Dear all,

gfortran's array bounds-checking code does a mostly reasonable
job for array sections in expressions and assignments, but
forgot the case that (rank-1) expressions can involve array
constructors, which have a shape ;-)

The attached patch walks over the loops generated by the
scalarizer, checks for the presence of a constructor, and
takes the first shape found as reference.  (If several
constructors are present, discrepancies in their shape
seems to be already detected at compile time).

For more details on what will be caught now see testcase.

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

Thanks,
Harald