Upgrade toolchain to nightly-2025-03-07 (#3931)

Changes required due to
- rust-lang/rust#138026: Make CrateItem::body() function return an
option
- rust-lang/rust#137728: Remove unsizing coercions for tuples

Resolves: #3930

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 and MIT licenses.

Author: tautschnig

kani-compiler/src/kani_middle/stubbing/mod.rs

@@ -130,7 +130,7 @@ pub fn validate_stub_const(tcx: TyCtxt, instance: Instance) -> bool {
     let item = CrateItem::try_from(instance).unwrap();
     let internal_instance = rustc_internal::internal(tcx, instance);
     let mut checker = StubConstChecker::new(tcx, internal_instance, item);
-    checker.visit_body(&item.body());
+    checker.visit_body(&item.expect_body());
     checker.is_valid()
 }
 

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2025-03-05"
+channel = "nightly-2025-03-07"
 components = ["llvm-tools", "rustc-dev", "rust-src", "rustfmt"]

tests/kani/SizeAndAlignOfDst/unsized_tuple.rs

@@ -138,7 +138,7 @@ impl OverallStats {
                 if !kind.is_fn() {
                     return None;
                 };
-                let unsafe_ops = FnUnsafeOperations::new(item.name()).collect(&item.body());
+                let unsafe_ops = FnUnsafeOperations::new(item.name()).collect(&item.expect_body());
                 let fn_sig = kind.fn_sig().unwrap();
                 let is_unsafe = fn_sig.skip_binder().safety == Safety::Unsafe;
                 self.fn_stats.get_mut(&item).unwrap().has_unsafe_ops =
@@ -167,7 +167,7 @@ impl OverallStats {
                 if !kind.is_fn() {
                     return None;
                 };
-                Some(FnLoops::new(item.name()).collect(&item.body()))
+                Some(FnLoops::new(item.name()).collect(&item.expect_body()))
             })
             .partition::<Vec<_>, _>(|props| props.has_loops());
 
@@ -179,7 +179,7 @@ impl OverallStats {
                 if !kind.is_fn() {
                     return None;
                 };
-                Some(FnLoops::new(item.name()).collect(&item.body()))
+                Some(FnLoops::new(item.name()).collect(&item.expect_body()))
             })
             .partition::<Vec<_>, _>(|props| props.has_iterators());
 
@@ -190,7 +190,7 @@ impl OverallStats {
                 if !kind.is_fn() {
                     return None;
                 };
-                let fn_props = FnLoops::new(item.name()).collect(&item.body());
+                let fn_props = FnLoops::new(item.name()).collect(&item.expect_body());
                 self.fn_stats.get_mut(&item).unwrap().has_loop_or_iterator =
                     Some(fn_props.has_iterators() || fn_props.has_loops());
                 Some(fn_props)
@@ -601,7 +601,7 @@ impl Recursion {
             .into_iter()
             .filter_map(|item| {
                 if let TyKind::RigidTy(RigidTy::FnDef(def, _)) = item.ty().kind() {
-                    let body = item.body();
+                    let body = item.expect_body();
                     let mut visitor = FnCallVisitor { body: &body, fns: vec![] };
                     visitor.visit_body(&body);
                     Some((def, visitor.fns))