re PR fortran/49630 ([OOP] ICE on obsolescent deferred-length type bound character function)

2018-06-21  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/49630
	* resolve.c (resolve_contained_fntype): Change standard ref.
	from F95 to F2003: C418. Correct a spelling error in a comment.
	It is an error for an abstract interface to have an assumed
	character length result.
	* trans-expr.c (gfc_conv_procedure_call): Likewise change the
	standard reference.

2018-06-21  Paul Thomas  <pault@gcc.gnu.org>

	PR fortran/49630
	* gfortran.dg/assumed_charlen_function_7.f90: New test.

From-SVN: r261868

gcc/fortran/ChangeLog

 2018-06-21  Paul Thomas  <pault@gcc.gnu.org>
 
+	PR fortran/49630
+	* resolve.c (resolve_contained_fntype): Change standard ref.
+	from F95 to F2003: C418. Correct a spelling error in a comment.
+	It is an error for an abstract interface to have an assumed
+	character length result.
+	* trans-expr.c (gfc_conv_procedure_call): Likewise change the
+	standard reference.
+
+2018-06-21  Paul Thomas  <pault@gcc.gnu.org>
+
 	PR fortran/83118
 	* resolve.c (resolve_ordinary_assign): Force the creation of a
 	vtable for assignment of non-polymorphic expressions to an

gcc/fortran/resolve.c

@@ -601,9 +601,10 @@ resolve_contained_fntype (gfc_symbol *sym, gfc_namespace *ns)
 	}
     }
 
-  /* Fortran 95 Draft Standard, page 51, Section 5.1.1.5, on the Character
+  /* Fortran 2003 Draft Standard, page 535, C418, on type-param-value
      type, lists the only ways a character length value of * can be used:
-     dummy arguments of procedures, named constants, and function results
+     dummy arguments of procedures, named constants, function results and
+     in allocate statements if the allocate_object is an assumed length dummy
      in external functions.  Internal function results and results of module
      procedures are not on this list, ergo, not permitted.  */
 
@@ -3103,7 +3104,7 @@ resolve_function (gfc_expr *expr)
       return false;
     }
 
-  /* If this ia a deferred TBP with an abstract interface (which may
+  /* If this is a deferred TBP with an abstract interface (which may
      of course be referenced), expr->value.function.esym will be set.  */
   if (sym && sym->attr.abstract && !expr->value.function.esym)
     {
@@ -3112,6 +3113,17 @@ resolve_function (gfc_expr *expr)
       return false;
     }
 
+  /* If this is a deferred TBP with an abstract interface, its result
+     cannot be an assumed length character (F2003: C418).  */
+  if (sym && sym->attr.abstract && sym->attr.function
+      && sym->result->ts.u.cl->length == NULL)
+    {
+      gfc_error ("ABSTRACT INTERFACE %qs at %L must not have an assumed "
+		 "character length result (F2003: C418)", sym->name,
+		 &sym->declared_at);
+      return false;
+    }
+
   /* Switch off assumed size checking and do this again for certain kinds
      of procedure, once the procedure itself is resolved.  */
   need_full_assumed_size++;

gcc/fortran/trans-expr.c

@@ -5941,7 +5941,7 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
     {
       if (ts.u.cl->length == NULL)
 	{
-	  /* Assumed character length results are not allowed by 5.1.1.5 of the
+	  /* Assumed character length results are not allowed by C418 of the 2003
 	     standard and are trapped in resolve.c; except in the case of SPREAD
 	     (and other intrinsics?) and dummy functions.  In the case of SPREAD,
 	     we take the character length of the first argument for the result.

gcc/testsuite/ChangeLog

 2018-06-21  Paul Thomas  <pault@gcc.gnu.org>
 
+	PR fortran/49630
+	* gfortran.dg/assumed_charlen_function_7.f90: New test.
+
+2018-06-21  Paul Thomas  <pault@gcc.gnu.org>
+
 	PR fortran/83118
 	* gfortran.dg/unlimited_polymorphic_30.f03: New test.
 

gcc/testsuite/gfortran.dg/assumed_charlen_function_7.f90

+! { dg-do compile }
+!
+! Test the fix for PR49630, comment #11.
+!
+! Contributed by Vittorio Zecca  <zeccav@gmail.com>
+!
+module abc
+  implicit none
+  type,abstract::abc_abstract
+  contains
+    procedure(abc_interface),deferred::abc_function
+  end type abc_abstract
+  type,extends(abc_abstract)::abc_type
+  contains
+    procedure::abc_function
+  end type abc_type
+  abstract interface
+    function abc_interface(this) ! { dg-error "assumed character length result" }
+      import abc_abstract
+      class(abc_abstract),intent(in)::this
+      character(len=*)::abc_interface
+    end function abc_interface
+  end interface
+contains
+  function abc_function(this)
+    class(abc_type),intent(in)::this
+    character(len=5)::abc_function
+    abc_function="hello"
+  end function abc_function
+  subroutine do_something(this)
+    class(abc_abstract),intent(in)::this
+    print *,this%abc_function()
+  end subroutine do_something
+end module abc