Auto merge of #71664 - Dylan-DPC:rollup-eng60x9, r=Dylan-DPC

Rollup of 5 pull requests

Successful merges:

 - #71217 (Suggest `;` or assignment to drop borrows in tail exprs)
 - #71286 (Add regression test for #69654)
 - #71296 (Change wording on read_vectored docs)
 - #71654 (Update link to unstable book for llvm_asm macro)
 - #71657 (Add #24949 assoc constant static recursion test)

Failed merges:

r? @ghost
This commit is contained in:
bors 2020-04-29 10:48:11 +00:00
commit e91aebc1a3
22 changed files with 332 additions and 39 deletions

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@ -1316,7 +1316,7 @@ pub(crate) mod builtin {
///
/// Read the [unstable book] for the usage.
///
/// [unstable book]: ../unstable-book/library-features/asm.html
/// [unstable book]: ../unstable-book/library-features/llvm-asm.html
#[unstable(
feature = "llvm_asm",
issue = "70173",

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@ -672,6 +672,9 @@ pub struct BlockTailInfo {
/// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
/// but not e.g., `let _x = { ...; tail };`
pub tail_result_is_ignored: bool,
/// `Span` of the tail expression.
pub span: Span,
}
/// A MIR local.

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@ -156,23 +156,32 @@ impl BorrowExplanation {
err.span_label(body.source_info(drop_loc).span, message);
if let Some(info) = &local_decl.is_block_tail {
// FIXME: use span_suggestion instead, highlighting the
// whole block tail expression.
let msg = if info.tail_result_is_ignored {
"The temporary is part of an expression at the end of a block. \
Consider adding semicolon after the expression so its temporaries \
are dropped sooner, before the local variables declared by the \
block are dropped."
if info.tail_result_is_ignored {
err.span_suggestion_verbose(
info.span.shrink_to_hi(),
"consider adding semicolon after the expression so its \
temporaries are dropped sooner, before the local variables \
declared by the block are dropped",
";".to_string(),
Applicability::MaybeIncorrect,
);
} else {
"The temporary is part of an expression at the end of a block. \
Consider forcing this temporary to be dropped sooner, before \
the block's local variables are dropped. \
For example, you could save the expression's value in a new \
local variable `x` and then make `x` be the expression \
at the end of the block."
err.note(
"the temporary is part of an expression at the end of a \
block;\nconsider forcing this temporary to be dropped sooner, \
before the block's local variables are dropped",
);
err.multipart_suggestion(
"for example, you could save the expression's value in a new \
local variable `x` and then make `x` be the expression at the \
end of the block",
vec![
(info.span.shrink_to_lo(), "let x = ".to_string()),
(info.span.shrink_to_hi(), "; x".to_string()),
],
Applicability::MaybeIncorrect,
);
};
err.note(msg);
}
}
}

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@ -173,7 +173,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
if let Some(expr) = expr {
let tail_result_is_ignored =
destination_ty.is_unit() || this.block_context.currently_ignores_tail_results();
this.block_context.push(BlockFrame::TailExpr { tail_result_is_ignored });
let span = match expr {
ExprRef::Hair(expr) => expr.span,
ExprRef::Mirror(ref expr) => expr.span,
};
this.block_context.push(BlockFrame::TailExpr { tail_result_is_ignored, span });
unpack!(block = this.into(destination, block, expr));
let popped = this.block_context.pop();

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@ -151,7 +151,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
}
this.block_context
.push(BlockFrame::TailExpr { tail_result_is_ignored: true });
.push(BlockFrame::TailExpr { tail_result_is_ignored: true, span: expr.span });
return Some(expr.span);
}
}

