return nil, errf("unsupported conversion for pre-bound parameter %q to type %q", value, ctype)
			}
			stmt.colValue = append(stmt.colValue, subsetVal)
		} else {
			stmt.placeholders++
			stmt.placeholderConverter = append(stmt.placeholderConverter, converterForType(ctype))
			stmt.colValue = append(stmt.colValue, value)
		}
	}
	return stmt, nil
}

// hook to simulate broken connections