Fix renaming crates as they come from 2 sources

Previously there was a verification in manifest parsing that the same dependency
must come from the same source, but this erroneously triggered an error to get
emitted when the `package` key was used to rename crates. The first change here
was to update that clause to key off the `rename` field rather than the `name`
field.

Afterwards, though, this exposed an existing bug in the implementation. During
compilation we have a `Resolve` which is a graph of crates, but we don't know
*why* each edge in the dependency graph exists. In other words we don't know,
when looking at an edge of the graph, what `Dependency` caused that edge to be
drawn. We need to know this when passing `--extern` flags because the
`Dependency` is what lists what's being renamed.

This commit then primarily refactors `Resolve::deps` from an iterator of package
ids to an iterator of a tuples. The first element is the package id from before
and the second element is a list of `Dependency` directives which caused the
edge to ber driven.

This refactoring cleaned up a few places in the backend where we had to work
around the lack of this knowledge. Namely this also fixes the extra test added
here.

Closes #5413

src/cargo/core/compiler/context/unit_dependencies.rs

@@ -64,22 +64,20 @@ fn compute_deps<'a, 'b, 'cfg>(
 
     let id = unit.pkg.package_id();
     let deps = cx.resolve.deps(id);
-    let mut ret = deps.filter(|dep| {
-        unit.pkg
-            .dependencies()
-            .iter()
-            .filter(|d| d.name() == dep.name() && d.version_req().matches(dep.version()))
-            .any(|d| {
+    let mut ret = deps
+        .filter(|&(_id, deps)| {
+            assert!(deps.len() > 0);
+            deps.iter().any(|dep| {
                 // If this target is a build command, then we only want build
                 // dependencies, otherwise we want everything *other than* build
                 // dependencies.
-                if unit.target.is_custom_build() != d.is_build() {
+                if unit.target.is_custom_build() != dep.is_build() {
                     return false;
                 }
 
                 // If this dependency is *not* a transitive dependency, then it
                 // only applies to test/example targets
-                if !d.is_transitive() && !unit.target.is_test() && !unit.target.is_example()
+                if !dep.is_transitive() && !unit.target.is_test() && !unit.target.is_example()
                     && !unit.profile.test
                 {
                     return false;
@@ -87,13 +85,13 @@ fn compute_deps<'a, 'b, 'cfg>(
 
                 // If this dependency is only available for certain platforms,
                 // make sure we're only enabling it for that platform.
-                if !cx.dep_platform_activated(d, unit.kind) {
+                if !cx.dep_platform_activated(dep, unit.kind) {
                     return false;
                 }
 
                 // If the dependency is optional, then we're only activating it
                 // if the corresponding feature was activated
-                if d.is_optional() && !cx.resolve.features(id).contains(&*d.name()) {
+                if dep.is_optional() && !cx.resolve.features(id).contains(&*dep.name()) {
                     return false;
                 }
 
@@ -101,17 +99,20 @@ fn compute_deps<'a, 'b, 'cfg>(
                 // actually used!
                 true
             })
-    }).filter_map(|id| match cx.get_package(id) {
-            Ok(pkg) => pkg.targets().iter().find(|t| t.is_lib()).map(|t| {
-                let unit = Unit {
-                    pkg,
-                    target: t,
-                    profile: lib_or_check_profile(unit, t, cx),
-                    kind: unit.kind.for_target(t),
-                };
-                Ok(unit)
-            }),
-            Err(e) => Some(Err(e)),
+        })
+        .filter_map(|(id, _)| {
+            match cx.get_package(id) {
+                Ok(pkg) => pkg.targets().iter().find(|t| t.is_lib()).map(|t| {
+                    let unit = Unit {
+                        pkg,
+                        target: t,
+                        profile: lib_or_check_profile(unit, t, cx),
+                        kind: unit.kind.for_target(t),
+                    };
+                    Ok(unit)
+                }),
+                Err(e) => Some(Err(e)),
+            }
         })
         .collect::<CargoResult<Vec<_>>>()?;
 
