diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 55c7e5f392416..15ff0bff849e7 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -3980,14 +3980,14 @@ impl<'a> Resolver<'a> {
                           container));
 
         err.span_label(span, format!("`{}` re{} here", name, new_participle));
-        if old_binding.span != syntax_pos::DUMMY_SP {
+        if old_binding.span != DUMMY_SP {
             err.span_label(self.session.codemap().def_span(old_binding.span),
                            format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
         }
 
         // See https://github.com/rust-lang/rust/issues/32354
         if old_binding.is_import() || new_binding.is_import() {
-            let binding = if new_binding.is_import() {
+            let binding = if new_binding.is_import() && new_binding.span != DUMMY_SP {
                 new_binding
             } else {
                 old_binding
@@ -4000,7 +4000,13 @@ impl<'a> Resolver<'a> {
                                            binding.is_renamed_extern_crate()) {
                 err.span_suggestion(binding.span,
                                     rename_msg,
-                                    format!("{} as Other{}", snippet, name));
+                                    if snippet.ends_with(';') {
+                                        format!("{} as Other{};",
+                                                &snippet[..snippet.len()-1],
+                                                name)
+                                    } else {
+                                        format!("{} as Other{}", snippet, name)
+                                    });
             } else {
                 err.span_label(binding.span, rename_msg);
             }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 8213d604b91b2..35e89652c998f 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -6131,6 +6131,7 @@ impl<'a> Parser<'a> {
         self.expect(&token::Semi)?;
 
         let prev_span = self.prev_span;
+
         Ok(self.mk_item(lo.to(prev_span),
                         ident,
                         ItemKind::ExternCrate(maybe_path),
diff --git a/src/test/ui/suggestions/issue-45799-bad-extern-crate-rename-suggestion-formatting.rs b/src/test/ui/suggestions/issue-45799-bad-extern-crate-rename-suggestion-formatting.rs
new file mode 100644
index 0000000000000..4d75127b645bd
--- /dev/null
+++ b/src/test/ui/suggestions/issue-45799-bad-extern-crate-rename-suggestion-formatting.rs
@@ -0,0 +1,13 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+extern crate std;
+fn main() {}
+//~^^ ERROR the name `std` is defined multiple times [E0259]
diff --git a/src/test/ui/suggestions/issue-45799-bad-extern-crate-rename-suggestion-formatting.stderr b/src/test/ui/suggestions/issue-45799-bad-extern-crate-rename-suggestion-formatting.stderr
new file mode 100644
index 0000000000000..d2ac15f7ffcb3
--- /dev/null
+++ b/src/test/ui/suggestions/issue-45799-bad-extern-crate-rename-suggestion-formatting.stderr
@@ -0,0 +1,14 @@
+error[E0259]: the name `std` is defined multiple times
+  --> $DIR/issue-45799-bad-extern-crate-rename-suggestion-formatting.rs:11:1
+   |
+11 | extern crate std;
+   | ^^^^^^^^^^^^^^^^^ `std` reimported here
+   |
+   = note: `std` must be defined only once in the type namespace of this module
+help: You can use `as` to change the binding name of the import
+   |
+11 | extern crate std as Otherstd;
+   |
+
+error: aborting due to previous error
+