type-bound procedures, use association, and rogue namespaces

[Steve Kargl]

On Thu, Jun 13, 2019 at 12:55:06PM -0700, Steve Kargl wrote:
> So, I've taken a look at PR 89647, and it seems that
> the mechanism for resolving type-bound procedures does
> not know about USE association.  In resolve.c,
> resolve_typebound_procedure() at lines 13540 (or so)
> we have a type-bound entity, but its symbol has not
> been resolved.  I've added this bit of code (sorry
> about whitespace)
> 
> if (!proc->resolved
>     && proc->attr.function == 0 && proc->attr.subroutine == 0)
>   {
>      gfc_symbol *tmp;
>      gfc_find_symbol (proc->name, gfc_current_ns->parent, 1, &tmp);
>      proc = tmp;
>    }
> 
> which actually finds the USE associated symbol.  With Ian's 
> code and setting a breakpoint in gdb
> 
> (gdb) b resolve.c:13545
> Breakpoint 1 at 0x85c618: file ../../gccx/gcc/fortran/resolve.c, line 13545.
> (gdb) run a.f90
> Starting program: /safe/sgk/work/x/libexec/gcc/x86_64-unknown-freebsd13.0/10.0.0/f951 a.f90
> 
> Breakpoint 1, resolve_typebound_procedure (stree=0x2023feb10)
>     at ../../gccx/gcc/fortran/resolve.c:13545
> 13545             proc = tmp;
> (gdb) p stree->n.tb->u.specific->n.sym
> $1 = (gfc_symbol *) 0x202eceb00
> (gdb) p proc
> $2 = (gfc_symbol *) 0x202eceb00
> (gdb) p tmp
> $3 = (gfc_symbol *) 0x202ecdf00
> (gdb) call debug(proc)
> || symbol: 'true'         
>   type spec : (UNKNOWN 0)
>   attributes: (PROCEDURE )
> (gdb) call debug(tmp)
> || symbol: 'true'         
>   type spec : (LOGICAL 4)
>   attributes: (PROCEDURE MODULE-PROC  USE-ASSOC(m1) FUNCTION IMPLICIT_PURE)
>   result: b
> 
> Doing the assignment 'proc = tmp' get me pass the first hurdle.
> Unfortnately, one needs to do something like 
> 
>   stree->n.tb->u.specific->n.sym = tmp;
> 
> as well, but this leads to an ICE (possibly from freeing the symbol
> twice).
> 
> I've tried the obvious modification of adding 'resolve_symbol (proc)'
> as the first statement in the above block of code.  This, indeed,
> resolves the symbol but it puts it in the namespace of the local 
> scope of the function.  It does not find the USE associated symbol
> (i.e., tmp).  I also looked for a gfc_copy_sym (proc, tmp) function,
> but came up empty.  So, how does one update a symbol and get it
> recognized as USE associated?
> 

Well, this feels like a kludge, but appears to work.  Anyone
who is familiar with type-bound procedures have a better
idea?

Index: gcc/fortran/resolve.c
===================================================================
--- gcc/fortran/resolve.c	(revision 272259)
+++ gcc/fortran/resolve.c	(working copy)
@@ -13536,14 +13537,34 @@ resolve_typebound_procedure (gfc_symtree* stree)
     }
   else
     {
+      /* If proc has not been resolved at this point, proc->name may 
+	 actually be a USE associated entity. See PR fortran/89647. */
+      if (!proc->resolved
+	  && proc->attr.function == 0 && proc->attr.subroutine == 0)
+	{
+	  gfc_symbol *tmp;
+	  gfc_find_symbol (proc->name, gfc_current_ns->parent, 1, &tmp);
+	  if (tmp->attr.use_assoc)
+	    {
+	      proc->module = tmp->module;
+	      proc->attr.proc = tmp->attr.proc;
+	      proc->attr.function = tmp->attr.function;
+	      proc->attr.subroutine = tmp->attr.subroutine;
+	      proc->attr.use_assoc = tmp->attr.use_assoc;
+	      proc->ts = tmp->ts;
+	      proc->result = tmp->result;
+	    }
+	}
+
       /* Check for F08:C465.  */
       if ((!proc->attr.subroutine && !proc->attr.function)
 	  || (proc->attr.proc != PROC_MODULE
 	      && proc->attr.if_source != IFSRC_IFBODY)
 	  || proc->attr.abstract)
 	{
-	  gfc_error ("%qs must be a module procedure or an external procedure with"
-		    " an explicit interface at %L", proc->name, &where);
+	  gfc_error ("%qs must be a module procedure or an external "
+		     "procedure with an explicit interface at %L",
+		     proc->name, &where);
 	  goto error;
 	}
     }
-- 
Steve