@@ -205,17 +206,15 @@ fn compute_deps_doc<'a, 'cfg>(
 ) -> CargoResult<Vec<Unit<'a>>> {
     let deps = cx.resolve
         .deps(unit.pkg.package_id())
-        .filter(|dep| {
-            unit.pkg
-                .dependencies()
-                .iter()
-                .filter(|d| d.name() == dep.name() && d.version_req().matches(dep.version()))
-                .any(|dep| match dep.kind() {
+        .filter(|&(_id, deps)| {
+            deps.iter().any(|dep| {
+                match dep.kind() {
                     DepKind::Normal => cx.dep_platform_activated(dep, unit.kind),
                     _ => false,
-                })
+                }
+            })
         })
-        .map(|dep| cx.get_package(dep));
+        .map(|(id, _deps)| cx.get_package(id));
 
     // To document a library, we depend on dependencies actually being
     // built. If we're documenting *all* libraries, then we also depend on

src/cargo/core/compiler/mod.rs

@@ -1094,23 +1094,30 @@ fn build_deps_args<'a, 'cfg>(
             }
             let mut v = OsString::new();
 
-            // Unfortunately right now Cargo doesn't have a great way to get a
-            // 1:1 mapping of entries in `dependencies()` to the actual crate
-            // we're depending on. Instead we're left to do some guesswork here
-            // to figure out what `Dependency` the `dep` unit corresponds to in
-            // `current` to see if we're renaming it.
-            //
-            // This I believe mostly works out for now, but we'll likely want
-            // to tighten up this in the future.
-            let name = current
-                .pkg
-                .dependencies()
-                .iter()
-                .filter(|d| d.matches_ignoring_source(dep.pkg.package_id()))
-                .filter_map(|d| d.rename())
-                .next();
+            let deps = {
+                let a = current.pkg.package_id();
+                let b = dep.pkg.package_id();
+                if a == b {
+                    &[]
+                } else {
+                    cx.resolve.dependencies_listed(a, b)
+                }
+            };
 
-            v.push(name.unwrap_or(&dep.target.crate_name()));
+            let crate_name = dep.target.crate_name();
+            let mut names = deps.iter()
+                .map(|d| d.rename().unwrap_or(&crate_name));
+            let name = names.next().unwrap_or(&crate_name);
+            for n in names {
+                if n == name {
+                    continue
+                }
+                bail!("multiple dependencies listed for the same crate must \
+                       all have the same name, but the dependency on `{}` \
+                       is listed as having different names", dep.pkg.package_id());
+            }
+
+            v.push(name);
             v.push("=");
             v.push(cx.files().out_dir(dep));
             v.push(&path::MAIN_SEPARATOR.to_string());

src/cargo/core/resolver/context.rs

@@ -269,17 +269,25 @@ impl Context {
         replacements
     }
 
-    pub fn graph(&self) -> Graph<PackageId> {
+    pub fn graph(&self)
+        -> (Graph<PackageId>, HashMap<(PackageId, PackageId), Vec<Dependency>>)
+    {
         let mut graph = Graph::new();
+        let mut deps = HashMap::new();
         let mut cur = &self.resolve_graph;
         while let Some(ref node) = cur.head {
             match node.0 {
-                GraphNode::Add(ref p) => graph.add(p.clone(), &[]),
-                GraphNode::Link(ref a, ref b) => graph.link(a.clone(), b.clone()),
+                GraphNode::Add(ref p) => graph.add(p.clone()),
+                GraphNode::Link(ref a, ref b, ref dep) => {
+                    graph.link(a.clone(), b.clone());
+                    deps.entry((a.clone(), b.clone()))
+                        .or_insert(Vec::new())
+                        .push(dep.clone());
+                }
             }
             cur = &node.1;
         }
-        graph
+        (graph, deps)
     }
 }
 

src/cargo/core/resolver/encode.rs

@@ -95,7 +95,7 @@ impl EncodableResolve {
             let mut g = Graph::new();
 
             for &(ref id, _) in live_pkgs.values() {
-                g.add(id.clone(), &[]);
+                g.add(id.clone());
             }
 
             for &(ref id, pkg) in live_pkgs.values() {
@@ -177,15 +177,15 @@ impl EncodableResolve {
             unused_patches.push(id);
         }
 
