1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use borrowck::BorrowckCtxt;
12 use rustc::middle::mem_categorization as mc;
13 use rustc::middle::ty;
14 use rustc::util::ppaux::UserString;
15 use std::cell::RefCell;
18 use syntax::print::pprust;
20 pub struct MoveErrorCollector<'tcx> {
21 errors: RefCell<Vec<MoveError<'tcx>>>
24 impl<'tcx> MoveErrorCollector<'tcx> {
25 pub fn new() -> MoveErrorCollector<'tcx> {
27 errors: RefCell::new(Vec::new())
31 pub fn add_error(&self, error: MoveError<'tcx>) {
32 self.errors.borrow_mut().push(error);
35 pub fn report_potential_errors<'a>(&self, bccx: &BorrowckCtxt<'a, 'tcx>) {
36 report_move_errors(bccx, &*self.errors.borrow())
40 pub struct MoveError<'tcx> {
41 move_from: mc::cmt<'tcx>,
42 move_to: Option<MoveSpanAndPath>
45 impl<'tcx> MoveError<'tcx> {
46 pub fn with_move_info(move_from: mc::cmt<'tcx>,
47 move_to: Option<MoveSpanAndPath>)
57 pub struct MoveSpanAndPath {
58 pub span: codemap::Span,
62 pub struct GroupedMoveErrors<'tcx> {
63 move_from: mc::cmt<'tcx>,
64 move_to_places: Vec<MoveSpanAndPath>
67 fn report_move_errors<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
68 errors: &Vec<MoveError<'tcx>>) {
69 let grouped_errors = group_errors_with_same_origin(errors);
70 for error in grouped_errors.iter() {
71 report_cannot_move_out_of(bccx, error.move_from.clone());
72 let mut is_first_note = true;
73 for move_to in error.move_to_places.iter() {
74 note_move_destination(bccx, move_to.span,
75 &move_to.ident, is_first_note);
76 is_first_note = false;
81 fn group_errors_with_same_origin<'tcx>(errors: &Vec<MoveError<'tcx>>)
82 -> Vec<GroupedMoveErrors<'tcx>> {
83 let mut grouped_errors = Vec::new();
84 for error in errors.iter() {
85 append_to_grouped_errors(&mut grouped_errors, error)
87 return grouped_errors;
89 fn append_to_grouped_errors<'tcx>(grouped_errors: &mut Vec<GroupedMoveErrors<'tcx>>,
90 error: &MoveError<'tcx>) {
91 let move_from_id = error.move_from.id;
92 debug!("append_to_grouped_errors(move_from_id={})", move_from_id);
93 let move_to = if error.move_to.is_some() {
94 vec!(error.move_to.clone().unwrap())
98 for ge in grouped_errors.iter_mut() {
99 if move_from_id == ge.move_from.id && error.move_to.is_some() {
100 debug!("appending move_to to list");
101 ge.move_to_places.extend(move_to.into_iter());
105 debug!("found a new move from location");
106 grouped_errors.push(GroupedMoveErrors {
107 move_from: error.move_from.clone(),
108 move_to_places: move_to
113 fn report_cannot_move_out_of<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
114 move_from: mc::cmt<'tcx>) {
115 match move_from.cat {
116 mc::cat_deref(_, _, mc::BorrowedPtr(..)) |
117 mc::cat_deref(_, _, mc::Implicit(..)) |
118 mc::cat_deref(_, _, mc::UnsafePtr(..)) |
119 mc::cat_static_item => {
122 format!("cannot move out of {}",
123 bccx.cmt_to_string(&*move_from))[]);
126 mc::cat_downcast(ref b, _) |
127 mc::cat_interior(ref b, _) => {
129 ty::ty_struct(did, _)
130 | ty::ty_enum(did, _) if ty::has_dtor(bccx.tcx, did) => {
133 format!("cannot move out of type `{}`, \
134 which defines the `Drop` trait",
135 b.ty.user_string(bccx.tcx))[]);
137 _ => panic!("this path should not cause illegal move")
140 _ => panic!("this path should not cause illegal move")
144 fn note_move_destination(bccx: &BorrowckCtxt,
145 move_to_span: codemap::Span,
146 pat_ident: &ast::Ident,
147 is_first_note: bool) {
148 let pat_name = pprust::ident_to_string(pat_ident);
152 "attempting to move value to here");
155 format!("to prevent the move, \
156 use `ref {0}` or `ref mut {0}` to capture value by \
160 bccx.span_note(move_to_span,
161 format!("and here (use `ref {0}` or `ref mut {0}`)",