(cpp) decltype(auto) preceded by specifiers

[Arcoth]

If constexpr decltype(auto) occurs in C++(14) code, decltype is not highlighted correctly, presumably since this looks like a function declaration with decltype being the name. This will also occur with other specifiers, e.g. friend, typedef, inline etc.

In fact, this can occur with keywords other than decltype. See e.g.

#define X
X new (p) int;

I'd suggest dropping that heuristic entirely.

[joshgoebel]

Is this still an issue?

Wouldn't it also be resolved by simply excluding keywords from IDENT_RE so that a keyword would never count as the name of a function? I assume there is no way to name a function a reserved keyword, correct?

[joshgoebel]

This is worth thought because the parser by default doesn't look for keywords first, it looks for "language constructs" (other parser rules) and then in-between those it will highlight any keywords. So the problem here is we first find what looks like a function and then we highlight it... so we're looking for a title at that point, not a keyword.

I wonder if this could be fixed with negative look-ahead, which is what I was hinting at.

I presume we "like" the ability to highlight function titles and that losing that would be a pretty big loss.

Can you provide a little more context regarding what constexpr decltype(auto) looks like in context of an actual C++ file?

[joshgoebel]

#define X
X new (p) int;

We're never going to be able to handle all edge cases involving pre-processor directives - since we don't have access to the actual source - only the raw source.

[joshgoebel]

@Arcoth Default arguments exist in C++, so couldn't one use ternary when defining a default argument? So wouldn't ? actually be valid? Might fixing that help here even if the highlighter itself was still a little confused?

[joshgoebel]

This will also occur with other specifiers, e.g. friend, typedef, inline etc.

As far as I can tell these just work, the only real issue is with auto type.

After my PR:

[joshgoebel]

@Arcoth Does that look right to you?