--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gfortran.dg/der_charlen_1.f90	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,24 @@
+! { dg-do compile }
+! PR 18990
+! we used to ICE on these examples
+module core
+  type, public  :: T
+     character(len=I)  :: str ! { dg-error "needs to be a constant specification expression" }
+  end type T
+  private
+CONTAINS
+  subroutine FOO(X)
+    type(T), intent(in)          :: X
+  end subroutine
+end module core
+
+module another_core
+  type :: T
+     character(len=*)  :: s ! { dg-error "needs to be a constant specification expr" }
+  end type T
+  private
+CONTAINS
+  subroutine FOO(X)
+    type(T), intent(in)          :: X
+  end subroutine
+end module another_core