-        Ok(Resolve {
-            graph: g,
-            empty_features: HashSet::new(),
-            features: HashMap::new(),
+        Ok(Resolve::new(
+            g,
+            HashMap::new(),
             replacements,
+            HashMap::new(),
             checksums,
             metadata,
             unused_patches,
-        })
+        ))
     }
 }
 
@@ -347,17 +347,17 @@ impl<'a, 'cfg> ser::Serialize for WorkspaceResolve<'a, 'cfg> {
     where
         S: ser::Serializer,
     {
-        let mut ids: Vec<&PackageId> = self.resolve.graph.iter().collect();
+        let mut ids: Vec<_> = self.resolve.iter().collect();
         ids.sort();
 
         let encodable = ids.iter()
             .filter_map(|&id| Some(encodable_resolve_node(id, self.resolve)))
             .collect::<Vec<_>>();
 
-        let mut metadata = self.resolve.metadata.clone();
+        let mut metadata = self.resolve.metadata().clone();
 
         for id in ids.iter().filter(|id| !id.source_id().is_path()) {
-            let checksum = match self.resolve.checksums[*id] {
+            let checksum = match self.resolve.checksums()[*id] {
                 Some(ref s) => &s[..],
                 None => "<none>",
             };
@@ -398,10 +398,7 @@ fn encodable_resolve_node(id: &PackageId, resolve: &Resolve) -> EncodableDepende
         Some(id) => (Some(encodable_package_id(id)), None),
         None => {
             let mut deps = resolve
-                .graph
-                .edges(id)
-                .into_iter()
-                .flat_map(|a| a)
+                .deps_not_replaced(id)
                 .map(encodable_package_id)
                 .collect::<Vec<_>>();
             deps.sort();

src/cargo/core/resolver/mod.rs

@@ -58,7 +58,6 @@ use core::{Dependency, PackageId, Registry, Summary};
 use core::PackageIdSpec;
 use core::interning::InternedString;
 use util::config::Config;
-use util::Graph;
 use util::errors::{CargoError, CargoResult};
 use util::profile;
 
@@ -123,25 +122,25 @@ pub fn resolve(
     let mut registry = RegistryQueryer::new(registry, replacements, try_to_use, minimal_versions);
     let cx = activate_deps_loop(cx, &mut registry, summaries, config)?;
 
-    let mut resolve = Resolve {
-        graph: cx.graph(),
-        empty_features: HashSet::new(),
-        checksums: HashMap::new(),
-        metadata: BTreeMap::new(),
-        replacements: cx.resolve_replacements(),
-        features: cx.resolve_features
+    let (graph, deps) = cx.graph();
+
+    let mut cksums = HashMap::new();
+    for summary in cx.activations.values().flat_map(|v| v.iter()) {
+        let cksum = summary.checksum().map(|s| s.to_string());
+        cksums.insert(summary.package_id().clone(), cksum);
+    }
+    let resolve = Resolve::new(
+        graph,
+        deps,
+        cx.resolve_replacements(),
+        cx.resolve_features
             .iter()
             .map(|(k, v)| (k.clone(), v.iter().map(|x| x.to_string()).collect()))
             .collect(),
-        unused_patches: Vec::new(),
-    };
-
-    for summary in cx.activations.values().flat_map(|v| v.iter()) {
-        let cksum = summary.checksum().map(|s| s.to_string());
-        resolve
-            .checksums
-            .insert(summary.package_id().clone(), cksum);
-    }
+        cksums,
+        BTreeMap::new(),
+        Vec::new(),
+    );
 
     check_cycles(&resolve, &cx.activations)?;
     trace!("resolved: {:?}", resolve);
@@ -402,7 +401,13 @@ fn activate_deps_loop(
                 dep.name(),
                 candidate.summary.version()
             );
-            let res = activate(&mut cx, registry, Some(&parent), candidate, &method);
+            let res = activate(
+                &mut cx,
+                registry,
+                Some((&parent, &dep)),
+                candidate,
+                &method,
+            );
 
             let successfully_activated = match res {
                 // Success! We've now activated our `candidate` in our context
@@ -615,14 +620,15 @@ fn activate_deps_loop(
 fn activate(
     cx: &mut Context,
     registry: &mut RegistryQueryer,
-    parent: Option<&Summary>,
+    parent: Option<(&Summary, &Dependency)>,
     candidate: Candidate,
     method: &Method,
 ) -> ActivateResult<Option<(DepsFrame, Duration)>> {
-    if let Some(parent) = parent {
+    if let Some((parent, dep)) = parent {
         cx.resolve_graph.push(GraphNode::Link(
             parent.package_id().clone(),
             candidate.summary.package_id().clone(),
+            dep.clone(),
         ));
     }
 
