error: expected `{`, found `std`
  --> $DIR/unsafe-block-without-braces.rs:3:9
   |
LL |     unsafe //{
   |     ------ while parsing this `unsafe` expression
LL |         std::mem::transmute::<f32, u32>(1.0);
   |         ^^^ expected `{`
   |
help: try placing this code inside a block
   |
LL |         { std::mem::transmute::<f32, u32>(1.0); }
   |         +                                       +

error: aborting due to 1 previous error