3 files changed, 80 insertions, 22 deletions

diff --git a/crates/ra_hir/src/code_model_impl/module.rs b/crates/ra_hir/src/code_model_impl/module.rs
index 7215236f9..2014f1090 100644
--- a/crates/ra_hir/src/code_model_impl/module.rs
+++ b/crates/ra_hir/src/code_model_impl/module.rs
@@ -147,7 +147,7 @@ impl Module {
             .def_id,
         );
 
-        for name in path.segments.iter() {
+        for segment in path.segments.iter() {
             let curr = match curr_per_ns.as_ref().take_types() {
                 Some(r) => r,
                 None => {
@@ -163,15 +163,17 @@ impl Module {
             curr_per_ns = match curr.resolve(db) {
                 Def::Module(m) => {
                     let scope = m.scope(db);
-                    match scope.get(&name) {
+                    match scope.get(&segment.name) {
                         Some(r) => r.def_id,
                         None => PerNs::none(),
                     }
                 }
                 Def::Enum(e) => {
                     // enum variant
-                    let matching_variant =
-                        e.variants(db).into_iter().find(|(n, _variant)| n == name);
+                    let matching_variant = e
+                        .variants(db)
+                        .into_iter()
+                        .find(|(n, _variant)| n == &segment.name);
 
                     match matching_variant {
                         Some((_n, variant)) => PerNs::both(variant.def_id(), e.def_id()),
diff --git a/crates/ra_hir/src/nameres.rs b/crates/ra_hir/src/nameres.rs
index 4efafd409..4874e82f3 100644
--- a/crates/ra_hir/src/nameres.rs
+++ b/crates/ra_hir/src/nameres.rs
@@ -221,10 +221,10 @@ where
             };
         }
         for (import_id, import_data) in input.imports.iter() {
-            if let Some(name) = import_data.path.segments.iter().last() {
+            if let Some(segment) = import_data.path.segments.iter().last() {
                 if !import_data.is_glob {
                     module_items.items.insert(
-                        name.clone(),
+                        segment.name.clone(),
                         Resolution {
                             def_id: PerNs::none(),
                             import: Some(import_id),
@@ -319,13 +319,13 @@ where
             PathKind::Crate => module_id.crate_root(&self.module_tree),
         };
 
-        for (i, name) in import.path.segments.iter().enumerate() {
+        for (i, segment) in import.path.segments.iter().enumerate() {
             let is_last = i == import.path.segments.len() - 1;
 
-            let def_id = match self.result.per_module[&curr].items.get(name) {
+            let def_id = match self.result.per_module[&curr].items.get(&segment.name) {
                 Some(res) if !res.def_id.is_none() => res.def_id,
                 _ => {
-                    log::debug!("path segment {:?} not found", name);
+                    log::debug!("path segment {:?} not found", segment.name);
                     return false;
                 }
             };
@@ -336,7 +336,7 @@ where
                 } else {
                     log::debug!(
                         "path segment {:?} resolved to value only, but is not last",
-                        name
+                        segment.name
                     );
                     return false;
                 };
@@ -358,17 +358,17 @@ where
                             log::debug!("resolving {:?} in other source root", path);
                             let def_id = module.resolve_path(self.db, &path);
                             if !def_id.is_none() {
-                                let name = path.segments.last().unwrap();
+                                let last_segment = path.segments.last().unwrap();
                                 self.update(module_id, |items| {
                                     let res = Resolution {
                                         def_id,
                                         import: Some(import_id),
                                     };
-                                    items.items.insert(name.clone(), res);
+                                    items.items.insert(last_segment.name.clone(), res);
                                 });
                                 log::debug!(
                                     "resolved import {:?} ({:?}) cross-source root to {:?}",
-                                    name,
+                                    last_segment.name,
                                     import,
                                     def_id.map(|did| did.loc(self.db))
                                 );
@@ -382,7 +382,7 @@ where
                     _ => {
                         log::debug!(
                             "path segment {:?} resolved to non-module {:?}, but is not last",
-                            name,
+                            segment.name,
                             type_def_id.loc(self.db)
                         );
                         return true; // this resolved to a non-module, so the path won't ever resolve
@@ -391,7 +391,7 @@ where
             } else {
                 log::debug!(
                     "resolved import {:?} ({:?}) within source root to {:?}",
-                    name,
+                    segment.name,
                     import,
                     def_id.map(|did| did.loc(self.db))
                 );
@@ -400,7 +400,7 @@ where
                         def_id,
                         import: Some(import_id),
                     };
-                    items.items.insert(name.clone(), res);
+                    items.items.insert(segment.name.clone(), res);
                 })
             }
         }
diff --git a/crates/ra_hir/src/path.rs b/crates/ra_hir/src/path.rs
index 7b0ce3b61..c3d14c689 100644
--- a/crates/ra_hir/src/path.rs
+++ b/crates/ra_hir/src/path.rs
@@ -1,11 +1,35 @@
+use std::sync::Arc;
+
 use ra_syntax::{ast, AstNode};
 
