Runtime error causes tests above to run twice and tests below to run never

[ccshan]

In the Beginning Student Language, running a program such as

(check-expect 1 1)
(check-expect 2 2)
(+ "hello" "world")
(check-expect 3 3)
(check-expect 4 4)
(check-expect 5 5)

produces the result

Both tests passed!+: expects a number, given "hello"
Both tests passed!

Similarly if (+ "hello" "world") is replaced by (cond [false "hello"])

This is confusing because

• The expression causing the runtime error is not highlighted in pink as usual (but rather, the cursor is moved to that expression, making it highlighted in gray due to parentheses)
• The runtime error message is not printed on its own line
• "Both tests passed!" is printed twice
• The tests below the runtime error are not run

[mfelleisen]

1. Use #lang htdp/bsl instead of the menu-based teaching languages. -- In that setting I can't reproduce the bug.

   • Using #lang comes with other advantages.

2. This bug seems to be new, but I don't have time today to check it out. @mikesperber ?

[mikesperber]

@ccshan As you'll notice, there's still no newline before the error message. It is surprisingly difficult to put one there without introducing spurious, conspicuous newlines in regular output. Can you live with that? (As @mfelleisen notes, the #lang versions don't have this problem.)

[ccshan]

I can live with that.