error: expected non-macro attribute, found attribute macro `derive`
  --> $DIR/issue-49934-errors.rs:1:10
   |
LL | fn foo<#[derive(Debug)] T>() {
   |          ^^^^^^ not a non-macro attribute

error: expected non-macro attribute, found attribute macro `derive`
  --> $DIR/issue-49934-errors.rs:3:11
   |
LL |         #[derive(Debug)]
   |           ^^^^^^ not a non-macro attribute

error: aborting due to 2 previous errors