Expand NameBinding to better represent bindings from imports

Author: jseyfried

src/librustc_resolve/build_reduced_graph.rs

@@ -19,7 +19,7 @@ use resolve_imports::ImportDirectiveSubclass::{self, SingleImport, GlobImport};
 use resolve_imports::ImportResolution;
 use Module;
 use Namespace::{self, TypeNS, ValueNS};
-use {NameBinding, DefOrModule};
+use {NameBinding, NameBindingKind};
 use {names_to_string, module_to_string};
 use ParentLink::{ModuleParentLink, BlockParentLink};
 use Resolver;
@@ -82,8 +82,8 @@ impl<'a> ToNameBinding<'a> for (Module<'a>, Span) {
 
 impl<'a> ToNameBinding<'a> for (Def, Span, DefModifiers) {
     fn to_name_binding(self) -> NameBinding<'a> {
-        let def = DefOrModule::Def(self.0);
-        NameBinding { modifiers: self.2, def_or_module: def, span: Some(self.1) }
+        let kind = NameBindingKind::Def(self.0);
+        NameBinding { modifiers: self.2, kind: kind, span: Some(self.1) }
     }
 }
 

src/librustc_resolve/lib.rs

@@ -951,21 +951,26 @@ bitflags! {
         // We need to track them to prohibit reexports like `pub use PrivEnum::Variant`.
         const PRIVATE_VARIANT = 1 << 2,
         const PRELUDE = 1 << 3,
+        const GLOB_IMPORTED = 1 << 4,
     }
 }
 
 // Records a possibly-private value, type, or module definition.
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct NameBinding<'a> {
-    modifiers: DefModifiers, // see note in ImportResolution about how to use this
-    def_or_module: DefOrModule<'a>,
+    modifiers: DefModifiers,
+    kind: NameBindingKind<'a>,
     span: Option<Span>,
 }
 
-#[derive(Clone, Debug)]
-enum DefOrModule<'a> {
+#[derive(Debug)]
+enum NameBindingKind<'a> {
     Def(Def),
     Module(Module<'a>),
+    Import {
+        binding: &'a NameBinding<'a>,
+        id: NodeId,
+    },
 }
 
 impl<'a> NameBinding<'a> {
@@ -976,20 +981,22 @@ impl<'a> NameBinding<'a> {
             DefModifiers::empty()
         } | DefModifiers::IMPORTABLE;
 
-        NameBinding { modifiers: modifiers, def_or_module: DefOrModule::Module(module), span: span }
+        NameBinding { modifiers: modifiers, kind: NameBindingKind::Module(module), span: span }
     }
 
     fn module(&self) -> Option<Module<'a>> {
-        match self.def_or_module {
-            DefOrModule::Module(ref module) => Some(module),
-            DefOrModule::Def(_) => None,
+        match self.kind {
+            NameBindingKind::Module(module) => Some(module),
+            NameBindingKind::Def(_) => None,
+            NameBindingKind::Import { binding, .. } => binding.module(),
         }
     }
 
     fn def(&self) -> Option<Def> {
-        match self.def_or_module {
-            DefOrModule::Def(def) => Some(def),
-            DefOrModule::Module(ref module) => module.def,
+        match self.kind {
+            NameBindingKind::Def(def) => Some(def),
+            NameBindingKind::Module(module) => module.def,
+            NameBindingKind::Import { binding, .. } => binding.def(),
         }
     }
 
@@ -1009,6 +1016,13 @@ impl<'a> NameBinding<'a> {
     fn is_extern_crate(&self) -> bool {
         self.module().map(|module| module.is_extern_crate).unwrap_or(false)
     }
+
+    fn is_import(&self) -> bool {
+        match self.kind {
+            NameBindingKind::Import { .. } => true,
+            _ => false,
+        }
+    }
 }
 
 /// Interns the names of the primitive types.

src/librustc_resolve/resolve_imports.rs

@@ -11,10 +11,9 @@
 use self::ImportDirectiveSubclass::*;
 
 use DefModifiers;
-use DefOrModule;
 use Module;
 use Namespace::{self, TypeNS, ValueNS};
-use NameBinding;
+use {NameBinding, NameBindingKind};
 use ResolveResult;
 use ResolveResult::*;
 use Resolver;
@@ -82,11 +81,22 @@ impl ImportDirective {
     // Given the binding to which this directive resolves in a particular namespace,
     // this returns the binding for the name this directive defines in that namespace.
     fn import<'a>(&self, binding: &'a NameBinding<'a>) -> NameBinding<'a> {
-        let mut binding = binding.clone();
+        let mut modifiers = match self.is_public {
+            true => DefModifiers::PUBLIC | DefModifiers::IMPORTABLE,
+            false => DefModifiers::empty(),
+        };
+        if let GlobImport = self.subclass {
+            modifiers = modifiers | DefModifiers::GLOB_IMPORTED;
+        }
         if self.shadowable == Shadowable::Always {
-            binding.modifiers = binding.modifiers | DefModifiers::PRELUDE;
+            modifiers = modifiers | DefModifiers::PRELUDE;
+        }
+
+        NameBinding {
+            kind: NameBindingKind::Import { binding: binding, id: self.id },
+            span: Some(self.span),
+            modifiers: modifiers,
         }
-        binding
     }
 }
 
@@ -216,7 +226,7 @@ impl<'a, 'b:'a, 'tcx:'b> ImportResolver<'a, 'b, 'tcx> {
 
                 let dummy_binding = self.resolver.new_name_binding(NameBinding {
                     modifiers: DefModifiers::IMPORTABLE,
-                    def_or_module: DefOrModule::Def(Def::Err),
+                    kind: NameBindingKind::Def(Def::Err),
                     span: None,
                 });