8 files changed, 99 insertions, 9 deletions

diff --git a/crates/ra_hir/src/function.rs b/crates/ra_hir/src/function.rs
index 5187dc051..2925beb16 100644
--- a/crates/ra_hir/src/function.rs
+++ b/crates/ra_hir/src/function.rs
@@ -27,7 +27,7 @@ impl Function {
         Function { fn_id }
     }
 
-    pub fn scope(&self, db: &impl HirDatabase) -> Arc<FnScopes> {
+    pub fn scopes(&self, db: &impl HirDatabase) -> Arc<FnScopes> {
         db.fn_scopes(self.fn_id)
     }
 
diff --git a/crates/ra_hir/src/function/scope.rs b/crates/ra_hir/src/function/scope.rs
index 863453291..a1a580979 100644
--- a/crates/ra_hir/src/function/scope.rs
+++ b/crates/ra_hir/src/function/scope.rs
@@ -1,7 +1,7 @@
 use rustc_hash::{FxHashMap, FxHashSet};
 
 use ra_syntax::{
-    AstNode, SmolStr, SyntaxNodeRef, TextRange,
+    AstNode, SmolStr, SyntaxNodeRef, TextUnit, TextRange,
     algo::generate,
     ast::{self, ArgListOwner, LoopBodyOwner, NameOwner},
 };
@@ -33,7 +33,7 @@ pub struct ScopeData {
 }
 
 impl FnScopes {
-    pub fn new(fn_def: ast::FnDef) -> FnScopes {
+    pub(crate) fn new(fn_def: ast::FnDef) -> FnScopes {
         let mut scopes = FnScopes {
             self_param: fn_def
                 .param_list()
@@ -57,6 +57,48 @@ impl FnScopes {
             self.scopes[scope].parent
         })
     }
+    pub fn scope_chain_for_offset<'a>(
+        &'a self,
+        offset: TextUnit,
+    ) -> impl Iterator<Item = ScopeId> + 'a {
+        let scope = self
+            .scope_for
+            .iter()
+            // find containin scope
+            .min_by_key(|(ptr, _scope)| {
+                (
+                    !(ptr.range().start() <= offset && offset <= ptr.range().end()),
+                    ptr.range().len(),
+                )
+            })
+            .map(|(ptr, scope)| self.adjust(*ptr, *scope, offset));
+
+        generate(scope, move |&scope| self.scopes[scope].parent)
+    }
+    // XXX: during completion, cursor might be outside of any particular
+    // expression. Try to figure out the correct scope...
+    fn adjust(&self, ptr: LocalSyntaxPtr, original_scope: ScopeId, offset: TextUnit) -> ScopeId {
+        let r = ptr.range();
+        let child_scopes = self
+            .scope_for
+            .iter()
+            .map(|(ptr, scope)| (ptr.range(), scope))
+            .filter(|(range, _)| range.start() <= offset && range.is_subrange(&r) && *range != r);
+
+        child_scopes
+            .max_by(|(r1, _), (r2, _)| {
+                if r2.is_subrange(&r1) {
+                    std::cmp::Ordering::Greater
+                } else if r1.is_subrange(&r2) {
+                    std::cmp::Ordering::Less
+                } else {
+                    r1.start().cmp(&r2.start())
+                }
+            })
+            .map(|(_ptr, scope)| *scope)
+            .unwrap_or(original_scope)
+    }
+
     pub fn resolve_local_name<'a>(&'a self, name_ref: ast::NameRef) -> Option<&'a ScopeEntry> {
         let mut shadowed = FxHashSet::default();
         let ret = self
@@ -144,6 +186,8 @@ impl ScopeEntry {
 }
 
 fn compute_block_scopes(block: ast::Block, scopes: &mut FnScopes, mut scope: ScopeId) {
+    // A hack for completion :(
+    scopes.set_scope(block.syntax(), scope);
     for stmt in block.statements() {
         match stmt {
             ast::Stmt::LetStmt(stmt) => {
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 5941a9ea3..f56214b47 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -39,7 +39,7 @@ use crate::{
 pub use self::{
     path::{Path, PathKind},
     krate::Crate,
-    module::{Module, ModuleId, Problem, nameres::ItemMap},
+    module::{Module, ModuleId, Problem, nameres::ItemMap, ModuleScope, Resolution},
     function::{Function, FnScopes},
 };
 
diff --git a/crates/ra_hir/src/module.rs b/crates/ra_hir/src/module.rs
index d5866f6ef..cd31e8cfe 100644
--- a/crates/ra_hir/src/module.rs
+++ b/crates/ra_hir/src/module.rs
@@ -16,7 +16,7 @@ use crate::{
     arena::{Arena, Id},
 };
 
-pub use self::nameres::ModuleScope;
+pub use self::nameres::{ModuleScope, Resolution};
 
