1 files changed, 233 insertions, 172 deletions

diff --git a/crates/ra_hir/src/resolve.rs b/crates/ra_hir/src/resolve.rs
index a77a9aeb1..d841593f8 100644
--- a/crates/ra_hir/src/resolve.rs
+++ b/crates/ra_hir/src/resolve.rs
@@ -1,7 +1,7 @@
 //! Name resolution.
 use std::sync::Arc;
 
-use rustc_hash::{FxHashMap, FxHashSet};
+use rustc_hash::FxHashSet;
 
 use crate::{
     code_model::Crate,
@@ -14,8 +14,9 @@ use crate::{
     impl_block::ImplBlock,
     name::{Name, SELF_PARAM, SELF_TYPE},
     nameres::{CrateDefMap, CrateModuleId, PerNs},
-    path::Path,
-    Adt, Enum, MacroDef, ModuleDef, Struct, Trait,
+    path::{Path, PathKind},
+    Adt, BuiltinType, Const, Enum, EnumVariant, Function, MacroDef, ModuleDef, Static, Struct,
+    Trait, TypeAlias,
 };
 
 #[derive(Debug, Clone, Default)]
@@ -37,69 +38,6 @@ pub(crate) struct ExprScope {
 }
 
 #[derive(Debug, Clone)]
-pub(crate) struct PathResult {
-    /// The actual path resolution
-    // FIXME: `PerNs<Resolution>` type doesn't make sense, as not every
-    // Resolution variant can appear in every namespace
-    resolution: PerNs<Resolution>,
-    /// The first index in the path that we
-    /// were unable to resolve.
-    /// When path is fully resolved, this is 0.
-    remaining_index: usize,
-}
-
-impl PathResult {
-    /// Returns the remaining index in the result
-    /// returns None if the path was fully resolved
-    pub(crate) fn remaining_index(&self) -> Option<usize> {
-        if self.remaining_index > 0 {
-            Some(self.remaining_index)
-        } else {
-            None
-        }
-    }
-
-    /// Consumes `PathResult` and returns the contained `PerNs<Resolution>`
-    /// if the path was fully resolved, meaning we have no remaining items
-    pub(crate) fn into_fully_resolved(self) -> PerNs<Resolution> {
-        if self.is_fully_resolved() {
-            self.resolution
-        } else {
-            PerNs::none()
-        }
-    }
-
-    /// Consumes `PathResult` and returns the resolution and the
-    /// remaining_index as a tuple.
-    pub(crate) fn into_inner(self) -> (PerNs<Resolution>, Option<usize>) {
-        let index = self.remaining_index();
-        (self.resolution, index)
-    }
-
-    /// Path is fully resolved when `remaining_index` is none
-    /// and the resolution contains anything
-    pub(crate) fn is_fully_resolved(&self) -> bool {
-        !self.resolution.is_none() && self.remaining_index().is_none()
-    }
-
-    fn empty() -> PathResult {
-        PathResult { resolution: PerNs::none(), remaining_index: 0 }
-    }
-
-    fn from_resolution(res: PerNs<Resolution>) -> PathResult {
-        PathResult::from_resolution_with_index(res, 0)
-    }
-
-    fn from_resolution_with_index(res: PerNs<Resolution>, remaining_index: usize) -> PathResult {
-        if res.is_none() {
-            PathResult::empty()
-        } else {
-            PathResult { resolution: res, remaining_index }
-        }
-    }
-}
-
-#[derive(Debug, Clone)]
 pub(crate) enum Scope {
     /// All the items and imported names of a module
     ModuleScope(ModuleItemMap),
@@ -112,25 +50,41 @@ pub(crate) enum Scope {
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum Resolution {
-    /// An item
-    Def(ModuleDef),
+pub enum TypeNs {
+    SelfType(ImplBlock),
+    GenericParam(u32),
+    Adt(Adt),
+    EnumVariant(EnumVariant),
+    TypeAlias(TypeAlias),
+    BuiltinType(BuiltinType),
+    Trait(Trait),
+    // Module belong to type ns, but the resovler is used when all module paths
+    // are fully resolved.
+    // Module(Module)
+}
+
+#[derive(Debug)]
+pub enum ValueOrPartial {
+    ValueNs(ValueNs),
+    Partial(TypeNs, usize),
+}
 
