diff --git a/src/assert.cc b/src/assert.cc
index 74b939a4..1edf1e45 100644
--- a/src/assert.cc
+++ b/src/assert.cc
@@ -19,7 +19,7 @@ struct assert_failed : logic_error
     assert_failed(String message)
         : m_message(std::move(message)) {}
 
-    const char* what() const override { return m_message.c_str(); }
+    StringView what() const override { return m_message; }
 private:
     String m_message;
 };
diff --git a/src/client.cc b/src/client.cc
index ae18ebe4..dcd575b8 100644
--- a/src/client.cc
+++ b/src/client.cc
@@ -79,7 +79,7 @@ void Client::handle_available_input(EventMode mode)
         }
         catch (Kakoune::runtime_error& error)
         {
-            context().print_status({ error.what(), get_face("Error") });
+            context().print_status({ error.what().str(), get_face("Error") });
             context().hooks().run_hook("RuntimeError", error.what(), context());
         }
         catch (Kakoune::client_removed&)
diff --git a/src/client_manager.cc b/src/client_manager.cc
index b1b97888..974be41f 100644
--- a/src/client_manager.cc
+++ b/src/client_manager.cc
@@ -41,7 +41,7 @@ Client* ClientManager::create_client(std::unique_ptr<UserInterface>&& ui,
     }
     catch (Kakoune::runtime_error& error)
     {
-        client->context().print_status({ error.what(), get_face("Error") });
+        client->context().print_status({ error.what().str(), get_face("Error") });
         client->context().hooks().run_hook("RuntimeError", error.what(),
                                            client->context());
     }
diff --git a/src/exception.cc b/src/exception.cc
index 2b8fedc0..e97f2b6c 100644
--- a/src/exception.cc
+++ b/src/exception.cc
@@ -7,7 +7,7 @@
 namespace Kakoune
 {
 
-const char* exception::what() const
+StringView exception::what() const
 {
     return typeid(*this).name();
 }
diff --git a/src/exception.hh b/src/exception.hh
index 08647637..fd29017c 100644
--- a/src/exception.hh
+++ b/src/exception.hh
@@ -9,7 +9,7 @@ namespace Kakoune
 struct exception
 {
     virtual ~exception() {}
-    virtual const char* what() const;
+    virtual StringView what() const;
 };
 
 struct runtime_error : exception
@@ -17,7 +17,7 @@ struct runtime_error : exception
     runtime_error(String what)
         : m_what(std::move(what)) {}
 
-    const char* what() const override { return m_what.c_str(); }
+    StringView what() const override { return m_what.c_str(); }
 
 private:
     String m_what;
diff --git a/src/main.cc b/src/main.cc
index 88ea11a0..bb17dc83 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -307,7 +307,7 @@ int run_client(StringView session, StringView init_command)
     }
     catch (connection_failed& e)
     {
-        fputs(e.what(), stderr);
+        fputs(e.what().zstr(), stderr);
         return -1;
     }
     return 0;
@@ -448,7 +448,7 @@ int run_filter(StringView keystr, ConstArrayView<StringView> files, bool quiet)
             {
                 if (not quiet)
                     fprintf(stderr, "error while applying keys to buffer '%s': %s\n",
-                            buffer.display_name().c_str(), err.what());
+                            buffer.display_name().c_str(), (const char*)err.what().zstr());
             }
         };
 
@@ -471,7 +471,7 @@ int run_filter(StringView keystr, ConstArrayView<StringView> files, bool quiet)
     }
     catch (Kakoune::runtime_error& err)
     {
-        fprintf(stderr, "error: %s\n", err.what());
+        fprintf(stderr, "error: %s\n", (const char*)err.what().zstr());
     }
 
     buffer_manager.clear_buffer_trash();
@@ -497,7 +497,7 @@ int run_pipe(StringView session)
     }
     catch (connection_failed& e)
     {
-        fputs(e.what(), stderr);
+        fputs(e.what().zstr(), stderr);
         return -1;
     }
     return 0;
@@ -592,7 +592,7 @@ int main(int argc, char* argv[])
         printf("Error: %s\n"
                "Valid switches:\n"
                "%s",
-               error.what(),
+               (const char*)error.what().zstr(),
                generate_switches_doc(param_desc.switches).c_str());
        return -1;
     }