rust-clippy/tests/ui/auxiliary/proc_macro_derive.rs

#![feature(repr128, proc_macro_quote)]
#![allow(incomplete_features)]
#![allow(clippy::field_reassign_with_default)]
#![allow(clippy::eq_op)]

extern crate proc_macro;

use proc_macro::{quote, Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};

#[proc_macro_derive(DeriveSomething)]
pub fn derive(_: TokenStream) -> TokenStream {
    // Should not trigger `used_underscore_binding`
    let _inside_derive = 1;
    assert_eq!(_inside_derive, _inside_derive);

    let output = quote! {
        // Should not trigger `useless_attribute`
        #[allow(dead_code)]
        extern crate rustc_middle;
    };
    output
}

#[proc_macro_derive(ImplStructWithStdDisplay)]
pub fn derive_std(_: TokenStream) -> TokenStream {
    quote! {
        struct A {}
        impl ::std::fmt::Display for A {
            fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
                write!(f, "A")
            }
        }
    }
}

#[proc_macro_derive(FieldReassignWithDefault)]
pub fn derive_foo(_input: TokenStream) -> TokenStream {
    quote! {
        #[derive(Default)]
        struct A {
            pub i: i32,
            pub j: i64,
        }
        #[automatically_derived]
        fn lint() {
            let mut a: A = Default::default();
            a.i = 42;
            a;
        }
    }
}

#[proc_macro_derive(StructAUseSelf)]
pub fn derive_use_self(_input: TokenStream) -> proc_macro::TokenStream {
    quote! {
        struct A;
        impl A {
            fn new() -> A {
                A
            }
        }
    }
}

#[proc_macro_derive(ClippyMiniMacroTest)]
pub fn mini_macro(_: TokenStream) -> TokenStream {
    quote!(
        #[allow(unused)]
        fn needless_take_by_value(s: String) {
            println!("{}", s.len());
        }
        #[allow(unused)]
        fn needless_loop(items: &[u8]) {
            for i in 0..items.len() {
                println!("{}", items[i]);
            }
        }
        fn line_wrapper() {
            println!("{}", line!());
        }
    )
}

#[proc_macro_derive(ExtraLifetimeDerive)]
#[allow(unused)]
pub fn extra_lifetime(_input: TokenStream) -> TokenStream {
    quote!(
        pub struct ExtraLifetime;

        impl<'b> ExtraLifetime {
            pub fn something<'c>() -> Self {
                Self
            }
        }
    )
}

#[allow(unused)]
#[proc_macro_derive(ArithmeticDerive)]
pub fn arithmetic_derive(_: TokenStream) -> TokenStream {
    <TokenStream as FromIterator<TokenTree>>::from_iter([
        Ident::new("fn", Span::call_site()).into(),
        Ident::new("_foo", Span::call_site()).into(),
        Group::new(Delimiter::Parenthesis, TokenStream::new()).into(),
        Group::new(
            Delimiter::Brace,
            <TokenStream as FromIterator<TokenTree>>::from_iter([
                Ident::new("let", Span::call_site()).into(),
                Ident::new("mut", Span::call_site()).into(),
                Ident::new("_n", Span::call_site()).into(),
                Punct::new('=', Spacing::Alone).into(),
                Literal::i32_unsuffixed(9).into(),
                Punct::new(';', Spacing::Alone).into(),
                Ident::new("_n", Span::call_site()).into(),
                Punct::new('=', Spacing::Alone).into(),
                Literal::i32_unsuffixed(9).into(),
                Punct::new('/', Spacing::Alone).into(),
                Literal::i32_unsuffixed(2).into(),
                Punct::new(';', Spacing::Alone).into(),
                Ident::new("_n", Span::call_site()).into(),
                Punct::new('=', Spacing::Alone).into(),
                Punct::new('-', Spacing::Alone).into(),
                Ident::new("_n", Span::call_site()).into(),
                Punct::new(';', Spacing::Alone).into(),
            ]),
        )
        .into(),
    ])
}

#[allow(unused)]
#[proc_macro_derive(ShadowDerive)]
pub fn shadow_derive(_: TokenStream) -> TokenStream {
    <TokenStream as FromIterator<TokenTree>>::from_iter([
        Ident::new("fn", Span::call_site()).into(),
        Ident::new("_foo", Span::call_site()).into(),
        Group::new(Delimiter::Parenthesis, TokenStream::new()).into(),
        Group::new(
            Delimiter::Brace,
            <TokenStream as FromIterator<TokenTree>>::from_iter([
                Ident::new("let", Span::call_site()).into(),
                Ident::new("_x", Span::call_site()).into(),
                Punct::new('=', Spacing::Alone).into(),
                Literal::i32_unsuffixed(2).into(),
                Punct::new(';', Spacing::Alone).into(),
                Ident::new("let", Span::call_site()).into(),
                Ident::new("_x", Span::call_site()).into(),
                Punct::new('=', Spacing::Alone).into(),
                Ident::new("_x", Span::call_site()).into(),
                Punct::new(';', Spacing::Alone).into(),
            ]),
        )
        .into(),
    ])
}

#[proc_macro_derive(StructIgnoredUnitPattern)]
pub fn derive_ignored_unit_pattern(_: TokenStream) -> TokenStream {
    quote! {
        struct A;
        impl A {
            fn a(&self) -> Result<(), ()> {
                unimplemented!()
            }

            pub fn b(&self) {
                let _ = self.a().unwrap();
            }
        }
    }
}