Update error messages and error descriptions

Author: petrochenkov

src/librustc_privacy/diagnostics.rs

@@ -21,13 +21,14 @@ trait Foo {
     fn dummy(&self) { }
 }
 
-pub trait Bar : Foo {} // error: private trait in exported type parameter bound
+pub trait Bar : Foo {} // error: private trait in public interface
 pub struct Bar<T: Foo>(pub T); // same error
 pub fn foo<T: Foo> (t: T) {} // same error
 ```
 
-To solve this error, please ensure that the trait is also public and accessible
-at the same level of the public functions or types which are bound on it.
+To solve this error, please ensure that the trait is also public. The trait
+can be made inaccessible if necessary by placing it into a private inner module,
+but it still has to be marked with `pub`.
 Example:
 
 ```
@@ -42,20 +43,22 @@ pub fn foo<T: Foo> (t: T) {} // ok!
 "##,
 
 E0446: r##"
-A private type was used in an exported type signature. Erroneous code example:
+A private type was used in an public type signature. Erroneous code example:
 
 ```
 mod Foo {
     struct Bar(u32);
 
-    pub fn bar() -> Bar { // error: private type in exported type signature
+    pub fn bar() -> Bar { // error: private type in public interface
         Bar(0)
     }
 }
 ```
 
-To solve this error, please ensure that the type is also public and accessible
-at the same level of the public functions or types which use it. Example:
+To solve this error, please ensure that the type is also public. The type
+can be made inaccessible if necessary by placing it into a private inner module,
+but it still has to be marked with `pub`.
+Example:
 
 ```
 mod Foo {

src/librustc_privacy/lib.rs

@@ -1136,7 +1136,7 @@ impl<'a, 'tcx: 'a, 'v> Visitor<'v> for SearchInterfaceForPrivateItemsVisitor<'a,
                             if item.vis != hir::Public {
                                 if !self.is_quiet {
                                     span_err!(self.tcx.sess, ty.span, E0446,
-                                              "private type in exported type signature");
+                                              "private type in public interface");
                                 }
                                 self.is_public = false;
                             }
@@ -1162,7 +1162,7 @@ impl<'a, 'tcx: 'a, 'v> Visitor<'v> for SearchInterfaceForPrivateItemsVisitor<'a,
                 if item.vis != hir::Public {
                     if !self.is_quiet {
                         span_err!(self.tcx.sess, trait_ref.path.span, E0445,
-                                  "private trait in exported type parameter bound");
+                                  "private trait in public interface");
                     }
                     self.is_public = false;
                 }

src/test/compile-fail/issue-18389.rs

@@ -14,7 +14,7 @@ use std::any::TypeId;
 trait Private<P, R> {
     fn call(&self, p: P, r: R);
 }
-pub trait Public: Private< //~ ERROR private trait in exported type parameter bound
+pub trait Public: Private< //~ ERROR private trait in public interface
     <Self as Public>::P,
     <Self as Public>::R
 > {

src/test/compile-fail/issue-22912.rs

@@ -20,7 +20,7 @@ trait PrivateTrait {
 }
 
 impl PublicTrait for PublicType {
-    type Item = PrivateType;  //~ ERROR private type in exported type signature
+    type Item = PrivateType;  //~ ERROR private type in public interface
 }
 
 // OK

src/test/compile-fail/issue-28325.rs

@@ -16,7 +16,7 @@ mod y {
     struct Bar { x: u32 }
 
     impl Foo {
-        pub fn foo(&self, x: Self, y: Bar) { } //~ ERROR private type in exported type signature
+        pub fn foo(&self, x: Self, y: Bar) { } //~ ERROR private type in public interface
     }
 }
 
@@ -26,9 +26,9 @@ mod x {
     struct Bar { _x: u32 }
 
     impl Foo {
-        pub fn foo(&self, _x: Self, _y: Bar) { } //~ ERROR private type in exported type signature
+        pub fn foo(&self, _x: Self, _y: Bar) { } //~ ERROR private type in public interface
         pub fn bar(&self) -> Bar { Bar { _x: self.x } }
-        //~^ ERROR private type in exported type signature
+        //~^ ERROR private type in public interface
     }
 }
 

src/test/compile-fail/issue-28450.rs

@@ -15,21 +15,21 @@ struct Priv;
 pub use self::private::public;
 
 mod private {
-    pub type Priv = super::Priv; //~ ERROR private type in exported type signature
+    pub type Priv = super::Priv; //~ ERROR private type in public interface
 
     pub fn public(_x: Priv) {
     }
 }
 
 struct __CFArray;
-pub type CFArrayRef = *const __CFArray; //~ ERROR private type in exported type signature
+pub type CFArrayRef = *const __CFArray; //~ ERROR private type in public interface
 trait Pointer { type Pointee; }
 impl<T> Pointer for *const T { type Pointee = T; }
 pub type __CFArrayRevealed = <CFArrayRef as Pointer>::Pointee;
-//~^ ERROR private type in exported type signature
+//~^ ERROR private type in public interface
 
 type Foo = u8;
-pub fn foo(f: Foo) {} //~ ERROR private type in exported type signature
+pub fn foo(f: Foo) {} //~ ERROR private type in public interface
 
 pub trait Exporter {
     type Output;
