fzf: Purge cdhist when running the cdhist widget

.config/fish/fzf.fish

@@ -107,6 +107,15 @@ end
 bind \e\cL __fzf-bcd-widget
 
 function __fzf-cdhist-widget -d 'cd to one of the previously visited location'
+	## Clear non-existent folders from cdhist.
+	set -l buf
+	for i in (seq 1 (count $dirprev))
+		set -l dir $dirprev[$i]
+		if test -d $dir
+			set buf $buf $dir
+		end
+	end
+	set dirprev $buf
 	## TODO: (fish upsteam bug) Cannot use eval here.
 	# string join \n $dirprev | tac | sed 1d | eval (__fzfcmd) +m $FZF_CDHIST_OPTS | read -l result
 	string join \n $dirprev | tac | sed 1d | fzf +m --preview='preview {}' | read -l result