problem with evaluating result

[dzc15331066]

(if-let ((results
	      (org-babel-eval
	       (format "%s run %s \"%s\" %s"
		       org-babel-go-command
		       (mapconcat 'identity (org-babel-go-as-list flags) " ")
		       (org-babel-process-file-name tmp-src-file)
		       (mapconcat #'(lambda (a)
				      ;; If there's a chance that the symbol is a
				      ;; ref, use that. Otherwise, just return the
				      ;; string form of the value.
				      (format "%S" (if (symbolp a)
						       (let* ((ref (symbol-name a))
							      (out (org-babel-read ref)))
							 (if (equal out ref)
							     (if (string-match "^\".*\"$" ref)
								 (read ref)
							       (org-babel-ref-resolve ref))
							   out))
						     a)))
				  (org-babel-go-as-list args) " ")) "")))

I encountered an "Invalid function" error when I evaluated results, then I find "if-let" in this code block in file "ob-go.el".I guess "if-let" is invalid in my emacs,so I change it into "let",and it works! Finally I find "if-let" is a macro in new Emacs.