Bug Report

• I would like to work on a fix!

Current behavior

Convert a TypeScript declare function with a body into a function.

Try it out link

Output:

"use strict";

function foo() {}

Input Code

declare function foo() {}

Expected behavior

It should throw an error like tsc(TypeScript Playground). And it should support errorRecovery.

Also babel/parser should return a node of TSDeclareFunction instead of FunctionDeclaration(declare: true).

Babel Configuration (babel.config.js, .babelrc, package.json#babel, cli command, .eslintrc)

• Filename: babel.config.js

{
  "presets": ["@babel/preset-typescript"]
}

Environment

I don't think environment information is needed because this issue is simple, but I will provide it if it is needed for you guys.

Possible Solution

Additional context

While working in Prettier, I notice that declare disappears. (Prettier Playground link)
It is possible to fix this issue on Prettier side, but I think this is the parser's responsibility.