chore: Upgrade to "nightly-2025-12-12

compiler/hash-exhaustiveness/src/deconstruct.rs

@@ -176,8 +176,10 @@ impl<E: ExhaustivenessEnv> ExhaustivenessChecker<'_, E> {
     fn collect_unreachable_pats(&self, pat: &DeconstructedPat, spans: &mut Vec<PatId>) {
         // We don't look at sub-patterns if we
         // already reported the whole pattern as  unreachable.
-        if !pat.is_reachable() && pat.id.is_some() {
-            spans.push(pat.id.unwrap());
+        if let Some(id) = pat.id
+            && !pat.is_reachable()
+        {
+            spans.push(id);
         } else {
             for p in pat.fields.iter_patterns() {
                 let p = self.get_pat(p);

compiler/hash-semantics/src/passes/inference/mod.rs

@@ -36,7 +36,8 @@ impl<E: SemanticEnv> InferencePass<'_, E> {
         infer_subject: impl Fn(T) -> TcResult<T>,
         subject_has_holes: impl Fn(T) -> Option<Atom>,
     ) -> TcResult<T> {
-        let subject = self.try_or_add_error(try { infer_subject(orig_subject)? });
+        let subject =
+            self.try_or_add_error(try { infer_subject(orig_subject).map_err(Into::into)? });
 
         // If we have an error, in diagnostics mode, exit.
         if self.has_errors() {

compiler/hash-utils/src/lib.rs

@@ -1,5 +1,5 @@
 //! Hash compiler general utilities
-#![feature(array_windows, cfg_select, decl_macro, impl_trait_in_assoc_type, type_alias_impl_trait)]
+#![feature(cfg_select, decl_macro, impl_trait_in_assoc_type, type_alias_impl_trait)]
 
 pub mod assert;
 pub mod counter;

compiler/hash-utils/src/printing.rs

@@ -216,8 +216,10 @@ impl<'a, T: fmt::Display + 'a> fmt::Display for SequenceDisplay<'a, T> {
 
                 // If we overflowed, and the limit is specified then we will
                 // print the specified number of missing variants
-                if self.options.limit.is_some() && overflow {
-                    let count = self.items.len() - self.options.limit.unwrap();
+                if let Some(limit) = self.options.limit
+                    && overflow
+                {
+                    let count = self.items.len() - limit;
                     write!(f, " {} {count} more", self.options.mode.as_conjunctive())?;
                 }
 

rust-toolchain.toml

@@ -1,4 +1,4 @@
 [toolchain]
-channel = "nightly-2025-10-30"
+channel = "nightly-2025-12-12"
 components = ["rustfmt", "clippy", "rustfmt"]
 profile = "minimal"

tests/testing-macros/src/lib.rs

@@ -2,7 +2,7 @@
 //! resources on the disk. This file primarily has the `generate_tests` macro
 //! that will read a directory and generate various test cases from the provided
 //! `case.hash` files and names of the directories that contain the cases.
-#![feature(iter_intersperse, try_find, track_path)]
+#![feature(iter_intersperse, try_find, proc_macro_tracked_path)]
 
 extern crate proc_macro;
 
@@ -211,7 +211,7 @@ pub fn generate_tests(input: TokenStream) -> TokenStream {
     // We need to specify that the file that the macro provides should be tracked
     // by `cargo` in order to pickup changes to the tree, or the contents of the
     // directory.
-    proc_macro::tracked_path::path(&input.path);
+    proc_macro::tracked::path(&input.path);
 
     let test_func = input.func;
     let test_path = PathBuf::from(&input.path);