From 2433526809644fd8990773b32a6c6e7286d20a95 Mon Sep 17 00:00:00 2001
From: Michael Hewson <michael@michaelhewson.ca>
Date: Wed, 19 Dec 2018 18:27:58 -0500
Subject: [PATCH] use `delay_span_bug` instead of `bug!` when doing layout
 sanity check

It's possible that `is_object_safe` is called on a trait that is ill-formed, and we shouldn't ICE unless there are no errors being raised. Using `delay_span_bug` solves this.

fixes #56806
---
 src/librustc/traits/object_safety.rs  | 23 ++++++++++++++++++-----
 src/test/ui/issues/issue-56806.rs     |  7 +++++++
 src/test/ui/issues/issue-56806.stderr | 12 ++++++++++++
 3 files changed, 37 insertions(+), 5 deletions(-)
 create mode 100644 src/test/ui/issues/issue-56806.rs
 create mode 100644 src/test/ui/issues/issue-56806.stderr

diff --git a/src/librustc/traits/object_safety.rs b/src/librustc/traits/object_safety.rs
index fe40141a5e123..3005a13e6644f 100644
--- a/src/librustc/traits/object_safety.rs
+++ b/src/librustc/traits/object_safety.rs
@@ -369,7 +369,15 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
 
                 match abi_of_ty(unit_receiver_ty) {
                     &Abi::Scalar(..) => (),
-                    abi => bug!("Receiver when Self = () should have a Scalar ABI, found {:?}", abi)
+                    abi => {
+                        self.sess.delay_span_bug(
+                            self.def_span(method.def_id),
+                            &format!(
+                                "Receiver when Self = () should have a Scalar ABI, found {:?}",
+                                abi
+                            ),
+                        );
+                    }
                 }
 
                 let trait_object_ty = self.object_ty_for_trait(
@@ -383,10 +391,15 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
 
                 match abi_of_ty(trait_object_receiver) {
                     &Abi::ScalarPair(..) => (),
-                    abi => bug!(
-                        "Receiver when Self = {} should have a ScalarPair ABI, found {:?}",
-                        trait_object_ty, abi
-                    )
+                    abi => {
+                        self.sess.delay_span_bug(
+                            self.def_span(method.def_id),
+                            &format!(
+                                "Receiver when Self = {} should have a ScalarPair ABI, found {:?}",
+                                trait_object_ty, abi
+                            ),
+                        );
+                    }
                 }
             }
         }
diff --git a/src/test/ui/issues/issue-56806.rs b/src/test/ui/issues/issue-56806.rs
new file mode 100644
index 0000000000000..b6454e578e6af
--- /dev/null
+++ b/src/test/ui/issues/issue-56806.rs
@@ -0,0 +1,7 @@
+pub trait Trait {
+    fn dyn_instead_of_self(self: Box<dyn Trait>);
+    //~^ ERROR invalid method receiver type: std::boxed::Box<(dyn Trait + 'static)>
+}
+
+pub fn main() {
+}
diff --git a/src/test/ui/issues/issue-56806.stderr b/src/test/ui/issues/issue-56806.stderr
new file mode 100644
index 0000000000000..2dd3add8f60e6
--- /dev/null
+++ b/src/test/ui/issues/issue-56806.stderr
@@ -0,0 +1,12 @@
+error[E0307]: invalid method receiver type: std::boxed::Box<(dyn Trait + 'static)>
+  --> $DIR/issue-56806.rs:2:34
+   |
+LL |     fn dyn_instead_of_self(self: Box<dyn Trait>);
+   |                                  ^^^^^^^^^^^^^^
+   |
+   = note: type must be `Self` or a type that dereferences to it
+   = help: consider changing to `self`, `&self`, `&mut self`, or `self: Box<Self>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0307`.