 /// `Module` is API entry point to get all the information
 /// about a particular module.
diff --git a/crates/ra_hir/src/module/nameres.rs b/crates/ra_hir/src/module/nameres.rs
index f44abc730..39e891cda 100644
--- a/crates/ra_hir/src/module/nameres.rs
+++ b/crates/ra_hir/src/module/nameres.rs
@@ -49,7 +49,7 @@ pub struct ModuleScope {
 }
 
 impl ModuleScope {
-    pub fn entries<'a>(&'a self) -> impl Iterator<Item = (&'a SmolStr, &Resolution)> + 'a {
+    pub fn entries<'a>(&'a self) -> impl Iterator<Item = (&'a SmolStr, &'a Resolution)> + 'a {
         self.items.iter()
     }
     pub fn get(&self, name: &SmolStr) -> Option<&Resolution> {
diff --git a/crates/ra_hir/src/module/nameres/tests.rs b/crates/ra_hir/src/module/nameres/tests.rs
index 9fa9146e3..3e29c3954 100644
--- a/crates/ra_hir/src/module/nameres/tests.rs
+++ b/crates/ra_hir/src/module/nameres/tests.rs
@@ -44,6 +44,25 @@ fn item_map_smoke_test() {
 }
 
 #[test]
+fn test_self() {
+    let (item_map, module_id) = item_map(
+        "
+            //- /lib.rs
+            mod foo;
+            use crate::foo::bar::Baz::{self};
+            <|>
+            //- /foo/mod.rs
+            pub mod bar;
+            //- /foo/bar.rs
+            pub struct Baz;
+        ",
+    );
+    let name = SmolStr::from("Baz");
+    let resolution = &item_map.per_module[&module_id].items[&name];
+    assert!(resolution.def_id.is_some());
+}
+
+#[test]
 fn item_map_across_crates() {
     let (mut db, sr) = MockDatabase::with_files(
         "
diff --git a/crates/ra_hir/src/path.rs b/crates/ra_hir/src/path.rs
index 4a2e427cd..e04d00900 100644
--- a/crates/ra_hir/src/path.rs
+++ b/crates/ra_hir/src/path.rs
@@ -76,17 +76,32 @@ fn expand_use_tree(
 ) {
     if let Some(use_tree_list) = tree.use_tree_list() {
         let prefix = match tree.path() {
+            // E.g. use something::{{{inner}}};
             None => prefix,
+            // E.g. `use something::{inner}` (prefix is `None`, path is `something`)
+            // or `use something::{path::{inner::{innerer}}}` (prefix is `something::path`, path is `inner`)
             Some(path) => match convert_path(prefix, path) {
                 Some(it) => Some(it),
                 None => return, // TODO: report errors somewhere
             },
         };
-        for tree in use_tree_list.use_trees() {
-            expand_use_tree(prefix.clone(), tree, cb);
+        for child_tree in use_tree_list.use_trees() {
+            expand_use_tree(prefix.clone(), child_tree, cb);
         }
     } else {
         if let Some(ast_path) = tree.path() {
+            // Handle self in a path.
+            // E.g. `use something::{self, <...>}`
+            if ast_path.qualifier().is_none() {
+                if let Some(segment) = ast_path.segment() {
+                    if segment.kind() == Some(ast::PathSegmentKind::SelfKw) {
+                        if let Some(prefix) = prefix {
+                            cb(prefix, Some(segment.syntax().range()));
+                            return;
+                        }
+                    }
+                }
+            }
             if let Some(path) = convert_path(prefix, ast_path) {
                 let range = if tree.has_star() {
                     None
@@ -96,6 +111,8 @@ fn expand_use_tree(
                 };
                 cb(path, range)
             }
+            // TODO: report errors somewhere
+            // We get here if we do
         }
     }
 }
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index ce2a0f2e8..a0165aef2 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -74,6 +74,16 @@ pub fn function_from_source(
     fn_def: ast::FnDef,
 ) -> Cancelable<Option<Function>> {
     let module = ctry!(module_from_child_node(db, file_id, fn_def.syntax())?);
+    let res = function_from_module(db, &module, fn_def);
+    Ok(Some(res))
+}
+
+pub fn function_from_module(
+    db: &impl HirDatabase,
+    module: &Module,
+    fn_def: ast::FnDef,
+) -> Function {
+    let file_id = module.source().file_id();
     let file_items = db.file_items(file_id);
     let item_id = file_items.id_of(file_id, fn_def.syntax());
     let source_item_id = SourceItemId {
@@ -86,7 +96,7 @@ pub fn function_from_source(
         module_id: module.module_id,
         source_item_id,
     };
-    Ok(Some(Function::new(def_loc.id(db))))
+    Function::new(def_loc.id(db))
 }
 
 pub fn function_from_child_node(