Merge subtree update for toolchain nightly-2026-02-05

.github/workflows/flux.yml

@@ -8,8 +8,8 @@ on:
     branches: [main]
 
 env:
-  FLUX_VERSION: "27e3ef52b52253a1d128aff7b80894bed4da0c95"
-  FIXPOINT_VERSION: "nightly-01-14-2026"
+  FLUX_VERSION: "9c1b5e278791f57eed1fd109816bbe180423fa9d"
+  FIXPOINT_VERSION: "nightly-2026-07-20"
 
 jobs:
   check-flux-on-core:

.github/workflows/kani.yml

@@ -35,6 +35,10 @@ jobs:
       WORKER_INDEX: ${{ matrix.partition }}
       # Total number of workers running this step
       WORKER_TOTAL: 4
+      # Cap parallel harness verification on ubuntu-latest: its 4-core/16 GB
+      # runners get OOM-killed when 4 memory-hungry harnesses (up to ~10 GB
+      # each, e.g. the ffi::c_str ones) run concurrently.
+      KANI_JOBS: ${{ matrix.os == 'ubuntu-latest' && 2 || '' }}
 
     steps:
       - name: Remove unnecessary software to free up disk space

library/Cargo.toml

@@ -12,7 +12,7 @@ members = [
 exclude = [
   # stdarch has its own Cargo workspace
   "stdarch",
-  "windows_targets"
+  "windows_link"
 ]
 
 [profile.release.package.compiler_builtins]
@@ -54,6 +54,32 @@ rustflags = ["-Cpanic=abort"]
 [profile.release.package.panic_abort]
 rustflags = ["-Cpanic=abort"]
 
+# The "dist" profile is used by bootstrap for prebuilt libstd artifacts
+# These settings ensure that the prebuilt artifacts support a variety of features
+# in the user's profile.
+[profile.dist]
+inherits = "release"
+codegen-units = 1
+debug = 1 # "limited"
+rustflags = [
+    # `profile.lto=off` implies `-Cembed-bitcode=no`, but unconditionally embedding
+    # bitcode is necessary for when users enable LTO.
+    # Required until Cargo can re-build the standard library based on the value
+    # of `profile.lto` in the user's profile.
+    "-Cembed-bitcode=yes",
+    # Enable frame pointers
+    "-Zunstable-options",
+    "-Cforce-frame-pointers=non-leaf",
+]
+
+[profile.dist.package.panic_abort]
+rustflags = [
+    "-Cpanic=abort",
+    "-Cembed-bitcode=yes",
+    "-Zunstable-options",
+    "-Cforce-frame-pointers=non-leaf",
+]
+
 [patch.crates-io]
 # See comments in `library/rustc-std-workspace-core/README.md` for what's going on here
 rustc-std-workspace-core = { path = 'rustc-std-workspace-core' }

library/alloc/Cargo.toml

@@ -22,7 +22,6 @@ safety = { path = "../contracts/safety" }
 [features]
 compiler-builtins-mem = ['compiler_builtins/mem']
 compiler-builtins-c = ["compiler_builtins/c"]
-compiler-builtins-no-f16-f128 = ["compiler_builtins/no-f16-f128"]
 # Choose algorithms that are optimized for binary size instead of runtime performance
 optimize_for_size = ["core/optimize_for_size"]