For example, the following `match` block has too many arms:
-```compile_fail
-match foo {
+```compile_fail,E0001
+match Some(0) {
Some(bar) => {/* ... */}
None => {/* ... */}
_ => {/* ... */} // All possible cases have already been handled
required in order to assign values to match expressions, or alternatively,
determine the flow of execution. Erroneous code example:
-```compile_fail
+```compile_fail,E0004
enum Terminator {
HastaLaVistaBaby,
TalkToMyHand,
Patterns used to bind names must be irrefutable, that is, they must guarantee
that a name will be extracted in all cases. Erroneous code example:
-```compile_fail
+```compile_fail,E0005
let x = Some(1);
let Some(y) = x;
// error: refutable pattern in local binding: `None` not covered
moved into a variable called `op_string` while simultaneously requiring the
inner `String` to be moved into a variable called `s`.
-```compile_fail
+```compile_fail,E0007
let x = Some("s".to_string());
match x {
referenced in the pattern guard code. Doing so however would prevent the name
from being available in the body of the match arm. Consider the following:
-```compile_fail
+```compile_fail,E0008
match Some("hi".to_string()) {
Some(s) if s.len() == 0 => {}, // use s.
_ => {},
Though this example seems innocuous and easy to solve, the problem becomes clear
when it encounters functions which consume the value:
-```compile_fail
+```compile_fail,E0008
struct A{}
impl A {
Erroneous code example:
-```compile_fail
+```compile_fail,E0009
struct X { x: (), }
let x = Some((X { x: () }, X { x: () }));
match was successful. If the match is irrefutable (when it cannot fail to
match), use a regular `let`-binding instead. For instance:
-```compile_fail
+```compile_fail,E0162
struct Irrefutable(i32);
let irr = Irrefutable(0);
// This fails to compile because the match is irrefutable.
if let Irrefutable(x) = irr {
// This body will always be executed.
- foo(x);
+ // ...
}
```
Try this instead:
-```ignore
+```
struct Irrefutable(i32);
let irr = Irrefutable(0);
let Irrefutable(x) = irr;
-foo(x);
+println!("{}", x);
```
"##,
match was successful. If the match is irrefutable (when it cannot fail to
match), use a regular `let`-binding inside a `loop` instead. For instance:
-```compile_fail
+```compile_fail,E0165
struct Irrefutable(i32);
let irr = Irrefutable(0);
loop variable, consider using a `match` or `if let` inside the loop body. For
instance:
-```compile_fail
+```compile_fail,E0297
let xs : Vec<Option<i32>> = vec!(Some(1), None);
// This fails because `None` is not covered.
exhaustive. For instance, the following would not match any arm if mutable
borrows were allowed:
-```compile_fail
+```compile_fail,E0301
match Some(()) {
None => { },
option if option.take().is_none() => {
exhaustive. For instance, the following would not match any arm if assignments
were allowed:
-```compile_fail
+```compile_fail,E0302
match Some(()) {
None => { },
- option if { option = None; false } { },
+ option if { option = None; false } => { },
Some(_) => { } // When the previous match failed, the option became `None`.
}
```
Updates to the borrow checker in a future version of Rust may remove this
restriction, but for now patterns must be rewritten without sub-bindings.
-```ignore
-// Before.
+Before:
+
+```compile_fail,E0303
match Some("hi".to_string()) {
ref op_string_ref @ Some(s) => {},
None => {},
}
+```
+
+After:
-// After.
+```
match Some("hi".to_string()) {
Some(ref s) => {
let op_string_ref = &Some(s);
constant expression that had to be evaluated. Attempting to divide by 0
or causing integer overflow are two ways to induce this error. For example:
-```compile_fail
+```compile_fail,E0080
enum Enum {
X = (1 << 500),
Y = (1 / 0)
In an array literal `[x; N]`, `N` is the number of elements in the array. This
must be an unsigned integer. Erroneous code example:
-```compile_fail
+```compile_fail,E0306
let x = [0i32; true]; // error: expected positive integer for repeat count,
// found boolean
```
--- /dev/null
+// Copyright 2016 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.
+
+trait Trait { type AssociatedType; }
+
+fn foo<T>(t: T) where T: Trait<AssociatedType=u32> {
+ println!("in foo");
+}
+
+impl Trait for i8 { type AssociatedType = &'static str; }
+
+fn main() {
+ foo(3_i8); //~ ERROR E0271
+}
--- /dev/null
+// Copyright 2016 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.
+
+trait Foo {}
+
+struct Bar<T>(T);
+
+impl<T> Foo for T where Bar<T>: Foo {} //~ ERROR E0275
+
+fn main() {
+}
--- /dev/null
+// Copyright 2016 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.
+
+trait Foo {
+ fn foo<T>(x: T);
+}
+
+impl Foo for bool {
+ fn foo<T>(x: T) where T: Copy {} //~ ERROR E0276
+}
+
+fn main() {
+}
--- /dev/null
+// Copyright 2016 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.
+
+trait Foo {
+ fn bar(&self);
+}
+
+fn some_func<T: Foo>(foo: T) {
+ foo.bar();
+}
+
+fn main() {
+ some_func(5i32); //~ ERROR E0277
+}
--- /dev/null
+// Copyright 2016 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.
+
+fn foo<F: Fn()>(x: F) { }
+
+fn main() {
+ foo(|y| { }); //~ ERROR E0281
+ //~^ ERROR E0281
+}
--- /dev/null
+// Copyright 2016 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.
+
+fn main() {
+ let x = "hello".chars().rev().collect(); //~ ERROR E0282
+}
--- /dev/null
+// Copyright 2016 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.
+
+trait Generator {
+ fn create() -> u32;
+}
+
+struct Impl;
+
+impl Generator for Impl {
+ fn create() -> u32 { 1 }
+}
+
+struct AnotherImpl;
+
+impl Generator for AnotherImpl {
+ fn create() -> u32 { 2 }
+}
+
+fn main() {
+ let cont: u32 = Generator::create(); //~ ERROR E0283
+}
--- /dev/null
+// Copyright 2016 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.
+
+#![recursion_limit] //~ ERROR E0296
+
+fn main() {}
--- /dev/null
+// Copyright 2016 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.
+
+fn main() {
+ let xs : Vec<Option<i32>> = vec!(Some(1), None);
+
+ for Some(x) in xs {} //~ ERROR E0297
+}
--- /dev/null
+// Copyright 2016 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.
+
+fn main() {
+ match Some(()) {
+ None => { },
+ option if option.take().is_none() => {}, //~ ERROR E0301
+ Some(_) => { }
+ }
+}
--- /dev/null
+// Copyright 2016 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.
+
+fn main() {
+ match Some(()) {
+ None => { },
+ option if { option = None; false } => { }, //~ ERROR E0302
+ Some(_) => { }
+ }
+}
--- /dev/null
+// Copyright 2016 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.
+
+fn main() {
+ match Some("hi".to_string()) {
+ ref op_string_ref @ Some(s) => {}, //~ ERROR E0303
+ //~^ ERROR E0009
+ None => {},
+ }
+}
projects / rust.git / commitdiff