diff --git a/src/cargo/core/interning.rs b/src/cargo/core/interning.rs
index 45dde58105c..352268dfc96 100644
--- a/src/cargo/core/interning.rs
+++ b/src/cargo/core/interning.rs
@@ -39,30 +39,37 @@ impl InternedString {
         cache.insert(s);
         InternedString { ptr: s.as_ptr(), len: s.len() }
     }
+    pub fn to_inner(&self) -> &'static str {
+        unsafe {
+            let slice = slice::from_raw_parts(self.ptr, self.len);
+            &str::from_utf8_unchecked(slice)
+        }
+    }
 }
 
 impl Deref for InternedString {
     type Target = str;
 
     fn deref(&self) -> &'static str {
-        unsafe {
-            let slice = slice::from_raw_parts(self.ptr, self.len);
-            &str::from_utf8_unchecked(slice)
-        }
+        self.to_inner()
     }
 }
 
 impl fmt::Debug for InternedString {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let str: &str = &*self;
-        write!(f, "InternedString {{ {} }}", str)
+        write!(f, "InternedString {{ {} }}", self.to_inner())
+    }
+}
+
+impl fmt::Display for InternedString {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.to_inner())
     }
 }
 
 impl Ord for InternedString {
     fn cmp(&self, other: &InternedString) -> Ordering {
-        let str: &str = &*self;
-        str.cmp(&*other)
+        self.to_inner().cmp(&*other)
     }
 }
 
diff --git a/src/cargo/core/package_id.rs b/src/cargo/core/package_id.rs
index ffb4330c627..dc8fde6249c 100644
--- a/src/cargo/core/package_id.rs
+++ b/src/cargo/core/package_id.rs
@@ -11,6 +11,7 @@ use serde::ser;
 
 use util::{CargoResult, ToSemver};
 use core::source::SourceId;
+use core::interning::InternedString;
 
 /// Identifier for a specific version of a package in a specific source.
 #[derive(Clone)]
@@ -20,7 +21,7 @@ pub struct PackageId {
 
 #[derive(PartialEq, PartialOrd, Eq, Ord)]
 struct PackageIdInner {
-    name: String,
+    name: InternedString,
     version: semver::Version,
     source_id: SourceId,
 }
@@ -63,7 +64,7 @@ impl<'de> de::Deserialize<'de> for PackageId {
 
         Ok(PackageId {
             inner: Arc::new(PackageIdInner {
-                name: name.to_string(),
+                name: InternedString::new(name),
                 version,
                 source_id,
             }),
@@ -102,21 +103,21 @@ impl PackageId {
         let v = version.to_semver()?;
         Ok(PackageId {
             inner: Arc::new(PackageIdInner {
-                name: name.to_string(),
+                name: InternedString::new(name),
                 version: v,
                 source_id: sid.clone(),
             }),
         })
     }
 
-    pub fn name(&self) -> &str { &self.inner.name }
+    pub fn name(&self) -> &str { self.inner.name.to_inner() }
     pub fn version(&self) -> &semver::Version { &self.inner.version }
     pub fn source_id(&self) -> &SourceId { &self.inner.source_id }
 
     pub fn with_precise(&self, precise: Option<String>) -> PackageId {
         PackageId {
             inner: Arc::new(PackageIdInner {
-                name: self.inner.name.to_string(),
+                name: self.inner.name,
                 version: self.inner.version.clone(),
                 source_id: self.inner.source_id.with_precise(precise),
             }),
@@ -126,7 +127,7 @@ impl PackageId {
     pub fn with_source_id(&self, source: &SourceId) -> PackageId {
         PackageId {
             inner: Arc::new(PackageIdInner {
-                name: self.inner.name.to_string(),
+                name: self.inner.name,
                 version: self.inner.version.clone(),
                 source_id: source.clone(),
             }),