diff --git a/genc/cc/base/context.cc b/genc/cc/base/context.cc
index 37716a1..79e67ca 100644
--- a/genc/cc/base/context.cc
+++ b/genc/cc/base/context.cc
@@ -38,17 +38,17 @@ std::shared_ptr<ContextStack> GetContextStack() {
 }
 
 void ContextStack::SetDefaultContext(std::shared_ptr<Context> ctx) {
-  absl::MutexLock lock(&mutex_);
+  absl::MutexLock lock(mutex_);
   default_context_ = ctx;
 }
 
 void ContextStack::AppendNestedContext(std::shared_ptr<Context> ctx) {
-  absl::MutexLock lock(&mutex_);
+  absl::MutexLock lock(mutex_);
   nested_contexts_.push_back(ctx);
 }
 
 absl::Status ContextStack::RemoveNestedContext(std::shared_ptr<Context> ctx) {
-  absl::MutexLock lock(&mutex_);
+  absl::MutexLock lock(mutex_);
   if (nested_contexts_.empty()) {
     return absl::FailedPreconditionError("No nested context on the stack.");
   }
@@ -61,7 +61,7 @@ absl::Status ContextStack::RemoveNestedContext(std::shared_ptr<Context> ctx) {
 }
 
 std::shared_ptr<Context> ContextStack::CurrentContext() const {
-  absl::ReaderMutexLock lock(&mutex_);
+  absl::ReaderMutexLock lock(mutex_);
   if (!nested_contexts_.empty()) {
     return nested_contexts_.back();
   }