Improve type narrowing on switch(true) statements

[ElianCordoba]

Bug Report

🔎 Search Terms

• switch narrowing
• switch(true)

🔗 Related issues

• Narrowing types by typeof inside switch (true) does not work #37178
• Control flow analysis: switch (true) case #8934

Maybe these ones too

• Alias type conditions to desctrutured variables #46143
• Generic type unnarrowed by switch...case #43873

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about type guards

⏯ Playground Link

Playground link with relevant code

💻 Code

const char = "(" as string;

// This works fine, char inside the if statements get's property narrowed to type "("
if (char === '(') {
  char;
}

// This doesn't work, char inside the case statement is of type string
switch (true) {
  case char === '(':
    char;
}

🙁 Actual behavior

Char inside the case statement in a switch(true) has a type string

🙂 Expected behavior

It should have type "("

[MartinJohns]

Duplicate of #37178. Used search terms: switch true in:title