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TypeScript: missing error on empty typeArguments and typeParameters #9462

armano2 opened this Issue Feb 6, 2019 · 1 comment


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armano2 commented Feb 6, 2019

Bug Report

Current Behavior
Babel does not report error on empty typeParameters and typeArguments

Input Code

const foo: Foo<>
function f1<>() {}

Expected behavior/code
babel should throw errors:

Type parameter list cannot be empty.
Type argument list cannot be empty.

Babel Configuration (.babelrc, package.json, cli command)

  const babel = require('@babel/parser');
  const plugins: ParserPlugin[] = [
  if (jsx) {

  return babel.parse(text, {
    sourceType: 'unambiguous',
    allowImportExportEverywhere: true,
    allowReturnOutsideFunction: true,
    ranges: true,


  • Babel version(s): 7.3.2
  • Node/npm version: 6-11
  • OS: ----
  • Monorepo: ---
  • How you are using Babel: @babel/parser -> parse

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babel-bot commented Feb 6, 2019

Hey @armano2! We really appreciate you taking the time to report an issue. The collaborators
on this project attempt to help as many people as possible, but we're a limited number of volunteers,
so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack
that typically always has someone willing to help. You can sign-up here
for an invite.

@armano2 armano2 changed the title TypeScript: Missing error on empty typeArguments and typeParameters TypeScript: missing error on empty typeArguments and typeParameters Feb 6, 2019

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