Add error explanations for E0055, E0089, E0192, E0261, E0262, E0263, E0318.

Author: Nick Hamann

src/librustc/diagnostics.rs

@@ -396,6 +396,54 @@ enum Method { GET, POST }
 ```
 "##,
 
+E0261: r##"
+When using a lifetime like `'a` in a type, it must be declared before being
+used.
+
+These two examples illustrate the problem:
+
+```
+// error, use of undeclared lifetime name `'a`
+fn foo(x: &'a str) { }
+
+struct Foo {
+    // error, use of undeclared lifetime name `'a`
+    x: &'a str,
+}
+```
+
+These can be fixed by declaring lifetime parameters:
+
+```
+fn foo<'a>(x: &'a str) { }
+
+struct Foo<'a> {
+    x: &'a str,
+}
+```
+"##,
+
+E0262: r##"
+Declaring certain lifetime names in parameters is disallowed. For example,
+because the `'static` lifetime is a special built-in lifetime name denoting
+the lifetime of the entire program, this is an error:
+
+```
+// error, illegal lifetime parameter name `'static`
+fn foo<'static>(x: &'static str) { }
+```
+"##,
+
+E0263: r##"
+A lifetime name cannot be declared more than once in the same scope. For
+example:
+
+```
+// error, lifetime name `'a` declared twice in the same scope
+fn foo<'a, 'b, 'a>(x: &'a str, y: &'b str) { }
+```
+"##,
+
 E0265: r##"
 This error indicates that a static or constant references itself.
 All statics and constants need to resolve to a value in an acyclic manner.
@@ -814,9 +862,6 @@ register_diagnostics! {
     E0136,
     E0138,
     E0139,
-    E0261, // use of undeclared lifetime name
-    E0262, // illegal lifetime parameter name
-    E0263, // lifetime name declared twice in same scope
     E0264, // unknown external lang item
     E0266, // expected item
     E0269, // not all control paths return a value

src/librustc_typeck/diagnostics.rs

@@ -274,6 +274,37 @@ let x_is_nonzero = x as bool;
 ```
 "##,
 
+E0055: r##"
+During a method call, a value is automatically dereferenced as many times as
+needed to make the value's type match the method's receiver. The catch is that
+the compiler will only attempt to dereference a number of times up to the
+recursion limit (which can be set via the `recursion_limit` attribute).
+
+For a somewhat artificial example:
+
+```
+#![recursion_limit="2"]
+
+struct Foo;
+
+impl Foo {
+    fn foo(&self) {}
+}
+
+fn main() {
+    let foo = Foo;
+    let ref_foo = &&Foo;
+
+    // error, reached the recursion limit while auto-dereferencing &&Foo
+    ref_foo.foo();
+}
+```
+
+One fix may be to increase the recursion limit. Note that it is possible to
+create an infinite recursion of dereferencing, in which case the only fix is to
+somehow break the recursion.
+"##,
+
 E0062: r##"
 This error indicates that during an attempt to build a struct or struct-like
 enum variant, one of the fields was specified more than once. Each field should
@@ -524,6 +555,31 @@ enum Empty {}
 ```
 "##,
 
+E0089: r##"
+Not enough type parameters were supplied for a function. For example:
+
+```
+fn foo<T, U>() {}
+
+fn main() {
+    foo::<f64>(); // error, expected 2 parameters, found 1 parameter
+}
+```
+
+Note that if a function takes multiple type parameters but you want the compiler
+to infer some of them, you can use type placeholders:
+
+```
+fn foo<T, U>(x: T) {}
+
+fn main() {
+    let x: bool = true;
+    foo::<f64>(x);    // error, expected 2 parameters, found 1 parameter
+    foo::<_, f64>(x); // same as `foo::<bool, f64>(x)`
+}
+```
+"##,
+
 E0106: r##"
 This error indicates that a lifetime is missing from a type. If it is an error
 inside a function signature, the problem may be with failing to adhere to the
@@ -678,6 +734,12 @@ it has been disabled for now.
 [iss20126]: https://github.com/rust-lang/rust/issues/20126
 "##,
 
+E0192: r##"
+Negative impls are only allowed for traits with default impls. For more
+information see the [opt-in builtin traits RFC](https://github.com/rust-lang/
+rfcs/blob/master/text/0019-opt-in-builtin-traits.md).
+"##,
+
 E0197: r##"
 Inherent implementations (one that do not implement a trait but provide
 methods associated with a type) are always safe because they are not
@@ -899,6 +961,12 @@ const C: [u32; u8::MAX + f64::EPSILON] = [];
 ```
 "##,
 
+E0318: r##"
+Default impls for a trait must be located in the same crate where the trait was
+defined. For more information see the [opt-in builtin traits RFC](https://github
+.com/rust-lang/rfcs/blob/master/text/0019-opt-in-builtin-traits.md).
+"##,
+
 E0322: r##"
 The `Sized` trait is a special trait built-in to the compiler for types with a
 constant size known at compile-time. This trait is automatically implemented
@@ -989,7 +1057,6 @@ register_diagnostics! {
     E0040, // explicit use of destructor method
     E0044, // foreign items may not have type parameters
     E0045, // variadic function must have C calling convention
-    E0055, // method has an incompatible type for trait
     E0057, // method has an incompatible type for trait
     E0059,
     E0060,
@@ -1004,7 +1071,6 @@ register_diagnostics! {
     E0086,
     E0087,
     E0088,
-    E0089,
     E0090,
     E0091,
     E0092,
@@ -1044,7 +1110,6 @@ register_diagnostics! {
     E0189, // deprecated: can only cast a boxed pointer to a boxed object
     E0190, // deprecated: can only cast a &-pointer to an &-object
     E0191, // value of the associated type must be specified
-    E0192, // negative impls are allowed just for `Send` and `Sync`
     E0193, // cannot bound type where clause bounds may only be attached to types
            // involving type parameters
     E0194,
@@ -1093,7 +1158,6 @@ register_diagnostics! {
     E0246, // illegal recursive type
     E0247, // found module name used as a type
     E0248, // found value name used as a type
-    E0318, // can't create default impls for traits outside their crates
     E0319, // trait impls for defaulted traits allowed just for structs/enums
     E0320, // recursive overflow during dropck
     E0321, // extended coherence rules for defaulted traits violated