-
Notifications
You must be signed in to change notification settings - Fork 12.5k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
implement feature tuple_struct_self_ctor
- Loading branch information
Showing
9 changed files
with
254 additions
and
41 deletions.
There are no files selected for viewing
33 changes: 33 additions & 0 deletions
33
src/doc/unstable-book/src/language-features/tuple-struct-self-ctor.md
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,33 @@ | ||
# `tuple_struct_self_ctor` | ||
|
||
The tracking issue for this feature is: [#51994] | ||
[#51994]: https://github.com/rust-lang/rust/issues/51994 | ||
|
||
------------------------ | ||
|
||
The `tuple_struct_self_ctor` feature gate lets you use the special `Self` | ||
identifier as a constructor and a pattern. | ||
|
||
A simple example is: | ||
|
||
```rust | ||
#![feature(tuple_struct_self_ctor)] | ||
|
||
struct ST(i32, i32); | ||
|
||
impl ST { | ||
fn new() -> Self { | ||
ST(0, 1) | ||
} | ||
|
||
fn ctor() -> Self { | ||
Self(1,2) // constructed by `Self`, it is the same as `ST(1, 2)` | ||
} | ||
|
||
fn pattern(self) { | ||
match self { | ||
Self(x, y) => println!("{} {}", x, y), // used as a pattern | ||
} | ||
} | ||
} | ||
``` |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,102 @@ | ||
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT | ||
// file at the top-level directory of this distribution and at | ||
// http://rust-lang.org/COPYRIGHT. | ||
// | ||
// 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. | ||
|
||
#![feature(tuple_struct_self_ctor)] | ||
|
||
#![allow(dead_code)] | ||
|
||
use std::fmt::Display; | ||
|
||
struct ST1(i32, i32); | ||
|
||
impl ST1 { | ||
fn new() -> Self { | ||
ST1(0, 1) | ||
} | ||
|
||
fn ctor() -> Self { | ||
Self(1,2) // Self as a constructor | ||
} | ||
|
||
fn pattern(self) { | ||
match self { | ||
Self(x, y) => println!("{} {}", x, y), // Self as a pattern | ||
} | ||
} | ||
} | ||
|
||
struct ST2<T>(T); // With type parameter | ||
|
||
impl<T> ST2<T> where T: Display { | ||
|
||
fn ctor(v: T) -> Self { | ||
Self(v) | ||
} | ||
|
||
fn pattern(&self) { | ||
match self { | ||
Self(ref v) => println!("{}", v), | ||
} | ||
} | ||
} | ||
|
||
struct ST3<'a>(&'a i32); // With lifetime parameter | ||
|
||
impl<'a> ST3<'a> { | ||
|
||
fn ctor(v: &'a i32) -> Self { | ||
Self(v) | ||
} | ||
|
||
fn pattern(self) { | ||
let Self(ref v) = self; | ||
println!("{}", v); | ||
} | ||
} | ||
|
||
struct ST4(usize); | ||
|
||
impl ST4 { | ||
fn map(opt: Option<usize>) -> Option<Self> { | ||
opt.map(Self) // use `Self` as a function passed somewhere | ||
} | ||
} | ||
|
||
struct ST5; // unit struct | ||
|
||
impl ST5 { | ||
fn ctor() -> Self { | ||
Self // `Self` as a unit struct value | ||
} | ||
|
||
fn pattern(self) -> Self { | ||
match self { | ||
Self => Self, // `Self` as a unit struct value for matching | ||
} | ||
} | ||
} | ||
|
||
fn main() { | ||
let v1 = ST1::ctor(); | ||
v1.pattern(); | ||
|
||
let v2 = ST2::ctor(10); | ||
v2.pattern(); | ||
|
||
let local = 42; | ||
let v3 = ST3::ctor(&local); | ||
v3.pattern(); | ||
|
||
let v4 = Some(1usize); | ||
let _ = ST4::map(v4); | ||
|
||
let v5 = ST5::ctor(); | ||
v5.pattern(); | ||
} |
19 changes: 19 additions & 0 deletions
19
src/test/ui/feature-gates/feature-gate-tuple-struct-self-ctor.rs
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,19 @@ | ||
// Copyright 2018 The Rust Project Developers. See the COPYRIGHT | ||
// file at the top-level directory of this distribution and at | ||
// http://rust-lang.org/COPYRIGHT. | ||
// | ||
// 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. | ||
|
||
struct ST(i32, i32); | ||
|
||
impl ST { | ||
fn ctor() -> Self { | ||
Self(1,2) | ||
//~^ ERROR: expected function, found self type `Self` [E0423] | ||
//~^^ ERROR: tuple struct Self constructors are unstable (see issue #51994) [E0658] | ||
} | ||
} |
20 changes: 20 additions & 0 deletions
20
src/test/ui/feature-gates/feature-gate-tuple-struct-self-ctor.stderr
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,20 @@ | ||
error[E0423]: expected function, found self type `Self` | ||
--> $DIR/feature-gate-tuple-struct-self-ctor.rs:15:9 | ||
| | ||
LL | Self(1,2) | ||
| ^^^^ not a function | ||
| | ||
= note: can't use `Self` as a constructor, you must use the implemented struct | ||
|
||
error[E0658]: tuple struct Self constructors are unstable (see issue #51994) | ||
--> $DIR/feature-gate-tuple-struct-self-ctor.rs:15:9 | ||
| | ||
LL | Self(1,2) | ||
| ^^^^^^^^^ | ||
| | ||
= help: add #![feature(tuple_struct_self_ctor)] to the crate attributes to enable | ||
|
||
error: aborting due to 2 previous errors | ||
|
||
Some errors occurred: E0423, E0658. | ||
For more information about an error, try `rustc --explain E0423`. |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -1,36 +1,20 @@ | ||
error[E0423]: expected function, found self type `Self` | ||
--> $DIR/tuple-struct-alias.rs:16:17 | ||
| | ||
LL | let s = Self(0, 1); //~ ERROR expected function | ||
| ^^^^ not a function | ||
| | ||
= note: can't use `Self` as a constructor, you must use the implemented struct | ||
|
||
error[E0532]: expected tuple struct/variant, found self type `Self` | ||
--> $DIR/tuple-struct-alias.rs:18:13 | ||
| | ||
LL | Self(..) => {} //~ ERROR expected tuple struct/variant | ||
| ^^^^ not a tuple struct/variant | ||
| | ||
= note: can't use `Self` as a constructor, you must use the implemented struct | ||
|
||
error[E0423]: expected function, found type alias `A` | ||
--> $DIR/tuple-struct-alias.rs:24:13 | ||
--> $DIR/tuple-struct-alias.rs:15:13 | ||
| | ||
LL | let s = A(0, 1); //~ ERROR expected function | ||
| ^ did you mean `S`? | ||
| | ||
= note: can't use a type alias as a constructor | ||
|
||
error[E0532]: expected tuple struct/variant, found type alias `A` | ||
--> $DIR/tuple-struct-alias.rs:26:9 | ||
--> $DIR/tuple-struct-alias.rs:17:9 | ||
| | ||
LL | A(..) => {} //~ ERROR expected tuple struct/variant | ||
| ^ did you mean `S`? | ||
| | ||
= note: can't use a type alias as a constructor | ||
|
||
error: aborting due to 4 previous errors | ||
error: aborting due to 2 previous errors | ||
|
||
Some errors occurred: E0423, E0532. | ||
For more information about an error, try `rustc --explain E0423`. |