Translation:This restaurant is good.
No, of course not. We do the same thing in Malay.
We remove the original subject, then replace it with something else. In this case, the original subject is 食べ物[たべもの], and the new subject is レストラン.
The original sentence would be このレストランの食べ物はおいしいです。
If you notice, English does the same thing.
"Tell the school I'm not going today."
Now, how can you tell the school? You can't! You can however tell the PEOPLE in the school.
"Tell the school staffs I'm not going today."
oishii is meant to describe the entire restaurant / service I think? I lot of people think oishii just means "delicious" but it's meant to describe the restaurant in general positively.
I believe you can say oishii to describe the food, atmosphere, service of a restaurant.
THOUGH, I AM A BEGINNER SO PLEASE CORRECT ME IF I'M WRONG!
It may seem nitpicky but I find this sort of thing useful because it draws attention to the different usage. Like in Japanese, おいしい not only is commonly used to refer to foods, but also, to restaurants. In English, on the other hand, it is a bit awkward to say "this restaurant is delicious". Having them force the more natural, whole-sentence level translation, I find very useful because it reminds me of this difference in usage.
This is why I love DuoLingo so much and why I think it's so much more effective for learning than simple flashcard-based systems.
I really don't understand why so many people are weirded out by calling a place that serves food "delicious." Do people really not ever say that?
"Let's eat! BurgerPlace is delicious." "SaladJoint tastes better though."
I was so sad that it wouldn't accept the literal translation.
Yes, that would be これはおいしいレストランです. Since we have このレストラン it must be "this restaurant" -- この/その/あの are always used together with a noun, while これ/それ/あれ are used on their own. Also, adjectives that are used as arguments to a noun ("good restaurant") are placed before the noun, just as in English, so when you have <noun>は<adjective>です it cannot mean "is <adjective> <noun>", only "<noun> is <adjective>".
We are not godzillas, and we do not eat a restaurant per se and chew the bricks, wood, and glass. However, it seems that in English 'a restaurant is delicious' appears weird (but I am not a native English speaker, so please correct me if I am wrong), but in colloquial Japanese it is OK. There is even 'eel-sentence': when eating in casual canteens, one may say 'ぼくはうなぎだ' (I, eel). In English it is weird to say 'I am an eel'; one says at least ' Mine is an eel'.
However, though it is commonly used, such sentences are disliked in formal styles. We should understand the sentence, but do not use it everywhere. There was an ad for jams in a newspaper in mid-1990s as 'make your kitchen table delicious' (translated). It was criticised fiercely: one of the parodies said to have the manager show in public how to eat a kitchen table with help of the product in question. In East Asia, written texts are things somehow holy, and some people want even ads to be written in 'correct', 'educated' languages.
You can think of kono as a contraction of kore and the particle no. kono effectively means this thing. Yes, I know kono is not a real contraction, but it helps to think like that. I have learned from Japanese that no can be in a sentence where it makes no sense. For example in Naruto, when someone is using a jutsu, they say something something no jutsu.
In Cantonese (my mother tongue), the sentence structure is similar - we say "This restaurant [is] tasty" - the restaurant gives/evokes a tasty sensation/feeling in you, and because it's a restaurant (context is important!), it implies the restaurant has good food, and thus "the restaurant is good".
Hopefully this helps you better understand how this Japanese > English translation works.
Addendum: it doesn't work if you use it on any place other than a restaurant. For example, if you say "This toy store [is] tasty!", that doesn't make sense in Cantonese, and I imagine it doesn't in Japanese either.
What makes sense would be something like "This toy store [is] playful!" Can a toy store itself play with you? No, but the toys it provides are fun to play with, right?
The descriptor fits if it evokes the appropriate sensation, in context of that place and the service it provides. A toy store can be funny. A train station can be fast. And so on.
Japanese can use adjectives in two ways: "The apples are red" or "red apples", these are different sentences although the meaning are very similar. The structure is more or less like English.(I see you have a German flag so you must be very familiar with that, right? :)
Here is a brief comparison:
This restaurant is good. -- このレストランは おいしい です。
This is a good restaurant. -- これは おいしいレストラン です。
(We don't use blanks in Japanese, I just typed them here to make it easier to understand. )
It confuses me how this app works sometimes. More often than not, it uses proper English grammar. But there are cases like this where they just want us to translate word-by-word. Context-wise in Japan it is how they say (probably) but "this restaurant is delicious" sounds really really weird in English.