--- a/src/google/protobuf/compiler/importer.cc	(d9b2a82a272102f9099f5bc0cb767279d3e89e3a)
+++ b/src/google/protobuf/compiler/importer.cc	(0dd6d02cb89a06c67e29040284d9239dfe0024b7)
@@ -442,7 +442,7 @@ bool DiskSourceTree::VirtualFileToDiskFile(absl::string_view virtual_file,
   return stream != nullptr;
 }
 
-io::ZeroCopyInputStream* DiskSourceTree::Open(absl::string_view filename) {
+io::ZeroCopyInputStream* DiskSourceTree::Open(const TProtoStringType& filename) {
   return OpenVirtualFile(filename, nullptr);
 }
 
--- a/src/google/protobuf/compiler/importer.h	(d9b2a82a272102f9099f5bc0cb767279d3e89e3a)
+++ b/src/google/protobuf/compiler/importer.h	(0dd6d02cb89a06c67e29040284d9239dfe0024b7)
@@ -245,7 +245,7 @@ class PROTOBUF_EXPORT SourceTree {
   // found.  The caller takes ownership of the returned object.  The filename
   // must be a path relative to the root of the source tree and must not
   // contain "." or ".." components.
-  virtual io::ZeroCopyInputStream* Open(absl::string_view filename) = 0;
+  virtual io::ZeroCopyInputStream* Open(const TProtoStringType& filename) = 0;
 
   // If Open() returns NULL, calling this method immediately will return an
   // description of the error.
@@ -322,7 +322,7 @@ class PROTOBUF_EXPORT DiskSourceTree : public SourceTree {
                              TProtoStringType* disk_file);
 
   // implements SourceTree -------------------------------------------
-  io::ZeroCopyInputStream* Open(absl::string_view filename) override;
+  io::ZeroCopyInputStream* Open(const TProtoStringType& filename) override;
 
   TProtoStringType GetLastErrorMessage() override;