constify Option methods
#143967
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constify Option methods
#143967
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oli-obk
commented
Jul 15, 2025
| F: ~const Destruct + ~const FnOnce() -> Option<T>, | ||
| //FIXME(const_hack): this `T: ~const Destruct` is unnecessary, but even precise live drops can't tell | ||
| // no value of type `T` gets dropped here | ||
| T: ~const Destruct, | ||
| { | ||
| match self { | ||
| x @ Some(_) => x, |
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This pattern was introduced in #116481 because it optimizes better.
fee1-dead
reviewed
Jul 15, 2025
Comment on lines
+1640
to
+1642
| //FIXME(const_hack): this `T: ~const Destruct` is unnecessary, but even precise live drops can't tell | ||
| // no value of type `T` gets dropped here |
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I have a feeling this will nerdsnipe me hard.
Here's how code is currently generated
#![feature(const_destruct)]
#![feature(const_trait_impl)]
use std::marker::Destruct;
pub const fn opt_or_else<T, F>(this: Option<T>, f: F) -> Option<T>
where
F: ~const Destruct + ~const FnOnce() -> Option<T>,
T: ~const Destruct
{
match this {
x @ Some(_) => x,
None => f()
}
}// MIR FOR CTFE
fn opt_or_else(_1: Option<T>, _2: F) -> Option<T> {
debug this => _1;
debug f => _2;
let mut _0: std::option::Option<T>;
let mut _3: isize;
let _4: std::option::Option<T>;
let mut _5: F;
let mut _6: ();
let mut _7: bool;
let mut _8: bool;
scope 1 {
debug x => _4;
}
bb0: {
_8 = const false;
_7 = const false;
_8 = const true;
_7 = const true;
_3 = discriminant(_1);
switchInt(move _3) -> [0: bb2, 1: bb3, otherwise: bb1];
}
bb1: {
unreachable;
}
bb2: {
StorageLive(_5);
_7 = const false;
_5 = move _2;
StorageLive(_6);
_6 = ();
ConstEvalCounter;
_0 = <F as FnOnce<()>>::call_once(move _5, move _6) -> [return: bb4, unwind: bb12];
}
bb3: {
StorageLive(_4);
_8 = const false;
_4 = move _1;
_0 = move _4;
StorageDead(_4);
goto -> bb9;
}
bb4: {
StorageDead(_6);
StorageDead(_5);
goto -> bb9;
}
bb5: {
switchInt(copy _8) -> [0: bb6, otherwise: bb10];
}
bb6: {
return;
}
bb7 (cleanup): {
resume;
}
bb8: {
drop(_2) -> [return: bb5, unwind: bb12];
}
bb9: {
switchInt(copy _7) -> [0: bb5, otherwise: bb8];
}
bb10: {
drop(_1) -> [return: bb6, unwind: bb7];
}
bb11 (cleanup): {
drop(_1) -> [return: bb7, unwind terminate(cleanup)];
}
bb12 (cleanup): {
switchInt(copy _8) -> [0: bb7, otherwise: bb11];
}
}looks like it tries to drop self at the None arm, which is just weird.
fee1-dead
requested changes
Jul 17, 2025
library/core/src/option.rs
Outdated
| @@ -649,7 +650,8 @@ impl<T> Option<T> { | |||
| #[must_use] | |||
| #[inline] | |||
| #[stable(feature = "is_some_and", since = "1.70.0")] | |||
| pub fn is_some_and(self, f: impl FnOnce(T) -> bool) -> bool { | |||
| #[rustc_const_unstable(feature = "const_option_ops", issue = "143956")] | |||
| pub const fn is_some_and(self, f: impl ~const Destruct + ~const FnOnce(T) -> bool) -> bool { | |||
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I think we should put FnOnce first, here and elsewhere in the PR. the destruct bound is noisy and likely to make it harder for someone to read the code.
