diff --git a/src/cargo/core/compiler/build_context/mod.rs b/src/cargo/core/compiler/build_context/mod.rs
index 0cacd1def58..c0cc12e7019 100644
--- a/src/cargo/core/compiler/build_context/mod.rs
+++ b/src/cargo/core/compiler/build_context/mod.rs
@@ -104,7 +104,7 @@ impl<'a, 'cfg> BuildContext<'a, 'cfg> {
 
         let crate_name = dep.target.crate_name();
         let mut names = deps.iter()
-            .map(|d| d.rename().unwrap_or(&crate_name));
+            .map(|d| d.rename().map(|s| s.as_str()).unwrap_or(&crate_name));
         let name = names.next().unwrap_or(&crate_name);
         for n in names {
             if n == name {
diff --git a/src/cargo/core/compiler/context/unit_dependencies.rs b/src/cargo/core/compiler/context/unit_dependencies.rs
index 54700106605..e8af68628c3 100644
--- a/src/cargo/core/compiler/context/unit_dependencies.rs
+++ b/src/cargo/core/compiler/context/unit_dependencies.rs
@@ -118,7 +118,7 @@ fn compute_deps<'a, 'cfg>(
 
             // If the dependency is optional, then we're only activating it
             // if the corresponding feature was activated
-            if dep.is_optional() && !bcx.resolve.features(id).contains(&*dep.name()) {
+            if dep.is_optional() && !bcx.resolve.features(id).contains(&*dep.name_in_toml()) {
                 return false;
             }
 
diff --git a/src/cargo/core/dependency.rs b/src/cargo/core/dependency.rs
index 1bed0220f1c..8e1ef3079c4 100644
--- a/src/cargo/core/dependency.rs
+++ b/src/cargo/core/dependency.rs
@@ -28,7 +28,7 @@ struct Inner {
     specified_req: bool,
     kind: Kind,
     only_match_name: bool,
-    rename: Option<String>,
+    rename: Option<InternedString>,
 
     optional: bool,
     default_features: bool,
@@ -66,7 +66,7 @@ impl ser::Serialize for Dependency {
     {
         let string_features: Vec<_> = self.features().iter().map(|s| s.to_string()).collect();
         SerializedDependency {
-            name: &*self.name(),
+            name: &*self.package_name(),
             source: self.source_id(),
             req: self.version_req().to_string(),
             kind: self.kind(),
@@ -74,7 +74,7 @@ impl ser::Serialize for Dependency {
             uses_default_features: self.uses_default_features(),
             features: &string_features,
             target: self.platform(),
-            rename: self.rename(),
+            rename: self.rename().map(|s| s.as_str()),
         }.serialize(s)
     }
 }
@@ -209,7 +209,49 @@ impl Dependency {
         &self.inner.req
     }
 
-    pub fn name(&self) -> InternedString {
+    /// This is the name of this `Dependency` as listed in `Cargo.toml`.
+    ///
+    /// Or in other words, this is what shows up in the `[dependencies]` section
+    /// on the left hand side. This is **not** the name of the package that's
+    /// being depended on as the dependency can be renamed. For that use
+    /// `package_name` below.
+    ///
+    /// Both of the dependencies below return `foo` for `name_in_toml`:
+    ///
+    /// ```toml
+    /// [dependencies]
+    /// foo = "0.1"
+    /// ```
+    ///
+    /// and ...
+    ///
+    /// ```toml
+    /// [dependencies]
+    /// foo = { version = "0.1", package = 'bar' }
+    /// ```
+    pub fn name_in_toml(&self) -> InternedString {
+        self.rename().unwrap_or(self.inner.name)
+    }
+
+    /// The name of the package that this `Dependency` depends on.
+    ///
+    /// Usually this is what's written on the left hand side of a dependencies
+    /// section, but it can also be renamed via the `package` key.
+    ///
+    /// Both of the dependencies below return `foo` for `package_name`:
+    ///
+    /// ```toml
+    /// [dependencies]
+    /// foo = "0.1"
+    /// ```
+    ///
+    /// and ...
+    ///
+    /// ```toml
+    /// [dependencies]
+    /// bar = { version = "0.1", package = 'foo' }
+    /// ```
+    pub fn package_name(&self) -> InternedString {
         self.inner.name
     }
 
@@ -240,8 +282,12 @@ impl Dependency {
         self.inner.platform.as_ref()
     }
 
