Use IntoIterator for array impl everywhere.

compiler/rustc_target/src/lib.rs

@@ -16,6 +16,7 @@
 #![feature(min_specialization)]
 #![feature(step_trait)]
 
+use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 
 #[macro_use]
@@ -47,12 +48,11 @@ const RUST_LIB_DIR: &str = "rustlib";
 /// `"lib*/rustlib/x86_64-unknown-linux-gnu"`.
 pub fn target_rustlib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
     let libdir = find_libdir(sysroot);
-    std::array::IntoIter::new([
+    PathBuf::from_iter([
         Path::new(libdir.as_ref()),
         Path::new(RUST_LIB_DIR),
         Path::new(target_triple),
     ])
-    .collect::<PathBuf>()
 }
 
 /// The name of the directory rustc expects libraries to be located.

compiler/rustc_target/src/spec/mod.rs

@@ -42,6 +42,7 @@ use rustc_serialize::json::{Json, ToJson};
 use rustc_span::symbol::{sym, Symbol};
 use std::collections::BTreeMap;
 use std::convert::TryFrom;
+use std::iter::FromIterator;
 use std::ops::{Deref, DerefMut};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
@@ -2173,12 +2174,11 @@ impl Target {
                 // Additionally look in the sysroot under `lib/rustlib/<triple>/target.json`
                 // as a fallback.
                 let rustlib_path = crate::target_rustlib_path(&sysroot, &target_triple);
-                let p = std::array::IntoIter::new([
+                let p = PathBuf::from_iter([
                     Path::new(sysroot),
                     Path::new(&rustlib_path),
                     Path::new("target.json"),
-                ])
-                .collect::<PathBuf>();
+                ]);
                 if p.is_file() {
                     return load_file(&p);
                 }