Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have searched for related issues and found none that matched my issue.
• I have read the FAQ and my problem is not listed.

Playground Link

https://typescript-eslint.io/play/#ts=5.5.4&fileType=.tsx&code=C4TwDgpgBAKgjAHgIJQgD2BAdgEwM5R7ABOAllgOYB8UAvFAAYAkA3kgL4MDcAsAFChIsAEzJUGbPkIly1OlCS8%2B-bAFcAtlACiUFvyhQAhvIBEAMwD2FkwBp9UAEamHh4rf7t%2B-ADYRgUNDgALlhELRp6cysTJV9-NGEQmFFw00trLiA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6Jge1tiacTJTIAhtEK18iALbF4QifQAexaIMocm6KImjQO0SODABfEEaA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

type T1<A extends string> = `${A}`; // <- linter suggests simplifying this
type T2<A extends string> = A;

enum E {
  a = "foo",
  b = "bar",
}

let x1: T1<E> = "foo";
let x2: T2<E> = "foo"; // <- compiler error, if we were to use the linter's suggested simplification

ESLint Config

module.exports = {
  parser: "@typescript-eslint/parser",
  rules: {
    "@typescript-eslint/no-unnecessary-template-expression": "error"
  },
};

tsconfig

{}

Expected Result

The "no-unnecessary-template-expression" rule suggests simplifying this:

type T<A extends string> = `${A}`;

To this:

type T<A extends string> = A;

But because these types are not equivalent, as demonstrated in the playground repro, it should not recommend this.

Actual Result

The rule suggests the simplification mentioned above.

Additional Info

Regarding why one might even want a type like this, see https://stackoverflow.com/q/52393730/. tl;dr it lets you flatten TypeScript enums-of-strings into a union of their string values.