Merge #742

742: Extern crate r=matklad a=flodiebold

This implements `extern crate` declarations by lowering them to (absolute) imports, and adds support for absolute paths. It also extracts the extern prelude from the per-module item map, and handles the special case of extern crates in the crate root adding to the extern prelude.

This means we finally resolve `Arc`, so it fixes #523 :smile: 

Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 3 insertions, 1 deletions

diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index a2ccd7cb9..2ed1fd1b8 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -601,7 +601,9 @@ Grammar(
         "UseTreeList": (
             collections: [["use_trees", "UseTree"]]
         ),
-        "ExternCrateItem": (),
+        "ExternCrateItem": (
+            options: ["NameRef", "Alias"],
+        ),
         "ArgList": (
             collections: [
                 ["args", "Expr"]