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@bors r=fee1-dead |
fmease
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Jul 17, 2025
…e1-dead constify `Option` methods r? `@fee1-dead` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
fmease
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Jul 17, 2025
…e1-dead constify `Option` methods r? ``@fee1-dead`` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
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Rollup of 15 pull requests Successful merges: - #142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - #143271 (Store the type of each GVN value) - #143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - #143719 (Emit warning when there is no space between `-o` and arg) - #143833 (Ban projecting into SIMD types [MCP838]) - #143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - #143879 (parse `const trait Trait`) - #143891 (Port `#[coverage]` to the new attribute system) - #143967 (constify `Option` methods) - #143985 (rustc_public: de-StableMIR-ize) - #144008 (Fix false positive double negations with macro invocation) - #144010 (Boostrap: add warning on `optimize = false`) - #144034 (tests: Test line number in debuginfo for diverging function calls) - #144049 (rustc-dev-guide subtree update) - #144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
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Jul 17, 2025
…e1-dead constify `Option` methods r? ```@fee1-dead``` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
bors
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Rollup of 12 pull requests Successful merges: - #142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - #143271 (Store the type of each GVN value) - #143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - #143719 (Emit warning when there is no space between `-o` and arg) - #143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - #143891 (Port `#[coverage]` to the new attribute system) - #143967 (constify `Option` methods) - #144008 (Fix false positive double negations with macro invocation) - #144010 (Boostrap: add warning on `optimize = false`) - #144034 (tests: Test line number in debuginfo for diverging function calls) - #144049 (rustc-dev-guide subtree update) - #144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 12 pull requests Successful merges: - #142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - #143271 (Store the type of each GVN value) - #143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - #143719 (Emit warning when there is no space between `-o` and arg) - #143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - #143891 (Port `#[coverage]` to the new attribute system) - #143967 (constify `Option` methods) - #144008 (Fix false positive double negations with macro invocation) - #144010 (Boostrap: add warning on `optimize = false`) - #144034 (tests: Test line number in debuginfo for diverging function calls) - #144049 (rustc-dev-guide subtree update) - #144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
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Jul 18, 2025
…e1-dead constify `Option` methods r? ````@fee1-dead```` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
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…e1-dead constify `Option` methods r? `````@fee1-dead````` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
matthiaskrgr
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…e1-dead constify `Option` methods r? ``````@fee1-dead`````` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
This was referenced Jul 18, 2025
bors
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Rollup of 11 pull requests Successful merges: - #142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - #143271 (Store the type of each GVN value) - #143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - #143719 (Emit warning when there is no space between `-o` and arg) - #143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - #143891 (Port `#[coverage]` to the new attribute system) - #143967 (constify `Option` methods) - #144008 (Fix false positive double negations with macro invocation) - #144010 (Boostrap: add warning on `optimize = false`) - #144049 (rustc-dev-guide subtree update) - #144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 11 pull requests Successful merges: - rust-lang/rust#142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - rust-lang/rust#143271 (Store the type of each GVN value) - rust-lang/rust#143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - rust-lang/rust#143719 (Emit warning when there is no space between `-o` and arg) - rust-lang/rust#143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - rust-lang/rust#143891 (Port `#[coverage]` to the new attribute system) - rust-lang/rust#143967 (constify `Option` methods) - rust-lang/rust#144008 (Fix false positive double negations with macro invocation) - rust-lang/rust#144010 (Boostrap: add warning on `optimize = false`) - rust-lang/rust#144049 (rustc-dev-guide subtree update) - rust-lang/rust#144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup of 11 pull requests Successful merges: - rust-lang/rust#142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - rust-lang/rust#143271 (Store the type of each GVN value) - rust-lang/rust#143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - rust-lang/rust#143719 (Emit warning when there is no space between `-o` and arg) - rust-lang/rust#143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - rust-lang/rust#143891 (Port `#[coverage]` to the new attribute system) - rust-lang/rust#143967 (constify `Option` methods) - rust-lang/rust#144008 (Fix false positive double negations with macro invocation) - rust-lang/rust#144010 (Boostrap: add warning on `optimize = false`) - rust-lang/rust#144049 (rustc-dev-guide subtree update) - rust-lang/rust#144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
Muscraft
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Jul 21, 2025
…e1-dead constify `Option` methods r? ```````@fee1-dead``````` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
Muscraft
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…iaskrgr Rollup of 11 pull requests Successful merges: - rust-lang#142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled) - rust-lang#143271 (Store the type of each GVN value) - rust-lang#143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions) - rust-lang#143719 (Emit warning when there is no space between `-o` and arg) - rust-lang#143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests) - rust-lang#143891 (Port `#[coverage]` to the new attribute system) - rust-lang#143967 (constify `Option` methods) - rust-lang#144008 (Fix false positive double negations with macro invocation) - rust-lang#144010 (Boostrap: add warning on `optimize = false`) - rust-lang#144049 (rustc-dev-guide subtree update) - rust-lang#144056 (Copy GCC sources into the build directory even outside CI) r? `@ghost` `@rustbot` modify labels: rollup
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…e1-dead constify `Option` methods r? ```````@fee1-dead``````` tracking issue: rust-lang#143956 these unblock making `PartialOrd` and `Ord` const without resorting to inlining some of these at call sites.
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r? @fee1-dead
tracking issue: #143956
these unblock making
PartialOrdandOrdconst without resorting to inlining some of these at call sites.