re PR fortran/84412 (Erroneous "Inquire statement identifies an internal file" error)

2018-02-18  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR libgfortran/84412
	* io/transfer.c (finalize_transfer): After completng an internal unit
	I/O operation, clear internal_unit_kind.

From-SVN: r257791

gcc/testsuite/gfortran.dg/inquire_18.f90

+! { dg-do run }
+! PR84412 Wrong "Inquire statement identifies an internal file" error 
+program bug
+  implicit none
+  integer          :: i
+  character(len=1) :: s
+  write (s,'(i1)') 0
+  open(newUnit=i,file='inquire_18.txt',status='unknown')
+  inquire(unit=i)
+  close(i, status="delete")
+end program bug

libgfortran/ChangeLog

+2018-02-18  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
+
+	PR libgfortran/84412
+	* io/transfer.c (finalize_transfer): After completng an internal unit
+	I/O operation, clear internal_unit_kind.
+
 2018-02-12  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	* libgfortran.h (GFC_ARRAY_DESCRIPTOR): Remove dimension

libgfortran/io/transfer.c

@@ -3993,6 +3993,10 @@ finalize_transfer (st_parameter_dt *dtp)
 
   if (dtp->u.p.unit_is_internal)
     {
+      /* The unit structure may be reused later so clear the
+	 internal unit kind.  */
+      dtp->u.p.current_unit->internal_unit_kind = 0;
+
       fbuf_destroy (dtp->u.p.current_unit);
       if (dtp->u.p.current_unit
 	  && (dtp->u.p.current_unit->child_dtio  == 0)