src/test/mir-opt/basic_assignment.rs

   1 // this tests move up progration, which is not yet implemented
   2
   3 // EMIT_MIR rustc.main.SimplifyCfg-initial.after.mir
   4
   5 // Check codegen for assignments (`a = b`) where the left-hand-side is
   6 // not yet initialized. Assignments tend to be absent in simple code,
   7 // so subtle breakage in them can leave a quite hard-to-find trail of
   8 // destruction.
   9
  10 fn main() {
  11     let nodrop_x = false;
  12     let nodrop_y;
  13
  14     // Since boolean does not require drop, this can be a simple
  15     // assignment:
  16     nodrop_y = nodrop_x;
  17
  18     let drop_x: Option<Box<u32>> = None;
  19     let drop_y;
  20
  21     // Since the type of `drop_y` has drop, we generate a `replace`
  22     // terminator:
  23     drop_y = drop_x;
  24 }