rust/tests/compile-fail/map_nil_fn.rs

#![feature(plugin)]
#![feature(const_fn)]
#![plugin(clippy)]

#![deny(clippy_pedantic)]
#![allow(unused, missing_docs_in_private_items)]

fn do_nothing<T>(_: T) {}

fn diverge<T>(_: T) -> ! {
    panic!()
}

fn plus_one(value: usize) -> usize {
    value + 1
}

struct HasOption {
    field: Option<usize>,
}

impl HasOption {
    fn do_option_nothing(self: &HasOption, value: usize) {}

    fn do_option_plus_one(self: &HasOption, value: usize) -> usize {
        value + 1
    }
}

#[cfg_attr(rustfmt, rustfmt_skip)]
fn main() {
    let x = HasOption { field: Some(10) };

    x.field.map(plus_one);
    let _ : Option<()> = x.field.map(do_nothing);

    x.field.map(do_nothing);
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil function
    //~| HELP try this
    //~| SUGGESTION if let Some(...) = x.field { do_nothing(...) }

    x.field.map(do_nothing);
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil function
    //~| HELP try this
    //~| SUGGESTION if let Some(...) = x.field { do_nothing(...) }

    x.field.map(diverge);
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil function
    //~| HELP try this
    //~| SUGGESTION if let Some(...) = x.field { diverge(...) }

    let captured = 10;
    if let Some(value) = x.field { do_nothing(value + captured) };
    let _ : Option<()> = x.field.map(|value| do_nothing(value + captured));

    x.field.map(|value| x.do_option_nothing(value + captured));
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { x.do_option_nothing(value + captured) }

    x.field.map(|value| { x.do_option_plus_one(value + captured); });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { x.do_option_plus_one(value + captured); }


    x.field.map(|value| do_nothing(value + captured));
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { do_nothing(value + captured) }

    x.field.map(|value| { do_nothing(value + captured) });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { do_nothing(value + captured) }

    x.field.map(|value| { do_nothing(value + captured); });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { do_nothing(value + captured) }

    x.field.map(|value| { { do_nothing(value + captured); } });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { do_nothing(value + captured) }


    x.field.map(|value| diverge(value + captured));
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { diverge(value + captured) }

    x.field.map(|value| { diverge(value + captured) });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { diverge(value + captured) }

    x.field.map(|value| { diverge(value + captured); });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { diverge(value + captured) }

    x.field.map(|value| { { diverge(value + captured); } });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { diverge(value + captured) }


    x.field.map(|value| plus_one(value + captured));
    x.field.map(|value| { plus_one(value + captured) });
    x.field.map(|value| { let y = plus_one(value + captured); });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { let y = plus_one(value + captured); }

    x.field.map(|value| { plus_one(value + captured); });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { plus_one(value + captured); }

    x.field.map(|value| { { plus_one(value + captured); } });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { plus_one(value + captured); }


    x.field.map(|ref value| { do_nothing(value + captured) });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(ref value) = x.field { do_nothing(value + captured) }


    x.field.map(|value| { do_nothing(value); do_nothing(value) });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { ... }

    x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
    //~^ ERROR called `map(f)` on an Option value where `f` is a nil closure
    //~| HELP try this
    //~| SUGGESTION if let Some(value) = x.field { ... }
}