-    pub fn rename(&self) -> Option<&str> {
-        self.inner.rename.as_ref().map(|s| &**s)
+    /// The renamed name of this dependency, if any.
+    ///
+    /// If the `package` key is used in `Cargo.toml` then this returns the same
+    /// value as `name_in_toml`.
+    pub fn rename(&self) -> Option<InternedString> {
+        self.inner.rename
     }
 
     pub fn set_kind(&mut self, kind: Kind) -> &mut Dependency {
@@ -286,7 +332,7 @@ impl Dependency {
     }
 
     pub fn set_rename(&mut self, rename: &str) -> &mut Dependency {
-        Rc::make_mut(&mut self.inner).rename = Some(rename.to_string());
+        Rc::make_mut(&mut self.inner).rename = Some(InternedString::new(rename));
         self
     }
 
@@ -296,7 +342,7 @@ impl Dependency {
         assert!(self.inner.req.matches(id.version()));
         trace!(
             "locking dep from `{}` with `{}` at {} to {}",
-            self.name(),
+            self.package_name(),
             self.version_req(),
             self.source_id(),
             id
@@ -347,7 +393,7 @@ impl Dependency {
 
     /// Returns true if the package (`sum`) can fulfill this dependency request.
     pub fn matches_ignoring_source(&self, id: &PackageId) -> bool {
-        self.name() == id.name() && self.version_req().matches(id.version())
+        self.package_name() == id.name() && self.version_req().matches(id.version())
     }
 
     /// Returns true if the package (`id`) can fulfill this dependency request.
diff --git a/src/cargo/core/registry.rs b/src/cargo/core/registry.rs
index 451efcb57e6..aa1a805add6 100644
--- a/src/cargo/core/registry.rs
+++ b/src/cargo/core/registry.rs
@@ -197,7 +197,7 @@ impl<'cfg> PackageRegistry<'cfg> {
         // of summaries which should be the same length as `deps` above.
         let unlocked_summaries = deps.iter()
             .map(|dep| {
-                debug!("registring a patch for `{}` with `{}`", url, dep.name());
+                debug!("registring a patch for `{}` with `{}`", url, dep.package_name());
 
                 // Go straight to the source for resolving `dep`. Load it as we
                 // normally would and then ask it directly for the list of summaries
@@ -207,7 +207,7 @@ impl<'cfg> PackageRegistry<'cfg> {
                         format_err!(
                             "failed to load source for a dependency \
                              on `{}`",
-                            dep.name()
+                            dep.package_name()
                         )
                     })?;
 
@@ -223,14 +223,14 @@ impl<'cfg> PackageRegistry<'cfg> {
                         "patch for `{}` in `{}` did not resolve to any crates. If this is \
                          unexpected, you may wish to consult: \
                          https://github.com/rust-lang/cargo/issues/4678",
-                        dep.name(),
+                        dep.package_name(),
                         url
                     ),
                 };
                 if summaries.next().is_some() {
                     bail!(
                         "patch for `{}` in `{}` resolved to more than one candidate",
-                        dep.name(),
+                        dep.package_name(),
                         url
                     )
                 }
@@ -238,7 +238,7 @@ impl<'cfg> PackageRegistry<'cfg> {
                     bail!(
                         "patch for `{}` in `{}` points to the same source, but \
                          patches must point to different sources",
-                        dep.name(),
+                        dep.package_name(),
                         url
                     );
                 }
@@ -306,7 +306,7 @@ impl<'cfg> PackageRegistry<'cfg> {
     fn query_overrides(&mut self, dep: &Dependency) -> CargoResult<Option<Summary>> {
         for s in self.overrides.iter() {
             let src = self.sources.get_mut(s).unwrap();
-            let dep = Dependency::new_override(&*dep.name(), s);
+            let dep = Dependency::new_override(&*dep.package_name(), s);
             let mut results = src.query_vec(&dep)?;
             if !results.is_empty() {
                 return Ok(Some(results.remove(0)));
@@ -369,21 +369,21 @@ http://doc.crates.io/specifying-dependencies.html#overriding-dependencies
                  modified to not match the previously resolved version\n\n\
                  {}",
                 override_summary.package_id().name(),
-                dep.name(),
+                dep.package_name(),
                 boilerplate
             );
             self.source_config.config().shell().warn(&msg)?;
             return Ok(());
         }
 
