setTimeout defined in lib.dom.d.ts is not type safe

TypeScript Version: 3.5.2

Search Terms:
settimeout type safe
Code

// A *self-contained* demonstration of the problem follows...
// Test this by running `tsc` on the command-line, rather than through another build tool such as Gulp, Webpack, etc.
const f = (foo: number) => console.log(foo + 1);
setTimeout(f, 0, 'a');

Expected behavior:
It shall not pass thanks to the type error.
Actual behavior:
It passes.
Playground Link:
https://www.typescriptlang.org/play/#code/MYewdgzgLgBAZjAvDAFHEIBcMwFcC2ARgKYBOAlEgHwyiQgA2xAdAyAOZoYwDUMAjOQDcAKAjEoAFQCW+YiFxQ0AGhgAGVQHIAhoULBgAE0PFNWwpuFA
Related Issues:
emm, maybe not.

Inspect the setTimeout declarations in lib.dom.d.ts and first reproduce the example with tsc or the linked TypeScript Playground. Done means the extra string argument is rejected when the callback accepts a number, with declaration tests or an equivalent compiler check passing.