Conditional function commands do not work inside of functions

(See also this comment on Reddit by Brian McNamara)

Conditional commands do not work inside of functions. Here's how to reproduce:

1. Create a function foo:bar with the following content:

   say foo:bar succeeded
   function foo:bar2 if @e[c=1]
   

   The [c=1] is important here, see MC-117661.

2. Create a second function foo:bar2 with the following content:

   say foo:bar2 succeeded
   

3. Run /reload.
4. Run /function foo:bar
5. Notice that the only thing written into the chat is foo:bar succeeded and the success message telling you that both commands have been run