Keep track of the whole error chain

Author: flaper87

src/librustc/middle/traits/select.rs

@@ -1928,6 +1928,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         }
     }
 
+    #[allow(unused_comparisons)]
     fn derived_cause(&self,
                      obligation: &TraitObligation<'tcx>,
                      variant: fn(Rc<ty::Binder<ty::TraitRef<'tcx>>>,
@@ -1945,7 +1946,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
          * reporting.
          */
 
-        if obligation.recursion_depth == 0 {
+        // NOTE(flaper87): As of now, it keeps track of the whole error
+        // chain. Ideally, we should have a way to configure this either
+        // by using -Z verbose or just a CLI argument.
+        if obligation.recursion_depth >= 0 {
             ObligationCause::new(obligation.cause.span,
                                  obligation.trait_ref.def_id().node,
                                  variant(obligation.trait_ref.clone(),

src/libsyntax/ext/deriving/bounds.rs

@@ -26,8 +26,11 @@ pub fn expand_deriving_bound<F>(cx: &mut ExtCtxt,
         MetaWord(ref tname) => {
             match tname.get() {
                 "Copy" => "Copy",
-                "Send" => "Send",
-                "Sync" => "Sync",
+                "Send" | "Sync" => {
+                    return cx.span_err(span,
+                                       format!("{} is an unsafe trait and it \
+                                               should be implemented explicitly", *tname)[])
+                }
                 ref tname => {
                     cx.span_bug(span,
                                 format!("expected built-in trait name but \

src/test/compile-fail/deriving-bounds.rs

@@ -8,8 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#[deriving(Sync(Bad),Send,Copy)]
+#[deriving(Copy(Bad))]
 //~^ ERROR unexpected value in deriving, expected a trait
 struct Test;
 
+#[deriving(Sync)]
+//~^ ERROR Sync is an unsafe trait and it should be implemented explicitly
+struct Test1;
+
 pub fn main() {}

src/test/compile-fail/issue-17718-static-sync.rs

@@ -14,6 +14,6 @@ struct Foo { marker: marker::NoSync }
 
 static FOO: uint = 3;
 static BAR: Foo = Foo { marker: marker::NoSync };
-//~^ ERROR: shared static items must have a type which implements Sync
+//~^ ERROR: the trait `core::kinds::Sync` is not implemented
 
 fn main() {}

src/test/compile-fail/issue-7013.rs

@@ -33,4 +33,5 @@ struct A {
 fn main() {
     let a = A {v: box B{v: None} as Box<Foo+Send>};
     //~^ ERROR the trait `core::kinds::Send` is not implemented
+    //~^^ ERROR the trait `core::kinds::Send` is not implemented
 }

src/test/compile-fail/issue-7364.rs

@@ -14,6 +14,8 @@ use std::cell::RefCell;
 // Regresion test for issue 7364
 static boxed: Box<RefCell<int>> = box RefCell::new(0);
 //~^ ERROR statics are not allowed to have custom pointers
-//~^^ ERROR: shared static items must have a type which implements Sync
+//~^^ ERROR: the trait `core::kinds::Sync` is not implemented for the type
+//~^^^ ERROR: the trait `core::kinds::Sync` is not implemented for the type
+//~^^^^ ERROR: the trait `core::kinds::Sync` is not implemented for the type
 
 fn main() { }

src/test/compile-fail/kindck-destructor-owned.rs

@@ -9,19 +9,6 @@
 // except according to those terms.
 
 
-use std::rc::Rc;
-
-struct Foo {
-    f: Rc<int>,
-}
-
-impl Drop for Foo {
-//~^ ERROR the trait `core::kinds::Send` is not implemented
-//~^^ NOTE cannot implement a destructor on a structure or enumeration that does not satisfy Send
-    fn drop(&mut self) {
-    }
-}
-
 struct Bar<'a> {
     f: &'a int,
 }

src/test/compile-fail/kindck-nonsendable-1.rs

@@ -17,6 +17,8 @@ fn bar<F:FnOnce() + Send>(_: F) { }
 
 fn main() {
     let x = Rc::new(3u);
-    bar(move|| foo(x)); //~ ERROR `core::kinds::Send` is not implemented
+    bar(move|| foo(x));
+    //~^ ERROR `core::kinds::Send` is not implemented
+    //~^^ ERROR `core::kinds::Send` is not implemented
 }
 

src/test/compile-fail/kindck-send-unsafe.rs

@@ -8,14 +8,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+extern crate core;
+
 fn assert_send<T:Send>() { }
 
-// unsafe ptrs are ok unless they point at unsendable things
-fn test70() {
-    assert_send::<*mut int>();
-}
 fn test71<'a>() {
-    assert_send::<*mut &'a int>(); //~ ERROR declared lifetime bound not satisfied
+    assert_send::<*mut &'a int>();
+    //~^ ERROR the trait `core::kinds::Send` is not implemented for the type
 }
 
 fn main() {

src/test/compile-fail/mut-not-freeze.rs

@@ -14,5 +14,8 @@ fn f<T: Sync>(_: T) {}
 
 fn main() {
     let x = RefCell::new(0i);
-    f(x); //~ ERROR `core::kinds::Sync` is not implemented
+    f(x);
+    //~^ ERROR `core::kinds::Sync` is not implemented
+    //~^^ ERROR `core::kinds::Sync` is not implemented
+    //~^^^ ERROR `core::kinds::Sync` is not implemented
 }