Add new error codes on privacy checking

src/librustc_privacy/diagnostics.rs

@@ -0,0 +1,235 @@
+// Copyright 2014 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.
+
+#![allow(non_snake_case)]
+
+register_long_diagnostics! {
+
+E0445: r##"
+A private trait was used on a public type parameter bound. Erroneous code
+examples:
+
+```
+trait Foo {
+    fn dummy(&self) { }
+}
+
+pub trait Bar : Foo {} // error: private trait in exported type parameter bound
+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.
+Example:
+
+```
+pub trait Foo { // we set the Foo trait public
+    fn dummy(&self) { }
+}
+
+pub trait Bar : Foo {} // ok!
+pub struct Bar<T: Foo>(pub T); // ok!
+pub fn foo<T: Foo> (t: T) {} // ok!
+```
+"##,
+
+E0446: r##"
+A private type was used in an exported type signature. Erroneous code example:
+
+```
+mod Foo {
+    struct Bar(u32);
+
+    pub fn bar() -> Bar { // error: private type in exported type signature
+        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:
+
+```
+mod Foo {
+    pub struct Bar(u32); // we set the Bar type public
+
+    pub fn bar() -> Bar { // ok!
+        Bar(0)
+    }
+}
+```
+"##,
+
+E0447: r##"
+The `pub` keyword was used inside a function. Erroneous code example:
+
+```
+fn foo() {
+    pub struct Bar; // error: visibility has no effect inside functions
+}
+```
+
+Since we cannot access items defined inside a function, the visibility of its
+items does not impact outer code. So using the `pub` keyword in this context
+is invalid.
+"##,
+
+E0448: r##"
+The `pub` keyword was used inside a public enum. Erroneous code example:
+
+```
+pub enum Foo {
+    pub Bar, // error: unnecessary `pub` visibility
+}
+```
+
+Since the enum is already public, adding `pub` on one its elements is
+unnecessary. Example:
+
+```
+enum Foo {
+    pub Bar, // ok!
+}
+
+// or:
+
+pub enum Foo {
+    Bar, // ok!
+}
+```
+"##,
+
+E0449: r##"
+A visibility qualifier was used when it was unnecessary. Erroneous code
+examples:
+
+```
+struct Bar;
+
+trait Foo {
+    fn foo();
+}
+
+pub impl Bar {} // error: unnecessary visibility qualifier
+
+pub impl Foo for Bar { // error: unnecessary visibility qualifier
+    pub fn foo() {} // error: unnecessary visibility qualifier
+}
+```
+
+To fix this error, please remove the visibility qualifier when it is not
+required. Example:
+
+```
+struct Bar;
+
+trait Foo {
+    fn foo();
+}
+
+// Directly implemented methods share the visibility of the type itself,
+// so `pub` is unnecessary here
+impl Bar {}
+
+// Trait methods share the visibility of the trait, so `pub` is
+// unnecessary in either case
+pub impl Foo for Bar {
+    pub fn foo() {}
+}
+```
+"##,
+
+E0450: r##"
+A tuple constructor was invoked while some of its fields are private. Erroneous
+code example:
+
+```
+mod Bar {
+    pub struct Foo(isize);
+}
+
+let f = Bar::Foo(0); // error: cannot invoke tuple struct constructor with
+                     //        private fields
+```
+
+To solve this issue, please ensure that all of the fields of the tuple struct
+are public. Alternatively, provide a new() method to the tuple struct to
+construct it from a given inner value. Example:
+
+```
+mod Bar {
+    pub struct Foo(pub isize); // we set its field to public
+}
+
+let f = Bar::Foo(0); // ok!
+
+// or:
+mod bar {
+    pub struct Foo(isize);
+
+    impl Foo {
+        pub fn new(x: isize) {
+            Foo(x)
+        }
+    }
+}
+
+let f = bar::Foo::new(1);
+```
+"##,
+
+E0451: r##"
+A struct constructor with private fields was invoked. Erroneous code example:
+
+```
+mod Bar {
+    pub struct Foo {
+        pub a: isize,
+        b: isize,
+    }
+}
+
+let f = Bar::Foo{ a: 0, b: 0 }; // error: field `b` of struct `Bar::Foo`
+                                //        is private
+```
+
+To fix this error, please ensure that all the fields of the struct, or
+implement a function for easy instantiation. Examples:
+
+```
+mod Bar {
+    pub struct Foo {
+        pub a: isize,
+        pub b: isize, // we set `b` field public
+    }
+}
+
+let f = Bar::Foo{ a: 0, b: 0 }; // ok!
+
+// or:
+mod Bar {
+    pub struct Foo {
+        pub a: isize,
+        b: isize, // still private
+    }
+
+    impl Foo {
+        pub fn new() -> Foo { // we create a method to instantiate `Foo`
+            Foo { a: 0, b: 0 }
+        }
+    }
+}
+
+let f = Bar::Foo::new(); // ok!
+```
+"##,
+
+}

src/librustc_privacy/lib.rs

@@ -50,6 +50,8 @@ use rustc::front::map as ast_map;
 use syntax::ast;
 use syntax::codemap::Span;
 
