Can't call conditional expression

[andy-hanson]

function f(x: i32): i32 { return x; }
function g(x: i32): i32 { return x + 2; }
export function test(b: boolean): i32 {
  return (b ? f : g)(1);
}

Currently fails with:

ERROR TS1005: ')' expected.

   return (b ? f : g)(1);
             ~

[MaxGraey]

Hmm, for this specific case when signatures are identical it pretty simple, we can just syntactic sugaring to b ? f(1) : g(1), but that about this:

function f(x: i32): i32 { return x; }
function g(x: i32, y: i32): i32 { return x + y; }

function test(b: boolean): i32 {
  return (b ? f : g)(1, 2);
}

This valid in Typescript btw.
Of course this could be translated to b ? f(1) : g(1, 2). But as for me it's a rather dangerous approach.

[andy-hanson]

You can already do this in master using let fn = b ? f : g;. It looks like AssemblyScript doesn't do function subtyping, so it's an error if f and g aren't exactly the same type.
However, there's apparently still an error for b ? f : g in the resolver, since this is just a temporary expression and there's no local variable to resolve to.
The semantic part of this problem seems basically the same as #251 -- compileCallExpression expects to just resolve the called expression and never compiles it, which is a problem since the called expression may contain arbitrary code.

[dcodeIO]

Yeah, it can't resolve to a concrete Function in this case, but there's also something I simply called FunctionTarget (basically an index bound to a signature) that should work, that is if the resolver had code to combine a left and right Function to a FunctionTarget.

[MaxGraey]

Resolved in #833