-        if let Some(id) = real_deps.get(0) {
+        if let Some(dep) = real_deps.get(0) {
             let msg = format!(
                 "\
                 path override for crate `{}` has altered the original list of
                 dependencies; the dependency on `{}` was removed\n\n
                 {}",
                 override_summary.package_id().name(),
-                id.name(),
+                dep.package_name(),
                 boilerplate
             );
             self.source_config.config().shell().warn(&msg)?;
@@ -439,7 +439,7 @@ impl<'cfg> Registry for PackageRegistry<'cfg> {
                          with `{}`, \
                          looking at sources",
                         patches.len(),
-                        dep.name(),
+                        dep.package_name(),
                         dep.source_id(),
                         dep.version_req()
                     );
@@ -451,7 +451,7 @@ impl<'cfg> Registry for PackageRegistry<'cfg> {
                         format_err!(
                             "failed to load source for a dependency \
                              on `{}`",
-                            dep.name()
+                            dep.package_name()
                         )
                     })?;
 
@@ -542,7 +542,7 @@ fn lock(locked: &LockedMap, patches: &HashMap<Url, Vec<PackageId>>, summary: Sum
         None => summary,
     };
     summary.map_dependencies(|dep| {
-        trace!("\t{}/{}/{}", dep.name(), dep.version_req(), dep.source_id());
+        trace!("\t{}/{}/{}", dep.package_name(), dep.version_req(), dep.source_id());
 
         // If we've got a known set of overrides for this summary, then
         // one of a few cases can arise:
@@ -578,7 +578,7 @@ fn lock(locked: &LockedMap, patches: &HashMap<Url, Vec<PackageId>>, summary: Sum
         // If anything does then we lock it to that and move on.
         let v = locked
             .get(dep.source_id())
-            .and_then(|map| map.get(&*dep.name()))
+            .and_then(|map| map.get(&*dep.package_name()))
             .and_then(|vec| vec.iter().find(|&&(ref id, _)| dep.matches_id(id)));
         if let Some(&(ref id, _)) = v {
             trace!("\tsecond hit on {}", id);
@@ -592,7 +592,7 @@ fn lock(locked: &LockedMap, patches: &HashMap<Url, Vec<PackageId>>, summary: Sum
         let v = patches.get(dep.source_id().url()).map(|vec| {
             let dep2 = dep.clone();
             let mut iter = vec.iter().filter(move |p| {
-                dep2.name() == p.name() && dep2.version_req().matches(p.version())
+                dep2.matches_ignoring_source(p)
             });
             (iter.next(), iter)
         });
diff --git a/src/cargo/core/resolver/conflict_cache.rs b/src/cargo/core/resolver/conflict_cache.rs
index 38a0ded781a..0f592cc3e23 100644
--- a/src/cargo/core/resolver/conflict_cache.rs
+++ b/src/cargo/core/resolver/conflict_cache.rs
@@ -81,7 +81,7 @@ impl ConflictCache {
             .entry(dep.clone())
             .or_insert_with(Vec::new);
         if !past.contains(con) {
-            trace!("{} adding a skip {:?}", dep.name(), con);
+            trace!("{} adding a skip {:?}", dep.package_name(), con);
             past.push(con.clone());
             for c in con.keys() {
                 self.dep_from_pid
diff --git a/src/cargo/core/resolver/context.rs b/src/cargo/core/resolver/context.rs
index 4689437caf8..b39bbd18f39 100644
--- a/src/cargo/core/resolver/context.rs
+++ b/src/cargo/core/resolver/context.rs
@@ -128,7 +128,7 @@ impl Context {
 
