https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103749
Bug ID: 103749
Summary: Misleading error message on template/non-template
conflict
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: drepper.fsp+rhbz at gmail dot com
Target Milestone: ---
This problem isn't new in the trunk version, it exists in all versions I
tested.
This is the code in question:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
struct foo {
template<typename>
friend struct bar;
};
struct bar {
int baz;
};
bar var;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is obviously buggy, the actual definition of 'bar' is not a template
class. This is exactly what clang tell me:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$ clang++ -c u.cc
u.cc:6:8: error: redefinition of 'bar' as different kind of symbol
struct bar {
^
u.cc:3:17: note: previous definition is here
friend struct bar;
^
u.cc:10:1: error: unknown type name 'bar'
bar var;
^
2 errors generated.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
With g++ the error messages are misleading and it also generates a lot more
unnecessary text:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$ g++ -c u.cc
u.cc:6:8: error: template argument required for ‘struct bar’
6 | struct bar {
| ^~~
u.cc:10:5: error: class template argument deduction failed:
10 | bar var;
| ^~~
u.cc:10:5: error: no matching function for call to ‘bar()’
u.cc:3:17: note: candidate: ‘template<class> bar()-> bar<
<template-parameter-1-1> >’
3 | friend struct bar;
| ^~~
u.cc:3:17: note: template argument deduction/substitution failed:
u.cc:10:5: note: couldn’t deduce template parameter
‘<template-parameter-1-1>’
10 | bar var;
| ^~~
u.cc:3:17: note: candidate: ‘template<class> bar(bar< <template-parameter-1-1>
>)-> bar< <template-parameter-1-1> >’
3 | friend struct bar;
| ^~~
u.cc:3:17: note: template argument deduction/substitution failed:
u.cc:10:5: note: candidate expects 1 argument, 0 provided
10 | bar var;
| ^~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
