Rollup merge of #36003 - GuillaumeGomez:err_codes, r=jonathandturner

Err codes

r? @jonathandturner

Author: Jonathan Turner

src/librustc/diagnostics.rs

@@ -1721,6 +1721,50 @@ fn cookie() -> ! { // error: definition of an unknown language item: `cookie`
 ```
 "##,
 
+E0525: r##"
+A closure was attempted to get used whereas it doesn't implement the expected
+trait.
+
+Erroneous code example:
+
+```compile_fail,E0525
+struct X;
+
+fn foo<T>(_: T) {}
+fn bar<T: Fn(u32)>(_: T) {}
+
+fn main() {
+    let x = X;
+    let closure = |_| foo(x); // error: expected a closure that implements
+                              //        the `Fn` trait, but this closure only
+                              //        implements `FnOnce`
+    bar(closure);
+}
+```
+
+In the example above, `closure` is an `FnOnce` closure whereas the `bar`
+function expected an `Fn` closure. In this case, it's simple to fix the issue,
+you just have to implement `Copy` and `Clone` traits on `struct X` and it'll
+be ok:
+
+```
+#[derive(Clone, Copy)] // We implement `Clone` and `Copy` traits.
+struct X;
+
+fn foo<T>(_: T) {}
+fn bar<T: Fn(u32)>(_: T) {}
+
+fn main() {
+    let x = X;
+    let closure = |_| foo(x);
+    bar(closure); // ok!
+}
+```
+
+To understand better how closures work in Rust, read:
+https://doc.rust-lang.org/book/closures.html
+"##,
+
 }
 
 
@@ -1760,5 +1804,4 @@ register_diagnostics! {
     E0490, // a value of type `..` is borrowed for too long
     E0491, // in type `..`, reference has a longer lifetime than the data it...
     E0495, // cannot infer an appropriate lifetime due to conflicting requirements
-    E0525  // expected a closure that implements `..` but this closure only implements `..`
 }

src/librustc_lint/types.rs

@@ -56,7 +56,6 @@ let Wrapping(x) = x;
 let y: usize = 1.wrapping_neg();
 assert_eq!(x, y);
 ```
-
 "##
 }
 

src/librustc_trans/diagnostics.rs

@@ -23,8 +23,10 @@ extern "platform-intrinsic" {
     fn simd_add<T>(a: T, b: T) -> T;
 }
 
-unsafe { simd_add(0, 1); }
-// error: invalid monomorphization of `simd_add` intrinsic
+fn main() {
+    unsafe { simd_add(0, 1); }
+    // error: invalid monomorphization of `simd_add` intrinsic
+}
 ```
 
 The generic type has to be a SIMD type. Example:

src/test/compile-fail/E0502.rs

@@ -0,0 +1,18 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn bar(x: &mut i32) {}
+fn foo(a: &mut i32) {
+    let ref y = a;
+    bar(a); //~ ERROR E0502
+}
+
+fn main() {
+}

src/test/compile-fail/E0503.rs

@@ -0,0 +1,15 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    let mut value = 3;
+    let _borrow = &mut value;
+    let _sum = value + 1; //~ ERROR E0503
+}

src/test/compile-fail/E0504.rs

@@ -0,0 +1,25 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct FancyNum {
+    num: u8,
+}
+
+fn main() {
+    let fancy_num = FancyNum { num: 5 };
+    let fancy_ref = &fancy_num;
+
+    let x = move || {
+        println!("child function: {}", fancy_num.num); //~ ERROR E0504
+    };
+
+    x();
+    println!("main function: {}", fancy_ref.num);
+}

src/test/compile-fail/E0505.rs

@@ -0,0 +1,21 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct Value {}
+
+fn eat(val: Value) {}
+
+fn main() {
+    let x = Value{};
+    {
+        let _ref_to_val: &Value = &x;
+        eat(x); //~ ERROR E0505
+    }
+}

src/test/compile-fail/E0506.rs

@@ -0,0 +1,21 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct FancyNum {
+    num: u8,
+}
+
+fn main() {
+    let mut fancy_num = FancyNum { num: 5 };
+    let fancy_ref = &fancy_num;
+    fancy_num = FancyNum { num: 6 }; //~ ERROR E0506
+
+    println!("Num: {}, Ref: {}", fancy_num.num, fancy_ref.num);
+}

src/test/compile-fail/E0507.rs

@@ -0,0 +1,23 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::cell::RefCell;
+
+struct TheDarkKnight;
+
+impl TheDarkKnight {
+    fn nothing_is_true(self) {}
+}
+
+fn main() {
+    let x = RefCell::new(TheDarkKnight);
+
+    x.borrow().nothing_is_true(); //~ ERROR E0507
+}

src/test/compile-fail/E0508.rs

@@ -0,0 +1,16 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct NonCopy;
+
+fn main() {
+    let array = [NonCopy; 1];
+    let _value = array[0]; //~ ERROR E0508
+}