     pub fn prev_active(&self, dep: &Dependency) -> &[Summary] {
         self.activations
-            .get(&(dep.name(), dep.source_id().clone()))
+            .get(&(dep.package_name(), dep.source_id().clone()))
             .map(|v| &v[..])
             .unwrap_or(&[])
     }
@@ -178,19 +178,19 @@ impl Context {
         for dep in deps {
             // Skip optional dependencies, but not those enabled through a
             // feature
-            if dep.is_optional() && !reqs.deps.contains_key(&dep.name()) {
+            if dep.is_optional() && !reqs.deps.contains_key(&dep.name_in_toml()) {
                 continue;
             }
             // So we want this dependency. Move the features we want from
             // `feature_deps` to `ret` and register ourselves as using this
             // name.
-            let base = reqs.deps.get(&dep.name()).unwrap_or(&default_dep);
-            used_features.insert(dep.name());
+            let base = reqs.deps.get(&dep.name_in_toml()).unwrap_or(&default_dep);
+            used_features.insert(dep.name_in_toml());
             let always_required = !dep.is_optional()
                 && !s
                     .dependencies()
                     .iter()
-                    .any(|d| d.is_optional() && d.name() == dep.name());
+                    .any(|d| d.is_optional() && d.name_in_toml() == dep.name_in_toml());
             if always_required && base.0 {
                 self.warnings.push(format!(
                     "Package `{}` does not have feature `{}`. It has a required dependency \
@@ -198,7 +198,7 @@ impl Context {
                      This is currently a warning to ease the transition, but it will become an \
                      error in the future.",
                     s.package_id(),
-                    dep.name()
+                    dep.name_in_toml()
                 ));
             }
             let mut base = base.1.clone();
@@ -220,8 +220,8 @@ impl Context {
         let remaining = reqs
             .deps
             .keys()
-            .filter(|&s| !used_features.contains(s))
-            .map(|s| s.as_str())
+            .cloned()
+            .filter(|s| !used_features.contains(s))
             .collect::<Vec<_>>();
         if !remaining.is_empty() {
             let features = remaining.join(", ");
@@ -298,10 +298,10 @@ fn build_requirements<'a, 'b: 'a>(
             all_features: true, ..
         } => {
             for key in s.features().keys() {
-                reqs.require_feature(InternedString::new(&key))?;
+                reqs.require_feature(*key)?;
             }
             for dep in s.dependencies().iter().filter(|d| d.is_optional()) {
-                reqs.require_dependency(dep.name());
+                reqs.require_dependency(dep.name_in_toml());
             }
         }
         Method::Required {
@@ -389,7 +389,7 @@ impl<'r> Requirements<'r> {
         for fv in self
             .summary
             .features()
-            .get(&feat)
+            .get(feat.as_str())
             .expect("must be a valid feature")
         {
             match *fv {
diff --git a/src/cargo/core/resolver/mod.rs b/src/cargo/core/resolver/mod.rs
index a8179d33471..95c53eee29b 100644
--- a/src/cargo/core/resolver/mod.rs
+++ b/src/cargo/core/resolver/mod.rs
@@ -263,14 +263,14 @@ fn activate_deps_loop(
             "{}[{}]>{} {} candidates",
             parent.name(),
             cur,
-            dep.name(),
+            dep.package_name(),
             candidates.len()
         );
         trace!(
             "{}[{}]>{} {} prev activations",
             parent.name(),
             cur,
-            dep.name(),
+            dep.package_name(),
             cx.prev_active(&dep).len()
         );
 
@@ -307,7 +307,7 @@ fn activate_deps_loop(
                 // It's our job here to backtrack, if possible, and find a
                 // different candidate to activate. If we can't find any
                 // candidates whatsoever then it's time to bail entirely.
-                trace!("{}[{}]>{} -- no candidates", parent.name(), cur, dep.name());
+                trace!("{}[{}]>{} -- no candidates", parent.name(), cur, dep.package_name());
 
                 // Use our list of `conflicting_activations` to add to our
                 // global list of past conflicting activations, effectively
@@ -400,7 +400,7 @@ fn activate_deps_loop(
                 "{}[{}]>{} trying {}",
                 parent.name(),
                 cur,
-                dep.name(),
+                dep.package_name(),
                 candidate.summary.version()
             );
             let res = activate(&mut cx, registry, Some((&parent, &dep)), candidate, &method);
@@ -551,7 +551,7 @@ fn activate_deps_loop(
                             "{}[{}]>{} skipping {} ",
                             parent.name(),
                             cur,
-                            dep.name(),
+                            dep.package_name(),
                             pid.version()
                         );
                         false
@@ -855,7 +855,7 @@ fn activation_error(
 ) -> CargoError {
     let graph = cx.graph();
     if !candidates.is_empty() {
-        let mut msg = format!("failed to select a version for `{}`.", dep.name());
+        let mut msg = format!("failed to select a version for `{}`.", dep.package_name());
         msg.push_str("\n    ... required by ");
         msg.push_str(&describe_path(&graph.path_to_top(parent.package_id())));
 
