https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64758
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
For this code:
enum class foo : bar { baz };
auto x = foo::baz;
We give:
e.C:1:6: warning: elaborated-type-specifier for a scoped enum must not use the
‘class’ keyword
1 | enum class foo : bar { baz };
| ~~~~ ^~~~~
| -----
e.C:1:16: error: found ‘:’ in nested-name-specifier, expected ‘::’
1 | enum class foo : bar { baz };
| ^
| ::
e.C:1:12: error: ‘foo’ has not been declared
1 | enum class foo : bar { baz };
| ^~~
e.C:1:22: error: expected unqualified-id before ‘{’ token
1 | enum class foo : bar { baz };
| ^
e.C:2:10: error: ‘foo’ has not been declared
2 | auto x = foo::baz;
| ^~~
Every one of these diagnostics is the result of bad error recovery from the
initial problem.
The warning is just nonsense. The first error is a bad recovery, we should not
assume it's a bested-name-specifier, we should assume it's an enum-base with an
undeclared type in the type-specifier-seq. The remaining errors are because we
failed to do anything useful with the bad enum definition.
I suggest that we should notice that ": bar" is bad, give an error about "bar"
being undeclared, and then act as though no enum-base was present for the rest
of the compilation. All the other diagnostics should vanish at that point.
We won't complain about a bogus elaborared-type-specifier that isn't present.
We won't say 'foo' is undeclared. We won't complain about expecting an
unqualified-id (when one is actually present, just not one we recognize), and
we won't complain about foo::baz being undeclared.