@@ -654,7 +660,7 @@ fn activate(
     };
 
     let now = Instant::now();
-    let deps = cx.build_deps(registry, parent, &candidate, method)?;
+    let deps = cx.build_deps(registry, parent.map(|p| p.0), &candidate, method)?;
     let frame = DepsFrame {
         parent: candidate,
         just_for_error_messages: false,
@@ -861,11 +867,11 @@ fn activation_error(
     candidates: &[Candidate],
     config: Option<&Config>,
 ) -> CargoError {
-    let graph = cx.graph();
+    let (graph, _) = cx.graph();
     if !candidates.is_empty() {
         let mut msg = format!("failed to select a version for `{}`.", dep.name());
         msg.push_str("\n    ... required by ");
-        msg.push_str(&describe_path(&graph, parent.package_id()));
+        msg.push_str(&describe_path(&graph.path_to_top(parent.package_id())));
 
         msg.push_str("\nversions that meet the requirements `");
         msg.push_str(&dep.version_req().to_string());
@@ -894,7 +900,7 @@ fn activation_error(
                 msg.push_str(link);
                 msg.push_str("` as well:\n");
             }
-            msg.push_str(&describe_path(&graph, p));
+            msg.push_str(&describe_path(&graph.path_to_top(p)));
         }
 
         let (features_errors, other_errors): (Vec<_>, Vec<_>) = other_errors
@@ -925,7 +931,7 @@ fn activation_error(
 
         for &(p, _) in other_errors.iter() {
             msg.push_str("\n\n  previously selected ");
-            msg.push_str(&describe_path(&graph, p));
+            msg.push_str(&describe_path(&graph.path_to_top(p)));
         }
 
         msg.push_str("\n\nfailed to select a version for `");
@@ -976,7 +982,7 @@ fn activation_error(
             versions
         );
         msg.push_str("required by ");
-        msg.push_str(&describe_path(&graph, parent.package_id()));
+        msg.push_str(&describe_path(&graph.path_to_top(parent.package_id())));
 
         // If we have a path dependency with a locked version, then this may
         // indicate that we updated a sub-package and forgot to run `cargo
@@ -997,7 +1003,7 @@ fn activation_error(
             dep.source_id()
         );
         msg.push_str("required by ");
-        msg.push_str(&describe_path(&graph, parent.package_id()));
+        msg.push_str(&describe_path(&graph.path_to_top(parent.package_id())));
 
         msg
     };
@@ -1017,11 +1023,10 @@ fn activation_error(
 }
 
 /// Returns String representation of dependency chain for a particular `pkgid`.
-fn describe_path(graph: &Graph<PackageId>, pkgid: &PackageId) -> String {
+fn describe_path(path: &[&PackageId]) -> String {
     use std::fmt::Write;
-    let dep_path = graph.path_to_top(pkgid);
-    let mut dep_path_desc = format!("package `{}`", dep_path[0]);
-    for dep in dep_path.iter().skip(1) {
+    let mut dep_path_desc = format!("package `{}`", path[0]);
+    for dep in path[1..].iter() {
         write!(dep_path_desc, "\n    ... which is depended on by `{}`", dep).unwrap();
     }
     dep_path_desc
@@ -1056,7 +1061,7 @@ fn check_cycles(resolve: &Resolve, activations: &Activations) -> CargoResult<()>
             bail!(
                 "cyclic package dependency: package `{}` depends on itself. Cycle:\n{}",
                 id,
-                describe_path(&resolve.graph, id)
+                describe_path(&resolve.path_to_top(id))
             );
         }
 

src/cargo/core/resolver/resolve.rs

@@ -4,8 +4,7 @@ use std::iter::FromIterator;
 
 use url::Url;
 
