handled.diff

diff --git a/lib/Mojo/Promise.pm b/lib/Mojo/Promise.pm
index 0c66018db..db09a0033 100644
--- a/lib/Mojo/Promise.pm
+++ b/lib/Mojo/Promise.pm
@@ -185,6 +185,7 @@ sub _defer {
   my $cbs = $self->{status} eq 'resolve' ? $self->{resolve} : $self->{reject};
   @{$self}{qw(cycle resolve reject)} = (undef, [], []);
 
+  $self->{handled} = 1 if $self->{status} eq 'reject' && @{ $cbs || [] };
   $self->ioloop->next_tick(sub { $_->(@$result) for @$cbs });
 }
 
@@ -228,6 +229,14 @@ sub _timer {
   return $self;
 }
 
+sub DESTROY {
+  no warnings 'uninitialized';
+  my $self = shift;
+  return if Mojo::Util::_global_destruction();
+  return if $self->{status} ne 'reject' || $self->{handled};
+  return $self->ioloop->reactor->emit(error => "Uncaught (in promise): @{$self->{result}}" );
+}
+
 1;
 
 =encoding utf8