[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
--- Comment #25 from Jonathan Wakely ---
(In reply to AK from comment #24)
> The recent error messages look much better. Maybe we can close this.
>
> prog.cpp: In member function ‘void A::bar()’:
> prog.cpp:6:23: error: could not convert ‘A::foo()’ from ‘void’ to ‘bool’
>void bar() { if (foo()) ; }
There are other issues being tracked here, like the one in comment 12.
[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
AK changed:
What|Removed |Added
CC||hiraditya at msn dot com
--- Comment #24 from AK ---
The recent error messages look much better. Maybe we can close this.
prog.cpp: In member function ‘void A::bar()’:
prog.cpp:6:23: error: could not convert ‘A::foo()’ from ‘void’ to ‘bool’
void bar() { if (foo()) ; }
[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238 --- Comment #22 from David Malcolm --- (In reply to Manuel López-Ibáñez from comment #20) [...] > I maintain my opinion that any user-facing diagnostic using %qE is > potentially broken. Thanks; I'm inclined to agree. Notes to self: implementation of %qE is in cp/error.c:cp_printer, which calls expr_to_string. $ grep "%qE" gcc/cp/*.c | wc -l 195
[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238 --- Comment #21 from Manuel López-Ibáñez --- (In reply to David Malcolm from comment #19) > /tmp/test2.cc:9:24: error: return-statement with a value, in function > returning 'void' [-fpermissive] > return P->bar() + *P; > ^ And that location is terrible, but that is a different issue.
[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
David Malcolm changed:
What|Removed |Added
CC||dmalcolm at gcc dot gnu.org
--- Comment #19 from David Malcolm ---
gcc trunk (r232888 fwiw) currently emits this for comment #0:
/tmp/test.cc: In member function ‘void A::bar()’:
/tmp/test.cc:4:23: error: could not convert ‘A::foo()’ from ‘void’ to ‘bool’
void bar() { if (foo()) ; }
~~~^~
and this for the dup reported in PR 50817:
/tmp/test2.cc: In function ‘void test(foo*)’:
/tmp/test2.cc:9:21: error: no match for ‘operator+’ (operand types are ‘int’
and ‘foo’)
return P->bar() + *P;
~^~~~
/tmp/test2.cc:9:24: error: return-statement with a value, in function returning
'void' [-fpermissive]
return P->bar() + *P;
^
Is it time to close this one out as fixed?
[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
--- Comment #20 from Manuel López-Ibáñez ---
(In reply to David Malcolm from comment #19)
> Is it time to close this one out as fixed?
with gcc HEAD 6.0.0 20160127 and the testcase in comment #12, I get:
prog.cc: In member function 'void B::bar()':
prog.cc:8:25: error: could not convert '(((A*)this) + ((sizetype)(*(long
int*)(((B*)this)->B::_vptr.B + 18446744073709551592u->A::foo()' from 'void'
to 'bool'
void bar() { if (foo()) ; }
~~~^~
Clang:
prog.cc:8:22: error: value of type 'void' is not contextually convertible to
'bool'
void bar() { if (foo()) ; }
^
I maintain my opinion that any user-facing diagnostic using %qE is potentially
broken.
[Bug c++/22238] Awful error messages with virtual functions
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238 --- Comment #23 from David Malcolm --- Created attachment 37496 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37496=edit Patch to fix the case in comment #12 (for next stage 1)
[Bug c++/22238] Awful error messages with virtual functions
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
Manuel López-Ibáñez manu at gcc dot gnu.org changed:
What|Removed |Added
Status|ASSIGNED|NEW
CC||jason at gcc dot gnu.org,
||manu at gcc dot gnu.org
AssignedTo|gdr at gcc dot gnu.org |unassigned at gcc dot
||gnu.org
--- Comment #16 from Manuel López-Ibáñez manu at gcc dot gnu.org 2011-12-01
17:27:01 UTC ---
I think this is a duplicate of another PR I cannot find, but everything boils
down to please kill %qE and stop pretty-printing expressions. Behold the
beauty of clang:
pr22238.cc:8:20: error: value of type 'void' is not contextually convertible to
'bool'
void bar() { if (foo()) ; }
^
1 error generated.
(it looks even prettier with the default colors!)
[Bug c++/22238] Awful error messages with virtual functions
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238 --- Comment #17 from Jonathan Wakely redi at gcc dot gnu.org 2011-12-01 17:39:24 UTC --- (In reply to comment #16) I think this is a duplicate of another PR I cannot find PR 50817 ?
[Bug c++/22238] Awful error messages with virtual functions
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238 --- Comment #18 from Manuel López-Ibáñez manu at gcc dot gnu.org 2011-12-01 17:50:25 UTC --- *** Bug 50817 has been marked as a duplicate of this bug. ***
[Bug c++/22238] Awful error messages with virtual functions
--- Comment #14 from reichelt at gcc dot gnu dot org 2007-08-21 19:56 --- The pointer_plus_exprt stuff has been fixed. We are now back to error messages like bug.cc: In member function 'void B::bar()': bug.cc:4: error: could not convert '(((A*)this) + ((unsigned int)(*(int*)( ((B*)this)-B::_vptr.B + 0xfff4u-A::foo()' to 'bool' -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
[Bug c++/22238] Awful error messages with virtual functions
--- Comment #15 from gdr at cs dot tamu dot edu 2007-08-21 20:27 --- Subject: Re: Awful error messages with virtual functions reichelt at gcc dot gnu dot org [EMAIL PROTECTED] writes: | The pointer_plus_exprt stuff has been fixed. | | We are now back to error messages like | | bug.cc: In member function 'void B::bar()': | bug.cc:4: error: could not convert '(((A*)this) + ((unsigned int)(*(int*)( | ((B*)this)-B::_vptr.B + 0xfff4u-A::foo()' to 'bool' Until we have a separate higher level representation in the C++ front-end, this is going to be hard to fix correctly. The alternative is that we don't print expressions at all -- but that cure seems to me to be worse than the disease. -- Gaby -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
[Bug c++/22238] Awful error messages with virtual functions
--- Comment #12 from reichelt at gcc dot gnu dot org 2007-06-17 23:40
---
Andrew, Gaby's testcase from comment #4 gets an even worse diagnostic
since the merge of the ptr_plus stuff:
=
struct A
{
void foo();
};
struct B : virtual A
{
void bar() { if (foo()) ; }
};
=
bug.cc: In member function 'void B::bar()':
bug.cc:8: error: could not convert '#'pointer_plus_expr' not supported by
dump_expr#expression error-A::foo()' to 'bool'
Would you mind having a look?
--
reichelt at gcc dot gnu dot org changed:
What|Removed |Added
CC||pinskia at gcc dot gnu dot
||org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
[Bug c++/22238] Awful error messages with virtual functions
--- Comment #13 from pinskia at gcc dot gnu dot org 2007-06-17 23:42 --- Would you mind having a look? I was going to fix the pretty printing of pointer_plus_expr for C++ after I returned from Japan. I already have a testcase which is better than the one here. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22238
