improve error note

src/libsyntax/parse/parser.rs

@@ -1828,7 +1828,7 @@ impl<'a> Parser<'a> {
             let mut err = self.struct_span_err(self.prev_span,
                 "unexpected `self` argument in function");
             err.span_label(self.prev_span,
-                "`self` is only valid as the first argument of a trait function");
+                "`self` is only valid as the first argument of an associated function");
             return Err(err);
         }
 

src/test/ui/invalid-self-argument/bare-fn-start.rs

@@ -1,5 +1,5 @@
 fn a(&self) { }
 //~^ ERROR unexpected `self` argument in function
-//~| NOTE `self` is only valid as the first argument of a trait function
+//~| NOTE `self` is only valid as the first argument of an associated function
 
 fn main() { }

src/test/ui/invalid-self-argument/bare-fn-start.stderr

@@ -2,7 +2,7 @@ error: unexpected `self` argument in function
   --> $DIR/bare-fn-start.rs:1:7
    |
 LL | fn a(&self) { }
-   |       ^^^^ `self` is only valid as the first argument of a trait function
+   |       ^^^^ `self` is only valid as the first argument of an associated function
 
 error: aborting due to previous error
 

src/test/ui/invalid-self-argument/bare-fn.rs

@@ -1,5 +1,5 @@
 fn b(foo: u32, &mut self) { }
 //~^ ERROR unexpected `self` argument in function
-//~| NOTE `self` is only valid as the first argument of a trait function
+//~| NOTE `self` is only valid as the first argument of an associated function
 
 fn main() { }

src/test/ui/invalid-self-argument/bare-fn.stderr

@@ -2,7 +2,7 @@ error: unexpected `self` argument in function
   --> $DIR/bare-fn.rs:1:21
    |
 LL | fn b(foo: u32, &mut self) { }
-   |                     ^^^^ `self` is only valid as the first argument of a trait function
+   |                     ^^^^ `self` is only valid as the first argument of an associated function
 
 error: aborting due to previous error
 

src/test/ui/invalid-self-argument/trait-fn.rs

@@ -3,7 +3,7 @@ struct Foo {}
 impl Foo {
     fn c(foo: u32, self) {}
     //~^ ERROR unexpected `self` argument in function
-    //~| NOTE `self` is only valid as the first argument of a trait function
+    //~| NOTE `self` is only valid as the first argument of an associated function
 
     fn good(&mut self, foo: u32) {}
 }

src/test/ui/invalid-self-argument/trait-fn.stderr

@@ -2,7 +2,7 @@ error: unexpected `self` argument in function
   --> $DIR/trait-fn.rs:4:20
    |
 LL |     fn c(foo: u32, self) {}
-   |                    ^^^^ `self` is only valid as the first argument of a trait function
+   |                    ^^^^ `self` is only valid as the first argument of an associated function
 
 error: aborting due to previous error