mir-borrowck: Move span_label calls for cannot_assign_to_borrowed() inside borrowck_errors.rs

Author: zilbuz

src/librustc_borrowck/borrowck/check_loans.rs

@@ -865,13 +865,7 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
                                    loan_path: &LoanPath<'tcx>,
                                    loan: &Loan) {
         self.bccx.cannot_assign_to_borrowed(
-            span, &self.bccx.loan_path_to_string(loan_path), Origin::Ast)
-            .span_label(loan.span,
-                       format!("borrow of `{}` occurs here",
-                               self.bccx.loan_path_to_string(loan_path)))
-            .span_label(span,
-                       format!("assignment to borrowed `{}` occurs here",
-                               self.bccx.loan_path_to_string(loan_path)))
+            span, loan.span, &self.bccx.loan_path_to_string(loan_path), Origin::Ast)
             .emit();
     }
 }

src/librustc_mir/borrow_check.rs

@@ -991,14 +991,8 @@ impl<'c, 'b, 'a: 'b+'c, 'gcx, 'tcx: 'a> MirBorrowckCtxt<'c, 'b, 'a, 'gcx, 'tcx>
                                            _: Context,
                                            (lvalue, span): (&Lvalue, Span),
                                            loan: &BorrowData) {
-        let describe_lvalue = self.describe_lvalue(lvalue);
-        let borrow_span = self.retrieve_borrow_span(loan);
-
         let mut err = self.tcx.cannot_assign_to_borrowed(
-            span, &self.describe_lvalue(lvalue), Origin::Mir);
-
-        err.span_label(borrow_span, format!("borrow of `{}` occurs here", describe_lvalue));
-        err.span_label(span, format!("assignment to borrowed `{}` occurs here", describe_lvalue));
+            span, self.retrieve_borrow_span(loan), &self.describe_lvalue(lvalue), Origin::Mir);
 
         err.emit();
     }

src/librustc_mir/util/borrowck_errors.rs

@@ -140,12 +140,17 @@ pub trait BorrowckErrors {
                          desc_new, msg_new, kind_new, noun_old, kind_old, msg_old, OGN=o)
     }
 
-    fn cannot_assign_to_borrowed(&self, span: Span, desc: &str, o: Origin)
+    fn cannot_assign_to_borrowed(&self, span: Span, borrow_span: Span, desc: &str, o: Origin)
                                  -> DiagnosticBuilder
     {
-        struct_span_err!(self, span, E0506,
+        let mut err = struct_span_err!(self, span, E0506,
                          "cannot assign to `{}` because it is borrowed{OGN}",
-                         desc, OGN=o)
+                         desc, OGN=o);
+
+        err.span_label(borrow_span, format!("borrow of `{}` occurs here", desc));
+        err.span_label(span, format!("assignment to borrowed `{}` occurs here", desc));
+
+        err
     }
 
     fn cannot_move_into_closure(&self, span: Span, desc: &str, o: Origin)