Fix a bug with cross-crate trait impls

Closes rust-lang#19056

Author: nrc

src/librustc/metadata/decoder.rs

@@ -1272,9 +1272,9 @@ pub fn each_impl<F>(cdata: Cmd, mut callback: F) where
 }
 
 pub fn each_implementation_for_type<F>(cdata: Cmd,
-                                    id: ast::NodeId,
-                                    mut callback: F) where
-    F: FnMut(ast::DefId),
+                                       id: ast::NodeId,
+                                       mut callback: F)
+    where F: FnMut(ast::DefId),
 {
     let item_doc = lookup_item(id, cdata.data());
     reader::tagged_docs(item_doc,

src/librustc/metadata/encoder.rs

@@ -1222,8 +1222,7 @@ fn encode_info_for_item(ecx: &EncodeContext,
         encode_attributes(rbml_w, item.attrs[]);
         encode_unsafety(rbml_w, unsafety);
         match ty.node {
-            ast::TyPath(ref path, _) if path.segments
-                                                        .len() == 1 => {
+            ast::TyPath(ref path, _) if path.segments.len() == 1 => {
                 let ident = path.segments.last().unwrap().identifier;
                 encode_impl_type_basename(rbml_w, ident);
             }
@@ -1351,6 +1350,9 @@ fn encode_info_for_item(ecx: &EncodeContext,
         // Encode the implementations of this trait.
         encode_extension_implementations(ecx, rbml_w, def_id);
 
+        // Encode inherent implementations for this trait.
+        encode_inherent_implementations(ecx, rbml_w, def_id);
+
         rbml_w.end_tag();
 
         // Now output the trait item info for each trait item.
@@ -1452,9 +1454,6 @@ fn encode_info_for_item(ecx: &EncodeContext,
 
             rbml_w.end_tag();
         }
-
-        // Encode inherent implementations for this trait.
-        encode_inherent_implementations(ecx, rbml_w, def_id);
       }
       ast::ItemMac(..) => {
         // macros are encoded separately

src/librustc/middle/ty.rs

@@ -128,7 +128,7 @@ impl ImplOrTraitItemContainer {
     }
 }
 
-#[deriving(Clone)]
+#[deriving(Clone, Show)]
 pub enum ImplOrTraitItem<'tcx> {
     MethodTraitItem(Rc<Method<'tcx>>),
     TypeTraitItem(Rc<AssociatedType>),
@@ -173,7 +173,7 @@ impl<'tcx> ImplOrTraitItem<'tcx> {
     }
 }
 
-#[deriving(Clone, Copy)]
+#[deriving(Clone, Copy, Show)]
 pub enum ImplOrTraitItemId {
     MethodTraitItemId(ast::DefId),
     TypeTraitItemId(ast::DefId),
@@ -232,7 +232,7 @@ impl<'tcx> Method<'tcx> {
     }
 }
 
-#[deriving(Clone, Copy)]
+#[deriving(Clone, Copy, Show)]
 pub struct AssociatedType {
     pub name: ast::Name,
     pub vis: ast::Visibility,
@@ -4931,10 +4931,11 @@ pub fn provided_trait_methods<'tcx>(cx: &ctxt<'tcx>, id: ast::DefId)
     }
 }
 
-/// Helper for looking things up in the various maps that are populated during typeck::collect
-/// (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc).  All of these share the pattern that if the
-/// id is local, it should have been loaded into the map by the `typeck::collect` phase.  If the
-/// def-id is external, then we have to go consult the crate loading code (and cache the result for
+/// Helper for looking things up in the various maps that are populated during
+/// typeck::collect (e.g., `cx.impl_or_trait_items`, `cx.tcache`, etc).  All of
+/// these share the pattern that if the id is local, it should have been loaded
+/// into the map by the `typeck::collect` phase.  If the def-id is external,
+/// then we have to go consult the crate loading code (and cache the result for
 /// the future).
 fn lookup_locally_or_in_crate_store<V, F>(descr: &str,
                                           def_id: ast::DefId,
@@ -5973,11 +5974,12 @@ pub fn populate_implementations_for_type_if_necessary(tcx: &ctxt,
         return
     }
 
+    debug!("populate_implementations_for_type_if_necessary: searching for {}", type_id);
+
     let mut inherent_impls = Vec::new();
     csearch::each_implementation_for_type(&tcx.sess.cstore, type_id,
             |impl_def_id| {
-        let impl_items = csearch::get_impl_items(&tcx.sess.cstore,
-                                                 impl_def_id);
+        let impl_items = csearch::get_impl_items(&tcx.sess.cstore, impl_def_id);
 
         // Record the trait->implementation mappings, if applicable.
         let associated_traits = csearch::get_impl_trait(tcx, impl_def_id);

src/librustc_typeck/check/method/probe.rs

@@ -267,6 +267,8 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
             return; // already visited
         }
 
+        debug!("assemble_inherent_impl_probe {}", impl_def_id);
+
         let method = match impl_method(self.tcx(), impl_def_id, self.method_name) {
             Some(m) => m,
             None => { return; } // No method with correct name on this impl
@@ -432,7 +434,7 @@ impl<'a,'tcx> ProbeContext<'a,'tcx> {
     }
 
     fn assemble_extension_candidates_for_trait(&mut self,
-                                           trait_def_id: ast::DefId) {
+                                               trait_def_id: ast::DefId) {
         debug!("assemble_extension_candidates_for_trait: trait_def_id={}",
                trait_def_id.repr(self.tcx()));
 
@@ -983,6 +985,7 @@ fn trait_method<'tcx>(tcx: &ty::ctxt<'tcx>,
                       -> Option<(uint, Rc<ty::Method<'tcx>>)>
 {
     let trait_items = ty::trait_items(tcx, trait_def_id);
+    debug!("trait_method; items: {}", trait_items);
     trait_items
         .iter()
         .filter(|item|

src/test/auxiliary/traitimpl.rs

@@ -0,0 +1,17 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test inherant trait impls work cross-crait.
+
+pub trait Bar<'a> for ?Sized : 'a {}
+
+impl<'a> Bar<'a> {
+    pub fn bar(&self) {}
+}

src/test/run-pass/trait-impl.rs

@@ -10,6 +10,10 @@
 
 // Test calling methods on an impl for a bare trait.
 
+// aux-build:traitimpl.rs
+extern crate traitimpl;
+use traitimpl::Bar;
+
 static mut COUNT: uint = 1;
 
 trait T {}
@@ -25,6 +29,9 @@ impl<'a> T+'a {
 
 impl T for int {}
 
+struct Foo;
+impl<'a> Bar<'a> for Foo {}
+
 fn main() {
     let x: &T = &42i;
 
@@ -33,4 +40,8 @@ fn main() {
     T::bar();
 
     unsafe { assert!(COUNT == 12); }
+
+    // Cross-crait case
+    let x: &Bar = &Foo;
+    x.bar();
 }