[7.x] Parameterless Component Methods Invokable With & Without Parens

[taylorotwell]

This change allows parameterless Blade component methods to be invoked using no parameters or using parameters:

{{ $foo }}

{{ $foo() }}

It's easy to forget that these methods currently are not able to called with parentheses. I have stumbled on this myself. This should be backward compatible since both ways of echoing the value are supported.

[imliam]

For the record, this fixes a concern brought up in laravel/ideas#2129

I still think this is a backwards-incompatible change. Say we have a function on the Blade component:

public function foo()
{
    return 'bar';
}

Which in turn we used in the Blade with $foo()

Prior to this change, $foo would be evaluated first, executing that public method. The resulting callable ('bar') would then be executed due to the parenthesis at the end - so in turn it would execute bar()

With this change, it would now only execute the foo method and not bar.

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I'm not using the former behaviour myself, but still, see it as a breaking change. I like the change and more consistent behaviour myself and would love to see it in 8.x

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Edit: I'd also note that this doesn't fix the discrepancy between whether or not $foo is a property or method - you can't tell from the Blade file itself and will run into issues if you have a property and method of the same name

[taylorotwell]

I'm not particularly concerned about that breaking change as I very sincerely doubt anyone is doing that.