rustc_resolve/imports.rs
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519
//! A bunch of methods and structures more or less related to resolving imports.
use std::cell::Cell;
use std::mem;
use rustc_ast::NodeId;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::intern::Interned;
use rustc_errors::codes::*;
use rustc_errors::{Applicability, MultiSpan, pluralize, struct_span_code_err};
use rustc_hir::def::{self, DefKind, PartialRes};
use rustc_hir::def_id::DefId;
use rustc_middle::metadata::{ModChild, Reexport};
use rustc_middle::{span_bug, ty};
use rustc_session::lint::BuiltinLintDiag;
use rustc_session::lint::builtin::{
AMBIGUOUS_GLOB_REEXPORTS, HIDDEN_GLOB_REEXPORTS, PUB_USE_OF_PRIVATE_EXTERN_CRATE,
REDUNDANT_IMPORTS, UNUSED_IMPORTS,
};
use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::hygiene::LocalExpnId;
use rustc_span::{Ident, Span, Symbol, kw};
use smallvec::SmallVec;
use tracing::debug;
use crate::Determinacy::{self, *};
use crate::Namespace::*;
use crate::diagnostics::{DiagMode, Suggestion, import_candidates};
use crate::errors::{
CannotBeReexportedCratePublic, CannotBeReexportedCratePublicNS, CannotBeReexportedPrivate,
CannotBeReexportedPrivateNS, CannotDetermineImportResolution, CannotGlobImportAllCrates,
ConsiderAddingMacroExport, ConsiderMarkingAsPub, IsNotDirectlyImportable,
ItemsInTraitsAreNotImportable,
};
use crate::{
AmbiguityError, AmbiguityKind, BindingKey, Finalize, ImportSuggestion, Module,
ModuleOrUniformRoot, NameBinding, NameBindingData, NameBindingKind, ParentScope, PathResult,
PerNS, ResolutionError, Resolver, ScopeSet, Segment, Used, module_to_string, names_to_string,
};
type Res = def::Res<NodeId>;
/// Contains data for specific kinds of imports.
#[derive(Clone)]
pub(crate) enum ImportKind<'ra> {
Single {
/// `source` in `use prefix::source as target`.
source: Ident,
/// `target` in `use prefix::source as target`.
/// It will directly use `source` when the format is `use prefix::source`.
target: Ident,
/// Bindings to which `source` refers to.
source_bindings: PerNS<Cell<Result<NameBinding<'ra>, Determinacy>>>,
/// Bindings introduced by `target`.
target_bindings: PerNS<Cell<Option<NameBinding<'ra>>>>,
/// `true` for `...::{self [as target]}` imports, `false` otherwise.
type_ns_only: bool,
/// Did this import result from a nested import? ie. `use foo::{bar, baz};`
nested: bool,
/// The ID of the `UseTree` that imported this `Import`.
///
/// In the case where the `Import` was expanded from a "nested" use tree,
/// this id is the ID of the leaf tree. For example:
///
/// ```ignore (pacify the merciless tidy)
/// use foo::bar::{a, b}
/// ```
///
/// If this is the import for `foo::bar::a`, we would have the ID of the `UseTree`
/// for `a` in this field.
id: NodeId,
},
Glob {
is_prelude: bool,
// The visibility of the greatest re-export.
// n.b. `max_vis` is only used in `finalize_import` to check for re-export errors.
max_vis: Cell<Option<ty::Visibility>>,
id: NodeId,
},
ExternCrate {
source: Option<Symbol>,
target: Ident,
id: NodeId,
},
MacroUse {
/// A field has been added indicating whether it should be reported as a lint,
/// addressing issue#119301.
warn_private: bool,
},
MacroExport,
}
/// Manually implement `Debug` for `ImportKind` because the `source/target_bindings`
/// contain `Cell`s which can introduce infinite loops while printing.
impl<'ra> std::fmt::Debug for ImportKind<'ra> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
use ImportKind::*;
match self {
Single {
ref source,
ref target,
ref source_bindings,
ref target_bindings,
ref type_ns_only,
ref nested,
ref id,
} => f
.debug_struct("Single")
.field("source", source)
.field("target", target)
// Ignore the nested bindings to avoid an infinite loop while printing.
