tweak the slogan

diff --git a/personal/_posts/2018-08-22-two-kinds-of-invariants.md b/personal/_posts/2018-08-22-two-kinds-of-invariants.md
index b403c70b1f58d38eb5cbde43728c310d6a4aa12e..a90dc47c9ba7cb25f812d7683280a1d2bc7e4415 100644 (file)
--- a/personal/_posts/2018-08-22-two-kinds-of-invariants.md
+++ b/personal/_posts/2018-08-22-two-kinds-of-invariants.md
@@ -180,7 +180,7 @@ My gut feeling is that it should not be (i.e., validity should require that `i32
 I have talked about two kinds of invariants that come with every type, the safety invariant and the validity invariant.
 For unsafe code authors, the slogan summarizing this post is:
 
-> *You must always be valid, but you must not always be safe.*
+> *You must always be valid, but you must only be safe in safe code.*
 
 I think we have enough experience writing unsafe code at this point that we can reasonably discuss which validity invariants make sense and which do not -- and I think that it is high time that we do so, because many unsafe code authors are wondering about these exact things all the time.