/effect command doesn't fail when target has a stronger effect

The bug

The /effect command is supposed to fail with an error message when all of the targets already have that same effect with a higher amplifier. Instead, currently it reports success despite doing nothing.

How to reproduce

1. /effect @p poison 30 1 

2. /effect @p poison 25 

Expected result

The command should fail since you already have a stronger effect

Observed result

The command says it succeeded, but the effect was not actually applied