https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79620
Bug ID: 79620
Summary: decltype() inside a lambda capturing-by-value
Product: gcc
Version: 6.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: lh_mouse at 126 dot com
Target Milestone: ---
The following example copied from the C++17 draft [N4582] fails to compile:
----------------------------------------
void f3() {
float x, &r = x;
[=] { // x and r are not captured (appearance in a
decltype operand is not an odr-use)
decltype(x) y1; // y1 has type float
decltype((x)) y2 = y1; // y2 has type float const& because this lambda
// is not mutable and x is an lvalue
decltype(r) r1 = y1; // r1 has type float& (transformation not
considered)
decltype((r)) r2 = y2; // r2 has type float const&
};
}
----------------------------------------
E:\Desktop>g++ -pedantic -pedantic-errors -std=c++14 test.cpp
test.cpp: In lambda function:
test.cpp:8:22: error: binding 'const float' to reference of type 'float&'
discards qualifiers
decltype((r)) r2 = y2; // r2 has type float const&
^~
