2016-11-08 00:21:53 -06:00
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error[E0499]: cannot borrow `f` as mutable more than once at a time
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2018-12-25 09:56:47 -06:00
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--> $DIR/borrowck-call-is-borrow-issue-12224.rs:12:16
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2016-11-08 00:21:53 -06:00
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2018-02-22 18:42:32 -06:00
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LL | f(Box::new(|| {
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2016-11-08 00:21:53 -06:00
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| - ^^ second mutable borrow occurs here
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| first mutable borrow occurs here
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2019-04-22 02:40:08 -05:00
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| first borrow later used by call
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2019-03-09 06:03:44 -06:00
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LL |
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2018-02-22 18:42:32 -06:00
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LL | f((Box::new(|| {})))
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2019-04-22 02:40:08 -05:00
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| - second borrow occurs due to use of `f` in closure
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2016-11-08 00:21:53 -06:00
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2019-04-22 02:40:08 -05:00
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error[E0596]: cannot borrow `*f` as mutable, as it is behind a `&` reference
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2018-12-25 09:56:47 -06:00
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--> $DIR/borrowck-call-is-borrow-issue-12224.rs:25:5
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2016-11-08 00:21:53 -06:00
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2018-02-22 18:42:32 -06:00
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LL | (*f)();
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2019-04-22 02:40:08 -05:00
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| ^^^^ `f` is a `&` reference, so the data it refers to cannot be borrowed as mutable
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2022-12-28 23:52:57 -06:00
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help: consider changing this to be a mutable reference
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LL | fn test2<F>(f: &mut F) where F: FnMut() {
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| ~~~~~~
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2016-11-08 00:21:53 -06:00
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2019-04-22 02:40:08 -05:00
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error[E0596]: cannot borrow `f.f` as mutable, as it is behind a `&` reference
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2018-12-25 09:56:47 -06:00
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--> $DIR/borrowck-call-is-borrow-issue-12224.rs:34:5
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2016-11-08 00:21:53 -06:00
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2018-02-22 18:42:32 -06:00
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LL | f.f.call_mut(())
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Use larger span for adjustments on method calls
Currently, we use a relatively 'small' span for THIR
expressions generated by an 'adjustment' (e.g. an autoderef,
autoborrow, unsizing). As a result, if a borrow generated
by an adustment ends up causing a borrowcheck error, for example:
```rust
let mut my_var = String::new();
let my_ref = &my_var
my_var.push('a');
my_ref;
```
then the span for the mutable borrow may end up referring
to only the base expression (e.g. `my_var`), rather than
the method call which triggered the mutable borrow
(e.g. `my_var.push('a')`)
Due to a quirk of the MIR borrowck implementation,
this doesn't always get exposed in migration mode,
but it does in many cases.
This commit makes THIR building consistently use 'larger'
spans for adjustment expressions
The intent of this change it make it clearer to users
when it's the specific way in which a variable is
used (for example, in a method call) that produdes
a borrowcheck error. For example, an error message
claiming that a 'mutable borrow occurs here' might
be confusing if it just points at a usage of a variable
(e.g. `my_var`), when no `&mut` is in sight. Pointing
at the entire expression should help to emphasize
that the method call itself is responsible for
the mutable borrow.
In several cases, this makes the `#![feature(nll)]` diagnostic
output match up exactly with the default (migration mode) output.
As a result, several `.nll.stderr` files end up getting removed
entirely.
2021-09-16 15:01:22 -05:00
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| ^^^^^^^^^^^^^^^^ `f` is a `&` reference, so the data it refers to cannot be borrowed as mutable
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2022-12-28 23:52:57 -06:00
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help: consider changing this to be a mutable reference
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LL | fn test4(f: &mut Test<'_>) {
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| ~~~~~~~~~~~~~
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2016-11-08 00:21:53 -06:00
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2019-05-05 06:02:32 -05:00
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error[E0507]: cannot move out of `f`, a captured variable in an `FnMut` closure
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2019-04-22 02:40:08 -05:00
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--> $DIR/borrowck-call-is-borrow-issue-12224.rs:57:13
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2016-11-08 00:21:53 -06:00
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2022-06-27 00:45:35 -05:00
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LL | let mut f = move |g: Box<dyn FnMut(isize)>, b: isize| {
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| ----- captured outer variable
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2018-03-23 04:57:28 -05:00
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...
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2022-06-27 00:45:35 -05:00
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LL | f(Box::new(|a| {
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| --- captured by this `FnMut` closure
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LL |
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LL | foo(f);
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| ^ move occurs because `f` has type `[closure@$DIR/borrowck-call-is-borrow-issue-12224.rs:52:17: 52:58]`, which does not implement the `Copy` trait
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2019-04-22 02:40:08 -05:00
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error[E0505]: cannot move out of `f` because it is borrowed
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--> $DIR/borrowck-call-is-borrow-issue-12224.rs:55:16
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2023-01-14 21:06:44 -06:00
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LL | let mut f = move |g: Box<dyn FnMut(isize)>, b: isize| {
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| ----- binding `f` declared here
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...
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2019-04-22 02:40:08 -05:00
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LL | f(Box::new(|a| {
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| - ^^^ move out of `f` occurs here
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| borrow of `f` occurs here
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LL |
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LL | foo(f);
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| - move occurs due to use in closure
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2016-11-08 00:21:53 -06:00
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2017-07-02 05:49:30 -05:00
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error: aborting due to 5 previous errors
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2016-11-08 00:21:53 -06:00
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2019-04-22 02:40:08 -05:00
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Some errors have detailed explanations: E0499, E0505, E0507, E0596.
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2018-03-03 08:59:40 -06:00
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For more information about an error, try `rustc --explain E0499`.
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