-    // FIXME: there's no way we can syntactically confuse a local with generic
-    // param, so these two should not be members of the single enum
-    /// A local binding (only value namespace)
+#[derive(Debug)]
+pub enum ValueNs {
     LocalBinding(PatId),
-    /// A generic parameter
-    GenericParam(u32),
-    SelfType(ImplBlock),
+    Function(Function),
+    Const(Const),
+    Static(Static),
+    Struct(Struct),
+    EnumVariant(EnumVariant),
 }
 
 impl Resolver {
     /// Resolve known trait from std, like `std::futures::Future`
     pub(crate) fn resolve_known_trait(&self, db: &impl HirDatabase, path: &Path) -> Option<Trait> {
-        let res = self.resolve_path_segments(db, path).into_fully_resolved().take_types()?;
+        let res = self.resolve_module_path(db, path).take_types()?;
         match res {
-            Resolution::Def(ModuleDef::Trait(it)) => Some(it),
+            ModuleDef::Trait(it) => Some(it),
             _ => None,
         }
     }
@@ -141,94 +95,214 @@ impl Resolver {
         db: &impl HirDatabase,
         path: &Path,
     ) -> Option<Struct> {
-        let res = self.resolve_path_segments(db, path).into_fully_resolved().take_types()?;
+        let res = self.resolve_module_path(db, path).take_types()?;
         match res {
-            Resolution::Def(ModuleDef::Adt(Adt::Struct(it))) => Some(it),
+            ModuleDef::Adt(Adt::Struct(it)) => Some(it),
             _ => None,
         }
     }
 
     /// Resolve known enum from std, like `std::result::Result`
     pub(crate) fn resolve_known_enum(&self, db: &impl HirDatabase, path: &Path) -> Option<Enum> {
-        let res = self.resolve_path_segments(db, path).into_fully_resolved().take_types()?;
+        let res = self.resolve_module_path(db, path).take_types()?;
         match res {
-            Resolution::Def(ModuleDef::Adt(Adt::Enum(it))) => Some(it),
+            ModuleDef::Adt(Adt::Enum(it)) => Some(it),
             _ => None,
         }
     }
 
-    pub(crate) fn resolve_name(&self, db: &impl HirDatabase, name: &Name) -> PerNs<Resolution> {
-        let mut resolution = PerNs::none();
+    /// pub only for source-binder
+    pub(crate) fn resolve_module_path(
+        &self,
+        db: &impl HirDatabase,
+        path: &Path,
+    ) -> PerNs<ModuleDef> {
+        let (item_map, module) = match self.module() {
+            Some(it) => it,
+            None => return PerNs::none(),
+        };
+        let (module_res, segment_index) = item_map.resolve_path(db, module, path);
+        if segment_index.is_some() {
+            return PerNs::none();
+        }
+        module_res
+    }
+
+    pub(crate) fn resolve_path_in_type_ns(
+        &self,
+        db: &impl HirDatabase,
+        path: &Path,
+    ) -> Option<(TypeNs, Option<usize>)> {
+        let first_name = &path.segments.first()?.name;
+        let skip_to_mod = path.kind != PathKind::Plain;
         for scope in self.scopes.iter().rev() {
-            resolution = resolution.or(scope.resolve_name(db, name));
-            if resolution.is_all() {
-                return resolution;
+            match scope {
+                Scope::ExprScope(_) => continue,
+                Scope::GenericParams(_) | Scope::ImplBlockScope(_) if skip_to_mod => continue,
+
+                Scope::GenericParams(params) => {
+                    if let Some(param) = params.find_by_name(first_name) {
+                        let idx = if path.segments.len() == 1 { None } else { Some(1) };
+                        return Some((TypeNs::GenericParam(param.idx), idx));
+                    }
+                }
+                Scope::ImplBlockScope(impl_) => {
+                    if first_name == &SELF_TYPE {
+                        let idx = if path.segments.len() == 1 { None } else { Some(1) };
+                        return Some((TypeNs::SelfType(*impl_), idx));
+                    }
+                }
+                Scope::ModuleScope(m) => {
+                    let (module_def, idx) = m.crate_def_map.resolve_path(db, m.module_id, path);
+                    let res = match module_def.take_types()? {
+                        ModuleDef::Adt(it) => TypeNs::Adt(it),
+                        ModuleDef::EnumVariant(it) => TypeNs::EnumVariant(it),
+
+                        ModuleDef::TypeAlias(it) => TypeNs::TypeAlias(it),
+                        ModuleDef::BuiltinType(it) => TypeNs::BuiltinType(it),
+
+                        ModuleDef::Trait(it) => TypeNs::Trait(it),
+
+                        ModuleDef::Function(_)
+                        | ModuleDef::Const(_)
+                        | ModuleDef::Static(_)
+                        | ModuleDef::Module(_) => return None,
+                    };
+                    return Some((res, idx));
+                }
             }
         }
-        resolution
+        None
     }
 
