fuzz: Use the 2024 edition

Make it possible for us to use `let` chains.

Author: tgross35

fuzz/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "rustc_apfloat-fuzz"
 version.workspace = true
-edition.workspace = true
+edition = "2024"
 publish = false
 
 [dependencies]

fuzz/build.rs

@@ -49,20 +49,6 @@ fn main() -> io::Result<()> {
         )
     }
 
-    // HACK(eddyb) work around https://github.com/rust-lang/cargo/issues/3676,
-    // by removing the env vars that Cargo appears to hardcode.
-    const CARGO_HARDCODED_ENV_VARS: &[(&str, &str)] = &[
-        ("SSL_CERT_DIR", "/etc/pki/tls/certs"),
-        ("SSL_CERT_FILE", "/etc/pki/tls/certs/ca-bundle.crt"),
-    ];
-    for &(var_name, cargo_hardcoded_value) in CARGO_HARDCODED_ENV_VARS {
-        if let Ok(value) = env::var(var_name) {
-            if value == cargo_hardcoded_value {
-                env::remove_var(var_name);
-            }
-        }
-    }
-
     let llvm_dir = llvm_root.join("llvm");
     let bc_out = out_dir.join("cxx_apf_fuzz.bc");
     let bc_opt_out = out_dir.join("cxx_apf_fuzz.opt.bc");
@@ -72,6 +58,9 @@ fn main() -> io::Result<()> {
     // Flags could probably be split between the frontend and backend.
     let clang_codegen_flags = ["-g", "-fPIC", "-fno-exceptions", "-O3", "-march=native"];
 
+    // Note that all commands clear the environment to work around
+    // https://github.com/rust-lang/cargo/issues/3676.
+
     // HACK(eddyb) first compile all the source files into one `.bc` file:
     // - "unity build" (w/ `--include`) lets `-o` specify path (no `--out-dir` sadly)
     // - LLVM `.bc` intermediate allows the steps below to reduce dependencies

fuzz/src/main.rs

@@ -167,8 +167,9 @@ macro_rules! float_reprs {
 
                 // FIXME: we are discarding status results here and not making use of rounding mode.
                 fn cxx_apf_eval_fuzz_op(op: FuzzOp<Self>) -> Self {
-                    extern "C" {
-                        fn $cxx_apf_eval_fuzz_op(
+                    // SAFETY: matches definition in `ap_fuzz.cpp`
+                    unsafe extern "C" {
+                        safe fn $cxx_apf_eval_fuzz_op(
                             opcode: u8,
                             round: u8,
                             ai: $repr,
@@ -192,11 +193,7 @@ macro_rules! float_reprs {
                     };
 
                     let mut out = 0;
-
-                    let _status = unsafe {
-                        $cxx_apf_eval_fuzz_op(op.tag(), 0, ai, bi, ci, &mut out)
-                    };
-
+                    let _status = $cxx_apf_eval_fuzz_op(op.tag(), 0, ai, bi, ci, &mut out);
                     Self(out)
                 }
 
@@ -885,6 +882,8 @@ fn main() {
     // of basic examples, e.g. every `FuzzOp` variant with `0.0` for all inputs
     // (and/or maybe testcases from known and/or fixed bugs, too).
     eprintln!(" - seed with `mkdir fuzz/in-foo && echo > fuzz/in-foo/empty`");
-    eprintln!(" - run with `cargo afl fuzz -i fuzz/in-foo -o fuzz/out-foo target/release/rustc_apfloat-fuzz`");
+    eprintln!(
+        " - run with `cargo afl fuzz -i fuzz/in-foo -o fuzz/out-foo target/release/rustc_apfloat-fuzz`"
+    );
     std::process::exit(1);
 }