@@ -881,7 +881,7 @@ fn activation_error(
         for &(p, r) in links_errors.iter() {
             if let ConflictReason::Links(ref link) = *r {
                 msg.push_str("\n\nthe package `");
-                msg.push_str(&*dep.name());
+                msg.push_str(&*dep.package_name());
                 msg.push_str("` links to the native library `");
                 msg.push_str(link);
                 msg.push_str("`, but it conflicts with a previous package which links to `");
@@ -900,11 +900,11 @@ fn activation_error(
                 msg.push_str("\n\nthe package `");
                 msg.push_str(&*p.name());
                 msg.push_str("` depends on `");
-                msg.push_str(&*dep.name());
+                msg.push_str(&*dep.package_name());
                 msg.push_str("`, with features: `");
                 msg.push_str(features);
                 msg.push_str("` but `");
-                msg.push_str(&*dep.name());
+                msg.push_str(&*dep.package_name());
                 msg.push_str("` does not have these features.\n");
             }
             // p == parent so the full path is redundant.
@@ -923,7 +923,7 @@ fn activation_error(
         }
 
         msg.push_str("\n\nfailed to select a version for `");
-        msg.push_str(&*dep.name());
+        msg.push_str(&*dep.package_name());
         msg.push_str("` which could resolve this conflict");
 
         return format_err!("{}", msg);
@@ -964,7 +964,7 @@ fn activation_error(
              location searched: {}\n\
              versions found: {}\n",
             dep.version_req(),
-            dep.name(),
+            dep.package_name(),
             dep.source_id(),
             versions
         );
@@ -993,14 +993,14 @@ fn activation_error(
         candidates.dedup();
         let mut candidates: Vec<_> = candidates
             .iter()
-            .map(|n| (lev_distance(&*new_dep.name(), &*n), n))
+            .map(|n| (lev_distance(&*new_dep.package_name(), &*n), n))
             .filter(|&(d, _)| d < 4)
             .collect();
         candidates.sort_by_key(|o| o.0);
         let mut msg = format!(
             "no matching package named `{}` found\n\
              location searched: {}\n",
-            dep.name(),
+            dep.package_name(),
             dep.source_id()
         );
         if !candidates.is_empty() {
diff --git a/src/cargo/core/resolver/types.rs b/src/cargo/core/resolver/types.rs
index fa842918977..74367540a1e 100644
--- a/src/cargo/core/resolver/types.rs
+++ b/src/cargo/core/resolver/types.rs
@@ -63,7 +63,7 @@ impl<'a> RegistryQueryer<'a> {
                 None => continue,
                 Some(replacement) => replacement,
             };
-            debug!("found an override for {} {}", dep.name(), dep.version_req());
+            debug!("found an override for {} {}", dep.package_name(), dep.version_req());
 
             let mut summaries = self.registry.query_vec(dep, false)?.into_iter();
             let s = summaries.next().ok_or_else(|| {
@@ -117,7 +117,7 @@ impl<'a> RegistryQueryer<'a> {
             }
 
             for dep in summary.dependencies() {
-                debug!("\t{} => {}", dep.name(), dep.version_req());
+                debug!("\t{} => {}", dep.package_name(), dep.version_req());
             }
 