-    pub(crate) fn resolve_path_as_macro(
+    pub(crate) fn resolve_path_in_type_ns_fully(
         &self,
         db: &impl HirDatabase,
         path: &Path,
-    ) -> Option<MacroDef> {
-        let (item_map, module) = self.module()?;
-        item_map.resolve_path(db, module, path).0.get_macros()
+    ) -> Option<TypeNs> {
+        let (res, unresolved) = self.resolve_path_in_type_ns(db, path)?;
+        if unresolved.is_some() {
+            return None;
+        }
+        Some(res)
     }
 
-    /// Returns the resolved path segments
-    /// Which may be fully resolved, empty or partially resolved.
-    pub(crate) fn resolve_path_segments(&self, db: &impl HirDatabase, path: &Path) -> PathResult {
-        if let Some(name) = path.as_ident() {
-            PathResult::from_resolution(self.resolve_name(db, name))
-        } else if path.is_self() {
-            PathResult::from_resolution(self.resolve_name(db, &SELF_PARAM))
-        } else {
-            let (item_map, module) = match self.module() {
-                Some(it) => it,
-                None => return PathResult::empty(),
-            };
-            let (module_res, segment_index) = item_map.resolve_path(db, module, path);
-
-            let def = module_res.map(Resolution::Def);
-
-            if let Some(index) = segment_index {
-                PathResult::from_resolution_with_index(def, index)
-            } else {
-                PathResult::from_resolution(def)
+    pub(crate) fn resolve_path_in_value_ns(
+        &self,
+        db: &impl HirDatabase,
+        path: &Path,
+    ) -> Option<ValueOrPartial> {
+        let n_segments = path.segments.len();
+        let tmp = SELF_PARAM;
+        let first_name = if path.is_self() { &tmp } else { &path.segments.first()?.name };
+        let skip_to_mod = path.kind != PathKind::Plain && !path.is_self();
+        for scope in self.scopes.iter().rev() {
+            match scope {
+                Scope::ExprScope(_) | Scope::GenericParams(_) | Scope::ImplBlockScope(_)
+                    if skip_to_mod =>
+                {
+                    continue
+                }
+
+                Scope::ExprScope(scope) if n_segments <= 1 => {
+                    let entry = scope
+                        .expr_scopes
+                        .entries(scope.scope_id)
+                        .iter()
+                        .find(|entry| entry.name() == first_name);
+
+                    if let Some(e) = entry {
+                        return Some(ValueOrPartial::ValueNs(ValueNs::LocalBinding(e.pat())));
+                    }
+                }
+                Scope::ExprScope(_) => continue,
+
+                Scope::GenericParams(params) if n_segments > 1 => {
+                    if let Some(param) = params.find_by_name(first_name) {
+                        let ty = TypeNs::GenericParam(param.idx);
+                        return Some(ValueOrPartial::Partial(ty, 1));
+                    }
+                }
+                Scope::GenericParams(_) => continue,
+
+                Scope::ImplBlockScope(impl_) if n_segments > 1 => {
+                    if first_name == &SELF_TYPE {
+                        let ty = TypeNs::SelfType(*impl_);
+                        return Some(ValueOrPartial::Partial(ty, 1));
+                    }
+                }
+                Scope::ImplBlockScope(_) => continue,
+
+                Scope::ModuleScope(m) => {
+                    let (module_def, idx) = m.crate_def_map.resolve_path(db, m.module_id, path);
+                    return match idx {
+                        None => {
+                            let value = match module_def.take_values()? {
+                                ModuleDef::Function(it) => ValueNs::Function(it),
+                                ModuleDef::Adt(Adt::Struct(it)) => ValueNs::Struct(it),
+                                ModuleDef::EnumVariant(it) => ValueNs::EnumVariant(it),
+                                ModuleDef::Const(it) => ValueNs::Const(it),
+                                ModuleDef::Static(it) => ValueNs::Static(it),
+
+                                ModuleDef::Adt(Adt::Enum(_))
+                                | ModuleDef::Adt(Adt::Union(_))
+                                | ModuleDef::Trait(_)
+                                | ModuleDef::TypeAlias(_)
+                                | ModuleDef::BuiltinType(_)
+                                | ModuleDef::Module(_) => return None,
+                            };
+                            Some(ValueOrPartial::ValueNs(value))
+                        }
+                        Some(idx) => {
+                            let ty = match module_def.take_types()? {
+                                ModuleDef::Adt(it) => TypeNs::Adt(it),
+                                ModuleDef::Trait(it) => TypeNs::Trait(it),
+                                ModuleDef::TypeAlias(it) => TypeNs::TypeAlias(it),
+                                ModuleDef::BuiltinType(it) => TypeNs::BuiltinType(it),
+
+                                ModuleDef::Module(_)
+                                | ModuleDef::Function(_)
+                                | ModuleDef::EnumVariant(_)
+                                | ModuleDef::Const(_)
+                                | ModuleDef::Static(_) => return None,
+                            };
+                            Some(ValueOrPartial::Partial(ty, idx))
+                        }
+                    };
+                }
             }
         }
+        None
     }
 
