From dd68685e48db23b340ec31024c4c4aa2d6180a16 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Tue, 30 Oct 2018 00:21:39 +0300
Subject: [PATCH] resolve: Fix ICE in macro import error recovery

---
 src/librustc_resolve/macros.rs         |  3 +++
 src/test/ui/imports/issue-55457.rs     |  8 +++++++
 src/test/ui/imports/issue-55457.stderr | 31 ++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 src/test/ui/imports/issue-55457.rs
 create mode 100644 src/test/ui/imports/issue-55457.stderr

diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index d5f344346c2d1..43a5fdb7a025f 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -449,6 +449,9 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
                     return Err(Determinacy::Determined);
                 }
             }
+            Def::Err => {
+                return Err(Determinacy::Determined);
+            }
             _ => panic!("expected `Def::Macro` or `Def::NonMacroAttr`"),
         }
 
diff --git a/src/test/ui/imports/issue-55457.rs b/src/test/ui/imports/issue-55457.rs
new file mode 100644
index 0000000000000..9c6750fd48c26
--- /dev/null
+++ b/src/test/ui/imports/issue-55457.rs
@@ -0,0 +1,8 @@
+use NonExistent; //~ ERROR unresolved import `NonExistent`
+use non_existent::non_existent; //~ ERROR unresolved import `non_existent`
+
+#[non_existent] //~ ERROR cannot determine resolution for the attribute macro `non_existent`
+#[derive(NonExistent)] //~ ERROR cannot determine resolution for the derive macro `NonExistent`
+struct S;
+
+fn main() {}
diff --git a/src/test/ui/imports/issue-55457.stderr b/src/test/ui/imports/issue-55457.stderr
new file mode 100644
index 0000000000000..363dec06237f4
--- /dev/null
+++ b/src/test/ui/imports/issue-55457.stderr
@@ -0,0 +1,31 @@
+error[E0432]: unresolved import `NonExistent`
+  --> $DIR/issue-55457.rs:1:5
+   |
+LL | use NonExistent; //~ ERROR unresolved import `NonExistent`
+   |     ^^^^^^^^^^^ no `NonExistent` in the root. Did you mean to use `non_existent`?
+
+error[E0432]: unresolved import `non_existent`
+  --> $DIR/issue-55457.rs:2:5
+   |
+LL | use non_existent::non_existent; //~ ERROR unresolved import `non_existent`
+   |     ^^^^^^^^^^^^ Maybe a missing `extern crate non_existent;`?
+
+error: cannot determine resolution for the derive macro `NonExistent`
+  --> $DIR/issue-55457.rs:5:10
+   |
+LL | #[derive(NonExistent)] //~ ERROR cannot determine resolution for the derive macro `NonExistent`
+   |          ^^^^^^^^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: cannot determine resolution for the attribute macro `non_existent`
+  --> $DIR/issue-55457.rs:4:3
+   |
+LL | #[non_existent] //~ ERROR cannot determine resolution for the attribute macro `non_existent`
+   |   ^^^^^^^^^^^^
+   |
+   = note: import resolution is stuck, try simplifying macro imports
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0432`.