diff --git a/lib/Dialect/mhlo/transforms/legalize_control_flow.cc b/lib/Dialect/mhlo/transforms/legalize_control_flow.cc
index b6e23a6..adf2a39 100644
--- a/lib/Dialect/mhlo/transforms/legalize_control_flow.cc
+++ b/lib/Dialect/mhlo/transforms/legalize_control_flow.cc
@@ -32,8 +32,6 @@ limitations under the License.
 #include "mlir/Pass/PassRegistry.h"
 #include "mlir/Support/LogicalResult.h"
 
-using mlir::PassRegistration;
-
 namespace mlir {
 namespace mhlo {
 namespace {
diff --git a/lib/Dialect/mhlo/transforms/lower_complex.cc b/lib/Dialect/mhlo/transforms/lower_complex.cc
index 9f7c946..90763b1 100644
--- a/lib/Dialect/mhlo/transforms/lower_complex.cc
+++ b/lib/Dialect/mhlo/transforms/lower_complex.cc
@@ -37,7 +37,6 @@ limitations under the License.
 
 using mlir::FunctionPass;
 using mlir::OwningRewritePatternList;
-using mlir::PassRegistration;
 using mlir::PassWrapper;
 
 namespace {
diff --git a/lib/Dialect/mhlo/transforms/lower_general_dot.cc b/lib/Dialect/mhlo/transforms/lower_general_dot.cc
index 8dec4bb..ada30a2 100644
--- a/lib/Dialect/mhlo/transforms/lower_general_dot.cc
+++ b/lib/Dialect/mhlo/transforms/lower_general_dot.cc
@@ -38,7 +38,6 @@ using mlir::LogicalResult;
 using mlir::MLIRContext;
 using mlir::OpRewritePattern;
 using mlir::OwningRewritePatternList;
-using mlir::PassRegistration;
 using mlir::PassWrapper;
 using mlir::PatternRewriter;
 using mlir::RankedTensorType;
diff --git a/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc b/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc
index 32a846e..febd442 100644
--- a/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc
+++ b/lib/Dialect/mhlo/transforms/optimize_mhlo_pass.cc
@@ -24,7 +24,6 @@ limitations under the License.
 #include "mlir/Transforms/DialectConversion.h"
 
 using mlir::FunctionPass;
-using mlir::PassRegistration;
 using mlir::PassWrapper;
 
 namespace {