Resolve 2 needless_pass_by_value lint warnings

TIL Rust doesn't have equational reasoning.. :-/
(can't inline the new "exec" bindings)

src/cargo/core/summary.rs

@@ -35,7 +35,7 @@ impl Summary {
     pub fn new<K>(
         pkg_id: PackageId,
         dependencies: Vec<Dependency>,
-        features: BTreeMap<K, Vec<impl AsRef<str>>>,
+        features: &BTreeMap<K, Vec<impl AsRef<str>>>,
         links: Option<impl AsRef<str>>,
         namespaced_features: bool,
     ) -> CargoResult<Summary>

src/cargo/ops/cargo_compile.rs

@@ -185,7 +185,8 @@ pub fn compile<'a>(
     ws: &Workspace<'a>,
     options: &CompileOptions<'a>,
 ) -> CargoResult<Compilation<'a>> {
-    compile_with_exec(ws, options, Arc::new(DefaultExecutor))
+    let exec: Arc<Executor> = Arc::new(DefaultExecutor);
+    compile_with_exec(ws, options, &exec)
 }
 
 /// Like `compile` but allows specifying a custom `Executor` that will be able to intercept build
@@ -193,7 +194,7 @@ pub fn compile<'a>(
 pub fn compile_with_exec<'a>(
     ws: &Workspace<'a>,
     options: &CompileOptions<'a>,
-    exec: Arc<Executor>,
+    exec: &Arc<Executor>,
 ) -> CargoResult<Compilation<'a>> {
     ws.emit_warnings()?;
     compile_ws(ws, None, options, exec)
@@ -203,7 +204,7 @@ pub fn compile_ws<'a>(
     ws: &Workspace<'a>,
     source: Option<Box<Source + 'a>>,
     options: &CompileOptions<'a>,
-    exec: Arc<Executor>,
+    exec: &Arc<Executor>,
 ) -> CargoResult<Compilation<'a>> {
     let CompileOptions {
         config,

src/cargo/ops/cargo_install.rs

@@ -12,7 +12,7 @@ use toml;
 
 use core::{Dependency, Edition, Package, PackageIdSpec, Source, SourceId};
 use core::{PackageId, Workspace};
-use core::compiler::DefaultExecutor;
+use core::compiler::{DefaultExecutor, Executor};
 use ops::{self, CompileFilter};
 use sources::{GitSource, PathSource, SourceConfigMap};
 use util::{internal, Config};
@@ -262,8 +262,9 @@ fn install_one(
         check_overwrites(&dst, pkg, &opts.filter, &list, force)?;
     }
 
+    let exec: Arc<Executor> = Arc::new(DefaultExecutor);
     let compile =
-        ops::compile_ws(&ws, Some(source), opts, Arc::new(DefaultExecutor)).chain_err(|| {
+        ops::compile_ws(&ws, Some(source), opts, &exec).chain_err(|| {
             if let Some(td) = td_opt.take() {
                 // preserve the temporary directory, so the user can inspect it
                 td.into_path();

src/cargo/ops/cargo_package.rs

@@ -10,7 +10,7 @@ use git2;
 use tar::{Archive, Builder, EntryType, Header};
 
 use core::{Package, Source, SourceId, Workspace};
-use core::compiler::{BuildConfig, CompileMode, DefaultExecutor};
+use core::compiler::{BuildConfig, CompileMode, DefaultExecutor, Executor};
 use sources::PathSource;
 use util::{self, internal, Config, FileLock};
 use util::paths;
@@ -333,6 +333,7 @@ fn run_verify(ws: &Workspace, tar: &FileLock, opts: &PackageOpts) -> CargoResult
     let pkg_fingerprint = src.last_modified_file(&new_pkg)?;
     let ws = Workspace::ephemeral(new_pkg, config, None, true)?;
 
+    let exec: Arc<Executor> = Arc::new(DefaultExecutor);
     ops::compile_ws(
         &ws,
         None,
@@ -350,7 +351,7 @@ fn run_verify(ws: &Workspace, tar: &FileLock, opts: &PackageOpts) -> CargoResult
             target_rustc_args: None,
             export_dir: None,
         },
-        Arc::new(DefaultExecutor),
+        &exec,
     )?;
 
     // Check that build.rs didn't modify any files in the src directory.

src/cargo/sources/registry/index.rs

@@ -253,7 +253,7 @@ impl<'cfg> RegistryIndex<'cfg> {
             .into_iter()
             .map(|dep| dep.into_dep(&self.source_id))
             .collect::<CargoResult<Vec<_>>>()?;
-        let summary = Summary::new(pkgid, deps, features, links, false)?;
+        let summary = Summary::new(pkgid, deps, &features, links, false)?;
         let summary = summary.set_checksum(cksum.clone());
         self.hashes
             .entry(name.as_str())

src/cargo/util/toml/mod.rs

@@ -893,7 +893,7 @@ impl TomlManifest {
         let summary = Summary::new(
             pkgid,
             deps,
-            me.features
+            &me.features
                 .as_ref()
                 .map(|x| {
                     x.iter()

tests/testsuite/resolve.rs

@@ -38,7 +38,7 @@ fn resolve_with_config(
         }
     }
     let mut registry = MyRegistry(registry);
-    let summary = Summary::new(pkg.clone(), deps, BTreeMap::<String, Vec<String>>::new(), None::<String>, false).unwrap();
+    let summary = Summary::new(pkg.clone(), deps, &BTreeMap::<String, Vec<String>>::new(), None::<String>, false).unwrap();
     let method = Method::Everything;
     let resolve = resolver::resolve(
         &[(summary, method)],
@@ -100,13 +100,13 @@ macro_rules! pkg {
         let pkgid = $pkgid.to_pkgid();
         let link = if pkgid.name().ends_with("-sys") {Some(pkgid.name().as_str())} else {None};
 
-        Summary::new(pkgid, d, BTreeMap::<String, Vec<String>>::new(), link, false).unwrap()
+        Summary::new(pkgid, d, &BTreeMap::<String, Vec<String>>::new(), link, false).unwrap()
     });
 
     ($pkgid:expr) => ({
         let pkgid = $pkgid.to_pkgid();
         let link = if pkgid.name().ends_with("-sys") {Some(pkgid.name().as_str())} else {None};
-        Summary::new(pkgid, Vec::new(), BTreeMap::<String, Vec<String>>::new(), link, false).unwrap()
+        Summary::new(pkgid, Vec::new(), &BTreeMap::<String, Vec<String>>::new(), link, false).unwrap()
     })
 }
 
@@ -121,7 +121,7 @@ fn pkg(name: &str) -> Summary {
     } else {
         None
     };
-    Summary::new(pkg_id(name), Vec::new(), BTreeMap::<String, Vec<String>>::new(), link, false).unwrap()
+    Summary::new(pkg_id(name), Vec::new(), &BTreeMap::<String, Vec<String>>::new(), link, false).unwrap()
 }
 
 fn pkg_id(name: &str) -> PackageId {
@@ -145,7 +145,7 @@ fn pkg_loc(name: &str, loc: &str) -> Summary {
     Summary::new(
         pkg_id_loc(name, loc),
         Vec::new(),
-        BTreeMap::<String, Vec<String>>::new(),
+        &BTreeMap::<String, Vec<String>>::new(),
         link,
         false,
     ).unwrap()