Reject argument command call taking a block with more trailing arguments

[Earlopain]

https://bugs.ruby-lang.org/issues/21168#note-5

The added code samples align with parse.y, except for foo(bar baz do end) which parse.y currently rejects but shouldn't.

[kddnewton]

I'm okay to merge this as-is, but I'm wondering if it indicates that we're passing accepts_command_call incorrectly somewhere or we're not checking it somewhere. Because this behavior should be controlled by that flag.

[Earlopain]

Let me check again later when I got some time. I didn't yet find the place where accepts_command_call would be relevant while making this PR

[Earlopain]

Actually, would accepts_command_call be relevant? It doesn't reject commands calls but any argument after a command call (that takes a block).

[kddnewton]

I think so, because

prism/src/prism.c

Line 15584 in 90a098d

} else if (accepts_command_call && (token_begins_expression_p(parser->current.type) || match3(parser, PM_TOKEN_USTAR, PM_TOKEN_USTAR_STAR, PM_TOKEN_UAMPERSAND)) && !match1(parser, PM_TOKEN_BRACE_LEFT)) {

rejects any arguments without parentheses, which is what we're trying to reject here.

[Earlopain]

(I just rebased and added foo(bar 1 do end,) as a syntax error test)

That accepts_command_call just decides if bar 1 do end should be allowed. parse_arguments_list gets called twice:

foo(bar 1 do end, 2)
    ^~~~~~~~~~~~~~~ # accepts_command_call is irrelevant, parens are present
        ^~~~~~~~    # accepts_command_call is true. Having it be false would reject the first argument to `foo`, which should be allowed.

Though it's not unreasonable to think that I am missing something or that the fix is better placed at a different location

[kddnewton]

Right, but I'm talking about the bar method call, which would have been called from here:

prism/src/prism.c

Line 18647 in 90a098d

if (parse_arguments_list(parser, &arguments, true, accepts_command_call, (uint16_t) (depth + 1))) {

.

[Earlopain]

Yeah, but that command call is allowed. Only stuff following it should be rejected, so I don't currently see how it would be relevant.

It's ok to reject this if you want to take this yourself. Looking at the proper solution to learn from later is good for me too, I have stared at this for a while longer now and am not really getting any further.

[kddnewton]

Ahh I'm sorry, I misread the ticket. I think this is definitely correct.