error: expected this to be of the form `... = "..."`
  --> $DIR/doc-attr.rs:4:7
   |
LL | #[doc(123)]
   |       ^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
note: the lint level is defined here
  --> $DIR/doc-attr.rs:2:9
   |
LL | #![deny(invalid_doc_attributes)]
   |         ^^^^^^^^^^^^^^^^^^^^^^

error: expected this to be of the form `... = "..."`
  --> $DIR/doc-attr.rs:7:7
   |
LL | #[doc("hello", "bar")]
   |       ^^^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!

error: expected this to be of the form `... = "..."`
  --> $DIR/doc-attr.rs:7:16
   |
LL | #[doc("hello", "bar")]
   |                ^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!

error: aborting due to 3 previous errors