+pub mod diagnostics;
+
 type Context<'a, 'tcx> = (&'a ty::MethodMap<'tcx>, &'a def::ExportMap);
 
 /// Result of a checking operation - None => no errors were found. Some => an
@@ -715,7 +717,8 @@ impl<'a, 'tcx> PrivacyVisitor<'a, 'tcx> {
             UnnamedField(idx) => format!("field #{} of {} is private",
                                          idx + 1, struct_desc),
         };
-        self.tcx.sess.span_err(span, &msg[..]);
+        span_err!(self.tcx.sess, span, E0451,
+                  "{}", &msg[..]);
     }
 
     // Given the ID of a method, checks to ensure it's in scope.
@@ -929,9 +932,9 @@ impl<'a, 'tcx, 'v> Visitor<'v> for PrivacyVisitor<'a, 'tcx> {
                         });
 
                     if any_priv {
-                        self.tcx.sess.span_err(expr.span,
-                                               "cannot invoke tuple struct constructor \
-                                                with private fields");
+                        span_err!(self.tcx.sess, expr.span, E0450,
+                                  "cannot invoke tuple struct constructor with private \
+                                   fields");
                     }
                 }
             }
@@ -1043,7 +1046,8 @@ impl<'a, 'tcx> SanePrivacyVisitor<'a, 'tcx> {
         let tcx = self.tcx;
         let check_inherited = |sp: Span, vis: hir::Visibility, note: &str| {
             if vis != hir::Inherited {
-                tcx.sess.span_err(sp, "unnecessary visibility qualifier");
+                span_err!(tcx.sess, sp, E0449,
+                          "unnecessary visibility qualifier");
                 if !note.is_empty() {
                     tcx.sess.span_note(sp, note);
                 }
@@ -1076,8 +1080,8 @@ impl<'a, 'tcx> SanePrivacyVisitor<'a, 'tcx> {
                     match v.node.vis {
                         hir::Public => {
                             if item.vis == hir::Public {
-                                tcx.sess.span_err(v.span, "unnecessary `pub` \
-                                                           visibility");
+                                span_err!(tcx.sess, v.span, E0448,
+                                          "unnecessary `pub` visibility");
                             }
                         }
                         hir::Inherited => {}
@@ -1098,7 +1102,8 @@ impl<'a, 'tcx> SanePrivacyVisitor<'a, 'tcx> {
         let tcx = self.tcx;
         fn check_inherited(tcx: &ty::ctxt, sp: Span, vis: hir::Visibility) {
             if vis != hir::Inherited {
-                tcx.sess.span_err(sp, "visibility has no effect inside functions");
+                span_err!(tcx.sess, sp, E0447,
+                          "visibility has no effect inside functions");
             }
         }
         let check_struct = |def: &hir::StructDef| {
@@ -1193,8 +1198,8 @@ impl<'a, 'tcx> VisiblePrivateTypesVisitor<'a, 'tcx> {
             if !self.tcx.sess.features.borrow().visible_private_types &&
                 self.path_is_private_type(trait_ref.trait_ref.ref_id) {
                     let span = trait_ref.trait_ref.path.span;
-                    self.tcx.sess.span_err(span, "private trait in exported type \
-                                                  parameter bound");
+                    span_err!(self.tcx.sess, span, E0445,
+                              "private trait in exported type parameter bound");
             }
         }
     }
@@ -1435,7 +1440,8 @@ impl<'a, 'tcx, 'v> Visitor<'v> for VisiblePrivateTypesVisitor<'a, 'tcx> {
         if let hir::TyPath(_, ref p) = t.node {
             if !self.tcx.sess.features.borrow().visible_private_types &&
                 self.path_is_private_type(t.id) {
-                self.tcx.sess.span_err(p.span, "private type in exported type signature");
+                span_err!(self.tcx.sess, p.span, E0446,
+                          "private type in exported type signature");
             }
         }
         visit::walk_ty(self, t)