-    /// Returns the fully resolved path if we were able to resolve it.
-    /// otherwise returns `PerNs::none`
-    pub(crate) fn resolve_path_without_assoc_items(
+    pub(crate) fn resolve_path_in_value_ns_fully(
         &self,
         db: &impl HirDatabase,
         path: &Path,
-    ) -> PerNs<Resolution> {
-        // into_fully_resolved() returns the fully resolved path or PerNs::none() otherwise
-        self.resolve_path_segments(db, path).into_fully_resolved()
+    ) -> Option<ValueNs> {
+        match self.resolve_path_in_value_ns(db, path)? {
+            ValueOrPartial::ValueNs(it) => Some(it),
+            ValueOrPartial::Partial(..) => None,
+        }
     }
 
-    pub(crate) fn all_names(&self, db: &impl HirDatabase) -> FxHashMap<Name, PerNs<Resolution>> {
-        let mut names = FxHashMap::default();
+    pub(crate) fn resolve_path_as_macro(
+        &self,
+        db: &impl HirDatabase,
+        path: &Path,
+    ) -> Option<MacroDef> {
+        let (item_map, module) = self.module()?;
+        item_map.resolve_path(db, module, path).0.get_macros()
+    }
+
+    pub(crate) fn process_all_names(
+        &self,
+        db: &impl HirDatabase,
+        f: &mut dyn FnMut(Name, ScopeDef),
+    ) {
         for scope in self.scopes.iter().rev() {
-            scope.collect_names(db, &mut |name, res| {
-                let current: &mut PerNs<Resolution> = names.entry(name).or_default();
-                if current.types.is_none() {
-                    current.types = res.types;
-                }
-                if current.values.is_none() {
-                    current.values = res.values;
-                }
-                if current.macros.is_none() {
-                    current.macros = res.macros;
-                }
-            });
+            scope.process_names(db, f);
         }
-        names
     }
 
     pub(crate) fn traits_in_scope(&self, db: &impl HirDatabase) -> FxHashSet<Trait> {
@@ -301,41 +375,28 @@ impl Resolver {
     }
 }
 
