Merge #603

603: fix completion bugs r=gfreezy a=gfreezy

The result is as below. 

before:
![image](https://user-images.githubusercontent.com/510012/51483467-0f641400-1dd4-11e9-9921-ef21d15cc343.png)

after:
![image](https://user-images.githubusercontent.com/510012/51483433-fb201700-1dd3-11e9-9730-c2a5d3dd5f5a.png)

Co-authored-by: gfreezy <[email protected]>

1 files changed, 7 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/ast.rs b/crates/ra_syntax/src/ast.rs
index 5a5f56057..bcbd4c60c 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -334,6 +334,13 @@ impl PathSegment {
         };
         Some(res)
     }
+
+    pub fn has_colon_colon(&self) -> bool {
+        match self.syntax.first_child().map(|s| s.kind()) {
+            Some(COLONCOLON) => true,
+            _ => false,
+        }
+    }
 }
 
 impl Path {