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diannedianne
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additional tests
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‎tests/ui/borrowck/format-args-temporary-scopes.e2021.stderr‎

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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:40:90
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|
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LL | println!("{:?}{:?}", (), match true { true => &"" as &dyn std::fmt::Debug, false => &temp() });
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| ------------------------------------------------------------^^^^^---
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:33:41
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|
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LL | println!("{:?}{:?}", (), if true { &format!("") } else { "" });
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| -----------^^^^^^^^^^^--------------
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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= note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:36:64
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|
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LL | println!("{:?}{:?}", (), if true { std::convert::identity(&format!("")) } else { "" });
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| ----------------------------------^^^^^^^^^^^---------------
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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= note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0716`.

‎tests/ui/borrowck/format-args-temporary-scopes.e2024.stderr‎

Lines changed: 65 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:13:25
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--> $DIR/format-args-temporary-scopes.rs:12:25
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|
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LL | println!("{:?}", { &temp() });
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| ---^^^^^---
@@ -11,7 +11,19 @@ LL | println!("{:?}", { &temp() });
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= note: consider using a `let` binding to create a longer lived value
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:19:29
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--> $DIR/format-args-temporary-scopes.rs:17:48
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|
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LL | println!("{:?}", { std::convert::identity(&temp()) });
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| --------------------------^^^^^^---
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:23:29
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|
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LL | println!("{:?}{:?}", { &temp() }, ());
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| ---^^^^^---
@@ -22,6 +34,56 @@ LL | println!("{:?}{:?}", { &temp() }, ());
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|
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= note: consider using a `let` binding to create a longer lived value
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error: aborting due to 2 previous errors
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:26:52
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|
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LL | println!("{:?}{:?}", { std::convert::identity(&temp()) }, ());
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| --------------------------^^^^^^---
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:40:90
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|
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LL | println!("{:?}{:?}", (), match true { true => &"" as &dyn std::fmt::Debug, false => &temp() });
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| ------------------------------------------------------------^^^^^---
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:33:41
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|
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LL | println!("{:?}{:?}", (), if true { &format!("") } else { "" });
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| -^^^^^^^^^^-
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| || |
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| || temporary value is freed at the end of this statement
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| |creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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= note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/format-args-temporary-scopes.rs:36:64
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|
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LL | println!("{:?}{:?}", (), if true { std::convert::identity(&format!("")) } else { "" });
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| ------------------------^^^^^^^^^^^-
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| | | |
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| | | temporary value is freed at the end of this statement
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| | creates a temporary value which is freed while still in use
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| borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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= note: this error originates in the macro `format` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: aborting due to 7 previous errors
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For more information about this error, try `rustc --explain E0716`.

‎tests/ui/borrowck/format-args-temporary-scopes.rs‎

Lines changed: 22 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,6 @@
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//! Test for #145784 as it relates to format arguments: arguments to macros such as `println!`
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//! should obey normal temporary scoping rules.
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//@ revisions: e2021 e2024
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//@ [e2021] check-pass
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//@ [e2021] edition: 2021
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//@ [e2024] edition: 2024
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@@ -13,9 +12,31 @@ fn main() {
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println!("{:?}", { &temp() });
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//[e2024]~^ ERROR: temporary value dropped while borrowed [E0716]
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// Arguments to function calls aren't extending expressions, so `temp()` is dropped at the end
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// of the block in Rust 2024.
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println!("{:?}", { std::convert::identity(&temp()) });
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//[e2024]~^ ERROR: temporary value dropped while borrowed [E0716]
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// In Rust 1.89, `format_args!` extended the lifetime of all extending expressions in its
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// arguments when provided with two or more arguments. This caused the result of `temp()` to
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// outlive the result of the block, making this compile.
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println!("{:?}{:?}", { &temp() }, ());
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//[e2024]~^ ERROR: temporary value dropped while borrowed [E0716]
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println!("{:?}{:?}", { std::convert::identity(&temp()) }, ());
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//[e2024]~^ ERROR: temporary value dropped while borrowed [E0716]
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// In real-world projects, this typically appeared in `if` expressions with a `&str` in one
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// branch and a reference to a `String` temporary in the other. Since the consequent and `else`
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// blocks of `if` expressions are temporary scopes in all editions, this affects Rust 2021 and
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// earlier as well.
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println!("{:?}{:?}", (), if true { &format!("") } else { "" });
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//~^ ERROR: temporary value dropped while borrowed [E0716]
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println!("{:?}{:?}", (), if true { std::convert::identity(&format!("")) } else { "" });
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//~^ ERROR: temporary value dropped while borrowed [E0716]
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// This has likewise occurred with `match`, affecting all editions.
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println!("{:?}{:?}", (), match true { true => &"" as &dyn std::fmt::Debug, false => &temp() });
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//~^ ERROR: temporary value dropped while borrowed [E0716]
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}

