Properly handle semantically anonymous functions

[dcodeIO]

Fixes the compiler not being able to refer back to named functions declared inside of functions, and makes sure that functions that are semantically anonymous (i.e. named but are part of an expression) do not conflict with named functions when initializing their program elements.

fixes #1652

• I've read the contributing guidelines

[MaxGraey]

Oh, nice! Does it allow dependent direct and indirect function call depend on context? Like:

const foo = (x: i32): i32 => {
  return x;
}

foo(2); // direct call

function test(): (x: i32) => i32 {
  return foo;
}

test()(2); // indirect call

and same for declaration functions:

function foo(x: i32): i32 {
  return x;
}

foo(2); // direct call

function test(): (x: i32) => i32 {
  return foo;
}

test()(2); // indirect call

[dcodeIO]

This currently always results in an indirect call due to using a local to refer back. I guess static lookups should be possible, though, similar to how it works on a non-function level. May need a bit more resolver infrastructure.

[MaxGraey]

Ok, probably better to do it in a separate PR