Merge pull request #38893 from jseyfried/backport_unused_qualification_lint

Backport "don't `unused_qualifications`-check global paths"

Author: nikomatsakis

src/librustc_resolve/lib.rs

@@ -2314,7 +2314,7 @@ impl<'a> Resolver<'a> {
             _ => return None,
         };
 
-        if path.len() == 1 || result.base_def == Def::Err {
+        if path.len() == 1 || result.base_def == Def::Err || global {
             return Some(result);
         }
 

src/test/compile-fail/lint-qualification.rs

@@ -21,8 +21,9 @@ fn main() {
 
     let _ = || -> Result<(), ()> { try!(Ok(())); Ok(()) }; // issue #37345
 
-    macro_rules! m {
-        () => { $crate::foo::bar(); }
-    }
-    m!(); // issue #37357
+    macro_rules! m { () => {
+        $crate::foo::bar(); // issue #37357
+        ::foo::bar(); // issue #38682
+    } }
+    m!();
 }