add resolver method to get all resolutions for a name

Author: QuietMisdreavus

src/librustc/hir/def.rs

@@ -16,6 +16,8 @@ use syntax_pos::Span;
 use hir;
 use ty;
 
+use std::iter::{once, Once, Chain};
+
 use self::Namespace::*;
 
 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
@@ -136,6 +138,24 @@ pub struct PerNS<T> {
     pub macro_ns: T,
 }
 
+impl<T> PerNS<T> {
+    /// Applies the given function to every item in the collection, returning the result.
+    pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> PerNS<U> {
+        PerNS {
+            value_ns: f(self.value_ns),
+            type_ns: f(self.type_ns),
+            macro_ns: f(self.macro_ns),
+        }
+    }
+}
+
+impl<T> PerNS<Option<T>> {
+    /// Returns whether there are no items in any namespace.
+    pub fn is_empty(&self) -> bool {
+        self.value_ns.is_none() && self.type_ns.is_none() && self.macro_ns.is_none()
+    }
+}
+
 impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
     type Output = T;
     fn index(&self, ns: Namespace) -> &T {
@@ -157,6 +177,16 @@ impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
     }
 }
 
+/// Iterates over the namespaces: first the Type, then the Value, then the Macro.
+impl<T> IntoIterator for PerNS<T> {
+    type Item = T;
+    type IntoIter = Chain<Chain<Once<T>, Once<T>>, Once<T>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        once(self.type_ns).chain(once(self.value_ns)).chain(once(self.macro_ns))
+    }
+}
+
 /// Definition mapping
 pub type DefMap = NodeMap<PerNS<Option<PathResolution>>>;
 

src/librustc/hir/lowering.rs

@@ -45,7 +45,7 @@ use hir;
 use hir::HirVec;
 use hir::map::{DefKey, DefPathData, Definitions};
 use hir::def_id::{DefId, DefIndex, DefIndexAddressSpace, CRATE_DEF_INDEX};
-use hir::def::{Def, PathResolution};
+use hir::def::{Def, PathResolution, PerNS};
 use lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES};
 use middle::cstore::CrateStore;
 use rustc_data_structures::indexed_vec::IndexVec;
@@ -149,9 +149,13 @@ pub trait Resolver {
     /// Resolve a hir path generated by the lowerer when expanding `for`, `if let`, etc.
     fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool);
 
-    /// Obtain the resolution for a node id
+    /// Obtain the resolution for a node id. Prefers resolutions in Types, then Values, then
+    /// Macros.
     fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution>;
 
+    /// Obtain resolutions for the given node id in all namespaces.
+    fn get_all_resolutions(&mut self, id: NodeId) -> PerNS<Option<PathResolution>>;
+
     /// We must keep the set of definitions up to date as we add nodes that weren't in the AST.
     /// This should only return `None` during testing.
     fn definitions(&mut self) -> &mut Definitions;

src/librustc_resolve/lib.rs

@@ -1490,6 +1490,10 @@ impl<'a> hir::lowering::Resolver for Resolver<'a> {
         None
     }
 
+    fn get_all_resolutions(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
+        self.def_map.get(&id).cloned().unwrap_or_default()
+    }
+
     fn definitions(&mut self) -> &mut Definitions {
         &mut self.definitions
     }