             candidate.replace = replace;
diff --git a/src/cargo/core/summary.rs b/src/cargo/core/summary.rs
index 53b6a4af0b6..ab6247312ca 100644
--- a/src/cargo/core/summary.rs
+++ b/src/cargo/core/summary.rs
@@ -41,17 +41,18 @@ impl Summary {
     ) -> CargoResult<Summary>
     where K: Borrow<str> + Ord + Display {
         for dep in dependencies.iter() {
-            if !namespaced_features && features.get(&*dep.name()).is_some() {
+            let feature = dep.name_in_toml();
+            if !namespaced_features && features.get(&*feature).is_some() {
                 bail!(
                     "Features and dependencies cannot have the \
                      same name: `{}`",
-                    dep.name()
+                    feature
                 )
             }
             if dep.is_optional() && !dep.is_transitive() {
                 bail!(
                     "Dev-dependencies are not allowed to be optional: `{}`",
-                    dep.name()
+                    feature
                 )
             }
         }
@@ -147,7 +148,7 @@ where K: Borrow<str> + Ord + Display {
     let mut dep_map = HashMap::new();
     for dep in dependencies.iter() {
         dep_map
-            .entry(dep.name().as_str())
+            .entry(dep.name_in_toml())
             .or_insert_with(Vec::new)
             .push(dep);
     }
diff --git a/src/cargo/ops/cargo_package.rs b/src/cargo/ops/cargo_package.rs
index fb0ff6a21d3..013f62fbdfb 100644
--- a/src/cargo/ops/cargo_package.rs
+++ b/src/cargo/ops/cargo_package.rs
@@ -145,7 +145,7 @@ fn verify_dependencies(pkg: &Package) -> CargoResult<()> {
                 "all path dependencies must have a version specified \
                  when packaging.\ndependency `{}` does not specify \
                  a version.",
-                dep.name()
+                dep.name_in_toml()
             )
         }
     }
diff --git a/src/cargo/ops/registry.rs b/src/cargo/ops/registry.rs
index e34f522b67e..0a2244bb794 100644
--- a/src/cargo/ops/registry.rs
+++ b/src/cargo/ops/registry.rs
@@ -108,7 +108,7 @@ fn verify_dependencies(pkg: &Package, registry_src: &SourceId) -> CargoResult<()
                     "all path dependencies must have a version specified \
                      when publishing.\ndependency `{}` does not specify \
                      a version",
-                    dep.name()
+                    dep.package_name()
                 )
             }
         } else if dep.source_id() != registry_src {
@@ -119,7 +119,10 @@ fn verify_dependencies(pkg: &Package, registry_src: &SourceId) -> CargoResult<()
                     bail!("crates cannot be published to crates.io with dependencies sourced from other\n\
                            registries either publish `{}` on crates.io or pull it into this repository\n\
                            and specify it with a path and version\n\
-                           (crate `{}` is pulled from {})", dep.name(), dep.name(), dep.source_id());
+                           (crate `{}` is pulled from {})",
+                          dep.package_name(),
+                          dep.package_name(),
+                          dep.source_id());
                 }
             } else {
                 bail!(
@@ -128,8 +131,8 @@ fn verify_dependencies(pkg: &Package, registry_src: &SourceId) -> CargoResult<()
                      specify a crates.io version as a dependency or pull it into this \
                      repository and specify it with a path and version\n(crate `{}` has \
                      repository path `{}`)",
-                    dep.name(),
-                    dep.name(),
+                    dep.package_name(),
+                    dep.package_name(),
                     dep.source_id()
                 );
             }
@@ -164,7 +167,7 @@ fn transmit(
             Ok(NewCrateDependency {
                 optional: dep.is_optional(),
                 default_features: dep.uses_default_features(),
-                name: dep.name().to_string(),
+                name: dep.package_name().to_string(),
                 features: dep.features().iter().map(|s| s.to_string()).collect(),
                 version_req: dep.version_req().to_string(),
                 target: dep.platform().map(|s| s.to_string()),
diff --git a/src/cargo/ops/resolve.rs b/src/cargo/ops/resolve.rs
index 88a1f68a331..05d2fc86247 100644
--- a/src/cargo/ops/resolve.rs
+++ b/src/cargo/ops/resolve.rs
@@ -522,7 +522,7 @@ fn register_previous_locks<'a>(
                 "poisoning {} because {} looks like it changed {}",
                 dep.source_id(),
                 member.package_id(),
-                dep.name()
+                dep.package_name()
             );
             for id in resolve
                 .iter()
diff --git a/src/cargo/sources/registry/index.rs b/src/cargo/sources/registry/index.rs
index 7541dd70c50..e53675bcaee 100644
--- a/src/cargo/sources/registry/index.rs
+++ b/src/cargo/sources/registry/index.rs
@@ -269,7 +269,8 @@ impl<'cfg> RegistryIndex<'cfg> {
         f: &mut FnMut(Summary),
     ) -> CargoResult<()> {
         let source_id = self.source_id.clone();