-use core::PackageIdSpec;
-use core::{PackageId, Summary};
+use core::{Dependency, PackageId, PackageIdSpec, Summary};
 use util::Graph;
 use util::errors::CargoResult;
 use util::graph::{Edges, Nodes};
@@ -19,21 +18,50 @@ use super::encode::Metadata;
 /// for each package.
 #[derive(PartialEq)]
 pub struct Resolve {
-    pub graph: Graph<PackageId>,
-    pub replacements: HashMap<PackageId, PackageId>,
-    pub empty_features: HashSet<String>,
-    pub features: HashMap<PackageId, HashSet<String>>,
-    pub checksums: HashMap<PackageId, Option<String>>,
-    pub metadata: Metadata,
-    pub unused_patches: Vec<PackageId>,
+    graph: Graph<PackageId>,
+    dependencies: HashMap<(PackageId, PackageId), Vec<Dependency>>,
+    replacements: HashMap<PackageId, PackageId>,
+    reverse_replacements: HashMap<PackageId, PackageId>,
+    empty_features: HashSet<String>,
+    features: HashMap<PackageId, HashSet<String>>,
+    checksums: HashMap<PackageId, Option<String>>,
+    metadata: Metadata,
+    unused_patches: Vec<PackageId>,
 }
 
 impl Resolve {
+    pub fn new(
+        graph: Graph<PackageId>,
+        dependencies: HashMap<(PackageId, PackageId), Vec<Dependency>>,
+        replacements: HashMap<PackageId, PackageId>,
+        features: HashMap<PackageId, HashSet<String>>,
+        checksums: HashMap<PackageId, Option<String>>,
+        metadata: Metadata,
+        unused_patches: Vec<PackageId>,
+    ) -> Resolve {
+        let reverse_replacements = replacements
+            .iter()
+            .map(|p| (p.1.clone(), p.0.clone()))
+            .collect();
+        Resolve {
+            graph,
+            dependencies,
+            replacements,
+            features,
+            checksums,
+            metadata,
+            unused_patches,
+            empty_features: HashSet::new(),
+            reverse_replacements,
+        }
+    }
+
     /// Resolves one of the paths from the given dependent package up to
     /// the root.
     pub fn path_to_top<'a>(&'a self, pkg: &'a PackageId) -> Vec<&'a PackageId> {
         self.graph.path_to_top(pkg)
     }
+
     pub fn register_used_patches(&mut self, patches: &HashMap<Url, Vec<Summary>>) {
         for summary in patches.values().flat_map(|v| v) {
             if self.iter().any(|id| id == summary.package_id()) {
@@ -141,6 +169,7 @@ unable to verify that `{0}` is the same as when the lockfile was generated
     pub fn deps(&self, pkg: &PackageId) -> Deps {
         Deps {
             edges: self.graph.edges(pkg),
+            id: pkg.clone(),
             resolve: self,
         }
     }
@@ -176,6 +205,35 @@ unable to verify that `{0}` is the same as when the lockfile was generated
     pub fn unused_patches(&self) -> &[PackageId] {
         &self.unused_patches
     }
+
+    pub fn checksums(&self) -> &HashMap<PackageId, Option<String>> {
+        &self.checksums
+    }
+
+    pub fn metadata(&self) -> &Metadata {
+        &self.metadata
+    }
+
+    pub fn dependencies_listed(&self, from: &PackageId, to: &PackageId) -> &[Dependency] {
+        // We've got a dependency on `from` to `to`, but this dependency edge
+        // may be affected by [replace]. If the `to` package is listed as the
+        // target of a replacement (aka the key of a reverse replacement map)
+        // then we try to find our dependency edge through that. If that fails
+        // then we go down below assuming it's not replaced.
+        //
+        // Note that we don't treat `from` as if it's been replaced because
+        // that's where the dependency originates from, and we only replace
+        // targets of dependencies not the originator.
+        if let Some(replace) = self.reverse_replacements.get(to) {
+            if let Some(deps) = self.dependencies.get(&(from.clone(), replace.clone())) {
+                return deps;
+            }
+        }
+        match self.dependencies.get(&(from.clone(), to.clone())) {
+            Some(ret) => ret,
+            None => panic!("no Dependency listed for `{}` => `{}`", from, to),
+        }
+    }
 }
 
