1 files changed, 22 insertions, 3 deletions
diff --git a/compiler/rustc_lint/src/non_fmt_panic.rs b/compiler/rustc_lint/src/non_fmt_panic.rs
index a919b3c82aa..f2fee67115d 100644
--- a/compiler/rustc_lint/src/non_fmt_panic.rs
+++ b/compiler/rustc_lint/src/non_fmt_panic.rs
@@ -49,9 +49,11 @@ impl<'tcx> LateLintPass<'tcx> for NonPanicFmt {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) {
         if let hir::ExprKind::Call(f, [arg]) = &expr.kind {
             if let &ty::FnDef(def_id, _) = cx.typeck_results().expr_ty(f).kind() {
+                let f_diagnostic_name = cx.tcx.get_diagnostic_name(def_id);
+
                 if Some(def_id) == cx.tcx.lang_items().begin_panic_fn()
                     || Some(def_id) == cx.tcx.lang_items().panic_fn()
-                    || Some(def_id) == cx.tcx.lang_items().panic_str()
+                    || f_diagnostic_name == Some(sym::panic_str)
                 {
                     if let Some(id) = f.span.ctxt().outer_expn_data().macro_def_id {
                         if matches!(
@@ -61,6 +63,22 @@ impl<'tcx> LateLintPass<'tcx> for NonPanicFmt {
                             check_panic(cx, f, arg);
                         }
                     }
+                } else if f_diagnostic_name == Some(sym::unreachable_display) {
+                    if let Some(id) = f.span.ctxt().outer_expn_data().macro_def_id {
+                        if cx.tcx.is_diagnostic_item(sym::unreachable_2015_macro, id) {
+                            check_panic(
+                                cx,
+                                f,
+                                // This is safe because we checked above that the callee is indeed
+                                // unreachable_display
+                                match &arg.kind {
+                                    // Get the borrowed arg not the borrow
+                                    hir::ExprKind::AddrOf(ast::BorrowKind::Ref, _, arg) => arg,
+                                    _ => bug!("call to unreachable_display without borrow"),
+                                },
+                            );
+                        }
+                    }
                 }
             }
         }
@@ -85,8 +103,8 @@ fn check_panic<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>, arg: &'tc
         return;
     }
 
-    // Find the span of the argument to `panic!()`, before expansion in the
-    // case of `panic!(some_macro!())`.
+    // Find the span of the argument to `panic!()` or `unreachable!`, before expansion in the
+    // case of `panic!(some_macro!())` or `unreachable!(some_macro!())`.
     // We don't use source_callsite(), because this `panic!(..)` might itself
     // be expanded from another macro, in which case we want to stop at that
     // expansion.
@@ -319,6 +337,7 @@ fn panic_call<'tcx>(cx: &LateContext<'tcx>, f: &'tcx hir::Expr<'tcx>) -> (Span,
                 | sym::std_panic_macro
                 | sym::assert_macro
                 | sym::debug_assert_macro
+                | sym::unreachable_macro
         ) {
             break;
         }