--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gfortran.dg/pr88072.f90	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,30 @@
+! { dg-do compile }
+! PR fortran/88072
+! Original code contributed by Andrew Wood <andrew at fluidgravity dot co.uk>
+module m1
+
+   implicit none
+
+   type, abstract, public :: t1
+      integer, dimension(:), allocatable :: i
+      contains
+         procedure(f1), deferred :: f
+   end type t1
+
+   type, extends(t1), public :: t2 ! { dg-error "must be ABSTRACT because" }
+      contains
+         procedure :: f => f2    ! { dg-error "mismatch for the overriding" }
+   end type t2
+
+   abstract interface
+      function f1(this)          ! { dg-error "must be dummy, allocatable or" }
+         import
+         class(t1) :: this
+         class(t1) :: f1
+      end function f1
+   end interface
+   contains
+      type(t2) function f2(this)
+         class(t2) :: this
+      end function f2
+end module m1