constify boolean methods by bend-n · Pull Request #151489 · rust-lang/rust

bend-n · 2026-01-22T12:32:29Z

// core::bool

impl bool {
    pub const fn then_some<T: [const] Destruct>(self, t: T) -> Option<T>;
    pub const fn then<T, F: [const] FnOnce() -> T + [const] Destruct>(self, f: F) -> Option<T>;
    pub const fn ok_or<E: [const] Destruct>(self, err: E) -> Result<(), E>;
    pub const fn ok_or_else<E, F: [const] FnOnce() -> E + [const] Destruct>;
}

will make tracking issue if pr liked

rustbot · 2026-01-22T12:32:34Z

r? @jhpratt

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SpriteOvO

Personally, I prefer the name const_bool_ops for this feature gate.

It would be nice if you could also remove the FIXME and enable these tests for const.

rust/library/coretests/tests/bool.rs

Lines 85 to 107 in d29e478

    
           #[test] 
        
           fn test_bool_to_option() { 
        
               assert_eq!(false.then_some(0), None); 
        
               assert_eq!(true.then_some(0), Some(0)); 
        
               assert_eq!(false.then(|| 0), None); 
        
               assert_eq!(true.then(|| 0), Some(0)); 
        
               /* FIXME(#110395) 
        
               const fn zero() -> i32 { 
        
                   0 
        
               } 
        
               const A: Option<i32> = false.then_some(0); 
        
               const B: Option<i32> = true.then_some(0); 
        
               const C: Option<i32> = false.then(zero); 
        
               const D: Option<i32> = true.then(zero); 
        
               assert_eq!(A, None); 
        
               assert_eq!(B, Some(0)); 
        
               assert_eq!(C, None); 
        
               assert_eq!(D, Some(0)); 
        
               */ 
        
           }

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jhpratt · 2026-01-23T01:28:25Z

My understanding is we're in the "constify everything" phase, so feel free to create a tracking issue. Let me know when that's done (and the PR updated with the issue number) and I'll approve it.

@rustbot author

rustbot · 2026-01-23T01:28:30Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

SpriteOvO · 2026-01-23T02:53:28Z

library/coretests/tests/bool.rs

 #[test]
 fn test_bool_to_result() {
    assert_eq!(false.ok_or(0), Err(0));
    assert_eq!(true.ok_or(0), Ok(()));
    assert_eq!(false.ok_or_else(|| 0), Err(0));
    assert_eq!(true.ok_or_else(|| 0), Ok(()));
 }


Could you also add some const test cases for ok_or ok_or_else here? Like the ones above. I forgot to say it yesterday, sorry 😅

bend-n · 2026-01-23T10:08:59Z

@rustbot ready

jhpratt · 2026-01-24T01:29:44Z

Thanks!

@bors r+ rollup

rust-bors · 2026-01-24T01:29:48Z

📌 Commit 207dcbb has been approved by jhpratt

It is now in the queue for this repository.

…s-under-feature-gate-const-bool, r=jhpratt constify boolean methods ```rs // core::bool impl bool { pub const fn then_some<T: [const] Destruct>(self, t: T) -> Option<T>; pub const fn then<T, F: [const] FnOnce() -> T + [const] Destruct>(self, f: F) -> Option<T>; pub const fn ok_or<E: [const] Destruct>(self, err: E) -> Result<(), E>; pub const fn ok_or_else<E, F: [const] FnOnce() -> E + [const] Destruct>; } ``` will make tracking issue if pr liked

@ghost

Rollup of 8 pull requests Successful merges: - #150556 (Add Tier 3 Thumb-mode targets for Armv7-A, Armv7-R and Armv8-R) - #151346 (add `simd_splat` intrinsic) - #151500 (hexagon: Add HVX target features) - #151505 (Various refactors to the proc_macro bridge) - #151517 (Enable reproducible binary builds with debuginfo on Linux) - #151482 (Add "Skip to main content" link for keyboard navigation in rustdoc) - #151489 (constify boolean methods) - #151551 (Don't use default build-script fingerprinting in `test`) r? @ghost

…s-under-feature-gate-const-bool, r=jhpratt constify boolean methods ```rs // core::bool impl bool { pub const fn then_some<T: [const] Destruct>(self, t: T) -> Option<T>; pub const fn then<T, F: [const] FnOnce() -> T + [const] Destruct>(self, f: F) -> Option<T>; pub const fn ok_or<E: [const] Destruct>(self, err: E) -> Result<(), E>; pub const fn ok_or_else<E, F: [const] FnOnce() -> E + [const] Destruct>; } ``` will make tracking issue if pr liked

