Prettier 3.8.1
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--parser typescript

Input:

This is a Prettier test

type B = {
  /* commentB */ [b in B]: string
}

type TSTypeLiteral = {
  /* literal */ b: string;
}

Output:

type B = {
  /* commentB */
  [b in B]: string;
};

type TSTypeLiteral = {
  /* literal */ b: string;
};

Expected output:

type B = {
  /* commentB */ [b in B]: string;
};

type TSTypeLiteral = {
  /* literal */ b: string;
};

Why?

Prettier handles inline block comments inconsistently between mapped types and regular type literal properties:

• TSTypeLiteral with property signature: comment stays inline ✓
• TSMappedType: comment is moved to a separate line ✗

Both cases have the same structure—a block comment preceding a type member—so they should be formatted consistently. The comment in the mapped type should remain on the same line as the member it annotates.