Unclassifiable statement error with procedure pointer using template named "structure_"

[Andrew Benson <abenson at carnegiescience dot edu>]

I've opened PR77584 

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77584

for the following bug.

In gfortran 7.0.0 (r240119) the following causes an error on compilation:

module bug
  abstract interface
     double precision function structure_()
     end function structure_
  end interface
contains
  double precision function a()
    procedure(structure_), pointer :: b
  end function a
end module bug

$ gfortran -v
Using built-in specs.
COLLECT_GCC=gfortran
COLLECT_LTO_WRAPPER=/home/abenson/Galacticus/Tools/libexec/gcc/x86_64-pc-
linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/home/abenson/Galacticus/
Tools --enable-languages=c,c++,fortran --disable-multilib
Thread model: posix
gcc version 7.0.0 20160913 (experimental) (GCC) 

$ gfortran -c tmp.F90 -o tmp.o
tmp.F90:8:4:

     procedure(structure_), pointer :: b
    1
Error: Unclassifiable statement at (1)


The problem seems to occur only if the interface name begins with "structure", 
so my guess is that this part of the name if being interpreted as a STRUCTURE 
statement.

-- 

* Andrew Benson: http://users.obs.carnegiescience.edu/abenson/contact.html

* Galacticus: http://sites.google.com/site/galacticusmodel