Wishlist: argument type inference for private methods and local functions

[vivainio]

TypeScript Version: 2.5

It should be possible to infer types of non-exported functions and private methods, as the types can be locally established by just looking at the file under compilation.

Code

function inferred(x):
  return x+x

// since we call the function with a number, we should be able to infer the type of x as number instead of "any"

const foo = inferred(2)

// complation should fail as no type can be inferred that supports both calls to 'inferred'.

const bar = inferred( { baz:1} )

[mhegazy]

Duplicate of #15114, #14078, #15016, #17428, #15196

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.