system/Model.php
protected function fillPlaceholders(array $rules, array $data): array
	{
		$replacements = [];

		foreach ($data as $key => $value)
		{
			$replacements["{{$key}}"] = $value;
		}

		if (! empty($replacements))
		{
			foreach ($rules as &$rule)
			{
				if (is_array($rule))
				{
					foreach ($rule as &$row)
					{
						// Should only be an `errors` array
						// which doesn't take placeholders.
						if (is_array($row))
						{
							continue;
						}

						$row = strtr($row, $replacements);
					}
					continue;
				}

				$rule = strtr($rule, $replacements);
			}
		}

		return $rules;
	}
protected function fillPlaceholders(array $rules, array $data): array
	{
		$replacements = [];

		foreach ($data as $key => $value)
		{
			$replacements["{{$key}}"] = $value;
		}

		if (! empty($replacements))
		{
			foreach ($rules as &$rule)
			{
				if (is_array($rule))
				{
					foreach ($rule as &$row)
					{
						// Should only be an `errors` array
						// which doesn't take placeholders.
						if (is_array($row))
						{
							continue;
						}

						$row = strtr($row, $replacements);
					}
					continue;
				}

				$rule = strtr($rule, $replacements);
			}
		}

		return $rules;
	}
Replace any placeholders within the rules with the values that
match the 'key' of any properties being set. For example, if
we had the following $data array:

[ 'id' => 13 ]

and the following rule:

'required|is_unique[users,email,id,{id}]'

The value of {id} would be replaced with the actual id in the form data:

'required|is_unique[users,email,id,13]'

@param array $rules
@param array $data

@return array