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@c410-f3r c410-f3r commented Jun 21, 2022

Tracking issue: #44838
Fifth step of #96496

The most non-invasive approach that will probably have very little to no performance impact.

Current behaviour

Captures are handled "on-the-fly", i.e., they are performed in the same place expressions are located.

// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !(
  { ***try capture `a` and then return `a`*** } > 1 && { ***try capture `b` and then return `b`*** } < 100
) {
  panic!( ... );
}

As such, some overhead is likely to occur (Specially with very large chains of conditions).

New behaviour for non-consuming operators

When an operator is known to not take self, then it is possible to capture variables AFTER the condition.

// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !( a > 1 && b < 100 ) {
  { ***try capture `a`*** }
  { ***try capture `b`*** }
  panic!( ... );
}

So the possible impact on the runtime execution time will be diminished.

r? @oli-obk

@rustbot rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jun 21, 2022
@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 21, 2022
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oli-obk commented Jun 21, 2022

@bors r+

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bors commented Jun 21, 2022

📌 Commit a0eba66 has been approved by oli-obk

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 21, 2022
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Thank you @oli-obk

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Jun 22, 2022
[RFC 2011] Optimize non-consuming operators

Tracking issue: rust-lang#44838
Fifth step of rust-lang#96496

The most non-invasive approach that will probably have very little to no performance impact.

## Current behaviour

Captures are handled "on-the-fly", i.e., they are performed in the same place expressions are located.

```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !(
  { ***try capture `a` and then return `a`*** } > 1 && { ***try capture `b` and then return `b`*** } < 100
) {
  panic!( ... );
}
```

As such, some overhead is likely to occur (Specially with very large chains of conditions).

## New behaviour for non-consuming operators

When an operator is known to not take `self`, then it is possible to capture variables **AFTER** the condition.

```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !( a > 1 && b < 100 ) {
  { ***try capture `a`*** }
  { ***try capture `b`*** }
  panic!( ... );
}
```

So the possible impact on the runtime execution time will be diminished.

r? `@oli-obk`
Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Jun 24, 2022
[RFC 2011] Optimize non-consuming operators

Tracking issue: rust-lang#44838
Fifth step of rust-lang#96496

The most non-invasive approach that will probably have very little to no performance impact.

## Current behaviour

Captures are handled "on-the-fly", i.e., they are performed in the same place expressions are located.

```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !(
  { ***try capture `a` and then return `a`*** } > 1 && { ***try capture `b` and then return `b`*** } < 100
) {
  panic!( ... );
}
```

As such, some overhead is likely to occur (Specially with very large chains of conditions).

## New behaviour for non-consuming operators

When an operator is known to not take `self`, then it is possible to capture variables **AFTER** the condition.

```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !( a > 1 && b < 100 ) {
  { ***try capture `a`*** }
  { ***try capture `b`*** }
  panic!( ... );
}
```

So the possible impact on the runtime execution time will be diminished.

r? ``@oli-obk``
Dylan-DPC added a commit to Dylan-DPC/rust that referenced this pull request Jun 28, 2022
[RFC 2011] Optimize non-consuming operators

Tracking issue: rust-lang#44838
Fifth step of rust-lang#96496

The most non-invasive approach that will probably have very little to no performance impact.

## Current behaviour

Captures are handled "on-the-fly", i.e., they are performed in the same place expressions are located.

```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !(
  { ***try capture `a` and then return `a`*** } > 1 && { ***try capture `b` and then return `b`*** } < 100
) {
  panic!( ... );
}
```

As such, some overhead is likely to occur (Specially with very large chains of conditions).

## New behaviour for non-consuming operators

When an operator is known to not take `self`, then it is possible to capture variables **AFTER** the condition.

```rust
// `let a = 1; let b = 2; assert!(a > 1 && b < 100);`

if !( a > 1 && b < 100 ) {
  { ***try capture `a`*** }
  { ***try capture `b`*** }
  panic!( ... );
}
```

So the possible impact on the runtime execution time will be diminished.

r? ```@oli-obk```
bors added a commit to rust-lang-ci/rust that referenced this pull request Jun 28, 2022
Rollup of 9 pull requests

Successful merges:

 - rust-lang#97346 (Remove a back-compat hack on lazy TAIT)
 - rust-lang#98261 (Remove `MAX_SUGGESTION_HIGHLIGHT_LINES`)
 - rust-lang#98337 ([RFC 2011] Optimize non-consuming operators)
 - rust-lang#98384 (Fix RSS reporting on macOS)
 - rust-lang#98420 (translation: lint fix + more migration)
 - rust-lang#98430 (Refactor iter adapters with less macros)
 - rust-lang#98555 (Hermit: Fix initializing lazy locks)
 - rust-lang#98595 (Implement `Send` and `Sync` for `ThinBox<T>`)
 - rust-lang#98597 (Remove unstable CStr/CString change from 1.62 release note)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit ec8477f into rust-lang:master Jun 28, 2022
@rustbot rustbot added this to the 1.64.0 milestone Jun 28, 2022
@fmease fmease added the F-generic_assert `#![feature(generic_assert)]` label Apr 8, 2024
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6 participants