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Date: Fri, 16 May 2003 20:06:00 -0000
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To: nobody@gcc.gnu.org
Cc: gcc-prs@gcc.gnu.org,
From: Wolfgang Bangerth <bangerth@ices.utexas.edu>
Subject: Re: c++/9452: [2003-05-03] ICE (segfault) using a dependent expression
 as argument for the template-id in the return type
Reply-To: Wolfgang Bangerth <bangerth@ices.utexas.edu>
X-SW-Source: 2003-05/txt/msg01888.txt.bz2
List-Id: <gcc-prs.sourceware.org>

The following reply was made to PR c++/9452; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ices.utexas.edu>
To: Giovanni Bajo <giovannibajo@libero.it>
Cc: gcc-bugs@gcc.gnu.org, <gcc-gnats@gcc.gnu.org>,
   Gabriel Dos Reis <gdr@integrable-solutions.net>
Subject: Re: c++/9452: [2003-05-03] ICE (segfault) using a dependent expression
 as argument for the template-id in the return type
Date: Fri, 16 May 2003 15:02:12 -0500 (CDT)

 > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=9452
 > 
 > I think the segfault happens while trying to format the error message.
 
 No, that's not the case. The error happens here (this is present mainline):
 
 #0  convert_from_reference (val=0x40159528)
     at ../../gcc-3.4-CVS/gcc/cp/cvt.c:557
 #1  0x08052c35 in prep_operand (operand=0x40159528)
     at ../../gcc-3.4-CVS/gcc/cp/call.c:3561
 #2  0x08052f79 in build_new_op (code=MINUS_EXPR, flags=3, arg1=0x40159528, 
     arg2=0x401a0f28, arg3=0x0) at ../../gcc-3.4-CVS/gcc/cp/call.c:3662
 #3  0x081143f6 in build_x_binary_op (code=MINUS_EXPR, arg1=0x40159528, 
     arg2=0x0) at ../../gcc-3.4-CVS/gcc/cp/typeck.c:2947
 #4  0x0809e635 in tsubst_template_arg_vector (t=0x401a0f50, args=0x40159510, 
     complain=tf_none) at ../../gcc-3.4-CVS/gcc/cp/pt.c:5676
 #5  0x0809ed80 in tsubst_aggr_type (t=0x401aabd0, args=0x40159510, 
     complain=tf_none, in_decl=0x0, entering_scope=0)
     at ../../gcc-3.4-CVS/gcc/cp/pt.c:5794
 #6  0x080a2d7c in tsubst (t=0x401aac3c, args=0x40159510, complain=tf_none, 
     in_decl=0x0) at ../../gcc-3.4-CVS/gcc/cp/pt.c:6578
 #7  0x080a1f34 in tsubst_function_type (t=0x401aac3c, args=0x40159510, 
     complain=tf_none, in_decl=0x401aabd0) at ../../gcc-3.4-CVS/gcc/cp/pt.c:6445
 #8  0x080a30e8 in tsubst (t=0x401ad000, args=0x40159510, complain=tf_none, 
     in_decl=0x0) at ../../gcc-3.4-CVS/gcc/cp/pt.c:6960
 #9  0x080aedbd in fn_type_unification (fn=0x401ad0d8, explicit_targs=0x0, 
     targs=0x401ad000, args=0x401ac7bc, return_type=0x0, strict=DEDUCE_CALL, 
     len=-1) at ../../gcc-3.4-CVS/gcc/cp/pt.c:8649
 
 The place in convert_reference is this:
 
 tree
 convert_from_reference (tree val)
 {
   tree type = TREE_TYPE (val);
 
   if (TREE_CODE (type) == OFFSET_TYPE)           -------- here
     type = TREE_TYPE (type);
   if (TREE_CODE (type) == REFERENCE_TYPE)
     return build_indirect_ref (val, NULL);
   return val;
 }
 
 and the reason is that type==0x0. Now, as to why that is happening...
 
 W.
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth              email:            bangerth@ices.utexas.edu
                                www: http://www.ices.utexas.edu/~bangerth/