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@ -242,6 +242,9 @@ enum BlockFrame {
///
/// Example: `let _ = { STMT_1; EXPR };`
tail_result_is_ignored: bool,
/// `Span` of the tail expression.
span: Span,
},
/// Generic mark meaning that the block occurred as a subexpression
@ -369,8 +372,8 @@ impl BlockContext {
match bf {
BlockFrame::SubExpr => continue,
BlockFrame::Statement { .. } => break,
&BlockFrame::TailExpr { tail_result_is_ignored } => {
return Some(BlockTailInfo { tail_result_is_ignored });
&BlockFrame::TailExpr { tail_result_is_ignored, span } => {
return Some(BlockTailInfo { tail_result_is_ignored, span });
}
}
}
@ -394,7 +397,7 @@ impl BlockContext {
// otherwise: use accumulated is_ignored state.
Some(
BlockFrame::TailExpr { tail_result_is_ignored: ignored }
BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. }
| BlockFrame::Statement { ignores_expr_result: ignored },
) => *ignored,
}

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@ -571,8 +571,9 @@ pub trait Read {
/// Like `read`, except that it reads into a slice of buffers.
///
/// Data is copied to fill each buffer in order, with the final buffer
/// written to possibly being only partially filled. This method must behave
/// as a single call to `read` with the buffers concatenated would.
/// written to possibly being only partially filled. This method must
/// behave equivalently to a single call to `read` with concatenated
/// buffers.
///
/// The default implementation calls `read` with either the first nonempty
/// buffer provided, or an empty one if none exists.

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@ -0,0 +1,15 @@
// Check for recursion involving references to impl-associated const.
trait Foo {
const BAR: u32;
}
const IMPL_REF_BAR: u32 = GlobalImplRef::BAR; //~ ERROR E0391
struct GlobalImplRef;
impl GlobalImplRef {
const BAR: u32 = IMPL_REF_BAR;
}
fn main() {}

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@ -0,0 +1,44 @@
error[E0391]: cycle detected when const-evaluating + checking `IMPL_REF_BAR`
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:7:1
|
LL | const IMPL_REF_BAR: u32 = GlobalImplRef::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: ...which requires const-evaluating + checking `IMPL_REF_BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:7:1
|
LL | const IMPL_REF_BAR: u32 = GlobalImplRef::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `IMPL_REF_BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:7:1
|
LL | const IMPL_REF_BAR: u32 = GlobalImplRef::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires normalizing `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 13:2>::BAR`...
note: ...which requires const-evaluating + checking `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:5
|
LL | const BAR: u32 = IMPL_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating + checking `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:5
|
LL | const BAR: u32 = IMPL_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:5
|
LL | const BAR: u32 = IMPL_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires processing `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:5
|
LL | const BAR: u32 = IMPL_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires normalizing `IMPL_REF_BAR`...
= note: ...which again requires const-evaluating + checking `IMPL_REF_BAR`, completing the cycle
= note: cycle used when running analysis passes on this crate
error: aborting due to previous error
For more information about this error, try `rustc --explain E0391`.

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@ -0,0 +1,17 @@
// Check for recursion involving references to trait-associated const default.
trait Foo {
const BAR: u32;
}
trait FooDefault {
const BAR: u32 = DEFAULT_REF_BAR;
}
const DEFAULT_REF_BAR: u32 = <GlobalDefaultRef>::BAR; //~ ERROR E0391
struct GlobalDefaultRef;
impl FooDefault for GlobalDefaultRef {}
fn main() {}

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@ -0,0 +1,44 @@
error[E0391]: cycle detected when const-evaluating + checking `DEFAULT_REF_BAR`
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:11:1
|
LL | const DEFAULT_REF_BAR: u32 = <GlobalDefaultRef>::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: ...which requires const-evaluating + checking `DEFAULT_REF_BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:11:1
|
LL | const DEFAULT_REF_BAR: u32 = <GlobalDefaultRef>::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `DEFAULT_REF_BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:11:1
|
LL | const DEFAULT_REF_BAR: u32 = <GlobalDefaultRef>::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires normalizing `<GlobalDefaultRef as FooDefault>::BAR`...
note: ...which requires const-evaluating + checking `FooDefault::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
|
LL | const BAR: u32 = DEFAULT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating + checking `FooDefault::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
|
LL | const BAR: u32 = DEFAULT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `FooDefault::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
|
LL | const BAR: u32 = DEFAULT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires processing `FooDefault::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
|
LL | const BAR: u32 = DEFAULT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires normalizing `DEFAULT_REF_BAR`...
= note: ...which again requires const-evaluating + checking `DEFAULT_REF_BAR`, completing the cycle
= note: cycle used when running analysis passes on this crate
error: aborting due to previous error
For more information about this error, try `rustc --explain E0391`.

