TYPO3 Core

What did you get? No error message at all?
Did you take a look at the messages displayed in Admin Panel?

No error message at all. Confirmed in 6.2.9 and 7.2.

I think I've found the error.

This function is from FluidTemplateContentObject.php, where $templateSource will evaluate to empty string if not found.

    /**
     * Set template
     *
     * @param array $conf With possibly set file resource
     * @return void
     * @throws \InvalidArgumentException
     */
    protected function setTemplate(array $conf) {
        // Fetch the Fluid template
        if (!empty($conf['template']) && !empty($conf['template.'])) {
            $templateSource = $this->cObj->cObjGetSingle($conf['template'], $conf['template.']);
            // $templateSource is empty string, should be NULL?
            $this->view->setTemplateSource($templateSource);
        } else {
            $file = isset($conf['file.']) ? $this->cObj->stdWrap($conf['file'], $conf['file.']) : $conf['file'];
            /** @var $templateService \TYPO3\CMS\Core\TypoScript\TemplateService */
            $templateService = $GLOBALS['TSFE']->tmpl;
            $templatePathAndFilename = $templateService->getFileName($file);
            $this->view->setTemplatePathAndFilename(PATH_site . $templatePathAndFilename);
        }
    }

But here in StandaloneView.php, $templateSource must be NULL to throw an error:

    /**
     * Returns the Fluid template source code
     *
     * @param string $actionName Name of the action. This argument is not used in this view!
     * @return string Fluid template source
     * @throws InvalidTemplateResourceException
     */
    protected function getTemplateSource($actionName = NULL) {
        if ($this->templateSource === NULL && $this->templatePathAndFilename === NULL) {
            throw new InvalidTemplateResourceException('No template has been specified. Use either setTemplateSource() or setTemplatePathAndFilename().', 1288085266);
        }
        if ($this->templateSource === NULL) {    // Also check for empty string here?
            if (!is_file($this->templatePathAndFilename)) {
                throw new InvalidTemplateResourceException('Template could not be found at "' . $this->templatePathAndFilename . '".', 1288087061);
            }
            $this->templateSource = file_get_contents($this->templatePathAndFilename);
        }
        return $this->templateSource;
    }

Additionally, one could check for errors directly in setTemplate(), to fail as early as possible.

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/37273

Applied in changeset 65cfbc4c7764140c5cc7db3f2b43fa40be53cfc6.