diff --git a/src/librustc_borrowck/borrowck/check_loans.rs b/src/librustc_borrowck/borrowck/check_loans.rs
index eed8f82b5d8..43e9cdd73c4 100644
--- a/src/librustc_borrowck/borrowck/check_loans.rs
+++ b/src/librustc_borrowck/borrowck/check_loans.rs
@@ -464,40 +464,36 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
 
             match (new_loan.kind, old_loan.kind) {
                 (ty::MutBorrow, ty::MutBorrow) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("cannot borrow `{}`{} as mutable \
-                                more than once at a time",
-                                nl, new_loan_msg))
+                    span_err!(self.bccx, new_loan.span, E0499,
+                              "cannot borrow `{}`{} as mutable \
+                               more than once at a time",
+                              nl, new_loan_msg);
                 }
 
                 (ty::UniqueImmBorrow, _) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("closure requires unique access to `{}` \
-                                but {} is already borrowed{}",
-                                nl, ol_pronoun, old_loan_msg));
+                    span_err!(self.bccx, new_loan.span, E0500,
+                              "closure requires unique access to `{}` \
+                               but {} is already borrowed{}",
+                              nl, ol_pronoun, old_loan_msg);
                 }
 
                 (_, ty::UniqueImmBorrow) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("cannot borrow `{}`{} as {} because \
-                                previous closure requires unique access",
-                                nl, new_loan_msg, new_loan.kind.to_user_str()));
+                    span_err!(self.bccx, new_loan.span, E0501,
+                              "cannot borrow `{}`{} as {} because \
+                               previous closure requires unique access",
+                              nl, new_loan_msg, new_loan.kind.to_user_str());
                 }
 
                 (_, _) => {
-                    self.bccx.span_err(
-                        new_loan.span,
-                        &format!("cannot borrow `{}`{} as {} because \
-                                {} is also borrowed as {}{}",
-                                nl,
-                                new_loan_msg,
-                                new_loan.kind.to_user_str(),
-                                ol_pronoun,
-                                old_loan.kind.to_user_str(),
-                                old_loan_msg));
+                    span_err!(self.bccx, new_loan.span, E0502,
+                              "cannot borrow `{}`{} as {} because \
+                               {} is also borrowed as {}{}",
+                              nl,
+                              new_loan_msg,
+                              new_loan.kind.to_user_str(),
+                              ol_pronoun,
+                              old_loan.kind.to_user_str(),
+                              old_loan_msg);
                 }
             }
 
@@ -617,11 +613,9 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
         match self.analyze_restrictions_on_use(id, copy_path, ty::ImmBorrow) {
             UseOk => { }
             UseWhileBorrowed(loan_path, loan_span) => {
-                self.bccx.span_err(
-                    span,
-                    &format!("cannot use `{}` because it was mutably borrowed",
-                            &self.bccx.loan_path_to_string(copy_path))
-                    );
+                span_err!(self.bccx, span, E0503,
+                          "cannot use `{}` because it was mutably borrowed",
+                          &self.bccx.loan_path_to_string(copy_path));
                 self.bccx.span_note(
                     loan_span,
                     &format!("borrow of `{}` occurs here",
@@ -642,18 +636,19 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
         match self.analyze_restrictions_on_use(id, move_path, ty::MutBorrow) {
             UseOk => { }
             UseWhileBorrowed(loan_path, loan_span) => {
-                let err_message = match move_kind {
+                match move_kind {
                     move_data::Captured =>
-                        format!("cannot move `{}` into closure because it is borrowed",
-                                &self.bccx.loan_path_to_string(move_path)),
+                        span_err!(self.bccx, span, E0504,
+                                  "cannot move `{}` into closure because it is borrowed",
+                                  &self.bccx.loan_path_to_string(move_path)),
                     move_data::Declared |
                     move_data::MoveExpr |
                     move_data::MovePat =>
-                        format!("cannot move out of `{}` because it is borrowed",
-                                &self.bccx.loan_path_to_string(move_path))
+                        span_err!(self.bccx, span, E0505,
+                                  "cannot move out of `{}` because it is borrowed",
+                                  &self.bccx.loan_path_to_string(move_path))
                 };
 