-        let summaries = self.summaries(dep.name().as_str(), load)?;
+        let name = dep.package_name().as_str();
+        let summaries = self.summaries(name, load)?;
         let summaries = summaries
             .iter()
             .filter(|&&(_, yanked)| dep.source_id().precise().is_some() || !yanked)
@@ -281,8 +282,8 @@ impl<'cfg> RegistryIndex<'cfg> {
         // this source, `<p_req>` is the version installed and `<f_req> is the
         // version requested (argument to `--precise`).
         let summaries = summaries.filter(|s| match source_id.precise() {
-            Some(p) if p.starts_with(&*dep.name()) && p[dep.name().len()..].starts_with('=') => {
-                let mut vers = p[dep.name().len() + 1..].splitn(2, "->");
+            Some(p) if p.starts_with(name) && p[name.len()..].starts_with('=') => {
+                let mut vers = p[name.len() + 1..].splitn(2, "->");
                 if dep
                     .version_req()
                     .matches(&Version::parse(vers.next().unwrap()).unwrap())
diff --git a/src/cargo/util/toml/mod.rs b/src/cargo/util/toml/mod.rs
index 220eab5c575..a2d7f162447 100644
--- a/src/cargo/util/toml/mod.rs
+++ b/src/cargo/util/toml/mod.rs
@@ -871,7 +871,7 @@ impl TomlManifest {
         {
             let mut names_sources = BTreeMap::new();
             for dep in &deps {
-                let name = dep.rename().unwrap_or_else(|| dep.name().as_str());
+                let name = dep.name_in_toml();
                 let prev = names_sources.insert(name.to_string(), dep.source_id());
                 if prev.is_some() && prev != Some(dep.source_id()) {
                     bail!(
diff --git a/src/doc/src/reference/unstable.md b/src/doc/src/reference/unstable.md
index fe137b84201..8263fd0550a 100644
--- a/src/doc/src/reference/unstable.md
+++ b/src/doc/src/reference/unstable.md
@@ -99,6 +99,24 @@ extern crate bar;  // registry `custom`
 extern crate baz;  // git repository
 ```
 
+Note that if you have an optional dependency like:
+
+```toml
+[dependencies]
+foo = { version = "0.1", package = 'bar', optional = true }
+```
+
+you're depending on the crate `bar` from crates.io, but your crate has a `foo`
+feature instead of a `bar` feature. That is, names of features take after the
+name of the dependency, not the package name, when renamed.
+
+Enabling transitive dependencies works similarly, for example we could add the
+following to the above manifest:
+
+```toml
+[features]
+log-debug = ['foo/log-debug'] # using 'bar/log-debug' would be an error!
+```
 
 ### publish-lockfile
 * Original Issue: [#2263](https://github.com/rust-lang/cargo/issues/2263)
diff --git a/tests/testsuite/rename_deps.rs b/tests/testsuite/rename_deps.rs
index aa103f7c9c8..4ce731e9b87 100644
--- a/tests/testsuite/rename_deps.rs
+++ b/tests/testsuite/rename_deps.rs
@@ -364,3 +364,103 @@ fn can_run_doc_tests() {
         )),
     );
 }
+
+#[test]
+fn features_still_work() {
+    Package::new("foo", "0.1.0").publish();
+    Package::new("bar", "0.1.0").publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "test"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                p1 = { path = 'a', features = ['b'] }
+                p2 = { path = 'b' }
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .file(
+            "a/Cargo.toml",
+            r#"
+                cargo-features = ["rename-dependency"]
+
+                [package]
+                name = "p1"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                b = { version = "0.1", package = "foo", optional = true }
+            "#,
+        )
+        .file("a/src/lib.rs", "extern crate b;")
+        .file(
+            "b/Cargo.toml",
+            r#"
+                cargo-features = ["rename-dependency"]
+
+                [package]
+                name = "p2"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                b = { version = "0.1", package = "bar", optional = true }
+
+                [features]
+                default = ['b']
+            "#,
+        )
+        .file("b/src/lib.rs", "extern crate b;")
+        .build();
+
+    assert_that(
+        p.cargo("build -v").masquerade_as_nightly_cargo(),
+        execs().with_status(0),
+    );
+}
+
+#[test]
+fn features_not_working() {
+    Package::new("foo", "0.1.0").publish();
+    Package::new("bar", "0.1.0").publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                cargo-features = ["rename-dependency"]
+                [package]
+                name = "test"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                a = { path = 'a', package = 'p1', optional = true }
+
+                [features]
+                default = ['p1']
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .file("a/Cargo.toml", &basic_manifest("p1", "0.1.0"))
+        .build();
+
+    assert_that(
+        p.cargo("build -v").masquerade_as_nightly_cargo(),
+        execs()
+            .with_status(101)
+            .with_stderr("\
+error: failed to parse manifest at `[..]`
+
+Caused by:
+  Feature `default` includes `p1` which is neither a dependency nor another feature
+")
+    );
+}