cargo fix fails, having introduced compilation warnings

[jimblandy]

I tried to use cargo fix --edition-idioms, but it printed a lot of errors and declined to fix some things.

I've attached the output.
output.txt

Meta

rustc --version --verbose:

cargo 1.52.0-nightly (90691f2bf 2021-03-16)
release: 1.52.0
commit-hash: 90691f2bfe9a50291a98983b1ed2feab51d5ca55
commit-date: 2021-03-16

[jimblandy]

I was able to get cargo fix --edition-idioms to succeed by fixing the following code manually.

The only change I made was to add an anonymous lifetime <'_> after std::fmt::Formatter in the Display impl.

macro_rules! stringy_enum {
    (pub enum $type:ident (parse error $error_type:ident :: $error_variant:ident) {
        $( $variant:ident = $name:tt ),* ,
    }) => {
        #[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
        pub enum $type {
            $( $variant ),*
        }

        impl $type {
            pub fn as_str(&self) -> &'static str {
                match self {
                    $( $type :: $variant => $name ),*
                }
            }
        }

        impl std::fmt::Display for $type {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
                f.write_str(self.as_str())
            }
        }

        impl std::str::FromStr for $type {
            type Err = $error_type;
            fn from_str(s: &str) -> std::result::Result<$type, $error_type> {
                Ok(match s {
                    $( $name => $type :: $variant ),* ,
                    _ => return Err($error_type :: $error_variant(s.to_string())),
                })
            }
        }
    }
}

Here's a sample use of the stringy_enum macro, if that helps:

stringy_enum! {
    pub enum SectionKind (parse error TreeError::ParseSectionKind) {
        Preface = "preface",
        Chapter = "chapter",
        Sect1 = "sect1",
        Sect2 = "sect2",
    }
}

[ehuss]

Hi! I think this is a duplicate of #55768. I believe the issue is that when a macro is invoked multiple times, rustc is issuing a warning for each invocation, and cargo fix is applying all the duplicate suggestions.

[fmease]

Closing as duplicate of #55768 which was fixed by #90446.