@@ -43,7 +43,7 @@ pub fn block() -> <Helper as Exporter>::Output {
     }
 
     impl Exporter for Helper {
-        type Output = Inner; //~ ERROR private type in exported type signature
+        type Output = Inner; //~ ERROR private type in public interface
     }
 
     Inner

src/test/compile-fail/lint-visible-private-types.rs

@@ -36,17 +36,17 @@ impl Public<Private<isize>> {
     fn d() -> Private<isize> { panic!() }
 }
 impl Public<isize> {
-    pub fn e(&self) -> Private<isize> { panic!() } //~ ERROR private type in exported type signature
+    pub fn e(&self) -> Private<isize> { panic!() } //~ ERROR private type in public interface
     fn f(&self) -> Private<isize> { panic!() }
 }
 
-pub fn x(_: Private<isize>) {} //~ ERROR private type in exported type signature
+pub fn x(_: Private<isize>) {} //~ ERROR private type in public interface
 
 fn y(_: Private<isize>) {}
 
 
 pub struct Foo {
-    pub x: Private<isize>, //~ ERROR private type in exported type signature
+    pub x: Private<isize>, //~ ERROR private type in public interface
     y: Private<isize>
 }
 
@@ -55,9 +55,9 @@ struct Bar {
 }
 
 pub enum Baz {
-    Baz1(Private<isize>), //~ ERROR private type in exported type signature
+    Baz1(Private<isize>), //~ ERROR private type in public interface
     Baz2 {
-        y: Private<isize> //~ ERROR private type in exported type signature
+        y: Private<isize> //~ ERROR private type in public interface
     },
 }
 
@@ -69,14 +69,14 @@ enum Qux {
 }
 
 pub trait PubTrait {
-    fn foo(&self) -> Private<isize> { panic!( )} //~ ERROR private type in exported type signature
-    fn bar(&self) -> Private<isize>; //~ ERROR private type in exported type signature
-    fn baz() -> Private<isize>; //~ ERROR private type in exported type signature
+    fn foo(&self) -> Private<isize> { panic!( )} //~ ERROR private type in public interface
+    fn bar(&self) -> Private<isize>; //~ ERROR private type in public interface
+    fn baz() -> Private<isize>; //~ ERROR private type in public interface
 }
 
 impl PubTrait for Public<isize> {
-    fn bar(&self) -> Private<isize> { panic!() } //~ ERROR private type in exported type signature
-    fn baz() -> Private<isize> { panic!() } //~ ERROR private type in exported type signature
+    fn bar(&self) -> Private<isize> { panic!() } //~ ERROR private type in public interface
+    fn baz() -> Private<isize> { panic!() } //~ ERROR private type in public interface
 }
 impl PubTrait for Public<Private<isize>> {
     fn bar(&self) -> Private<isize> { panic!() }
@@ -117,7 +117,7 @@ impl ParamTrait<Private<isize>> for Private<isize> {
     fn foo() -> Private<isize> { panic!( )}
 }
 
-impl<T: ParamTrait<Private<isize>>>  //~ ERROR private type in exported type signature
+impl<T: ParamTrait<Private<isize>>>  //~ ERROR private type in public interface
      ParamTrait<T> for Public<i8> {
     fn foo() -> T { panic!() }
 }

src/test/compile-fail/priv_in_pub_sig_priv_mod.rs

@@ -14,12 +14,12 @@
 mod a {
     struct Priv;
 
-    pub fn expose_a() -> Priv { //~Error: private type in exported type signature
+    pub fn expose_a() -> Priv { //~Error: private type in public interface
         panic!();
     }
 
     mod b {
-        pub fn expose_b() -> super::Priv { //~Error: private type in exported type signature
+        pub fn expose_b() -> super::Priv { //~Error: private type in public interface
             panic!();
         }
     }

src/test/compile-fail/visible-private-types-generics.rs

@@ -14,52 +14,52 @@ trait Foo {
 
 pub fn f<
     T
-    : Foo //~ ERROR private trait in exported type parameter bound
+    : Foo //~ ERROR private trait in public interface
 >() {}
 
 pub fn g<T>() where
     T
-    : Foo //~ ERROR private trait in exported type parameter bound
+    : Foo //~ ERROR private trait in public interface
 {}
 
 pub struct S;
 
 impl S {
     pub fn f<
         T
-        : Foo //~ ERROR private trait in exported type parameter bound
+        : Foo //~ ERROR private trait in public interface
     >() {}
 
     pub fn g<T>() where
         T
-        : Foo //~ ERROR private trait in exported type parameter bound
+        : Foo //~ ERROR private trait in public interface
     {}
 }
 
 pub struct S1<
     T
-    : Foo //~ ERROR private trait in exported type parameter bound
+    : Foo //~ ERROR private trait in public interface
 > {
     x: T
 }
 
 pub struct S2<T> where
     T
-    : Foo //~ ERROR private trait in exported type parameter bound
+    : Foo //~ ERROR private trait in public interface
 {
     x: T
 }
 
 pub enum E1<
     T
-    : Foo //~ ERROR private trait in exported type parameter bound
+    : Foo //~ ERROR private trait in public interface
 > {
     V1(T)
 }
 
 pub enum E2<T> where
     T
-    : Foo //~ ERROR private trait in exported type parameter bound
+    : Foo //~ ERROR private trait in public interface
 {
     V2(T)
 }

src/test/compile-fail/visible-private-types-supertrait.rs

@@ -12,6 +12,6 @@ trait Foo {
     fn dummy(&self) { }
 }
 
-pub trait Bar : Foo {} //~ ERROR private trait in exported type
+pub trait Bar : Foo {} //~ ERROR private trait in public interface
 
 fn main() {}