On: What would it take to add refinement types to Rust...

[loeg]

Uh, seemingly, yeah. 10+11 = 21. No bounds checking on addition or assignment.

https://onlinegdb.com/3KhhaReLV

[int_19h → loeg]

That is just this one particular implementation of Pascal (unsure which one). The language spec does say that it is an error to assign a value out of range, but as far as what this actually means, it only says that "a complying processor is required to provide documentation concerning its treatment of errors".

[dannymi → loeg]

  $ cat a.pp
  {$R+}
  var
    a: 1..12;
    b: 1..12;
    c: 1..12;
  begin
    a := 10;
    b := 11;
    c := a + b;
    Writeln(c)
  end.
  $ fpc a.pp
  Free Pascal Compiler version 3.2.2 [2021/05/19] for x86_64
  Copyright (c) 1993-2021 by Florian Klaempfl and others
  Target OS: Linux for x86-64
  Compiling a.pp
  Linking a
  12 lines compiled, 0.1 sec
  $ ./a
  Runtime error 201 at $00000000004010D8
    $00000000004010D8
    $0000000000422EEC