 impl fmt::Debug for Resolve {
@@ -191,17 +249,18 @@ impl fmt::Debug for Resolve {
 
 pub struct Deps<'a> {
     edges: Option<Edges<'a, PackageId>>,
+    id: PackageId,
     resolve: &'a Resolve,
 }
 
 impl<'a> Iterator for Deps<'a> {
-    type Item = &'a PackageId;
+    type Item = (&'a PackageId, &'a [Dependency]);
 
-    fn next(&mut self) -> Option<&'a PackageId> {
-        self.edges
-            .as_mut()
-            .and_then(|e| e.next())
-            .map(|id| self.resolve.replacement(id).unwrap_or(id))
+    fn next(&mut self) -> Option<(&'a PackageId, &'a [Dependency])> {
+        let id = self.edges.as_mut()?.next()?;
+        let id_ret = self.resolve.replacement(id).unwrap_or(id);
+        let deps = &self.resolve.dependencies[&(self.id.clone(), id.clone())];
+        Some((id_ret, deps))
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {

src/cargo/core/resolver/types.rs

@@ -394,5 +394,5 @@ impl<T> Drop for RcList<T> {
 
 pub enum GraphNode {
     Add(PackageId),
-    Link(PackageId, PackageId),
+    Link(PackageId, PackageId, Dependency),
 }

src/cargo/ops/cargo_compile.rs

@@ -397,8 +397,7 @@ pub fn compile_ws<'a>(
 
         // Include features enabled for use by dependencies so targets can also use them with the
         // required-features field when deciding whether to be built or skipped.
-        let deps = resolve_with_overrides.deps(package_id);
-        for dep in deps {
+        for (dep, _) in resolve_with_overrides.deps(package_id) {
             for feature in resolve_with_overrides.features(dep) {
                 features.insert(dep.name().to_string() + "/" + feature);
             }

src/cargo/ops/cargo_fetch.rs

@@ -1,5 +1,5 @@
 use core::compiler::{BuildConfig, Kind, TargetInfo};
-use core::{Package, PackageId, PackageSet, Resolve, Workspace};
+use core::{PackageSet, Resolve, Workspace};
 use ops;
 use std::collections::HashSet;
 use util::CargoResult;
@@ -18,57 +18,45 @@ pub fn fetch<'a>(
 ) -> CargoResult<(Resolve, PackageSet<'a>)> {
     let (packages, resolve) = ops::resolve_ws(ws)?;
 
-    fetch_for_target(ws, options.config, &options.target, &resolve, &packages)?;
+    let jobs = Some(1);
+    let build_config = BuildConfig::new(ws.config(), jobs, &options.target, None)?;
+    let target_info = TargetInfo::new(ws.config(), &build_config, Kind::Target)?;
+    {
+        let mut fetched_packages = HashSet::new();
+        let mut deps_to_fetch = ws.members()
+            .map(|p| p.package_id())
+            .collect::<Vec<_>>();
+
+        while let Some(id) = deps_to_fetch.pop() {
+            if !fetched_packages.insert(id) {
+                continue;
+            }
+
+            packages.get(id)?;
+            let deps = resolve.deps(id)
+                .filter(|&(_id, deps)| {
+                    deps.iter()
+                        .any(|d| {
+                            // If no target was specified then all dependencies can
+                            // be fetched.
+                            let target = match options.target {
+                                Some(ref t) => t,
+                                None => return true,
+                            };
+                            // If this dependency is only available for certain
+                            // platforms, make sure we're only fetching it for that
+                            // platform.
+                            let platform = match d.platform() {
+                                Some(p) => p,
+                                None => return true,
+                            };
+                            platform.matches(target, target_info.cfg())
+                        })
+                })
+                .map(|(id, _deps)| id);
+            deps_to_fetch.extend(deps);
+        }
+    }
 
