https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105344
Bug ID: 105344
Summary: std::source_location::curent() seemingly treated as a
pure function in template specializations
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jan at twosigma dot com
Target Milestone: ---
When using std::source_location::current().line() in certain contexts on two
different lines, gcc seems to incorrectly think the expression refers to the
same value.
Testcase:
#include <source_location>
#include <utility>
template <int i, class = void> struct foo;
// Two following two specializations are different, yet gcc errors out,
// claiming they are the same.
template <int i>
struct foo<i, std::enable_if_t<i == std::source_location::current().line()>> {
static constexpr int num = i;
};
template <int i>
struct foo<i, std::enable_if_t<i == std::source_location::current().line()>> {
static constexpr int num = i;
};
This outputs:
<source>:14:8: error: redefinition of 'struct foo<i, typename std::enable_if<(i
== std::source_location::current().std::source_location::line()), void>::type>'
14 | struct foo<i, std::enable_if_t<i ==
std::source_location::current().line()>> {
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:9:8: note: previous definition of 'struct foo<i, typename
std::enable_if<(i ==
std::source_location::current().std::source_location::line()), void>::type>'
9 | struct foo<i, std::enable_if_t<i ==
std::source_location::current().line()>> {
|
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Compiler returned: 1
https://godbolt.org/z/ozf1MbG3n shows this code works fine under MSVC.