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@ -0,0 +1,15 @@
// Check for recursion involving references to trait-associated const.
trait Foo {
const BAR: u32;
}
const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR; //~ ERROR E0391
struct GlobalTraitRef;
impl Foo for GlobalTraitRef {
const BAR: u32 = TRAIT_REF_BAR;
}
fn main() {}

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@ -0,0 +1,44 @@
error[E0391]: cycle detected when const-evaluating + checking `TRAIT_REF_BAR`
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:7:1
|
LL | const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: ...which requires const-evaluating + checking `TRAIT_REF_BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:7:1
|
LL | const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `TRAIT_REF_BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:7:1
|
LL | const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires normalizing `<GlobalTraitRef as Foo>::BAR`...
note: ...which requires const-evaluating + checking `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:5
|
LL | const BAR: u32 = TRAIT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating + checking `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:5
|
LL | const BAR: u32 = TRAIT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:5
|
LL | const BAR: u32 = TRAIT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires processing `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 13:2>::BAR`...
--> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:5
|
LL | const BAR: u32 = TRAIT_REF_BAR;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires normalizing `TRAIT_REF_BAR`...
= note: ...which again requires const-evaluating + checking `TRAIT_REF_BAR`, completing the cycle
= note: cycle used when running analysis passes on this crate
error: aborting due to previous error
For more information about this error, try `rustc --explain E0391`.

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@ -0,0 +1,18 @@
#![feature(const_generics)]
#![allow(incomplete_features)]
trait Bar<O> {}
impl<O> Bar<O> for [u8; O] {}
//~^ ERROR expected value, found type parameter `O`
struct Foo<const O: usize> {}
impl<const O: usize> Foo<O>
where
[u8; O]: Bar<[(); O]>,
{
fn foo() {}
}
fn main() {
Foo::foo();
}

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@ -0,0 +1,14 @@
error[E0423]: expected value, found type parameter `O`
--> $DIR/issue-69654.rs:5:25
|
LL | impl<O> Bar<O> for [u8; O] {}
| ^ help: a tuple variant with a similar name exists: `Ok`
|
::: $SRC_DIR/libcore/result.rs:LL:COL
|
LL | Ok(#[stable(feature = "rust1", since = "1.0.0")] T),
| --------------------------------------------------- similarly named tuple variant `Ok` defined here
error: aborting due to previous error
For more information about this error, try `rustc --explain E0423`.

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@ -13,7 +13,10 @@ LL |
LL | ;
| - ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `D`
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | D("other").next(&_thing1);
| ^
error: aborting due to previous error

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@ -13,7 +13,10 @@ LL | }
| `counter` dropped here while still borrowed
| ... and the borrow might be used here, when that temporary is dropped and runs the destructor for type `std::result::Result<MutexGuard<'_>, ()>`
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | if let Ok(_) = counter.lock() { };
| ^
error: aborting due to previous error

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@ -12,7 +12,12 @@ LL | }
| `stmt` dropped here while still borrowed
| ... and the borrow might be used here, when that temporary is dropped and runs the destructor for type `std::iter::Map<Rows<'_>, [closure@$DIR/issue-54556-stephaneyfx.rs:28:14: 28:23]>`
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | let x = rows.map(|row| row).next(); x
| ^^^^^^^ ^^^
error: aborting due to previous error