     Ok((resolve, packages))
 }
-
-fn fetch_for_target<'a, 'cfg: 'a>(
-    ws: &'a Workspace<'cfg>,
-    config: &'cfg Config,
-    target: &Option<String>,
-    resolve: &'a Resolve,
-    packages: &'a PackageSet<'cfg>,
-) -> CargoResult<HashSet<&'a PackageId>> {
-    let mut fetched_packages = HashSet::new();
-    let mut deps_to_fetch = Vec::new();
-    let jobs = Some(1);
-    let build_config = BuildConfig::new(config, jobs, target, None)?;
-    let target_info = TargetInfo::new(config, &build_config, Kind::Target)?;
-    let root_package_ids = ws.members().map(Package::package_id).collect::<Vec<_>>();
-
-    deps_to_fetch.extend(root_package_ids);
-
-    while let Some(id) = deps_to_fetch.pop() {
-        if !fetched_packages.insert(id) {
-            continue;
-        }
-
-        let package = packages.get(id)?;
-        let deps = resolve.deps(id);
-        let dependency_ids = deps.filter(|dep| {
-            package
-                .dependencies()
-                .iter()
-                .filter(|d| d.name() == dep.name() && d.version_req().matches(dep.version()))
-                .any(|d| {
-                    // If no target was specified then all dependencies can be fetched.
-                    let target = match *target {
-                        Some(ref t) => t,
-                        None => return true,
-                    };
-                    // If this dependency is only available for certain platforms,
-                    // make sure we're only fetching it for that platform.
-                    let platform = match d.platform() {
-                        Some(p) => p,
-                        None => return true,
-                    };
-                    platform.matches(target, target_info.cfg())
-                })
-        }).collect::<Vec<_>>();
-
-        deps_to_fetch.extend(dependency_ids);
-    }
-
-    Ok(fetched_packages)
-}

src/cargo/ops/cargo_generate_lockfile.rs

@@ -132,7 +132,7 @@ pub fn update_lockfile(ws: &Workspace, opts: &UpdateOptions) -> CargoResult<()>
             return;
         }
         set.insert(dep);
-        for dep in resolve.deps(dep) {
+        for dep in resolve.deps_not_replaced(dep) {
             fill_with_deps(resolve, dep, set, visited);
         }
     }

src/cargo/ops/cargo_output_metadata.rs

@@ -109,7 +109,7 @@ where
         .iter()
         .map(|id| Node {
             id,
-            dependencies: resolve.deps(id).collect(),
+            dependencies: resolve.deps(id).map(|p| p.0).collect(),
             features: resolve.features_sorted(id),
         })
         .collect::<Vec<_>>()

src/cargo/util/graph.rs

@@ -22,11 +22,10 @@ impl<N: Eq + Hash + Clone> Graph<N> {
         }
     }
 
-    pub fn add(&mut self, node: N, children: &[N]) {
+    pub fn add(&mut self, node: N) {
         self.nodes
             .entry(node)
-            .or_insert_with(HashSet::new)
-            .extend(children.iter().cloned());
+            .or_insert_with(HashSet::new);
     }
 
     pub fn link(&mut self, node: N, child: N) {

src/cargo/util/toml/mod.rs

@@ -742,8 +742,8 @@ impl TomlManifest {
         {
             let mut names_sources = BTreeMap::new();
             for dep in &deps {
-                let name = dep.name();
-                let prev = names_sources.insert(name, dep.source_id());
+                let name = dep.rename().unwrap_or(dep.name().as_str());
+                let prev = names_sources.insert(name.to_string(), dep.source_id());
                 if prev.is_some() && prev != Some(dep.source_id()) {
                     bail!(
                         "Dependency '{}' has different source paths depending on the build \

tests/testsuite/rename_deps.rs

@@ -1,6 +1,8 @@
-use cargotest::support::{execs, project};
-use cargotest::support::registry::Package;
 use cargotest::ChannelChanger;
+use cargotest::support::git;
+use cargotest::support::paths;
+use cargotest::support::registry::Package;
+use cargotest::support::{execs, project};
 use hamcrest::assert_that;
 
