Typo in Quality::ceilOut<TAmounts> template: undefined identifier ceil_TAmounts_helper

[Krypto-Whitehat]

Summary

While reading Quality.h I noticed a typo in the templated overload of Quality::ceilOut<TAmounts<In, Out>>: it calls ceil_TAmounts_helper(...), but the private helper is named ceilTAmountsHelper (no underscores). The three sibling templates (ceilIn, ceilInStrict, ceilOutStrict) all call the correctly spelled ceilTAmountsHelper.

Location

include/xrpl/protocol/Quality.h, line 355:

template <class In, class Out>
TAmounts<In, Out>
Quality::ceilOut(TAmounts<In, Out> const& amount, Out const& limit) const
{
    // Construct a function pointer to the function we want to call.
    static constexpr Amounts (Quality::*kCeilOutFnPtr)(Amounts const&, STAmount const&) const =
        &Quality::ceilOut;

    return ceil_TAmounts_helper(amount, limit, amount.out, kCeilOutFnPtr);  // <-- typo
}

The correctly spelled helper is declared around line 222 and defined around line 307 (Quality::ceilTAmountsHelper).

Why the build is not broken today

This is latent dead code: the template is never instantiated anywhere in the codebase. The existing callers resolve to the non-template overload Quality::ceilOut(Amounts const&, STAmount const&):

• src/test/protocol/Quality_test.cpp:65 - the test helper constructs Amounts (a pair of STAmount), so it picks the STAmount overload.
• src/test/app/AMMCalc_test.cpp:234 - steps is std::vector<std::pair<Amounts, bool>> (line 49), so amts is again Amounts, not TAmounts<IOUAmount, IOUAmount>.

Since template code is only type-checked at instantiation, the misspelled name goes unnoticed until someone actually calls ceilOut with TAmounts<In, Out> arguments, at which point they get a confusing compile error about an undefined identifier.

Impact

None at runtime. This is purely a code quality issue. It removes a trap for future callers of the typed (IOUAmount / XRPAmount) ceilOut overload.

Suggested fix

One word rename:

-    return ceil_TAmounts_helper(amount, limit, amount.out, kCeilOutFnPtr);
+    return ceilTAmountsHelper(amount, limit, amount.out, kCeilOutFnPtr);

Optionally, a small unit test that instantiates ceilOut<TAmounts<IOUAmount, IOUAmount>> (mirroring the existing ceilIn tests) would prevent this class of typo from regressing.