auto merge of #15426 : aochagavia/rust/str, r=alexcrichton

* Deprecated `str::from_utf8_owned` in favor of `String::from_utf8`
* Deprecated `str::from_utf8_lossy` in favor of `String::from_utf8_lossy`
* Deprecated `str::from_utf16` in favor of `String::from_utf16`
* Deprecated `str::from_utf16_lossy` in favor of `String::from_utf16_lossy`
* Deprecated `str::from_chars` in favor of `String::from_chars`
* Deprecated `str::from_char` in favor of `String::from_char` and `.to_string()`
* Deprecated `str::from_byte` in favor of `String::from_byte`

[breaking-change]

src/compiletest/procsrv.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::str;
 use std::io::process::{ProcessExit, Command, Process, ProcessOutput};
 use std::dynamic_lib::DynamicLibrary;
 
@@ -25,7 +24,7 @@ fn add_target_env(cmd: &mut Command, lib_path: &str, aux_path: Option<&str>) {
     // Add the new dylib search path var
     let var = DynamicLibrary::envvar();
     let newpath = DynamicLibrary::create_path(path.as_slice());
-    let newpath = str::from_utf8(newpath.as_slice()).unwrap().to_string();
+    let newpath = String::from_utf8(newpath).unwrap();
     cmd.env(var.to_string(), newpath);
 }
 
@@ -55,8 +54,8 @@ pub fn run(lib_path: &str,
 
             Some(Result {
                 status: status,
-                out: str::from_utf8(output.as_slice()).unwrap().to_string(),
-                err: str::from_utf8(error.as_slice()).unwrap().to_string()
+                out: String::from_utf8(output).unwrap(),
+                err: String::from_utf8(error).unwrap()
             })
         },
         Err(..) => None

src/compiletest/runtest.rs

@@ -158,7 +158,7 @@ fn run_pretty_test(config: &Config, props: &TestProps, testfile: &Path) {
         match props.pp_exact { Some(_) => 1, None => 2 };
 
     let src = File::open(testfile).read_to_end().unwrap();
-    let src = str::from_utf8(src.as_slice()).unwrap().to_string();
+    let src = String::from_utf8(src.clone()).unwrap();
     let mut srcs = vec!(src);
 
     let mut round = 0;
@@ -185,10 +185,10 @@ fn run_pretty_test(config: &Config, props: &TestProps, testfile: &Path) {
         Some(ref file) => {
             let filepath = testfile.dir_path().join(file);
             let s = File::open(&filepath).read_to_end().unwrap();
-            str::from_utf8(s.as_slice()).unwrap().to_string()
-          }
-          None => { (*srcs.get(srcs.len() - 2u)).clone() }
-        };
+            String::from_utf8(s).unwrap()
+        }
+        None => { (*srcs.get(srcs.len() - 2u)).clone() }
+    };
     let mut actual = (*srcs.get(srcs.len() - 1u)).clone();
 
     if props.pp_exact.is_some() {
@@ -582,8 +582,8 @@ fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path)
                     process.wait_with_output().unwrap();
 
                 (status,
-                 str::from_utf8(output.as_slice()).unwrap().to_string(),
-                 str::from_utf8(error.as_slice()).unwrap().to_string())
+                 String::from_utf8(output).unwrap(),
+                 String::from_utf8(error).unwrap())
             },
             Err(e) => {
                 fatal(format!("Failed to setup Python process for \
@@ -813,7 +813,7 @@ fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
                 c
             }
         } ).collect();
-        str::from_chars(c.as_slice()).to_string()
+        String::from_chars(c.as_slice())
     }
 
     #[cfg(target_os = "win32")]