Wrote test to check polymorphic array handling in where construct

Author: EbinJose2002

flang/test/Lower/polymorphic-array.f90

@@ -0,0 +1,27 @@
+! RUN: bbc -emit-fir %s -o - | FileCheck %s
+
+! Checks that no fir store is present with fir.class<none> as the first operand.
+! Regression test for bug: FIR lowering failure on polymorphic assignment.
+
+! CHECK-NOT: fir.store{{.*}}!fir.class<none>
+module m1
+  type x
+  end type x
+  logical,parameter::t=.true.,f=.false.
+  logical::mask(3)=[t,f,t]
+end module m1
+
+subroutine s1
+  use m1
+  class(*),allocatable::v(:),u(:)
+  allocate(x::v(3))
+  allocate(x::u(3))
+  where(mask)
+     u=v
+  end where
+end subroutine s1
+
+program main
+  call s1
+  print *,'pass'
+end program main