Regression tests for link backtracking optimizations: . [[some unrelated text [link] [link]: foo .
[[some unrelated text link
. . [[some unrelated text [[link]] [[link]]: foo .[[some unrelated text [link]
. This is not a valid emphasis, because \n considered a whitespace: . **test ** ** test** ** test ** .**test **
** test**
** test **
. The same for strikethrough: . ~~test ~~ ~~ test~~ ~~ test ~~ .~~test ~~
~~ test~~
~~ test ~~
. Link label has priority over emphasis (not covered by stmd tests): . [**link]()** **[link**]() .**link**
**link**
.