Set of fixes to improve borrowcks that weren't updated

Author: Jonathan Turner

src/librustc_borrowck/borrowck/check_loans.rs

@@ -663,23 +663,39 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
             UseOk => { }
             UseWhileBorrowed(loan_path, loan_span) => {
                 let mut err = match move_kind {
-                    move_data::Captured =>
+                    move_data::Captured => {
                         struct_span_err!(self.bccx, span, E0504,
                                          "cannot move `{}` into closure because it is borrowed",
-                                         &self.bccx.loan_path_to_string(move_path)),
+                                         &self.bccx.loan_path_to_string(move_path))
+                        .span_label(
+                            loan_span,
+                            &format!("borrow of `{}` occurs here",
+                                    &self.bccx.loan_path_to_string(&loan_path))
+                            )
+                        .span_label(
+                            span,
+                            &format!("move into closure occurs here")
+                            )
+                    }
                     move_data::Declared |
                     move_data::MoveExpr |
-                    move_data::MovePat =>
+                    move_data::MovePat => {
                         struct_span_err!(self.bccx, span, E0505,
                                          "cannot move out of `{}` because it is borrowed",
                                          &self.bccx.loan_path_to_string(move_path))
+                        .span_label(
+                            loan_span,
+                            &format!("borrow of `{}` occurs here",
+                                    &self.bccx.loan_path_to_string(&loan_path))
+                            )
+                        .span_label(
+                            span,
+                            &format!("move out of `{}` occurs here",
+                                &self.bccx.loan_path_to_string(move_path))
+                            )
+                    }
                 };
 
-                err.span_note(
-                    loan_span,
-                    &format!("borrow of `{}` occurs here",
-                            &self.bccx.loan_path_to_string(&loan_path))
-                    );
                 err.emit();
             }
         }
@@ -845,9 +861,12 @@ impl<'a, 'tcx> CheckLoanCtxt<'a, 'tcx> {
         struct_span_err!(self.bccx, span, E0506,
                          "cannot assign to `{}` because it is borrowed",
                          self.bccx.loan_path_to_string(loan_path))
-            .span_note(loan.span,
+            .span_label(loan.span,
                        &format!("borrow of `{}` occurs here",
                                self.bccx.loan_path_to_string(loan_path)))
+            .span_label(span,
+                       &format!("assignment to `{}` occurs here",
+                               self.bccx.loan_path_to_string(loan_path)))
             .emit();
     }
 }

src/librustc_borrowck/borrowck/gather_loans/move_error.rs

@@ -72,7 +72,7 @@ fn report_move_errors<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
         let mut err = report_cannot_move_out_of(bccx, error.move_from.clone());
         let mut is_first_note = true;
         for move_to in &error.move_to_places {
-            note_move_destination(&mut err, move_to.span,
+            err = note_move_destination(err, move_to.span,
                                   move_to.name, is_first_note);
             is_first_note = false;
         }
@@ -124,6 +124,10 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
             struct_span_err!(bccx, move_from.span, E0507,
                              "cannot move out of {}",
                              move_from.descriptive_string(bccx.tcx))
+            .span_label(
+                move_from.span,
+                &format!("move occurs here")
+                )
         }
 
         Categorization::Interior(ref b, mc::InteriorElement(Kind::Index, _)) => {
@@ -159,22 +163,24 @@ fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
     }
 }
 
-fn note_move_destination(err: &mut DiagnosticBuilder,
+fn note_move_destination(mut err: DiagnosticBuilder,
                          move_to_span: codemap::Span,
                          pat_name: ast::Name,
-                         is_first_note: bool) {
+                         is_first_note: bool) -> DiagnosticBuilder {
     if is_first_note {
-        err.span_note(
+        err = err.span_label(
             move_to_span,
-            "attempting to move value to here");
+            &format!("attempting to move value to here"));
         err.help(
             &format!("to prevent the move, \
                       use `ref {0}` or `ref mut {0}` to capture value by \
                       reference",
                      pat_name));
+        err
     } else {
         err.span_note(move_to_span,
                       &format!("and here (use `ref {0}` or `ref mut {0}`)",
                                pat_name));
+        err
     }
 }

src/librustc_borrowck/borrowck/mod.rs

@@ -620,11 +620,13 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
         }
 
         // General fallback.
+        let span = err.span.clone();
         let mut db = self.struct_span_err(
             err.span,
             &self.bckerr_to_string(&err));
         self.note_and_explain_bckerr(&mut db, err);
-        db.emit();
+        db.span_label(span, &format!("cannot borrow"))
+          .emit();
     }
 
     pub fn report_use_of_moved_value(&self,
@@ -647,7 +649,10 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                     self.tcx.sess, use_span, E0381,
                     "{} of possibly uninitialized variable: `{}`",
                     verb,
-                    self.loan_path_to_string(lp)).emit();
+                    self.loan_path_to_string(lp))
+                .span_label(use_span, &format!("use of possibly uninitialized `{}`",
+                    self.loan_path_to_string(lp)))
+                .emit();
                 return;
             }
             _ => {

src/libsyntax/errors/snippet/mod.rs

@@ -612,6 +612,7 @@ impl FileInfo {
                         styled_buffer.set_style(0, p, Style::UnderlinePrimary);
                     } else {
                         styled_buffer.putc(1, p, '-', Style::UnderlineSecondary);
+                        styled_buffer.set_style(0, p, Style::UnderlineSecondary);
                     }
                 }
             }