`Unhandled node type: string` triggers across 4 distinct bash structures

Summary

The hook message Unhandled node type: string appears in the command confirmation prompt for at
least four structurally distinct bash patterns. Each triggers the same message, which makes it
difficult to tell from the prompt which structure is the root cause. Listing them here in case
it helps maintainers identify whether one code path covers all four or each is a separate gap.

Reproduction

Structure (a) -- same-type nested quotes: "outer $(cmd "$VAR")"

echo "value: $(echo "$HOME")"

Expected: passes without error, or prompts with a message specific to nested same-type quotes.
Observed: Unhandled node type: string

---

Structure (b) -- for-loop with \ line continuation and a pipe in the body

for f in a.txt \
  b.txt; do
  grep -c "hello" "$f" | head -1
done

Expected: passes without error, or prompts with a message specific to complex loop bodies.
Observed: Unhandled node type: string

---

Structure (c) -- BRE alternation (\|) inside a double-quoted grep pattern

grep "alpha\|beta" file.txt

Expected: passes without error (standard BRE syntax).
Observed: Unhandled node type: string

---

Structure (d) -- reverse same-type nesting: $(outer "$(inner)")

BASE=$(dirname "$(git rev-parse --git-common-dir)")

Expected: passes without error.
Observed: Unhandled node type: string

Notes

Related symptom reports that surface the same message: #42085, #43246, #50144, #55479, #49483.
None of those enumerate which bash structures produce this error. Listing the four structures here
in case it accelerates root-cause analysis.

Environment

• claude-code version: 2.1.118
• OS: macOS 26.4.1
• Shell: /bin/zsh
• Notes: heavy use of git worktrees and multiple language toolchains