 #[test]
@@ -145,3 +147,171 @@ fn rename_with_different_names() {
         execs().with_status(0),
     );
 }
+
+#[test]
+fn lots_of_names() {
+    Package::new("foo", "0.1.0")
+        .file("src/lib.rs", "pub fn foo1() {}")
+        .publish();
+    Package::new("foo", "0.2.0")
+        .file("src/lib.rs", "pub fn foo() {}")
+        .publish();
+    Package::new("foo", "0.1.0")
+        .file("src/lib.rs", "pub fn foo2() {}")
+        .alternative(true)
+        .publish();
+
+    let g = git::repo(&paths::root().join("another"))
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+                authors = []
+            "#,
+        )
+        .file("src/lib.rs", "pub fn foo3() {}")
+        .build();
+
+    let p = project("foo")
+        .file(
+            "Cargo.toml",
+            &format!(r#"
+                cargo-features = ["alternative-registries", "rename-dependency"]
+
+                [package]
+                name = "test"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                foo = "0.2"
+                foo1 = {{ version = "0.1", package = "foo" }}
+                foo2 = {{ version = "0.1", registry = "alternative", package = "foo" }}
+                foo3 = {{ git = '{}', package = "foo" }}
+                foo4 = {{ path = "foo", package = "foo" }}
+            "#,
+            g.url())
+        )
+        .file(
+            "src/lib.rs",
+            "
+                extern crate foo;
+                extern crate foo1;
+                extern crate foo2;
+                extern crate foo3;
+                extern crate foo4;
+
+                pub fn foo() {
+                    foo::foo();
+                    foo1::foo1();
+                    foo2::foo2();
+                    foo3::foo3();
+                    foo4::foo4();
+                }
+            ",
+        )
+        .file(
+            "foo/Cargo.toml",
+            r#"
+                [project]
+                name = "foo"
+                version = "0.1.0"
+                authors = []
+            "#,
+        )
+        .file("foo/src/lib.rs", "pub fn foo4() {}")
+        .build();
+
+    assert_that(
+        p.cargo("build -v").masquerade_as_nightly_cargo(),
+        execs().with_status(0),
+    );
+}
+
+#[test]
+fn rename_and_patch() {
+    Package::new("foo", "0.1.0").publish();
+
+    let p = project("foo")
+        .file(
+            "Cargo.toml",
+            r#"
+                cargo-features = ["rename-dependency"]
+
+                [package]
+                name = "test"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                bar = { version = "0.1", package = "foo" }
+
+                [patch.crates-io]
+                foo = { path = "foo" }
+            "#,
+        )
+        .file(
+            "src/lib.rs",
+            "
+                extern crate bar;
+
+                pub fn foo() {
+                    bar::foo();
+                }
+            ",
+        )
+        .file(
+            "foo/Cargo.toml",
+            r#"
+                [project]
+                name = "foo"
+                version = "0.1.0"
+                authors = []
+            "#,
+        )
+        .file("foo/src/lib.rs", "pub fn foo() {}")
+        .build();
+
+    assert_that(
+        p.cargo("build -v").masquerade_as_nightly_cargo(),
+        execs().with_status(0),
+    );
+}
+
+#[test]
+fn rename_twice() {
+    Package::new("foo", "0.1.0").publish();
+
+    let p = project("foo")
+        .file(
+            "Cargo.toml",
+            r#"
+                cargo-features = ["rename-dependency"]
+
+                [package]
+                name = "test"
+                version = "0.1.0"
+                authors = []
+
+                [dependencies]
+                bar = { version = "0.1", package = "foo" }
+                [build-dependencies]
+                foo = { version = "0.1" }
+            "#,
+        )
+        .file("src/lib.rs", "",)
+        .build();
+
+    assert_that(
+        p.cargo("build -v").masquerade_as_nightly_cargo(),
+        execs().with_status(101)
+            .with_stderr("\
+[UPDATING] registry `[..]`
+[DOWNLOADING] foo v0.1.0 (registry [..])
+error: multiple dependencies listed for the same crate must all have the same \
+name, but the dependency on `foo v0.1.0` is listed as having different names
+")
+    );
+}