‎tests/ui/borrowck/super-let-in-if-block.rs‎

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//! Test that `super let` bindings in `if` expressions' blocks have the same scope as the result
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//! of the block.
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#![feature(super_let)]
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fn main() {
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// For `super let` in an extending `if`, the binding `temp` should live in the scope of the
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// outer `let` statement.
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let x = if true {
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super let temp = ();
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&temp
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} else {
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super let temp = ();
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&temp
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};
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x;
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// For `super let` in non-extending `if`, the binding `temp` should live in the temporary scope
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// the `if` expression is in.
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// TODO: make this not an error
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std::convert::identity(if true {
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super let temp = ();
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&temp
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//~^ ERROR `temp` does not live long enough
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} else {
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super let temp = ();
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&temp
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//~^ ERROR `temp` does not live long enough
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});
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}

‎tests/ui/borrowck/super-let-in-if-block.stderr‎

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error[E0597]: `temp` does not live long enough
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--> $DIR/super-let-in-if-block.rs:22:9
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|
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LL | std::convert::identity(if true {
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| ---------------------- borrow later used by call
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LL | super let temp = ();
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| ---- binding `temp` declared here
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LL | &temp
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| ^^^^^ borrowed value does not live long enough
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LL |
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LL | } else {
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| - `temp` dropped here while still borrowed
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error[E0597]: `temp` does not live long enough
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--> $DIR/super-let-in-if-block.rs:26:9
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|
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LL | std::convert::identity(if true {
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| ---------------------- borrow later used by call
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...
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LL | super let temp = ();
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| ---- binding `temp` declared here
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LL | &temp
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| ^^^^^ borrowed value does not live long enough
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LL |
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LL | });
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| - `temp` dropped here while still borrowed
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0597`.

‎tests/ui/borrowck/super-let-projection-extension.rs‎

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//! Demonstrates a case where `{ super let x = temp(); &x }` =/= `&temp()`, a variant of which is
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//! observable on stable Rust via the `pin!` macro: `pin!($EXPR)` and `&mut $EXPR` may use different
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//! scopes for their temporaries.
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#![feature(super_let)]
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use std::pin::pin;
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fn temp() {}
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fn main() {
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// This is fine, since the temporary is extended to the end of the block:
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let a = &*&temp();
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a;
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let b = &mut *&mut temp();
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b;
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// The temporary is dropped at the end of the outer `let` initializer:
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let c = &*{ super let x = temp(); &x };
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//~^ ERROR `x` does not live long enough
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c;
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let d = &mut *pin!(temp());
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//~^ ERROR temporary value dropped while borrowed
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d;
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}

‎tests/ui/borrowck/super-let-projection-extension.stderr‎

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error[E0597]: `x` does not live long enough
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--> $DIR/super-let-projection-extension.rs:19:39
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|
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LL | let c = &*{ super let x = temp(); &x };
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| - ^^ - `x` dropped here while still borrowed
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| | |
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| | borrowed value does not live long enough
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| binding `x` declared here
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LL |
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LL | c;
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| - borrow later used here
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/super-let-projection-extension.rs:22:19
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|
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LL | let d = &mut *pin!(temp());
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| ^^^^^^^^^^^^- temporary value is freed at the end of this statement
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| |
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| creates a temporary value which is freed while still in use
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LL |
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LL | d;
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| - borrow later used here
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|
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= note: consider using a `let` binding to create a longer lived value
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= note: this error originates in the macro `pin` (in Nightly builds, run with -Z macro-backtrace for more info)
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error: aborting due to 2 previous errors
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Some errors have detailed explanations: E0597, E0716.
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For more information about an error, try `rustc --explain E0597`.

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