : i32
+  // CHECK-NEXT: %p1 = hw.wire [[Pa]] sym @parameter_p1 : i32
   %0 = moore.constant 1 : l32
   %p1 = moore.named_constant parameter %0 : l32
 
   // CHECK-NEXT: [[LPa:%.+]] = hw.constant 2 : i32
-  // CHECK-NEXT: %lp1 = hw.wire [[LPa]] sym @localparameter:lp1 : i32
+  // CHECK-NEXT: %lp1 = hw.wire [[LPa]] sym @localparameter_lp1 : i32
   %1 = moore.constant 2 : l32
   %lp1 = moore.named_constant localparam %1 : l32
 
   // CHECK-NEXT: [[SPa:%.+]] = hw.constant 3 : i32
-  // CHECK-NEXT: %sp1 = hw.wire [[SPa]] sym @specparameter:sp1 : i32
+  // CHECK-NEXT: %sp1 = hw.wire [[SPa]] sym @specparameter_sp1 : i32
   %2 = moore.constant 3 : l32
   %sp1 = moore.named_constant specparam %2 : l32
 }