Merge #1677

1677: Associated types r=flodiebold a=flodiebold

This implements basic support for (fully qualified) associated type projections:
 - handle fully qualified paths like `<T as Trait>::AssocType` (basically desugaring to something like `Trait<Self=T>::AssocType`)
 - lower these to a new `Ty::Projection` enum variant
 - also introduce `Ty::UnselectedProjection` for cases like `T::AssocType` where the trait from which the type comes isn't specified, but these aren't handled further so far
 - in inference, normalize these projections using Chalk: basically, when encountering a type e.g. from a type annotation or signature, we replace these `Ty::Projection`s by type variables and add obligations to normalize the associated type

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

1 files changed, 1 insertions, 0 deletions

diff --git a/crates/ra_assists/src/auto_import.rs b/crates/ra_assists/src/auto_import.rs
index a32e2f9b6..1158adbbc 100644
--- a/crates/ra_assists/src/auto_import.rs
+++ b/crates/ra_assists/src/auto_import.rs
@@ -71,6 +71,7 @@ fn compare_path_segment(a: &SmolStr, b: &ast::PathSegment) -> bool {
             ast::PathSegmentKind::SelfKw => a == "self",
             ast::PathSegmentKind::SuperKw => a == "super",
             ast::PathSegmentKind::CrateKw => a == "crate",
+            ast::PathSegmentKind::Type { .. } => false, // not allowed in imports
         }
     } else {
         false