https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86375
Bug ID: 86375
Summary: Lambda call in template parameter causes compile time
error
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: antoshkka at gmail dot com
Target Milestone: ---
Following example fail to compile:
template <int I> struct stuff {};
stuff< [](){ return 42; }() > a; // Calling a constexpr lambda
Error message:
lambda-expression in template-argument
stuff< [](){ return 42; }() > a;
Replacing the lambda with variable that holds lambda works well:
template <int I> struct stuff {};
auto f = [](){ return 42; };
stuff< f() > b; // OK
Clang compiles the first example well.
