src/Configuration/PropertyConfigPass.php
private function getFormTypeOptionsOfProperty(array $mergedConfig, array $guessedConfig, array $userDefinedConfig)
    {
        $resolvedFormOptions = $mergedConfig['type_options'];

        // if the user has defined a 'type', the type options
        // must be reset so they don't get mixed with the form components guess.
        // Only the 'required' and user defined option are kept
        if (
            isset($userDefinedConfig['type'], $guessedConfig['fieldType'])
            && $userDefinedConfig['type'] !== $guessedConfig['fieldType']
        ) {
            $resolvedFormOptions = \array_merge(
                \array_intersect_key($resolvedFormOptions, ['required' => null]),
                isset($userDefinedConfig['type_options']) ? $userDefinedConfig['type_options'] : []
            );
        }
        // if the user has defined the "type" or "type_options"
        // AND the "type" is the same as the default one
        elseif (
            (
                isset($userDefinedConfig['type'])
                && isset($guessedConfig['fieldType'])
                && $userDefinedConfig['type'] === $guessedConfig['fieldType']
            ) || (
                !isset($userDefinedConfig['type']) && isset($userDefinedConfig['type_options'])
            )
        ) {
            $resolvedFormOptions = \array_merge(
                $resolvedFormOptions,
                isset($userDefinedConfig['type_options']) ? $userDefinedConfig['type_options'] : []
            );
        }

        return $resolvedFormOptions;
    }
private function getFormTypeOptionsOfProperty(array $mergedConfig, array $guessedConfig, array $userDefinedConfig)
    {
        $resolvedFormOptions = $mergedConfig['type_options'];

        // if the user has defined a 'type', the type options
        // must be reset so they don't get mixed with the form components guess.
        // Only the 'required' and user defined option are kept
        if (
            isset($userDefinedConfig['type'], $guessedConfig['fieldType'])
            && $userDefinedConfig['type'] !== $guessedConfig['fieldType']
        ) {
            $resolvedFormOptions = \array_merge(
                \array_intersect_key($resolvedFormOptions, ['required' => null]),
                isset($userDefinedConfig['type_options']) ? $userDefinedConfig['type_options'] : []
            );
        }
        // if the user has defined the "type" or "type_options"
        // AND the "type" is the same as the default one
        elseif (
            (
                isset($userDefinedConfig['type'])
                && isset($guessedConfig['fieldType'])
                && $userDefinedConfig['type'] === $guessedConfig['fieldType']
            ) || (
                !isset($userDefinedConfig['type']) && isset($userDefinedConfig['type_options'])
            )
        ) {
            $resolvedFormOptions = \array_merge(
                $resolvedFormOptions,
                isset($userDefinedConfig['type_options']) ? $userDefinedConfig['type_options'] : []
            );
        }

        return $resolvedFormOptions;
    }
Resolves from type options of field

@param array $mergedConfig
@param array $guessedConfig
@param array $userDefinedConfig

@return array