[no-unexpected-multiline]: False positive with template string

[jacobrask]

Repro

const IssueTitle = styled.h3<{
  size: StartpageComponentCarousel['params']['size'];
}>`
  display: inline-block;
`;

Gives no-unexpected-multiline error.

Versions

package	version
@typescript-eslint/eslint-plugin	X.Y.Z
@typescript-eslint/parser	1.1.0
TypeScript	3.2.4
ESLint	5.12.1
node	X.Y.Z
npm	X.Y.Z

[bradzacher]

The problem here is that the code with a type paremeter produces the following AST:

styled.h3<{
  size: StartpageComponentCarousel['params']['size'];
}>`
  display: inline-block;
`

{
  type: "TaggedTemplateExpression",
  tag: {
    type: "MemberExpression",
    // ...
    loc: {
      start: { line: 1, column: 19 },
      end: { line: 1, column: 28 }
    }
  },
  typeParameter: {
    type: "TSTypeParameterInstantiation",
    // ...
    loc: {
      start: { line: 1, column: 28 },
      end: { line: 3, column: 2 }
    }
  },
  qasi: {
    type: "TemplateLiteral",
    // ...
    loc: {
      start: { line: 3, column: 2 },
      end: { line: 5, column: 1 }
    }
  },
}

Notice that the tag ends, and the qasi starts on different lines.
Without the type parameter, the two instead end and start on the same line, respectively.

no-unexpected-multiline is hardcoded to ensure this relationship holds true.
We'll have to bring this rule into the plugin in order to fix this, as it's a TS specfic case.

[bradzacher]

potentially will be fixed upstream?
eslint/eslint#11650
eslint/eslint#11698

[bradzacher]

This will be fixed by
eslint/eslint#11698

which is approved and will be merged imminently.
I'm going to close this. Feel free to track the final progress over at the PR