#127sema: implement break from blocks that are not the current block

let print = @extern("console").log;

fn something(a: int) -> bool {
  if a == 0 {
    return false;
  }

  a > 100
}

fn main {
  print(something(0xFF), something(0));
}

This generates the following Hir:

%0 = +0 module {
  ...
  %8 = +0 declaration something (16) [fb5a2dd6240dea2dfe9fd8bd5899c752] (
    %22 = +0 block [
      %21 = +0 func {
        params:  [ %int32_type ]
        return_type: %bool_type
        captures:  []
        body: %9 = -1 block [
          %10 = -1 param(0)
          %11 = -10 number 0
          %12 = -9 eq(%10, %11)
          %15 = -5 if(%12) {
            yes: %14 = -6 block [
              %13 = -7 break(%9, %bool_false)
            ]
            no: %void
          }
          %16 = -5 ensure_void(%15)
          %17 = -3 number 100
          %18 = -2 gt(%10, %17)
          %19 = -1 coercion(%bool_type, %18)
          %20 = -1 break(%9, %19)
        ]
      }
      %23 = +0 break(%22, %21)
    ]
  )
  ...
}

Analyzing %13 hits a TODO because the block %9 is not the current frame's block (%13). Semantic analysis must emit an Air break instruction, mark %14 as comptime known .never, then continue analysis of %15 and analyze instructions %16 through %20. It would also coerce %bool_false to the result type of %9, which I don't remember off the top of my head how that even works.

I think this is a regression from 0.1.6 but I am not certain.

Milestone: 0.2.0.

~clover changed the status to Todo · 1 year ago