Fix miri UB: use transmute_copy for function pointer identity checks - #8432

#!/bin/bash
set -euo pipefail

echo "== repo files matching slot/vm_ops/method.rs =="
fd -a 'slot\.rs$|vm_ops\.rs$|method\.rs$|slot_defs\.rs$' crates/vm/src | sed 's#^\./##'

echo
echo "== rust toolchain files =="
git ls-files | rg '(^|/)(rust-toolchain(\.toml)?|Cargo\.toml|Cargo\.lock)$' || true
if [ -f rust-toolchain ]; then cat -n rust-toolchain; fi
if [ -f rust-toolchain.toml ]; then cat -n rust-toolchain.toml; fi
if [ -f Cargo.toml ]; then rg -n 'edition|rust-version|rustc' Cargo.toml || true; fi

echo
echo "== fn_addr and fn_addr_eq occurrences =="
rg -n -C 2 '\bfn_addr\b|fn_addr_eq|transmute_copy' crates || true

echo
echo "== relevant slot.rs sections around fn_addr and call sites =="
python3 - <<'PY'
from pathlib import Path
p = Path("crates/vm/src/types/slot.rs")
lines = p.read_text().splitlines()
for i in [1, 940, 990, 2150, 2174]:
    start=max(1,i-5); end=min(len(lines),i+15)
    print(f"\n--- {p}:{start}-{end} ---")
    for n in range(start,end+1):
        print(f"{n:5}: {lines[n-1]}")
PY

echo
echo "== relevant vm_ops.rs section around existing fn_addr_eq =="
p="crates/vm/src/vm/vm_ops.rs"
lines=p.read_text().splitlines()
for start,end in [(330,375),(980,1045),(1060,1115)]:
    print(f"\n--- {p}:{start}-{end} ---")
    for n in range(start,end+1):
        if n <= len(lines):
            print(f"{n:5}: {lines[n-1]}")

echo
echo "== relevant slot_defs.rs copyslot_if_none section =="
p="crates/vm/src/types/slot_defs.rs"
if p.exists():
    lines=p.read_text().splitlines()
    rg -n "copyslot_if_none|fn_addr|fn_addr_eq" $p || true
    for start,end in [(1,80), (200,300), (300,400)]:
        matches=[i for i,l in enumerate(lines,1) if 'copyslot_if_none' in l or 'fn_addr' in l]
        if any(start-m <= s <= end+m for s in matches):
            print(f"\n--- {p}:{start}-{end} ---")
            for n in range(start,end+1):
                print(f"{n:5}: {lines[n-1]}")
else:
    fd -a 'slot_defs\.rs$' .