1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
use lint;
use rustc::ty::TyCtxt;
use syntax::ast;
use syntax_pos::{Span, DUMMY_SP};
use rustc::hir::def_id::LOCAL_CRATE;
use rustc::hir::itemlikevisit::ItemLikeVisitor;
use rustc::hir;
use rustc::util::nodemap::DefIdSet;
struct CheckVisitor<'a, 'tcx: 'a> {
tcx: TyCtxt<'a, 'tcx, 'tcx>,
used_trait_imports: DefIdSet,
}
impl<'a, 'tcx> CheckVisitor<'a, 'tcx> {
fn check_import(&self, id: ast::NodeId, span: Span) {
let def_id = self.tcx.hir.local_def_id(id);
if !self.tcx.maybe_unused_trait_import(def_id) {
return;
}
let import_def_id = self.tcx.hir.local_def_id(id);
if self.used_trait_imports.contains(&import_def_id) {
return;
}
let msg = if let Ok(snippet) = self.tcx.sess.codemap().span_to_snippet(span) {
format!("unused import: `{}`", snippet)
} else {
"unused import".to_string()
};
self.tcx.lint_node(lint::builtin::UNUSED_IMPORTS, id, span, &msg);
}
}
impl<'a, 'tcx, 'v> ItemLikeVisitor<'v> for CheckVisitor<'a, 'tcx> {
fn visit_item(&mut self, item: &hir::Item) {
if item.vis == hir::Public || item.span == DUMMY_SP {
return;
}
if let hir::ItemUse(ref path, _) = item.node {
self.check_import(item.id, path.span);
}
}
fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem) {
}
fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem) {
}
}
pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
let mut used_trait_imports = DefIdSet();
for &body_id in tcx.hir.krate().bodies.keys() {
let item_def_id = tcx.hir.body_owner_def_id(body_id);
let imports = tcx.used_trait_imports(item_def_id);
debug!("GatherVisitor: item_def_id={:?} with imports {:#?}", item_def_id, imports);
used_trait_imports.extend(imports.iter());
}
let mut visitor = CheckVisitor { tcx, used_trait_imports };
tcx.hir.krate().visit_all_item_likes(&mut visitor);
for &(def_id, span) in tcx.maybe_unused_extern_crates(LOCAL_CRATE).iter() {
if let Some(id) = tcx.hir.as_local_node_id(def_id) {
if tcx.hir.find(id).is_none() {
continue
}
}
let cnum = tcx.extern_mod_stmt_cnum(def_id).unwrap();
if tcx.is_compiler_builtins(cnum) {
continue
}
if tcx.is_panic_runtime(cnum) {
continue
}
if tcx.has_global_allocator(cnum) {
continue
}
assert_eq!(def_id.krate, LOCAL_CRATE);
let hir_id = tcx.hir.definitions().def_index_to_hir_id(def_id.index);
let id = tcx.hir.definitions().find_node_for_hir_id(hir_id);
let lint = lint::builtin::UNUSED_EXTERN_CRATES;
let msg = "unused extern crate";
tcx.lint_node(lint, id, span, msg);
}
}