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@ -12,7 +12,10 @@ LL |
LL | ;
| - ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `D`
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | D(&_thing1).end();
| ^
error: aborting due to previous error

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@ -8,7 +8,10 @@ LL | { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } ; //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | { let mut _t1 = D(Box::new("t1")); D(&_t1).end(); } ; // suggest `;`
| ^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:13:55
@ -20,7 +23,10 @@ LL | { { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } } ; //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | { { let mut _t1 = D(Box::new("t1")); D(&_t1).end(); } } ; // suggest `;`
| ^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:16:55
@ -32,7 +38,10 @@ LL | { { let mut _t1 = D(Box::new("t1")); D(&_t1).end() }; } //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | { { let mut _t1 = D(Box::new("t1")); D(&_t1).end(); }; } // suggest `;`
| ^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:19:55
@ -44,7 +53,10 @@ LL | let _ = { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } ; //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | let _ = { let mut _t1 = D(Box::new("t1")); D(&_t1).end(); } ; // suggest `;`
| ^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:22:55
@ -56,7 +68,10 @@ LL | let _u = { let mut _t1 = D(Box::new("t1")); D(&_t1).unit() } ; //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | let _u = { let mut _t1 = D(Box::new("t1")); D(&_t1).unit(); } ; // suggest `;`
| ^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:25:55
@ -68,7 +83,12 @@ LL | let _x = { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } ; //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | let _x = { let mut _t1 = D(Box::new("t1")); let x = D(&_t1).end(); x } ; // `let x = ...; x`
| ^^^^^^^ ^^^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:30:55
@ -80,7 +100,12 @@ LL | _y = { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } ; // `l
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | _y = { let mut _t1 = D(Box::new("t1")); let x = D(&_t1).end(); x } ; // `let x = ...; x`
| ^^^^^^^ ^^^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:37:55
@ -93,7 +118,10 @@ LL | fn f_local_ref() { let mut _t1 = D(Box::new("t1")); D(&_t1).unit() } //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped.
help: consider adding semicolon after the expression so its temporaries are dropped sooner, before the local variables declared by the block are dropped
|
LL | fn f_local_ref() { let mut _t1 = D(Box::new("t1")); D(&_t1).unit(); } // suggest `;`
| ^
error[E0597]: `_t1` does not live long enough
--> $DIR/issue-54556-used-vs-unused-tails.rs:40:55
@ -106,7 +134,12 @@ LL | fn f() -> String { let mut _t1 = D(Box::new("t1")); D(&_t1).end() } //
| | borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | fn f() -> String { let mut _t1 = D(Box::new("t1")); let x = D(&_t1).end(); x } // `let x = ...; x`
| ^^^^^^^ ^^^
error: aborting due to 9 previous errors

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@ -11,7 +11,12 @@ LL | };
| |
| `*a` dropped here while still borrowed
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | let x = *a.borrow() + 1; x
| ^^^^^^^ ^^^
error: aborting due to previous error

View File

@ -12,7 +12,12 @@ LL | }
| `y` dropped here while still borrowed
| ... and the borrow might be used here, when that temporary is dropped and runs the destructor for type `std::cell::Ref<'_, std::string::String>`
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | let x = y.borrow().clone(); x
| ^^^^^^^ ^^^
error[E0597]: `y` does not live long enough
--> $DIR/issue-23338-locals-die-before-temps-of-body.rs:17:9
@ -27,7 +32,12 @@ LL | };
| |
| `y` dropped here while still borrowed
|
= note: The temporary is part of an expression at the end of a block. Consider forcing this temporary to be dropped sooner, before the block's local variables are dropped. For example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block.
= note: the temporary is part of an expression at the end of a block;
consider forcing this temporary to be dropped sooner, before the block's local variables are dropped
help: for example, you could save the expression's value in a new local variable `x` and then make `x` be the expression at the end of the block
|
LL | let x = y.borrow().clone(); x
| ^^^^^^^ ^^^
error: aborting due to 2 previous errors