Upgrade toolchain to 7/12 (#3337)

Upgrade toolchain to 7/12

Relevant PRs: rust-lang/rust#127176
and
rust-lang/rust#125507


Resolves #3319

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

kani-compiler/src/codegen_cprover_gotoc/codegen/typ.rs

@@ -574,7 +574,7 @@ impl<'tcx> GotocCtx<'tcx> {
             ty::Ref(_, t, _) | ty::RawPtr(t, _) => self.codegen_ty_ref(*t),
             ty::FnDef(def_id, args) => {
                 let instance =
-                    Instance::resolve(self.tcx, ty::ParamEnv::reveal_all(), *def_id, args)
+                    Instance::try_resolve(self.tcx, ty::ParamEnv::reveal_all(), *def_id, args)
                         .unwrap()
                         .unwrap();
                 self.codegen_fndef_type(instance)

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2024-07-01"
+channel = "nightly-2024-07-12"
 components = ["llvm-tools", "rustc-dev", "rust-src", "rustfmt"]

tests/expected/function-contract/const_fn_with_effect.rs

@@ -1,11 +1,13 @@
 // Copyright Kani Contributors
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 // kani-flags: -Zfunction-contracts -Zmem-predicates
+// compile-flags: -Znext-solver
 
 //! Check that Kani contract can be applied to a constant function.
 //! <https://github.com/model-checking/kani/issues/3258>
 
 #![feature(effects)]
+#![allow(incomplete_features)]
 
 #[kani::requires(kani::mem::can_dereference(arg))]
 const unsafe fn dummy<T>(arg: *const T) -> T {

tools/compiletest/src/json.rs

@@ -35,6 +35,7 @@ struct FutureBreakageItem {
 }
 
 #[derive(Deserialize, Clone)]
+#[allow(dead_code)]
 struct DiagnosticSpanMacroExpansion {
     /// name of macro that was applied (e.g., "foo!" or "#[derive(Eq)]")
     _macro_decl_name: String,