fix completion for super::super::

Author: JoshMcguigan

crates/ra_hir_def/src/path/lower.rs

@@ -101,8 +101,12 @@ pub(super) fn lower_path(mut path: ast::Path, hygiene: &Hygiene) -> Option<Path>
                 break;
             }
             ast::PathSegmentKind::SuperKw => {
-                kind = PathKind::Super(1);
-                break;
+                let nested_super_count = if let PathKind::Super(n) = kind {
+                    n
+                } else {
+                    0
+                };
+                kind = PathKind::Super(nested_super_count + 1);
             }
         }
         path = match qualifier(&path) {

crates/ra_ide/src/completion/complete_dot.rs

@@ -545,4 +545,43 @@ mod tests {
         "###
         )
     }
+
+    #[test]
+    fn test_super_super_completion() {
+        assert_debug_snapshot!(
+        do_ref_completion(
+                r"
+                mod a {
+                    const A: usize = 0;
+
+                    mod b {
+                        const B: usize = 0;
+
+                        mod c {
+                            use super::super::<|>
+                        }
+                    }
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "A",
+                source_range: [217; 217),
+                delete: [217; 217),
+                insert: "A",
+                kind: Const,
+            },
+            CompletionItem {
+                label: "b",
+                source_range: [217; 217),
+                delete: [217; 217),
+                insert: "b",
+                kind: Module,
+            },
+        ]
+        "###
+        );
+    }
 }