Fixed incorrect error explanation

Author: christopherdumas

src/librustc_typeck/diagnostics.rs

@@ -1535,11 +1535,11 @@ For information on the design of the orphan rules, see [RFC 1023].
 
 E0118: r##"
 Rust can't find a base type for an implementation you are providing, or the type
-cannot have an implementation. For example, a typedef can't have an
-implementation, since it isn't its own type (this was done in PR #6087):
+cannot have an implementation. For example, only a named type or a trait can
+have an implementation:
 
 ```
-type NineString = [char, ..9]
+type NineString = [char, ..9] // This isn't a named type (struct, enum or trait)
 impl NineString {
     // Some code here
 }