Update toolchain to 2024-08-05 (#3416)

* Remove `gen_function_local_variable` and `initializer_fn_name`, the
last uses of both of which were removed in #3305.
* Mark `arg_count`, which was introduced in #3363, as `allow(dead_code)`
as it will soon be used.
* Mark `insert_bb`, which was introduced in #3382, as `allow(dead_code)`
as it will soon be used.

The toolchain upgrade to 2024-08-04 includes several bugfixes to
dead-code analysis in rustc, explaining why we the recent PRs as listed
above weren't flagged before for introducing dead code.

Resolves: #3411

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/context/goto_ctx.rs

@@ -139,17 +139,6 @@ impl<'tcx> GotocCtx<'tcx> {
         sym
     }
 
-    // Generate a Symbol Expression representing a function variable from the MIR
-    pub fn gen_function_local_variable(
-        &mut self,
-        c: u64,
-        fname: &str,
-        t: Type,
-        loc: Location,
-    ) -> Symbol {
-        self.gen_stack_variable(c, fname, "var", t, loc)
-    }
-
     /// Given a counter `c` a function name `fname, and a prefix `prefix`, generates a new function local variable
     /// It is an error to reuse an existing `c`, `fname` `prefix` tuple.
     fn gen_stack_variable(

kani-compiler/src/codegen_cprover_gotoc/utils/names.rs

@@ -45,10 +45,6 @@ impl<'tcx> GotocCtx<'tcx> {
         (name, base_name)
     }
 
-    pub fn initializer_fn_name(var_name: &str) -> String {
-        format!("{var_name}_init")
-    }
-
     /// The name for a tuple field
     pub fn tuple_fld_name(n: usize) -> String {
         format!("{n}")

kani-compiler/src/kani_middle/transform/body.rs

@@ -54,6 +54,7 @@ impl MutableBody {
         &self.locals
     }
 
+    #[allow(dead_code)]
     pub fn arg_count(&self) -> usize {
         self.arg_count
     }
@@ -330,6 +331,7 @@ impl MutableBody {
     /// `InsertPosition` is `InsertPosition::Before`, `source` will point to the same instruction as
     /// before. If `InsertPosition` is `InsertPosition::After`, `source` will point to the
     /// terminator of the newly inserted basic block.
+    #[allow(dead_code)]
     pub fn insert_bb(
         &mut self,
         mut bb: BasicBlock,

rust-toolchain.toml

@@ -2,5 +2,5 @@
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
 [toolchain]
-channel = "nightly-2024-08-03"
+channel = "nightly-2024-08-05"
 components = ["llvm-tools", "rustc-dev", "rust-src", "rustfmt"]