error: expected one of `)`, `,`, or `::`, found `(`
  --> $DIR/malformed-derive-entry.rs:1:14
   |
LL | #[derive(Copy(Bad))]
   |              ^ expected one of `)`, `,`, or `::`

error: expected one of `)`, `,`, or `::`, found `=`
  --> $DIR/malformed-derive-entry.rs:4:14
   |
LL | #[derive(Copy="bad")]
   |              ^ expected one of `)`, `,`, or `::`

error: malformed `derive` attribute input
  --> $DIR/malformed-derive-entry.rs:7:1
   |
LL | #[derive]
   | ^^^^^^^^^ help: missing traits to be derived: `#[derive(Trait1, Trait2, ...)]`

error: aborting due to 3 previous errors