Merge pull request rust-lang#1752 from rust-lang/gh1744

Remove an uneeded 'static lifetime

listings/ch12-an-io-project/listing-12-09/src/main.rs

@@ -22,7 +22,7 @@ struct Config {
 
 // ANCHOR: here
 impl Config {
-    fn new(args: &[String]) -> Result<Config, &'static str> {
+    fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-10/src/main.rs

@@ -29,7 +29,7 @@ struct Config {
 }
 
 impl Config {
-    fn new(args: &[String]) -> Result<Config, &'static str> {
+    fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-11/src/main.rs

@@ -37,7 +37,7 @@ struct Config {
 }
 
 impl Config {
-    fn new(args: &[String]) -> Result<Config, &'static str> {
+    fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-12/src/main.rs

@@ -38,7 +38,7 @@ struct Config {
 }
 
 impl Config {
-    fn new(args: &[String]) -> Result<Config, &'static str> {
+    fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-13/src/lib.rs

@@ -8,7 +8,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         // --snip--
         // ANCHOR_END: here
         if args.len() < 3 {

listings/ch12-an-io-project/listing-12-14/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-15/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-16/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-17/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-18/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-19/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-20/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-21/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-22/src/lib.rs

@@ -10,7 +10,7 @@ pub struct Config {
 // ANCHOR_END: here
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-23/src/lib.rs

@@ -14,7 +14,7 @@ pub struct Config {
 
 // ANCHOR: here
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/listing-12-24/src/lib.rs

@@ -9,7 +9,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/no-listing-01-handling-errors-in-main/src/main.rs

@@ -41,7 +41,7 @@ struct Config {
 }
 
 impl Config {
-    fn new(args: &[String]) -> Result<Config, &'static str> {
+    fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/no-listing-02-using-search-in-run/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/output-only-02-missing-lifetimes/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/output-only-03-multiple-matches/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch12-an-io-project/output-only-04-no-matches/src/lib.rs

@@ -7,7 +7,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch13-functional-features/listing-12-23-reproduced/src/lib.rs

@@ -10,7 +10,7 @@ pub struct Config {
 
 // ANCHOR: ch13
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch13-functional-features/listing-12-24-reproduced/src/lib.rs

@@ -9,7 +9,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

listings/ch13-functional-features/listing-13-25/src/lib.rs

@@ -9,7 +9,7 @@ pub struct Config {
 }
 
 impl Config {
-    pub fn new(args: &[String]) -> Result<Config, &'static str> {
+    pub fn new(args: &[String]) -> Result<Config, &str> {
         if args.len() < 3 {
             return Err("not enough arguments");
         }

src/ch12-03-improving-error-handling-and-modularity.md

@@ -277,10 +277,7 @@ next listing.
 `Config::new`</span>
 
 Our `new` function now returns a `Result` with a `Config` instance in the
-success case and a `&'static str` in the error case. Recall from [“The Static
-Lifetime”][the-static-lifetime]<!-- ignore --> section in Chapter 10 that
-`&'static str` is the type of string literals, which is our error message type
-for now.
+success case and a `&str` in the error case.
 
 We’ve made two changes in the body of the `new` function: instead of calling
 `panic!` when the user doesn’t pass enough arguments, we now return an `Err`
@@ -318,7 +315,7 @@ is an `Err` value, this method calls the code in the *closure*, which is an
 anonymous function we define and pass as an argument to `unwrap_or_else`. We’ll
 cover closures in more detail in [Chapter 13][ch13]<!-- ignore -->. For now,
 you just need to know that `unwrap_or_else` will pass the inner value of the
-`Err`, which in this case is the static string `not enough arguments` that we
+`Err`, which in this case is the static string `"not enough arguments"` that we
 added in Listing 12-9, to our closure in the argument `err` that appears
 between the vertical pipes. The code in the closure can then use the `err`
 value when it runs.
@@ -498,7 +495,6 @@ Let’s take advantage of this newfound modularity by doing something that would
 have been difficult with the old code but is easy with the new code: we’ll
 write some tests!
 
-[the-static-lifetime]: ch10-03-lifetime-syntax.html#the-static-lifetime
 [ch13]: ch13-00-functional-features.html
 [ch9-custom-types]: ch09-03-to-panic-or-not-to-panic.html#creating-custom-types-for-validation
 [ch9-error-guidelines]: ch09-03-to-panic-or-not-to-panic.html#guidelines-for-error-handling

src/ch13-03-improving-our-io-project.md

@@ -89,6 +89,16 @@ signature of the `Config::new` function so the parameter `args` has the type
 `args` and we’ll be mutating `args` by iterating over it, we can add the `mut`
 keyword into the specification of the `args` parameter to make it mutable.
 
+We also needed to specify that the string slice error type can now only have
+the `'static` lifetime. Because we’re only ever returning string literals, this
+was true before. However, when we had a reference in the parameters, there was
+the possibility that the reference in the return type could have had the same
+lifetime as the reference in the parameters. The rules that we discussed in the
+[“Lifetime Elision”][lifetime-elision] section of Chapter 10 applied, and we
+weren’t required to annotate the lifetime of `&str`. With the change to `args`,
+the lifetime elision rules no longer apply, and we must specify the `'static`
+lifetime.
+
 #### Using `Iterator` Trait Methods Instead of Indexing
 
 Next, we’ll fix the body of `Config::new`. The standard library documentation
@@ -165,3 +175,5 @@ the iterator must pass.
 But are the two implementations truly equivalent? The intuitive assumption
 might be that the more low-level loop will be faster. Let’s talk about
 performance.
+
+[lifetime-elision]: ch10-03-lifetime-syntax.html#lifetime-elision