[PATCH] D18683: Fix bug with duplicate struct types in Linker

[Rafael Espíndola via llvm-commits]

> I get that it's an open-source project and use-cases only get supported if someone contributes time, so I'm trying to help here. The change makes the code simpler, internally consistent and fixes a use case that previously worked.
>
> Are you just saying that IRMover is only meant to work for the particular use-case of the LLVM linker and other people who are trying to use it as a utiltiy to move IR between modules just need to deal with it?

Not necessarily, but the invariant you are trying to support is not
the direction we are trying to move. In fact, it is the opposite. You
are trying to say that if there is a type with a given name in the
destination it will be safe to assume it will be use when linking in
code.

The direction we are trying to move to is that types are non recursive
and always structurally merged.

Cheers,
Rafael