Update platform010 & platform010-aarch64 symlinks

Summary:
Release notes: https://blog.rust-lang.org/2026/05/28/Rust-1.96.0/

- Stabilized features:
    - `feature(assert_matches)`

- Wasm targets no longer pass `--allow-undefined` to the linker ([rust#149868](rust-lang/rust#149868))

- Changes in the computation of *"private type in public interface"*

- New ambiguities surfaced by `ambiguous_glob_imports` lint ([rust#114095](rust-lang/rust#114095))

- New warning on unneeded `#![feature(…)]`

- New error on mismatched `-Zbranch-protection` between dependencies

Reviewed By: ship-it-ship-it, diliop, opsound

Differential Revision: D108384430

fbshipit-source-id: 60c3a5a98e7eabdff47eb1db213f28a29111c11d

Author: David Tolnay

app/buck2_external_cells/src/lib.rs

@@ -11,7 +11,6 @@
 // Internal stable rustc still treats `assert_matches` as unstable; OSS nightly has stabilized it
 // and denies the now-redundant feature gate.
 #![allow(stable_features)]
-#![feature(assert_matches)]
 #![feature(once_cell_try)]
 
 use std::sync::Arc;

app/buck2_interpreter_for_build/src/attrs/coerce/attr_type/query.rs

@@ -80,7 +80,7 @@ impl QueryAttrTypeExt for QueryAttrType {
                     query
                         .as_str()
                         .substr_range(l)
-                        .map(|range| ((range.start, range.len()), p))
+                        .map(|range| ((range.start, range.end - range.start), p))
                         .ok_or_else(|| internal_error!("Not found in query"))
                 })
                 .try_collect()?,

docs/getting_started/install.md

@@ -40,8 +40,8 @@ Buck2 currently requires a nightly Rust toolchain. The simplest setup is via
 you. Once it's installed, build and install `buck2` directly from GitHub:
 
 ```bash
-rustup install nightly-2026-02-28
-cargo +nightly-2026-02-28 install --git https://github.com/facebook/buck2.git buck2
+rustup install nightly-2026-04-11
+cargo +nightly-2026-04-11 install --git https://github.com/facebook/buck2.git buck2
 ```
 
 This installs `buck2` into a suitable directory such as `$HOME/.cargo/bin`,

rust-toolchain

@@ -9,6 +9,6 @@
 #     has a dependency on buck2 git trunk.
 # * Update `../monarch/rust-toolchain` (one instance)
 
-# @rustc_version: rustc 1.95.0-nightly (3a70d0349 2026-02-27)
-channel = "nightly-2026-02-28"
+# @rustc_version: rustc 1.96.0-nightly (02c7f9bec 2026-04-10)
+channel = "nightly-2026-04-11"
 components = ["llvm-tools-preview", "rust-src"]