Inconsistent formatting between functions and function-like macros

[newpavlov]

Rustfmt accepts the following code without issues:

pub const FOO: &str = foo("
    foo
    bar
");

But if we are to replace foo with a function-like macro:

pub const FOO: &str = foo!("
    foo
    bar
");

Rustfmt wants to reformat it as:

pub const FOO: &str = foo!(
    "
    foo
    bar
"
);

The resulting formatting is far from beautiful, space inefficient, and inconsistent with how rustfmt handles functions.

This issue is quite annoying in practice for example when code uses the hex-literal crate.

[calebcartwright]

Thanks for sharing.

I'm not 100% convinced the handling for standard function calls is operating correctly either, as some more twisted versions of the input can produce some similarly strange outputs, though it's certainly more consistently bad with macro calls.