Missing -Wc++98-compat-extra-semi warning in a class definition

[Quuxplusone]

Bugzilla Link	PR46607
Status	NEW
Importance	P normal
Reported by	Haoxin Tu (haoxintu@gmail.com)
Reported on	2020-07-06 09:47:11 -0700
Last modified on	2020-07-06 11:26:40 -0700
Version	trunk
Hardware	PC Linux
CC	llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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Hi, all.

This code, test.cc, Clang gives the right -Wc++98-compat-extra-semi warning in
a normal function defintion but misses the warning in function defined inside a
class definition.

$cat test.cc
void foo () { }; //warning
template  <typename> void foo() {}; //warning
class A {
    void foo () { }; //no warning
    template  <typename> void foo() {}; //no warning
};

$clang++ -c -Wc++98-compat-extra-semi test.cc
test.cc:1:16: warning: extra ';' outside of a function is incompatible with
C++98 [-Wc++98-compat-extra-semi]
void foo () { }; //warning
               ^
test.cc:2:35: warning: extra ';' outside of a function is incompatible with
C++98 [-Wc++98-compat-extra-semi]
template  <typename> void foo() {}; //warning
                                  ^
2 warnings generated.

I guess Clang should treats the same with above four lines. Is clang dealing
with this code for intentionally?

Every version from clang 7.0 to trunk behaves the same.

Thanks,
Haoxin

[Quuxplusone]

The C++98 specification strangely permitted an optional semicolon after a
member function definition:

member-declaration:
    function-definition ;[opt]

As a consequence, clang allows a single semicolon in this position but
diagnoses if there are two or more semicolons.

I think the case with a member function *template* is a minor bug, though: that
uses a different grammar production that does not permit a trailing semicolon,
so pedantically we should diagnose that, even though it will make the behaviour
in your testcase look even more arbitrary.