diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index cf92deaf7ca..f8d99302298 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,10 @@
+2006-07-07  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/28237
+	PR fortran/23420
+	* io.c (resolve_tag): Any integer that is not an assigned
+	variable is an error.
+
 2006-07-06  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
 
 	PR fortran/28129
diff --git a/gcc/fortran/io.c b/gcc/fortran/io.c
index aab5d39dc34..725e2da6655 100644
--- a/gcc/fortran/io.c
+++ b/gcc/fortran/io.c
@@ -1063,6 +1063,13 @@ resolve_tag (const io_tag * tag, gfc_expr * e)
 		  return FAILURE;
 		}
 	    }
+	  else if (e->ts.type == BT_INTEGER)
+	    {
+	      gfc_error ("scalar '%s' FORMAT tag at %L is not an ASSIGNED "
+			 "variable", gfc_basic_typename (e->ts.type), &e->where);
+	      return FAILURE;
+	    }
+
 	  return SUCCESS;
 	}
       else
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 272acc98a1b..095a51ced6d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2006-07-07  Paul Thomas  <pault@gcc.gnu.org>
+
+	PR fortran/28237
+	PR fortran/23420
+	* gfortran.dg/print_fmt_5.f90: New test.
+
 2006-07-06  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
 
 	PR fortran/28129
diff --git a/gcc/testsuite/gfortran.dg/print_fmt_5.f90 b/gcc/testsuite/gfortran.dg/print_fmt_5.f90
new file mode 100644
index 00000000000..fb37d753971
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/print_fmt_5.f90
@@ -0,0 +1,45 @@
+! { dg-do compile }
+! print_fmt_5.f90
+! Test of fix for PR28237 and the last bit of PR23420.  See
+! below for the description of the problem.
+!
+program r
+  character(12) :: for = '(i5)', left = '(i', right = ')'
+  integer :: i, j
+  integer :: h(4) &
+    = (/1h(, 1hi, 1h5, 1h)/)! { dg-warning "HOLLERITH|Hollerith" }
+  namelist /mynml/ i
+  i = fact ()
+!
+! All these are "legal" things to do; note however the warnings
+! for extensions or obsolete features!
+!
+  print *, fact()
+  print 100, fact()
+  print '(i5)', fact()
+  print mynml      ! { dg-warning "is an extension" }
+  do i = 1, 5
+    print trim(left)//char(iachar('0') + i)//trim(right), i
+  end do
+  assign 100 to i  ! { dg-warning "ASSIGN statement" }
+  print i, fact()  ! { dg-warning "ASSIGNED variable" }
+  print h, fact () ! { dg-warning "Non-character in FORMAT" }
+!
+! These are not and caused a segfault in trans-io:560
+!
+! PR28237
+  print fact()     ! { dg-error "not an ASSIGNED variable" }
+! original PR23420
+  print precision(1.2_8) ! { dg-error "type default CHARACTER" }
+! PR23420 points 4 and 5
+  print j + j      ! { dg-error "not an ASSIGNED variable" }
+! An extension of the above, encountered in writing the fix
+  write (*, fact())! { dg-error "not an ASSIGNED variable" }
+ 100 format (i5)
+contains
+  function fact()
+    integer :: fact
+    fact = 1
+  end function fact
+end
+