Rollup merge of #54488 - zackmdavis:and_the_case_of_the_unused_crate, r=estebank

in which we include attributes in unused `extern crate` suggestion spans

![unused_extern](https://user-images.githubusercontent.com/1076988/45921698-50243e80-be6f-11e8-930a-7b2a33b4935c.png)

Resolves #54400.

r? @estebank

diff --cc src/librustc_typeck/check_unused.rs
index de4ab527e1559c155702bf5057bf312b8fa8b78d,3dbd5f2017ee492a85dbdae888bd4d24e76f4418..62ffffab07661304f48df4af1bdd9a0baa587413
--- 1/src/librustc_typeck/check_unused.rs
--- 2/src/librustc_typeck/check_unused.rs
+++ b/src/librustc_typeck/check_unused.rs
@@@ -137,10 -136,19 +137,16 @@@ fn unused_crates_lint<'tcx>(tcx: TyCtxt
          // We do this in any edition.
          if extern_crate.warn_if_unused {
              if let Some(&span) = unused_extern_crates.get(&extern_crate.def_id) {
 -                assert_eq!(extern_crate.def_id.krate, LOCAL_CRATE);
 -                let hir_id = tcx.hir.definitions().def_index_to_hir_id(extern_crate.def_id.index);
 -                let id = tcx.hir.hir_to_node_id(hir_id);
                  let msg = "unused extern crate";
+ 
+                 // Removal suggestion span needs to include attributes (Issue #54400)
+                 let span_with_attrs = tcx.get_attrs(extern_crate.def_id).iter()
+                     .map(|attr| attr.span)
+                     .fold(span, |acc, attr_span| acc.to(attr_span));
+ 
                  tcx.struct_span_lint_node(lint, id, span, msg)
                      .span_suggestion_short_with_applicability(
-                         span,
+                         span_with_attrs,
                          "remove it",
                          String::new(),
                          Applicability::MachineApplicable)