-use crate::{Name, AsName};
+use crate::{Name, AsName, type_ref::TypeRef};
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Path {
     pub kind: PathKind,
-    pub segments: Vec<Name>,
+    pub segments: Vec<PathSegment>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct PathSegment {
+    pub name: Name,
+    pub args_and_bindings: Option<Arc<GenericArgs>>,
+}
+
+/// Generic arguments to a path segment (e.g. the `i32` in `Option<i32>`). This
+/// can (in the future) also include bindings of associated types, like in
+/// `Iterator<Item = Foo>`.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct GenericArgs {
+    pub args: Vec<GenericArg>,
+    // someday also bindings
+}
+
+/// A single generic argument.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum GenericArg {
+    Type(TypeRef),
+    // or lifetime...
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -34,7 +58,17 @@ impl Path {
         loop {
             let segment = path.segment()?;
             match segment.kind()? {
-                ast::PathSegmentKind::Name(name) => segments.push(name.as_name()),
+                ast::PathSegmentKind::Name(name) => {
+                    let args = segment
+                        .type_arg_list()
+                        .and_then(GenericArgs::from_ast)
+                        .map(Arc::new);
+                    let segment = PathSegment {
+                        name: name.as_name(),
+                        args_and_bindings: args,
+                    };
+                    segments.push(segment);
+                }
                 ast::PathSegmentKind::CrateKw => {
                     kind = PathKind::Crate;
                     break;
@@ -88,7 +122,23 @@ impl Path {
         if self.kind != PathKind::Plain || self.segments.len() > 1 {
             return None;
         }
-        self.segments.first()
+        self.segments.first().map(|s| &s.name)
+    }
+}
+
+impl GenericArgs {
+    fn from_ast(node: &ast::TypeArgList) -> Option<GenericArgs> {
+        let mut args = Vec::new();
+        for type_arg in node.type_args() {
+            let type_ref = TypeRef::from_ast_opt(type_arg.type_ref());
+            args.push(GenericArg::Type(type_ref));
+        }
+        // lifetimes and assoc type args ignored for now
+        if args.len() > 0 {
+            Some(GenericArgs { args })
+        } else {
+            None
+        }
     }
 }
 
@@ -96,7 +146,10 @@ impl From<Name> for Path {
     fn from(name: Name) -> Path {
         Path {
             kind: PathKind::Plain,
-            segments: vec![name],
+            segments: vec![PathSegment {
+                name,
+                args_and_bindings: None,
+            }],
         }
     }
 }
@@ -160,7 +213,10 @@ fn convert_path(prefix: Option<Path>, path: &ast::Path) -> Option<Path> {
                 kind: PathKind::Plain,
                 segments: Vec::with_capacity(1),
             });
-            res.segments.push(name.as_name());
+            res.segments.push(PathSegment {
+                name: name.as_name(),
+                args_and_bindings: None, // no type args in use
+            });
             res
         }
         ast::PathSegmentKind::CrateKw => {