Merlin_typer: catch exceptions during checks
Merlin_typer: catch exceptions during checks

fxfactorial/merlin,ocaml/merlin,rgrinberg/merlin,ocaml/merlin,dra27/merlin,fxfactorial/merlin,the-lambda-church/merlin,dra27/merlin,the-lambda-church/merlin,rgrinberg/merlin,ocaml/merlin,rgrinberg/merlin,ocaml/merlin,the-lambda-church/merlin,rgrinberg/merlin,fxfactorial/merlin,dra27/merlin,fxfactorial/merlin,dra27/merlin