diff --git a/inst/include/cpp11/data_frame.hpp b/inst/include/cpp11/data_frame.hpp
index a4748de0..6be16400 100644
--- a/inst/include/cpp11/data_frame.hpp
+++ b/inst/include/cpp11/data_frame.hpp
@@ -1,7 +1,6 @@
 #pragma once
 
-#include <cstdlib>  // for abs
-#include <cstdlib>
+#include <cstdlib>           // for abs
 #include <initializer_list>  // for initializer_list
 #include <string>            // for string, basic_string
 #include <utility>           // for move
diff --git a/inst/include/cpp11/external_pointer.hpp b/inst/include/cpp11/external_pointer.hpp
index a62134ec..133feab4 100644
--- a/inst/include/cpp11/external_pointer.hpp
+++ b/inst/include/cpp11/external_pointer.hpp
@@ -38,7 +38,7 @@ class external_pointer {
 
     T* ptr = static_cast<T*>(R_ExternalPtrAddr(p));
 
-    if (ptr == NULL) {
+    if (ptr == nullptr) {
       return;
     }
 
diff --git a/inst/include/cpp11/function.hpp b/inst/include/cpp11/function.hpp
index 42fbdcf6..448a6b27 100644
--- a/inst/include/cpp11/function.hpp
+++ b/inst/include/cpp11/function.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <string.h>  // for strcmp
+#include <cstring>  // for std::strcmp (@pachadotdev use std qualifiers)
 
 #include <cstdio>   // for snprintf
 #include <string>   // for string, basic_string
diff --git a/inst/include/cpp11/list.hpp b/inst/include/cpp11/list.hpp
index be29bb2a..66cd99c7 100644
--- a/inst/include/cpp11/list.hpp
+++ b/inst/include/cpp11/list.hpp
@@ -79,7 +79,8 @@ inline r_vector<SEXP>::r_vector(std::initializer_list<named_arg> il)
     : cpp11::r_vector<SEXP>(safe[Rf_allocVector](VECSXP, il.size())),
       capacity_(il.size()) {
   unwind_protect([&] {
-    SEXP names = Rf_allocVector(STRSXP, capacity_);
+    SEXP names;
+    PROTECT(names = Rf_allocVector(STRSXP, capacity_));
     Rf_setAttrib(data_, R_NamesSymbol, names);
 
     auto it = il.begin();
@@ -91,6 +92,8 @@ inline r_vector<SEXP>::r_vector(std::initializer_list<named_arg> il)
       SEXP name = Rf_mkCharCE(it->name(), CE_UTF8);
       SET_STRING_ELT(names, i, name);
     }
+
+    UNPROTECT(1);
   });
 }
 
diff --git a/inst/include/cpp11/r_vector.hpp b/inst/include/cpp11/r_vector.hpp
index 576f4fe6..b2e512fe 100644
--- a/inst/include/cpp11/r_vector.hpp
+++ b/inst/include/cpp11/r_vector.hpp
@@ -865,7 +865,8 @@ inline r_vector<T>::r_vector(std::initializer_list<named_arg> il)
   }
 
   unwind_protect([&] {
-    SEXP names = Rf_allocVector(STRSXP, capacity_);
+    SEXP names;
+    PROTECT(names = Rf_allocVector(STRSXP, capacity_));
     Rf_setAttrib(data_, R_NamesSymbol, names);
 
     auto it = il.begin();
@@ -890,6 +891,8 @@ inline r_vector<T>::r_vector(std::initializer_list<named_arg> il)
       SEXP name = Rf_mkCharCE(it->name(), CE_UTF8);
       SET_STRING_ELT(names, i, name);
     }
+
+    UNPROTECT(1);
   });
 }