Dear all,

I intend to commit the attached patch as obvious to mainline
within the next 24h unless someone complains.  It replaces a
lazy gfc_internal_error by an explicit error message and an
error recovery path.

As a side-effect, we now diagnose a previously missed error
in testcase gfortran.dg/associate_54.f90 similarly to Intel.

Regtested on x86_64-pc-linux-gnu.

Thanks,
Harald