Using declarations like a statement leads to strange bugs.

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### 🔎 Search Terms

function declaration statement

### 🕗 Version & Regression Information

v 5.9.3

### ⏯ Playground Link

https://www.typescriptlang.org/play/?target=99#code/JYMwBAFALgTgrgUwJRgG4EMZgB5gLxgAMA3ALABQAxgPYB2AztQDYIB0T1A5hNksWAHoB1ANYUKIalggsoYYPiL8FAHjABmZQGotKDFgBWi4GSp1GLdlwgGUQhDBhT5tMDQC2AB2AsAXGCNgejA4egQAEzAAIwRJGARohGBaTjB0enpgTloAGjBaajAHJyxksHhaKGB3BLA68XJQSFhEFBA4WkoqujAQCBQAbwBfCX6hAqLHZzKPbxYwKpq8qLg5YunXCsWEfwBJV3pYYC6wd2pwhJoLvPbO7oY3dFc6JgBPRLALyiZMCLS5KDUTxgFioBBMMAbTIXNLRDiUERgIA

### 💻 Code

```ts
if (true) var x = 0;
console.log(x); //ok

for (let i = 0; i < 3; i++) var j = i;
console.log(j) //error in compile: j is used before being assign, no error in runtime

if (true) function f() {}
f()//no error in compile time, but error in runtime: In strict mode code, functions can only be declared at top level or inside a block
```

### 🙁 Actual behavior

-

### 🙂 Expected behavior

-

### Additional information about the issue

The questions above was raised only in academic purpose. I understand that there are no real use cases to apply code above.

Inizia con il TypeScript Playground collegato e riproduci i tre esempi di dichiarazione dell’issue, confrontando la diagnostica del compilatore con il comportamento a runtime. L’issue non specifica un risultato atteso, quindi stabilisci se la correzione prevista sia una diagnostica, una modifica al codice emesso o una semantica JavaScript documentata prima di identificare l’area pertinente del compilatore e i test.

Scritto dal modello di indicizzazione a partire dal testo della issue.