diff --git a/src/frontends/lean/frontend_elaborator.cpp b/src/frontends/lean/frontend_elaborator.cpp
index 787f04bb9..0430d8209 100644
--- a/src/frontends/lean/frontend_elaborator.cpp
+++ b/src/frontends/lean/frontend_elaborator.cpp
@@ -507,7 +507,7 @@ public:
     }
 };
 
-frontend_elaborator::frontend_elaborator(environment const & env):m_ptr(new imp(env)) {}
+frontend_elaborator::frontend_elaborator(environment const & env):m_ptr(std::make_shared<imp>(env)) {}
 frontend_elaborator::~frontend_elaborator() {}
 std::pair<expr, metavar_env> frontend_elaborator::operator()(expr const & e) { return m_ptr->elaborate(e); }
 std::tuple<expr, expr, metavar_env> frontend_elaborator::operator()(name const & n, expr const & t, expr const & e) {
diff --git a/src/kernel/environment.cpp b/src/kernel/environment.cpp
index c979ee4cd..97eb697b2 100644
--- a/src/kernel/environment.cpp
+++ b/src/kernel/environment.cpp
@@ -461,14 +461,14 @@ environment_cell::~environment_cell() {
 }
 
 environment::environment():
-    m_ptr(new environment_cell()) {
+    m_ptr(std::make_shared<environment_cell>()) {
     m_ptr->m_this = m_ptr;
     m_ptr->m_type_checker.reset(new type_checker(*this));
 }
 
 // used when creating a new child environment
 environment::environment(std::shared_ptr<environment_cell> const & parent, bool):
-    m_ptr(new environment_cell(parent)) {
+    m_ptr(std::make_shared<environment_cell>(parent)) {
     m_ptr->m_this = m_ptr;
     m_ptr->m_type_checker.reset(new type_checker(*this));
 }
diff --git a/src/kernel/environment.h b/src/kernel/environment.h
index 806594855..dd30e6429 100644
--- a/src/kernel/environment.h
+++ b/src/kernel/environment.h
@@ -78,10 +78,10 @@ class environment_cell {
     bool already_imported(name const & n) const;
     bool mark_imported_core(name n);
 
-    environment_cell(std::shared_ptr<environment_cell> const & parent);
 
 public:
     environment_cell();
+    environment_cell(std::shared_ptr<environment_cell> const & parent);
     ~environment_cell();
 
     /** \brief Return true iff this environment has children environments. */
diff --git a/src/library/io_state.cpp b/src/library/io_state.cpp
index 7fbe2d58b..989b78284 100644
--- a/src/library/io_state.cpp
+++ b/src/library/io_state.cpp
@@ -11,15 +11,15 @@ Author: Leonardo de Moura
 namespace lean {
 io_state::io_state():
     m_formatter(mk_simple_formatter()),
-    m_regular_channel(new stdout_channel()),
-    m_diagnostic_channel(new stderr_channel()) {
+    m_regular_channel(std::make_shared<stdout_channel>()),
+    m_diagnostic_channel(std::make_shared<stderr_channel>()) {
 }
 
 io_state::io_state(options const & opts, formatter const & fmt):
     m_options(opts),
     m_formatter(fmt),
-    m_regular_channel(new stdout_channel()),
-    m_diagnostic_channel(new stderr_channel()) {
+    m_regular_channel(std::make_shared<stdout_channel>()),
+    m_diagnostic_channel(std::make_shared<stderr_channel>()) {
 }
 
 io_state::~io_state() {}
diff --git a/src/library/tactic/tactic.cpp b/src/library/tactic/tactic.cpp
index 60382a0ba..211a0851c 100644
--- a/src/library/tactic/tactic.cpp
+++ b/src/library/tactic/tactic.cpp
@@ -176,7 +176,7 @@ tactic trace_state_tactic() {
 tactic suppress_trace(tactic const & t) {
     return mk_tactic([=](ro_environment const & env, io_state const & io, proof_state const & s) -> proof_state_seq {
             io_state new_io(io);
-            std::shared_ptr<output_channel> out(new string_output_channel());
+            std::shared_ptr<output_channel> out(std::make_shared<string_output_channel>());
             new_io.set_diagnostic_channel(out);
             return t(env, new_io, s);
         });
diff --git a/src/tests/frontends/lean/pp.cpp b/src/tests/frontends/lean/pp.cpp
index 711abbb83..5f6cda659 100644
--- a/src/tests/frontends/lean/pp.cpp
+++ b/src/tests/frontends/lean/pp.cpp
@@ -72,7 +72,7 @@ static void tst4() {
 
 static void tst5() {
     environment env; io_state ios; init_frontend(env, ios);
-    std::shared_ptr<string_output_channel> out(new string_output_channel());
+    std::shared_ptr<string_output_channel> out(std::make_shared<string_output_channel>());
     ios.set_regular_channel(out);
     ios.set_option(name{"pp", "unicode"}, true);
     ios.set_option(name{"lean", "pp", "notation"}, true);
@@ -92,7 +92,7 @@ static expr mk_deep(unsigned depth) {
 
 static void tst6() {
     environment env; io_state ios; init_frontend(env, ios);
-    std::shared_ptr<string_output_channel> out(new string_output_channel());
+    std::shared_ptr<string_output_channel> out(std::make_shared<string_output_channel>());
     ios.set_regular_channel(out);
     expr t = mk_deep(10);
     ios.set_option(name{"lean", "pp", "max_depth"}, 5);
diff --git a/src/util/script_state.cpp b/src/util/script_state.cpp
index 9241f65d3..56b9e5db6 100644
--- a/src/util/script_state.cpp
+++ b/src/util/script_state.cpp
@@ -133,7 +133,7 @@ script_state to_script_state(lua_State * L) {
 }
 
 script_state::script_state():
-    m_ptr(new imp()) {
+    m_ptr(std::make_shared<imp>()) {
     m_ptr->save_weak_ptr(m_ptr);
 }