-                self.bccx.span_err(span, &err_message[..]);
                 self.bccx.span_note(
                     loan_span,
                     &format!("borrow of `{}` occurs here",
@@ -820,10 +815,9 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
                                    span: Span,
                                    loan_path: &LoanPath<'tcx>,
                                    loan: &Loan) {
-        self.bccx.span_err(
-            span,
-            &format!("cannot assign to `{}` because it is borrowed",
-                    self.bccx.loan_path_to_string(loan_path)));
+        span_err!(self.bccx, span, E0506,
+                  "cannot assign to `{}` because it is borrowed",
+                  self.bccx.loan_path_to_string(loan_path));
         self.bccx.span_note(
             loan.span,
             &format!("borrow of `{}` occurs here",
diff --git a/src/librustc_borrowck/borrowck/gather_loans/move_error.rs b/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
index c39b1a9da07..bbcf5193342 100644
--- a/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
+++ b/src/librustc_borrowck/borrowck/gather_loans/move_error.rs
@@ -119,18 +119,18 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
         mc::cat_deref(_, _, mc::Implicit(..)) |
         mc::cat_deref(_, _, mc::UnsafePtr(..)) |
         mc::cat_static_item => {
-            bccx.span_err(move_from.span,
-                          &format!("cannot move out of {}",
-                                  move_from.descriptive_string(bccx.tcx)));
+            span_err!(bccx, move_from.span, E0507,
+                      "cannot move out of {}",
+                      move_from.descriptive_string(bccx.tcx));
         }
 
         mc::cat_interior(ref b, mc::InteriorElement(Kind::Index, _)) => {
             let expr = bccx.tcx.map.expect_expr(move_from.id);
             if let hir::ExprIndex(..) = expr.node {
-                bccx.span_err(move_from.span,
-                              &format!("cannot move out of type `{}`, \
-                                        a non-copy fixed-size array",
-                                       b.ty));
+                span_err!(bccx, move_from.span, E0508,
+                          "cannot move out of type `{}`, \
+                           a non-copy fixed-size array",
+                          b.ty);
             }
         }
 
@@ -139,11 +139,10 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
             match b.ty.sty {
                 ty::TyStruct(def, _) |
                 ty::TyEnum(def, _) if def.has_dtor() => {
-                    bccx.span_err(
-                        move_from.span,
-                        &format!("cannot move out of type `{}`, \
-                                 which defines the `Drop` trait",
-                                b.ty));
+                    span_err!(bccx, move_from.span, E0509,
+                              "cannot move out of type `{}`, \
+                               which defines the `Drop` trait",
+                              b.ty);
                 },
                 _ => {
                     bccx.span_bug(move_from.span, "this path should not cause illegal move")
diff --git a/src/librustc_borrowck/diagnostics.rs b/src/librustc_borrowck/diagnostics.rs
index e94a214309d..ede1bb58ce6 100644
--- a/src/librustc_borrowck/diagnostics.rs
+++ b/src/librustc_borrowck/diagnostics.rs
@@ -263,12 +263,46 @@ fn mutable() {
 You can read more about cell types in the API documentation:
 
 https://doc.rust-lang.org/std/cell/
-"##
+"##,
+
+E0499: r##"
+A variable was borrowed as mutable more than once. Erroneous code example:
+
+```
+let mut i = 0;
+let mut x = &mut i;
+let mut a = &mut i;
+// error: cannot borrow `i` as mutable more than once at a time
+```
+
+Please note that in rust, you can have as many reference on a variable as you
+want, but only one can be mutable. Example:
+
+
+```
+let mut i = 0;
+let mut x = &mut i;
+let mut a = &i;
+let mut b = &i;
+let mut c = &i;
+// ...
+```
+"##,
 
 }
 
 register_diagnostics! {
     E0385, // {} in an aliasable location
     E0388, // {} in a static location
-    E0389  // {} in a `&` reference
+    E0389, // {} in a `&` reference
+    E0500, // closure requires unique access to `..` but .. is already borrowed
+    E0501, // cannot borrow `..`.. as .. because previous closure requires unique access
+    E0502, // cannot borrow `..`.. as .. because .. is also borrowed as ...
+    E0503, // cannot use `..` because it was mutably borrowed
+    E0504, // cannot move `..` into closure because it is borrowed
+    E0505, // cannot move out of `..` because it is borrowed
+    E0506, // cannot assign to `..` because it is borrowed
+    E0507, // cannot move out of ..
+    E0508, // cannot move out of type `..`, a non-copy fixed-size array
+    E0509, // cannot move out of type `..`, which defines the `Drop` trait
 }