explicitly say that we are assuming post-desugaring place expressions

src/behavior-considered-undefined.md

@@ -110,7 +110,9 @@ type. (If there is no `*` projection in the place expression, then this is
 accessing the field of a local and rustc will guarantee proper alignment. If
 there are multiple `*` projection, then each of them incurs a load of the
 pointer-to-be-dereferenced itself from memory, and each of these loads is
-subject to the alignment constraint.)
+subject to the alignment constraint. Note that some `*` projections can be
+omitted in surface Rust syntax due to automatic dereferencing; we are
+considering the fully expanded place expression here.)
 
 For instance, if `ptr` has type `*const S` where `S` has an alignment of 8, then
 `ptr` must be 8-aligned or else `(*ptr).f` is "based on an misaligned pointer".