https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78850
Bug ID: 78850
Summary: Parameter of returned generic lambda allegedly shadows
parameter of free function
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: daiw at gmx dot net
Target Milestone: ---
Compiling the following code
template <typename X, typename F>
auto apply(X x, F f)
{
return f(x);
}
template <typename Y>
auto add_value(Y y)
{
return [y](auto x)
{
return x + y;
};
}
int main()
{
apply(1, add_value(2));
}
with g++ (e.g. v. 5.4, but also newer ones) gives false shadow warnings:
https://godbolt.org/g/MMJ51o
$ g++ -Wshadow -Werror -std=c++14 shadow_test.cpp
shadow_test.cpp: In instantiation of ‘add_value(Y)::<lambda(auto:1)> [with
auto:1 = int; Y = int]’:
shadow_test.cpp:4:13: required from ‘auto apply(X, F) [with X = int; F =
add_value(Y) [with Y = int]::<lambda(auto:1)>]’
shadow_test.cpp:18:26: required from here
shadow_test.cpp:10:22: error: declaration of ‘int x’ shadows a parameter
[-Werror=shadow]
return [y](auto x)
^
shadow_test.cpp:2:14: note: shadowed declaration is here
auto apply(X x, F f)
^
cc1plus: all warnings being treated as errors
Corresponding SO post:
http://stackoverflow.com/questions/41208811/parameter-of-returned-generic-lambda-allegedly-shadows-parameter-of-free-functio
