Give an error number for "borrowed data escapes outside of closure"

src/librustc_mir/borrow_check/nll/region_infer/error_reporting/mod.rs

@@ -13,6 +13,7 @@ use borrow_check::nll::region_infer::RegionInferenceContext;
 use borrow_check::nll::region_infer::error_reporting::region_name::RegionNameSource;
 use borrow_check::nll::type_check::Locations;
 use borrow_check::nll::universal_regions::DefiningTy;
+use util::borrowck_errors::{BorrowckErrors, Origin};
 use rustc::hir::def_id::DefId;
 use rustc::infer::error_reporting::nice_region_error::NiceRegionError;
 use rustc::infer::InferCtxt;
@@ -395,9 +396,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                                              category, span, errors_buffer);
         }
 
-        let mut diag = infcx.tcx.sess.struct_span_err(
-            span, &format!("borrowed data escapes outside of {}", escapes_from),
-        );
+        let mut diag = infcx.tcx.borrowed_data_escapes_closure(span, escapes_from, Origin::Mir);
 
         if let Some((Some(outlived_fr_name), outlived_fr_span)) = outlived_fr_name_and_span {
             diag.span_label(

src/librustc_mir/diagnostics.rs

@@ -2339,6 +2339,7 @@ register_diagnostics! {
 //  E0471, // constant evaluation error (in pattern)
 //    E0385, // {} in an aliasable location
     E0493, // destructors cannot be evaluated at compile-time
+    E0521,  // borrowed data escapes outside of closure
     E0524, // two closures require unique access to `..` at the same time
     E0526, // shuffle indices are not constant
     E0594, // cannot assign to {}

src/librustc_mir/util/borrowck_errors.rs

@@ -717,6 +717,24 @@ pub trait BorrowckErrors<'cx>: Sized + Copy {
         self.cancel_if_wrong_origin(err, o)
     }
 
+    fn borrowed_data_escapes_closure(
+        self,
+        escape_span: Span,
+        escapes_from: &str,
+        o: Origin,
+    ) -> DiagnosticBuilder<'cx> {
+        let err = struct_span_err!(
+            self,
+            escape_span,
+            E0521,
+            "borrowed data escapes outside of {}{OGN}",
+            escapes_from,
+            OGN = o
+        );
+
+        self.cancel_if_wrong_origin(err, o)
+    }
+
     fn thread_local_value_does_not_live_long_enough(
         self,
         span: Span,

src/test/ui/borrowck/issue-45983.nll.stderr

@@ -1,4 +1,4 @@
-error: borrowed data escapes outside of closure
+error[E0521]: borrowed data escapes outside of closure
   --> $DIR/issue-45983.rs:36:18
    |
 LL |     let x = None;
@@ -18,4 +18,5 @@ LL |     give_any(|y| x = Some(y));
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0594`.
+Some errors occurred: E0521, E0594.
+For more information about an error, try `rustc --explain E0521`.

src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr

@@ -13,7 +13,7 @@ LL | |     })
                for<'r> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BrNamed(crate0:DefIndex(0:0), 'r)) u32>))
            ]
 
-error: borrowed data escapes outside of closure
+error[E0521]: borrowed data escapes outside of closure
   --> $DIR/propagate-approximated-shorter-to-static-comparing-against-free.rs:32:9
    |
 LL |     foo(cell, |cell_a, cell_x| {
@@ -80,4 +80,5 @@ LL | }
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0597`.
+Some errors occurred: E0521, E0597.
+For more information about an error, try `rustc --explain E0521`.

src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr

@@ -34,7 +34,7 @@ LL | | }
    |
    = note: defining type: DefId(0/0:6 ~ propagate_approximated_shorter_to_static_no_bound[317d]::supply[0]) with substs []
 
-error: borrowed data escapes outside of function
+error[E0521]: borrowed data escapes outside of function
   --> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:45:5
    |
 LL |   fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
@@ -61,3 +61,4 @@ LL |         demand_y(x, y, x.get())
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0521`.

src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr

@@ -33,7 +33,7 @@ LL | | }
    |
    = note: defining type: DefId(0/0:6 ~ propagate_approximated_shorter_to_static_wrong_bound[317d]::supply[0]) with substs []
 
-error: borrowed data escapes outside of function
+error[E0521]: borrowed data escapes outside of function
   --> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:48:5
    |
 LL |   fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
@@ -59,3 +59,4 @@ LL |         demand_y(x, y, x.get())
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0521`.