diff --git a/src/library/io_state.cpp b/src/library/io_state.cpp
index ed9da376d..04f71565f 100644
--- a/src/library/io_state.cpp
+++ b/src/library/io_state.cpp
@@ -37,7 +37,7 @@ io_state::io_state(options const & opts, formatter_factory const & fmtf):
     m_regular_channel(std::make_shared<stdout_channel>()),
     m_diagnostic_channel(std::make_shared<stderr_channel>()) {
 }
-io_state::io_state(io_state const & ios, std::shared_ptr<output_channel> const & r, std::shared_ptr<output_channel> const d):
+io_state::io_state(io_state const & ios, std::shared_ptr<output_channel> const & r, std::shared_ptr<output_channel> const & d):
     m_options(ios.m_options),
     m_formatter_factory(ios.m_formatter_factory),
     m_regular_channel(r),
diff --git a/src/library/io_state.h b/src/library/io_state.h
index 25888092a..889b3e01d 100644
--- a/src/library/io_state.h
+++ b/src/library/io_state.h
@@ -26,7 +26,7 @@ public:
     io_state();
     io_state(formatter_factory const & fmtf);
     io_state(options const & opts, formatter_factory const & fmtf);
-    io_state(io_state const & ios, std::shared_ptr<output_channel> const & r, std::shared_ptr<output_channel> const d);
+    io_state(io_state const & ios, std::shared_ptr<output_channel> const & r, std::shared_ptr<output_channel> const & d);
     io_state(io_state const & ios, options const & o);
     ~io_state();