Issue 31906: String literals next to each other does not cause error

This seems too obvious to have been missed, but also too strange behaviour to be on purpose.

The following works for some reason (note there's no + between the words)
>>> variable = "first" "second"
>>> print(variable)
"firstsecond"

In a file, if you're missing a comma between two string literals, it combines them into one string (instead of throwing a syntax error). E.G:

>>> a = ["first",
... "second"
... "third"]
>>> print(a)
["first" "secondthird"]

BUT, the same thing with variables (thankfully) does not work.
>>> a = "first"
>>> b = "second"
>>> c = a b
Throws a syntax error.

The same sort of thing also breaks for integers.
>>> a = 4 7
throws a syntax error.

This just seems wrong to me. Is it? Has this been discussed a million times before?