diff --git a/Shell/AST.cpp b/Shell/AST.cpp
index 8639bdc90be..5943f33663b 100644
--- a/Shell/AST.cpp
+++ b/Shell/AST.cpp
@@ -546,7 +546,7 @@ void CloseFdRedirection::dump(int level) const
 RefPtr<Value> CloseFdRedirection::run(RefPtr<Shell>)
 {
     Command command;
-    command.redirections.append(*new CloseRedirection(m_fd));
+    command.redirections.append(adopt(*new CloseRedirection(m_fd)));
     return create<CommandValue>(move(command));
 }
 
@@ -1122,8 +1122,8 @@ RefPtr<Value> Pipe::run(RefPtr<Shell> shell)
 
     auto pipe_write_end = new FdRedirection(STDIN_FILENO, -1, Rewiring::Close::Destination);
     auto pipe_read_end = new FdRedirection(STDOUT_FILENO, -1, pipe_write_end, Rewiring::Close::RefreshDestination);
-    first_in_right.redirections.append(*pipe_write_end);
-    last_in_left.redirections.append(*pipe_read_end);
+    first_in_right.redirections.append(adopt(*pipe_write_end));
+    last_in_left.redirections.append(adopt(*pipe_read_end));
     last_in_left.should_wait = false;
     last_in_left.is_pipe_source = true;
 
@@ -1238,7 +1238,7 @@ RefPtr<Value> ReadRedirection::run(RefPtr<Shell> shell)
     StringBuilder builder;
     builder.join(" ", path_segments);
 
-    command.redirections.append(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::Read));
+    command.redirections.append(adopt(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::Read)));
     return create<CommandValue>(move(command));
 }
 
@@ -1265,7 +1265,7 @@ RefPtr<Value> ReadWriteRedirection::run(RefPtr<Shell> shell)
     StringBuilder builder;
     builder.join(" ", path_segments);
 
-    command.redirections.append(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::ReadWrite));
+    command.redirections.append(adopt(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::ReadWrite)));
     return create<CommandValue>(move(command));
 }
 
@@ -1758,7 +1758,7 @@ RefPtr<Value> WriteAppendRedirection::run(RefPtr<Shell> shell)
     StringBuilder builder;
     builder.join(" ", path_segments);
 
-    command.redirections.append(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::WriteAppend));
+    command.redirections.append(adopt(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::WriteAppend)));
     return create<CommandValue>(move(command));
 }
 
@@ -1785,7 +1785,7 @@ RefPtr<Value> WriteRedirection::run(RefPtr<Shell> shell)
     StringBuilder builder;
     builder.join(" ", path_segments);
 
-    command.redirections.append(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::Write));
+    command.redirections.append(adopt(*new PathRedirection(builder.to_string(), m_fd, PathRedirection::Write)));
     return create<CommandValue>(move(command));
 }
 
diff --git a/Shell/AST.h b/Shell/AST.h
index 531e560bf27..d70ba1218b1 100644
--- a/Shell/AST.h
+++ b/Shell/AST.h
@@ -48,10 +48,11 @@ struct Position {
     bool contains(size_t offset) const { return start_offset <= offset && offset <= end_offset; }
 };
 
+struct FdRedirection;
 struct Rewiring : public RefCounted<Rewiring> {
     int source_fd { -1 };
     int dest_fd { -1 };
-    Rewiring* other_pipe_end { nullptr };
+    FdRedirection* other_pipe_end { nullptr };
     enum class Close {
         None,
         Source,
@@ -67,7 +68,7 @@ struct Rewiring : public RefCounted<Rewiring> {
     {
     }
 
-    Rewiring(int source, int dest, Rewiring* other_end, Close close)
+    Rewiring(int source, int dest, FdRedirection* other_end, Close close)
         : source_fd(source)
         , dest_fd(dest)
         , other_pipe_end(other_end)
@@ -121,20 +122,30 @@ private:
     virtual bool is_path_redirection() const override { return true; }
 };
 
