error: expected one of `:`, `;`, or `=`, found `+`
  --> $DIR/pat-ranges-3.rs:4:19
   |
LL |     let 10 ..= 10 + 3 = 12; //~ expected one of `:`, `;`, or `=`, found `+`
   |                   ^ expected one of `:`, `;`, or `=` here

error: aborting due to previous error