This happens because the name of captured variables is the same but the
type is not. The type is merge after the branch but not checked to be
compatible with the function type.

A simple fix should disallow merging the functions because they capture
variables of different types.

This is a particularly nasty bug because it does not surface until
running the code. It may cause strictly less validation than expected
but never more (i.e. funds may get locked but not be stolen)

deep session