-impl Scope {
-    fn resolve_name(&self, db: &impl HirDatabase, name: &Name) -> PerNs<Resolution> {
-        match self {
-            Scope::ModuleScope(m) => {
-                if name == &SELF_PARAM {
-                    PerNs::types(Resolution::Def(m.crate_def_map.mk_module(m.module_id).into()))
-                } else {
-                    m.crate_def_map
-                        .resolve_name_in_module(db, m.module_id, name)
-                        .map(Resolution::Def)
-                }
-            }
-            Scope::GenericParams(gp) => match gp.find_by_name(name) {
-                Some(gp) => PerNs::types(Resolution::GenericParam(gp.idx)),
-                None => PerNs::none(),
-            },
-            Scope::ImplBlockScope(i) => {
-                if name == &SELF_TYPE {
-                    PerNs::types(Resolution::SelfType(*i))
-                } else {
-                    PerNs::none()
-                }
-            }
-            Scope::ExprScope(e) => {
-                let entry =
-                    e.expr_scopes.entries(e.scope_id).iter().find(|entry| entry.name() == name);
-                match entry {
-                    Some(e) => PerNs::values(Resolution::LocalBinding(e.pat())),
-                    None => PerNs::none(),
-                }
-            }
-        }
+/// For IDE only
+pub enum ScopeDef {
+    ModuleDef(ModuleDef),
+    MacroDef(MacroDef),
+    GenericParam(u32),
+    SelfType(ImplBlock),
+    LocalBinding(PatId),
+    Unknown,
+}
+
+impl From<PerNs<ModuleDef>> for ScopeDef {
+    fn from(def: PerNs<ModuleDef>) -> Self {
+        def.take_types()
+            .or_else(|| def.take_values())
+            .map(ScopeDef::ModuleDef)
+            .or_else(|| def.get_macros().map(ScopeDef::MacroDef))
+            .unwrap_or(ScopeDef::Unknown)
     }
+}
 
-    fn collect_names(&self, db: &impl HirDatabase, f: &mut dyn FnMut(Name, PerNs<Resolution>)) {
+impl Scope {
+    fn process_names(&self, db: &impl HirDatabase, f: &mut dyn FnMut(Name, ScopeDef)) {
         match self {
             Scope::ModuleScope(m) => {
                 // FIXME: should we provide `self` here?
@@ -346,32 +407,32 @@ impl Scope {
                 //     }),
                 // );
                 m.crate_def_map[m.module_id].scope.entries().for_each(|(name, res)| {
-                    f(name.clone(), res.def.map(Resolution::Def));
+                    f(name.clone(), res.def.into());
                 });
                 m.crate_def_map[m.module_id].scope.legacy_macros().for_each(|(name, macro_)| {
-                    f(name.clone(), PerNs::macros(macro_));
+                    f(name.clone(), ScopeDef::MacroDef(macro_));
                 });
                 m.crate_def_map.extern_prelude().iter().for_each(|(name, def)| {
-                    f(name.clone(), PerNs::types(Resolution::Def(*def)));
+                    f(name.clone(), ScopeDef::ModuleDef(*def));
                 });
                 if let Some(prelude) = m.crate_def_map.prelude() {
                     let prelude_def_map = db.crate_def_map(prelude.krate);
                     prelude_def_map[prelude.module_id].scope.entries().for_each(|(name, res)| {
-                        f(name.clone(), res.def.map(Resolution::Def));
+                        f(name.clone(), res.def.into());
                     });
                 }
             }
             Scope::GenericParams(gp) => {
                 for param in &gp.params {
-                    f(param.name.clone(), PerNs::types(Resolution::GenericParam(param.idx)))
+                    f(param.name.clone(), ScopeDef::GenericParam(param.idx))
                 }
             }
             Scope::ImplBlockScope(i) => {
-                f(SELF_TYPE, PerNs::types(Resolution::SelfType(*i)));
+                f(SELF_TYPE, ScopeDef::SelfType(*i));
             }
             Scope::ExprScope(e) => {
                 e.expr_scopes.entries(e.scope_id).iter().for_each(|e| {
-                    f(e.name().clone(), PerNs::values(Resolution::LocalBinding(e.pat())));
+                    f(e.name().clone(), ScopeDef::LocalBinding(e.pat()));
                 });
             }
         }