diff options
| -rw-r--r-- | src/librustc_borrowck/diagnostics.rs | 217 | ||||
| -rw-r--r-- | src/librustc_typeck/diagnostics.rs | 4 |
2 files changed, 112 insertions, 109 deletions
diff --git a/src/librustc_borrowck/diagnostics.rs b/src/librustc_borrowck/diagnostics.rs index f1792c7f6f5..88f739d1c74 100644 --- a/src/librustc_borrowck/diagnostics.rs +++ b/src/librustc_borrowck/diagnostics.rs @@ -17,7 +17,7 @@ This error occurs when an attempt is made to use data captured by a closure, when that data may no longer exist. It's most commonly seen when attempting to return a closure: -```compile_fail +```compile_fail,E0373 fn foo() -> Box<Fn(u32) -> u32> { let x = 0u32; Box::new(|y| x + y) @@ -31,7 +31,7 @@ unsafe. Another situation where this might be encountered is when spawning threads: -```compile_fail +```compile_fail,E0373 fn foo() { let x = 0u32; let y = 1u32; @@ -66,7 +66,7 @@ about safety. E0381: r##" It is not allowed to use or capture an uninitialized variable. For example: -```compile_fail +```compile_fail,E0381 fn main() { let x: i32; let y = x; // error, use of possibly uninitialized variable @@ -88,7 +88,7 @@ E0382: r##" This error occurs when an attempt is made to use a variable after its contents have been moved elsewhere. For example: -```compile_fail +```compile_fail,E0382 struct MyStruct { s: u32 } fn main() { @@ -180,8 +180,8 @@ E0384: r##" This error occurs when an attempt is made to reassign an immutable variable. For example: -```compile_fail -fn main(){ +```compile_fail,E0384 +fn main() { let x = 3; x = 5; // error, reassignment of immutable variable } @@ -191,7 +191,7 @@ By default, variables in Rust are immutable. To fix this error, add the keyword `mut` after the keyword `let` when declaring the variable. For example: ``` -fn main(){ +fn main() { let mut x = 3; x = 5; } @@ -204,7 +204,7 @@ reference stored inside an immutable container. For example, this can happen when storing a `&mut` inside an immutable `Box`: -```compile_fail +```compile_fail,E0386 let mut x: i64 = 1; let y: Box<_> = Box::new(&mut x); **y = 2; // error, cannot assign to data in an immutable container @@ -234,7 +234,7 @@ E0387: r##" This error occurs when an attempt is made to mutate or mutably reference data that a closure has captured immutably. Examples of this error are shown below: -```compile_fail +```compile_fail,E0387 // Accepts a function or a closure that captures its environment immutably. // Closures passed to foo will not be able to mutate their closed-over state. fn foo<F: Fn()>(f: F) { } @@ -317,9 +317,9 @@ mutable reference (`&(&mut T)`). Example of erroneous code: -```compile_fail +```compile_fail,E0389 struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -339,7 +339,7 @@ To fix this, either remove the outer reference: ``` struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -377,7 +377,7 @@ fn main() { E0499: r##" A variable was borrowed as mutable more than once. Erroneous code example: -```compile_fail +```compile_fail,E0499 let mut i = 0; let mut x = &mut i; let mut a = &mut i; @@ -462,7 +462,7 @@ capturing. Example of erroneous code: -```compile_fail +```compile_fail,E0501 fn inside_closure(x: &mut i32) { // Actions which require unique access } @@ -532,7 +532,7 @@ has already been borrowed as immutable. Example of erroneous code: -```compile_fail +```compile_fail,E0502 fn bar(x: &mut i32) {} fn foo(a: &mut i32) { let ref y = a; // a is borrowed as immutable. @@ -561,7 +561,7 @@ A value was used after it was mutably borrowed. Example of erroneous code: -```compile_fail +```compile_fail,E0503 fn main() { let mut value = 3; // Create a mutable borrow of `value`. This borrow @@ -618,9 +618,9 @@ closure. Example of erroneous code: -```compile_fail +```compile_fail,E0504 struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -646,7 +646,7 @@ rather than moving: ``` struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -669,7 +669,7 @@ the borrow using a scoped block: ``` struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -698,7 +698,7 @@ use std::sync::Arc; use std::thread; struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -716,14 +716,94 @@ fn main() { ``` "##, +E0505: r##" +A value was moved out while it was still borrowed. + +Erroneous code example: + +```compile_fail,E0505 +struct Value {} + +fn eat(val: Value) {} + +fn main() { + let x = Value{}; + { + let _ref_to_val: &Value = &x; + eat(x); + } +} +``` + +Here, the function `eat` takes the ownership of `x`. However, +`x` cannot be moved because it was borrowed to `_ref_to_val`. +To fix that you can do few different things: + +* Try to avoid moving the variable. +* Release borrow before move. +* Implement the `Copy` trait on the type. + +Examples: + +``` +struct Value {} + +fn eat(val: &Value) {} + +fn main() { + let x = Value{}; + { + let _ref_to_val: &Value = &x; + eat(&x); // pass by reference, if it's possible + } +} +``` + +Or: + +``` +struct Value {} + +fn eat(val: Value) {} + +fn main() { + let x = Value{}; + { + let _ref_to_val: &Value = &x; + } + eat(x); // release borrow and then move it. +} +``` + +Or: + +``` +#[derive(Clone, Copy)] // implement Copy trait +struct Value {} + +fn eat(val: Value) {} + +fn main() { + let x = Value{}; + { + let _ref_to_val: &Value = &x; + eat(x); // it will be copied here. + } +} +``` + +You can find more information about borrowing in the rust-book: +http://doc.rust-lang.org/stable/book/references-and-borrowing.html +"##, + E0506: r##" This error occurs when an attempt is made to assign to a borrowed value. Example of erroneous code: -```compile_fail +```compile_fail,E0506 struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -743,7 +823,7 @@ Alternatively, we can move out of `fancy_num` into a second `fancy_num`: ``` struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -760,7 +840,7 @@ a scoped block: ``` struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -781,7 +861,7 @@ Or by moving the reference into a function: ``` struct FancyNum { - num: u8 + num: u8, } fn main() { @@ -800,89 +880,10 @@ fn print_fancy_ref(fancy_ref: &FancyNum){ ``` "##, -E0505: r##" -A value was moved out while it was still borrowed. -Erroneous code example: - -```compile_fail -struct Value {} - -fn eat(val: Value) {} - -fn main() { - let x = Value{}; - { - let _ref_to_val: &Value = &x; - eat(x); - } -} -``` - -Here, the function `eat` takes the ownership of `x`. However, -`x` cannot be moved because it was borrowed to `_ref_to_val`. -To fix that you can do few different things: - -* Try to avoid moving the variable. -* Release borrow before move. -* Implement the `Copy` trait on the type. - -Examples: - -``` -struct Value {} - -fn eat(val: &Value) {} - -fn main() { - let x = Value{}; - { - let _ref_to_val: &Value = &x; - eat(&x); // pass by reference, if it's possible - } -} -``` - -Or: - -``` -struct Value {} - -fn eat(val: Value) {} - -fn main() { - let x = Value{}; - { - let _ref_to_val: &Value = &x; - } - eat(x); // release borrow and then move it. -} -``` - -Or: - -``` -#[derive(Clone, Copy)] // implement Copy trait -struct Value {} - -fn eat(val: Value) {} - -fn main() { - let x = Value{}; - { - let _ref_to_val: &Value = &x; - eat(x); // it will be copied here. - } -} -``` - -You can find more information about borrowing in the rust-book: -http://doc.rust-lang.org/stable/book/references-and-borrowing.html -"##, - E0507: r##" You tried to move out of a value which was borrowed. Erroneous code example: -```compile_fail +```compile_fail,E0507 use std::cell::RefCell; struct TheDarkKnight; @@ -999,7 +1000,7 @@ A value was moved out of a non-copy fixed-size array. Example of erroneous code: -```compile_fail +```compile_fail,E0508 struct NonCopy; fn main() { @@ -1044,7 +1045,7 @@ implements the `Drop` trait. Example of erroneous code: -```compile_fail +```compile_fail,E0509 struct FancyNum { num: usize } diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs index db11b9041f5..5956d35d84a 100644 --- a/src/librustc_typeck/diagnostics.rs +++ b/src/librustc_typeck/diagnostics.rs @@ -2469,6 +2469,8 @@ extern crate collections; use collections::range::RangeArgument; impl<T> RangeArgument<T> for T { } // error + +fn main() {} ``` To work around this, it can be covered with a local type, `MyType`: @@ -3226,7 +3228,7 @@ E0370: r##" The maximum value of an enum was reached, so it cannot be automatically set in the next enum value. Erroneous code example: -```compile_fail,E0370 +```compile_fail #[deny(overflowing_literals)] enum Foo { X = 0x7fffffffffffffff, |