@ghost

Rollup of 8 pull requests Successful merges: - #150556 (Add Tier 3 Thumb-mode targets for Armv7-A, Armv7-R and Armv8-R) - #151500 (hexagon: Add HVX target features) - #151505 (Various refactors to the proc_macro bridge) - #151517 (Enable reproducible binary builds with debuginfo on Linux) - #151482 (Add "Skip to main content" link for keyboard navigation in rustdoc) - #151489 (constify boolean methods) - #151551 (Don't use default build-script fingerprinting in `test`) - #151555 (Fix compilation of std/src/sys/pal/uefi/tests.rs) r? @ghost

…s-under-feature-gate-const-bool, r=jhpratt constify boolean methods ```rs // core::bool impl bool { pub const fn then_some<T: [const] Destruct>(self, t: T) -> Option<T>; pub const fn then<T, F: [const] FnOnce() -> T + [const] Destruct>(self, f: F) -> Option<T>; pub const fn ok_or<E: [const] Destruct>(self, err: E) -> Result<(), E>; pub const fn ok_or_else<E, F: [const] FnOnce() -> E + [const] Destruct>; } ``` will make tracking issue if pr liked

@ghost

…uwer Rollup of 8 pull requests Successful merges: - #150556 (Add Tier 3 Thumb-mode targets for Armv7-A, Armv7-R and Armv8-R) - #151259 (Fix is_ascii performance regression on AVX-512 CPUs when compiling with -C target-cpu=native) - #151500 (hexagon: Add HVX target features) - #151517 (Enable reproducible binary builds with debuginfo on Linux) - #151482 (Add "Skip to main content" link for keyboard navigation in rustdoc) - #151489 (constify boolean methods) - #151551 (Don't use default build-script fingerprinting in `test`) - #151555 (Fix compilation of std/src/sys/pal/uefi/tests.rs) r? @ghost

Rollup merge of #151489 - bend-n:constify-all-boolean-methods-under-feature-gate-const-bool, r=jhpratt constify boolean methods ```rs // core::bool impl bool { pub const fn then_some<T: [const] Destruct>(self, t: T) -> Option<T>; pub const fn then<T, F: [const] FnOnce() -> T + [const] Destruct>(self, f: F) -> Option<T>; pub const fn ok_or<E: [const] Destruct>(self, err: E) -> Result<(), E>; pub const fn ok_or_else<E, F: [const] FnOnce() -> E + [const] Destruct>; } ``` will make tracking issue if pr liked

rustbot assigned jhpratt Jan 22, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jan 22, 2026

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bend-n force-pushed the constify-all-boolean-methods-under-feature-gate-const-bool branch from fec2775 to 06a0024 Compare January 22, 2026 17:25

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 23, 2026

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Tracking Issue for const_bool #151531

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reenable tests

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bend-n force-pushed the constify-all-boolean-methods-under-feature-gate-const-bool branch from 06a0024 to bbef137 Compare January 23, 2026 07:26

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constify boolean methods

207dcbb

bend-n force-pushed the constify-all-boolean-methods-under-feature-gate-const-bool branch from bbef137 to 207dcbb Compare January 23, 2026 08:12

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jan 23, 2026

rust-bors bot 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 Jan 24, 2026

jhpratt mentioned this pull request Jan 24, 2026

Rollup of 8 pull requests #151562

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jhpratt mentioned this pull request Jan 24, 2026

Rollup of 8 pull requests #151570

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This was referenced Jan 24, 2026

Rollup of 9 pull requests #151574

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Rollup of 8 pull requests #151575

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rust-bors bot merged commit 474c9fe into rust-lang:main Jan 24, 2026
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rustbot added this to the 1.95.0 milestone Jan 24, 2026

bend-n deleted the constify-all-boolean-methods-under-feature-gate-const-bool branch January 24, 2026 18:07

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constify boolean methods#151489

constify boolean methods#151489
rust-bors[bot] merged 2 commits intorust-lang:mainfrom
bend-n:constify-all-boolean-methods-under-feature-gate-const-bool

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	#[test]
	fn test_bool_to_option() {
	assert_eq!(false.then_some(0), None);
	assert_eq!(true.then_some(0), Some(0));
	assert_eq!(false.then(\|\| 0), None);
	assert_eq!(true.then(\|\| 0), Some(0));

	/* FIXME(#110395)
	const fn zero() -> i32 {
	0
	}

	const A: Option<i32> = false.then_some(0);
	const B: Option<i32> = true.then_some(0);
	const C: Option<i32> = false.then(zero);
	const D: Option<i32> = true.then(zero);

	assert_eq!(A, None);
	assert_eq!(B, Some(0));
	assert_eq!(C, None);
	assert_eq!(D, Some(0));
	*/
	}

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