Remove redundant suffixes from `Try` (`TryType`, `TryTrait`) by nxsaken · Pull Request #155229 · rust-lang/rust

nxsaken · 2026-04-13T08:05:59Z

Feature: try_trait_v2_residual (#91285)

The main part is renaming Residual::TryType into Try (+ residual_into_try_type into residual_into_try) to reflect the symmetry between Try::Residual: Residual and Residual::Try: Try. I went ahead and changed all similar references except for try_trait* (there it makes sense because it distinguishes the trait feature from the block feature and prevents clashing with the keyword).

r? @scottmcm

rustbot · 2026-04-13T08:06:03Z

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri, @RalfJung, @oli-obk, @lcnr

rust-analyzer is developed in its own repository. If possible, consider making this change to rust-lang/rust-analyzer instead.

cc @rust-lang/rust-analyzer

ChayimFriedman2

rust-analyzer should support both forms, at least for some time.

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nxsaken · 2026-04-13T11:18:58Z

Let me check my intuition.

I need to add the renamed lang item symbol (into_try_type) back under another name, say,

ResidualIntoTry,    sym::into_try,      FunctionId;
ResidualIntoTryOld, sym::into_try_type, FunctionId;

and then, this:

Some(TryBlock::Homogeneous { .. }) => {
    self.lang_path(lang_items.ResidualIntoTry)
}

seems to be the only mention of ResidualIntoTry in rust-analyzer, where self.lang_path(..) returns Option<Path>, and lang_items.ResidualIntoTry is Option<FunctionId>. Should I Option::or one of them to fallback to ResidualIntoTryOld?

If this is correct, I should only do it in rust-analyzer, not in the compiler? And how can someone tell when it's safe to remove?

lnicola · 2026-04-13T11:49:07Z

The main concern is that rust-analyzer should work with both old and new versions of the standard library. The compiler only needs to support the matching one.

If this is correct, I should only do it in rust-analyzer, not in the compiler?

Yes.

And how can someone tell when it's safe to remove?

Add a comment like "// TODO: change [stuff, maybe point to your commit] when dropping support for 1.95" (or whatever is the last stable toolchain that uses the old names).

ChayimFriedman2

rust-analyzer changes LGTM.

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scottmcm · 2026-04-18T03:57:29Z

-    r: R,
-) -> <R as Residual<O>>::TryType {
+#[lang = "into_try"]
+pub const fn residual_into_try<R: [const] Residual<O>, O>(r: R) -> <R as Residual<O>>::Try {


I would suggest just leaving this function alone. It's perma-unstable, only here for implementing the desugaring. To especially if it affects R-A, can leave it as the same lang item.

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scottmcm · 2026-04-18T03:58:53Z

    ///         #[allow(unreachable_code)]
    ///         // If there is an enclosing `try {...}`:
-    ///         break 'catch_target Residual::into_try_type(residual),
+    ///         break 'catch_target Residual::into_try(residual),


If you're going to update, might as well make it actually correct, since it's not part of Residual any more.

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scottmcm · 2026-04-18T04:05:06Z

        this: Self,
        f: impl FnOnce(T) -> R,
-    ) -> <R::Residual as Residual<Box<R::Output>>>::TryType
+    ) -> <R::Residual as Residual<Box<R::Output>>>::Try


In core we do this using a type alias which is why that didn't need changing; should alloc switch to using that too?

Suggested change

) -> <R::Residual as Residual<Box<R::Output>>>::Try

) -> ChangeOutputType<R, Box<R::Output>>

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scottmcm · 2026-04-18T04:05:54Z

-    TryTraitFromResidual,    sym::from_residual,       from_residual_fn,           Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
-    TryTraitFromOutput,      sym::from_output,         from_output_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
-    TryTraitBranch,          sym::branch,              branch_fn,                  Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
-    TryTraitFromYeet,        sym::from_yeet,           from_yeet_fn,               Target::Fn,             GenericRequirement::None;
-    ResidualIntoTryType,     sym::into_try_type,       into_try_type_fn,           Target::Fn,             GenericRequirement::None;
+    TryFromResidual,    sym::from_residual,       from_residual_fn,           Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+    TryFromOutput,      sym::from_output,         from_output_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+    TryBranch,          sym::branch,              branch_fn,                  Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
+    TryFromYeet,        sym::from_yeet,           from_yeet_fn,               Target::Fn,             GenericRequirement::None;
+    ResidualIntoTry,    sym::into_try,            into_try_fn,                Target::Fn,             GenericRequirement::None;


fix: this file uses vertical alignment for the columns, so please fix that.

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The rest of the items have been misaligned all along. Do you want me to realign everything?

scottmcm · 2026-04-18T04:06:19Z

@rustbot author

rustbot · 2026-04-18T04:06:25Z

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

TryType, TryTrait -> Try

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rustbot assigned scottmcm Apr 13, 2026

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ChayimFriedman2 reviewed Apr 13, 2026

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Support the old lang item in rust-analyzer

69f2576

nxsaken force-pushed the Residual-TryType branch from 3908d69 to 69f2576 Compare April 13, 2026 12:20

ChayimFriedman2 approved these changes Apr 13, 2026

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scottmcm reviewed Apr 18, 2026

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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 Apr 18, 2026

	) -> <R::Residual as Residual<Box<R::Output>>>::Try
	) -> ChangeOutputType<R, Box<R::Output>>

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