Rustfmt breaks macros due to changes

[alexkazik]

Describe the bug

The contents of macros are changed.

Input:

test_macro!(pub fn test_fn(); "foobar");

Output:

test_macro!(fn test_fn();, "foobar");

Expected behavior

Unchanged, or "formatted" but not keywords/symbols removed/added.

Meta

• rustfmt version: rustfmt 1.4.30-nightly (acd9486 2020-12-20)
• From where did you install rustfmt?: rustup
• How do you run rustfmt: cargo fmt --all

[Ekleog]

I have just hit a similar issue with rustfmt 1.4.29-nightly (70ce182 2020-12-04) (installed from the nixpkgs-mozilla overlay, that grabs from the rustup repository):

fn main() {
    quote!(type Foo: Bar;);
}

becomes

fn main() {
    quote!(
        type Foo: Bar = impl Bar;
    );
}

(where the result is not even valid stable rust code)

[zyctree]

the same,

could use {} like test_macro! { pub fn test_fn(); "foobar" }; to avoid this change

[alexkazik]

Thanks for the tip with {}.

[JakkuSakura]

debug!(meta ?= meta, "Ready to subscribe"); is being formatted as debug!(meta? = meta, "Ready to subscribe"); and thus breaking tracing-log
forward!(S<>) is formatted as forward!(S), breaking my macro.

[ytmimi]

closing this as a duplicate of #4375