Should a TAB after quoting start start a code block?

What should happen to this input: >\t#\tFoo\n>\tbar\n>\tbaz\n?

The Spec 5.1 says a block quote marker starts with > and an optional space. Because \t is not a space, it’s not part of the block quote marker.

Dingus parses this example as normal text while removing the block quote marker > it parses the text as indented code block.

A tab is not four spaces. It moves the “cursor” past the next tab stop (every fourth column). You need to read and understand the section on tabs.

But really quick:

    The first tab on each line moves the "cursor" to col 4, meaning there are
    only 3 virtual spaces between the > and the content. Because the block
    quote will consume one space (the optional padding), it really means
    there are only 2 spaces prefixing the content, 2 short of the 4 you need
    for a code block. Add 1 then 2 spaces after the tab to confirm this.
    |   This second tab pushes to col 8, so 3 spaces after #
    |   |
    V   V
>   #   Foo
>   bar
>   baz