Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 266912)
+++ gcc/fortran/resolve.c	(working copy)
@@ -15493,7 +15493,10 @@ check_data_variable (gfc_data_variable *var, locus *wh
     e = e->value.function.actual->expr;
 
   if (e->expr_type != EXPR_VARIABLE)
-    gfc_internal_error ("check_data_variable(): Bad expression");
+    {
+      gfc_error ("Expecting definable entity near %L", where);
+      return false;
+    }
 
   sym = e->symtree->n.sym;
 
@@ -15501,6 +15504,7 @@ check_data_variable (gfc_data_variable *var, locus *wh
     {
       gfc_error ("BLOCK DATA element %qs at %L must be in COMMON",
 		 sym->name, &sym->declared_at);
+      return false;
     }
 
   if (e->ref == NULL && sym->as)
Index: gcc/testsuite/gfortran.dg/pr88048.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr88048.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/pr88048.f90	(working copy)
@@ -0,0 +1,7 @@
+! { dg-do compile }
+! PR fortran/88048
+program p
+   integer, parameter :: a(2) = 1
+   data a(2) /a(1)/                 ! { dg-error "definable entity" }
+   print *, a
+end