Updated error message E0388

Author: Adam Medziński

src/librustc_borrowck/borrowck/mod.rs

@@ -910,9 +910,11 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
             }
             mc::AliasableStatic |
             mc::AliasableStaticMut => {
-                struct_span_err!(
+                let mut err = struct_span_err!(
                     self.tcx.sess, span, E0388,
-                    "{} in a static location", prefix)
+                    "{} in a static location", prefix);
+                err.span_label(span, &format!("cannot write data in a static definition"));
+                err
             }
             mc::AliasableBorrowed => {
                 struct_span_err!(

src/test/compile-fail/E0017.rs

@@ -16,6 +16,7 @@ const CR: &'static mut i32 = &mut C; //~ ERROR E0017
 static STATIC_REF: &'static mut i32 = &mut X; //~ ERROR E0017
                                               //~| ERROR E0017
                                               //~| ERROR E0388
+                                              //~| NOTE cannot write data in a static definition
 static CONST_REF: &'static mut i32 = &mut C; //~ ERROR E0017
                                              //~| ERROR E0017