Make resolve_path a bit nicer

Author: flodiebold

crates/ra_hir/src/nameres.rs

@@ -390,13 +390,14 @@ impl ItemMap {
         original_module: Module,
         path: &Path,
     ) -> (PerNs<ModuleDef>, ReachedFixedPoint) {
-        let mut segments = path.segments.iter().enumerate();
+        let mut segments = path.segments.iter();
+        // Handle crate/self/super, or the first segment
         let mut curr_per_ns: PerNs<ModuleDef> = match path.kind {
             PathKind::Crate => PerNs::types(original_module.crate_root(db).into()),
             PathKind::Self_ => PerNs::types(original_module.into()),
             PathKind::Plain => {
                 let segment = match segments.next() {
-                    Some((_, segment)) => segment,
+                    Some(segment) => segment,
                     None => return (PerNs::none(), ReachedFixedPoint::Yes),
                 };
                 // Resolve in:
@@ -424,19 +425,20 @@ impl ItemMap {
             PathKind::Abs => {
                 // 2018-style absolute path -- only extern prelude
                 let segment = match segments.next() {
-                    Some((_, segment)) => segment,
+                    Some(segment) => segment,
                     None => return (PerNs::none(), ReachedFixedPoint::Yes),
                 };
                 if let Some(def) = self.extern_prelude.get(&segment.name) {
                     log::debug!("absolute path {:?} resolved to crate {:?}", path, def);
                     PerNs::types(*def)
                 } else {
-                    return (PerNs::none(), ReachedFixedPoint::Yes);
+                    return (PerNs::none(), ReachedFixedPoint::No); // extern crate declarations can add to the extern prelude
                 }
             }
         };
 
-        for (i, segment) in segments {
+        // Go through the rest of the segments
+        while let Some(segment) = segments.next() {
             let curr = match curr_per_ns.as_ref().take_types() {
                 Some(r) => r,
                 None => {
@@ -454,7 +456,7 @@ impl ItemMap {
                 ModuleDef::Module(module) => {
                     if module.krate != original_module.krate {
                         let path = Path {
-                            segments: path.segments[i..].iter().cloned().collect(),
+                            segments: segments.cloned().collect(),
                             kind: PathKind::Self_,
                         };
                         log::debug!("resolving {:?} in other crate", path);