  Migration to OCaml 5 requires updating a lot of C bindings due to the removal
of naked pointer support. Writing OCaml user-defined primitives in C is a
necessity, but is unsafe and error-prone. It does not benefit from either
OCaml's or C's type checking, and existing C static analysers are not aware of
the OCaml GC safety rules, and cannot infer them from existing macros alone.The
alternative is automatically generating C stubs, which requires correctly
managing value lifetimes. Having a static analyser for OCaml to C interfaces is
useful outside the OCaml 5 porting effort too.
  After some motivating examples of real bugs in C bindings a static analyser
is presented that finds these known classes of bugs. The tool works on the
OCaml abstract parse and typed trees, and generates a header file and a caller
model. Together with a simplified model of the OCaml runtime this is used as
input to a static analysis framework, Goblint. An analysis is developed that
tracks dereferences of OCaml values, and together with the existing framework
reports incorrect dereferences. An example is shown how to extend the analysis
to cover more safety properties.
  The tools and runtime models are generic and could be reused with other
static analysis tools.
