From 3d54e56ed4898c2b01dd008f12ab41cf54710f43 Mon Sep 17 00:00:00 2001
From: Philipp Hansch <dev@phansch.net>
Date: Fri, 26 Jan 2018 07:51:27 +0100
Subject: [PATCH] Add workaround for hidden outer attribute

If the snippet is empty, it's an attribute that was inserted during macro
expansion and we want to ignore those, because they could come from external
sources that the user has no control over.
For some reason these attributes don't have any expansion info on them, so
we have to check it this way until there is a better way.
---
 clippy_lints/src/attrs.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/clippy_lints/src/attrs.rs b/clippy_lints/src/attrs.rs
index 5df932a8d93..939fdf1fae9 100644
--- a/clippy_lints/src/attrs.rs
+++ b/clippy_lints/src/attrs.rs
@@ -263,6 +263,10 @@ fn check_attrs(cx: &LateContext, span: Span, name: &Name, attrs: &[Attribute]) {
 
     for attr in attrs {
         if attr.style == AttrStyle::Outer {
+            if !is_present_in_source(cx, attr.span) {
+                return;
+            }
+
             let attr_to_item_span = Span::new(attr.span.lo(), span.lo(), span.ctxt());
 
             if let Some(snippet) = snippet_opt(cx, attr_to_item_span) {
@@ -319,3 +323,17 @@ fn is_word(nmi: &NestedMetaItem, expected: &str) -> bool {
         false
     }
 }
+
+// If the snippet is empty, it's an attribute that was inserted during macro
+// expansion and we want to ignore those, because they could come from external
+// sources that the user has no control over.
+// For some reason these attributes don't have any expansion info on them, so
+// we have to check it this way until there is a better way.
+fn is_present_in_source(cx: &LateContext, span: Span) -> bool {
+    if let Some(snippet) = snippet_opt(cx, span) {
+        if snippet.is_empty() {
+            return false;
+        }
+    }
+    true
+}