[BUG] Empty template argument list is ill-formed

[JohelEGP]

Title: Empty template argument list is ill-formed.

Description:

Despite the grammar allowing it:

//G template-id:
//G     identifier '<' template-argument-list? '>'

Minimal reproducer (https://cpp2.godbolt.org/z/TvMhbhcTq):

main: () = { std::plus<>(); }

Commands:

cppfront -clean-cpp1 main.cpp2
clang++17 -std=c++2b -stdlib=libc++ -lc++abi -pedantic-errors -Wall -Wextra -Wconversion -I . main.cpp

Expected result:

A well-formed program.

Actual result and error:

Output.

main.cpp2...

main.cpp2(1,12): error: ill-formed initializer (at '{')
main.cpp2(1,1): error: unexpected text at end of Cpp2 code section (at 'main')
main.cpp2(1,0): error: parse failed for section starting here