-struct FdRedirection : public Redirection
-    , public Rewiring {
-
-    virtual Result<RefPtr<Rewiring>, String> apply() const override { return static_cast<RefPtr<Rewiring>>(this); }
+struct FdRedirection : public Redirection {
+    virtual Result<RefPtr<Rewiring>, String> apply() const override
+    {
+        return RefPtr<Rewiring>(adopt(*new Rewiring(source_fd, dest_fd, other_pipe_end, action)));
+    }
     virtual ~FdRedirection();
     FdRedirection(int source, int dest, Rewiring::Close close)
-        : Rewiring(source, dest, close)
+        : FdRedirection(source, dest, nullptr, close)
     {
     }
-    FdRedirection(int source, int dest, Rewiring* pipe_end, Rewiring::Close close)
-        : Rewiring(source, dest, pipe_end, close)
+
+    FdRedirection(int source, int dest, FdRedirection* pipe_end, Rewiring::Close close)
+        : source_fd(source)
+        , dest_fd(dest)
+        , other_pipe_end(pipe_end)
+        , action(close)
     {
     }
 
+    int source_fd { -1 };
+    int dest_fd { -1 };
+    FdRedirection* other_pipe_end { nullptr };
+    Rewiring::Close action { Rewiring::Close::None };
+
 private:
     virtual bool is_fd_redirection() const override { return true; }
 };
diff --git a/Shell/Builtin.cpp b/Shell/Builtin.cpp
index a1130947204..c3184eefa4e 100644
--- a/Shell/Builtin.cpp
+++ b/Shell/Builtin.cpp
@@ -698,7 +698,7 @@ int Shell::builtin_shift(int argc, const char** argv)
     }
 
     if (!argv_->is_list())
-        argv_ = *new AST::ListValue({ argv_ });
+        argv_ = adopt(*new AST::ListValue({ argv_ }));
 
     auto& values = static_cast<AST::ListValue*>(argv_.ptr())->values();
     if ((size_t)count > values.size()) {
diff --git a/Shell/Shell.cpp b/Shell/Shell.cpp
index 25ee4b5fd2d..cf6c66a9f70 100644
--- a/Shell/Shell.cpp
+++ b/Shell/Shell.cpp
@@ -287,8 +287,8 @@ Vector<AST::Command> Shell::expand_aliases(Vector<AST::Command> initial_commands
                         auto* ast = static_cast<AST::Execute*>(subcommand_ast.ptr());
                         subcommand_ast = ast->command();
                     }
-                    AST::Node& substitute = *new AST::Join(subcommand_ast->position(), subcommand_ast, *new AST::CommandLiteral(subcommand_ast->position(), command));
-                    for (auto& subst_command : substitute.run(*this)->resolve_as_commands(*this)) {
+                    RefPtr<AST::Node> substitute = adopt(*new AST::Join(subcommand_ast->position(), subcommand_ast, adopt(*new AST::CommandLiteral(subcommand_ast->position(), command))));
+                    for (auto& subst_command : substitute->run(*this)->resolve_as_commands(*this)) {
                         if (!subst_command.argv.is_empty() && subst_command.argv.first() == argv0) // Disallow an alias resolving to itself.
                             commands.append(subst_command);
                         else
@@ -596,8 +596,7 @@ Vector<RefPtr<Job>> Shell::run_commands(Vector<AST::Command>& commands)
                 auto path_redir = (const AST::PathRedirection*)redir.ptr();
                 dbg() << "redir path " << (int)path_redir->direction << " " << path_redir->path << " <-> " << path_redir->fd;
             } else if (redir->is_fd_redirection()) {
-                auto fd_redir = (const AST::FdRedirection*)redir.ptr();
-                dbg() << "redir fd " << fd_redir->source_fd << " -> " << fd_redir->dest_fd;
+                dbg() << "redir fd " << redir->source_fd << " -> " << redir->dest_fd;
             } else if (redir->is_close_redirection()) {
                 auto close_redir = (const AST::CloseRedirection*)redir.ptr();
                 dbg() << "close fd " << close_redir->fd;
diff --git a/Shell/main.cpp b/Shell/main.cpp
index d191474d911..be79d761d5c 100644
--- a/Shell/main.cpp
+++ b/Shell/main.cpp
@@ -187,7 +187,7 @@ int main(int argc, char** argv)
         Vector<String> args;
         for (auto* arg : script_args)
             args.empend(arg);
-        shell->set_local_variable("ARGV", *new AST::ListValue(move(args)));
+        shell->set_local_variable("ARGV", adopt(*new AST::ListValue(move(args))));
     }
 
     if (command_to_run) {