tests/test_generics.rs

// Copyright 2018 Syn Developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![cfg(feature = "extra-traits")]
#![feature(rustc_private)]

extern crate syn;
use syn::*;

#[macro_use]
extern crate quote;

extern crate proc_macro2;
use proc_macro2::{Span, TokenStream};

#[macro_use]
mod macros;

mod common;

#[test]
fn test_split_for_impl() {
    // <'a, 'b: 'a, #[may_dangle] T: 'a = ()> where T: Debug
    let generics = Generics {
        gt_token: Some(Default::default()),
        lt_token: Some(Default::default()),
        params: punctuated![
            GenericParam::Lifetime(LifetimeDef {
                attrs: Default::default(),
                lifetime: Lifetime::new("'a", Span::call_site()),
                bounds: Default::default(),
                colon_token: None,
            }),
            GenericParam::Lifetime(LifetimeDef {
                attrs: Default::default(),
                lifetime: Lifetime::new("'b", Span::call_site()),
                bounds: punctuated![Lifetime::new("'a", Span::call_site())],
                colon_token: Some(token::Colon::default()),
            }),
            GenericParam::Type(TypeParam {
                attrs: vec![
                    Attribute {
                        bracket_token: Default::default(),
                        pound_token: Default::default(),
                        style: AttrStyle::Outer,
                        path: "may_dangle".into(),
                        tts: TokenStream::empty(),
                        is_sugared_doc: false,
                    },
                ],
                ident: "T".into(),
                bounds: punctuated![
                    TypeParamBound::Lifetime(Lifetime::new("'a", Span::call_site())),
                ],
                default: Some(
                    TypeTuple {
                        elems: Default::default(),
                        paren_token: Default::default(),
                    }.into(),
                ),
                colon_token: Some(Default::default()),
                eq_token: Default::default(),
            }),
        ],
        where_clause: Some(WhereClause {
            where_token: Default::default(),
            predicates: punctuated![
                WherePredicate::Type(PredicateType {
                    lifetimes: None,
                    colon_token: Default::default(),
                    bounded_ty: TypePath {
                        qself: None,
                        path: "T".into(),
                    }.into(),
                    bounds: punctuated![
                        TypeParamBound::Trait(TraitBound {
                            paren_token: None,
                            modifier: TraitBoundModifier::None,
                            lifetimes: None,
                            path: "Debug".into(),
                        }),
                    ],
                }),
            ],
        }),
    };

    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
    let tokens = quote! {
        impl #impl_generics MyTrait for Test #ty_generics #where_clause {}
    };
    let expected = concat!(
        "impl < 'a , 'b : 'a , # [ may_dangle ] T : 'a > ",
        "MyTrait for Test < 'a , 'b , T > ",
        "where T : Debug { }"
    );
    assert_eq!(expected, tokens.to_string());

    let turbofish = ty_generics.as_turbofish();
    let tokens = quote! {
        Test #turbofish
    };
    let expected = "Test :: < 'a , 'b , T >";
    assert_eq!(expected, tokens.to_string());
}

#[test]
fn test_ty_param_bound() {
    let tokens = quote!('a);
    let expected = TypeParamBound::Lifetime(Lifetime::new("'a", Span::call_site()));
    assert_eq!(
        expected,
        common::parse::syn::<TypeParamBound>(tokens.into())
    );

    let tokens = quote!('_);
    let expected = TypeParamBound::Lifetime(Lifetime::new("'_", Span::call_site()));
    assert_eq!(
        expected,
        common::parse::syn::<TypeParamBound>(tokens.into())
    );

    let tokens = quote!(Debug);
    let expected = TypeParamBound::Trait(TraitBound {
        paren_token: None,
        modifier: TraitBoundModifier::None,
        lifetimes: None,
        path: "Debug".into(),
    });
    assert_eq!(
        expected,
        common::parse::syn::<TypeParamBound>(tokens.into())
    );

    let tokens = quote!(?Sized);
    let expected = TypeParamBound::Trait(TraitBound {
        paren_token: None,
        modifier: TraitBoundModifier::Maybe(Default::default()),
        lifetimes: None,
        path: "Sized".into(),
    });
    assert_eq!(
        expected,
        common::parse::syn::<TypeParamBound>(tokens.into())
    );
}