.field(
"source_bindings",
&source_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))),
)
.field(
"target_bindings",
&target_bindings.clone().map(|b| b.into_inner().map(|_| format_args!(".."))),
)
.field("type_ns_only", type_ns_only)
.field("nested", nested)
.field("id", id)
.finish(),
Glob { ref is_prelude, ref max_vis, ref id } => f
.debug_struct("Glob")
.field("is_prelude", is_prelude)
.field("max_vis", max_vis)
.field("id", id)
.finish(),
ExternCrate { ref source, ref target, ref id } => f
.debug_struct("ExternCrate")
.field("source", source)
.field("target", target)
.field("id", id)
.finish(),
MacroUse { .. } => f.debug_struct("MacroUse").finish(),
MacroExport => f.debug_struct("MacroExport").finish(),
}
}
}
/// One import.
#[derive(Debug, Clone)]
pub(crate) struct ImportData<'ra> {
pub kind: ImportKind<'ra>,
/// Node ID of the "root" use item -- this is always the same as `ImportKind`'s `id`
/// (if it exists) except in the case of "nested" use trees, in which case
/// it will be the ID of the root use tree. e.g., in the example
/// ```ignore (incomplete code)
/// use foo::bar::{a, b}
/// ```
/// this would be the ID of the `use foo::bar` `UseTree` node.
/// In case of imports without their own node ID it's the closest node that can be used,
/// for example, for reporting lints.
pub root_id: NodeId,
/// Span of the entire use statement.
pub use_span: Span,
/// Span of the entire use statement with attributes.
pub use_span_with_attributes: Span,
/// Did the use statement have any attributes?
pub has_attributes: bool,
/// Span of this use tree.
pub span: Span,
/// Span of the *root* use tree (see `root_id`).
pub root_span: Span,
pub parent_scope: ParentScope<'ra>,
pub module_path: Vec<Segment>,
/// The resolution of `module_path`.
pub imported_module: Cell<Option<ModuleOrUniformRoot<'ra>>>,
pub vis: ty::Visibility,
}
/// All imports are unique and allocated on a same arena,
/// so we can use referential equality to compare them.
pub(crate) type Import<'ra> = Interned<'ra, ImportData<'ra>>;
impl<'ra> ImportData<'ra> {
pub(crate) fn is_glob(&self) -> bool {
matches!(self.kind, ImportKind::Glob { .. })
}
pub(crate) fn is_nested(&self) -> bool {
match self.kind {
ImportKind::Single { nested, .. } => nested,
_ => false,
}
}
pub(crate) fn id(&self) -> Option<NodeId> {
match self.kind {
ImportKind::Single { id, .. }
| ImportKind::Glob { id, .. }
| ImportKind::ExternCrate { id, .. } => Some(id),
ImportKind::MacroUse { .. } | ImportKind::MacroExport => None,
}
}
fn simplify(&self, r: &Resolver<'_, '_>) -> Reexport {
let to_def_id = |id| r.local_def_id(id).to_def_id();
match self.kind {
ImportKind::Single { id, .. } => Reexport::Single(to_def_id(id)),
ImportKind::Glob { id, .. } => Reexport::Glob(to_def_id(id)),
ImportKind::ExternCrate { id, .. } => Reexport::ExternCrate(to_def_id(id)),
ImportKind::MacroUse { .. } => Reexport::MacroUse,
ImportKind::MacroExport => Reexport::MacroExport,
}
}
}
/// Records information about the resolution of a name in a namespace of a module.
#[derive(Clone, Default, Debug)]
pub(crate) struct NameResolution<'ra> {
/// Single imports that may define the name in the namespace.
/// Imports are arena-allocated, so it's ok to use pointers as keys.
pub single_imports: FxHashSet<Import<'ra>>,
/// The least shadowable known binding for this name, or None if there are no known bindings.
pub binding: Option<NameBinding<'ra>>,
pub shadowed_glob: Option<NameBinding<'ra>>,
}
impl<'ra> NameResolution<'ra> {
/// Returns the binding for the name if it is known or None if it not known.
pub(crate) fn binding(&self) -> Option<NameBinding<'ra>> {
self.binding.and_then(|binding| {
if !binding.is_glob_import() || self.single_imports.is_empty() {
Some(binding)
} else {
None
}
})
}
}
/// An error that may be transformed into a diagnostic later. Used to combine multiple unresolved
/// import errors within the same use tree into a single diagnostic.
#[derive(Debug, Clone)]
struct UnresolvedImportError {
span: Span,
label: Option<String>,
note: Option<String>,
suggestion: Option<Suggestion>,
candidates: Option<Vec<ImportSuggestion>>,
segment: Option<Symbol>,
/// comes from `PathRes::Failed { module }`
module: Option<DefId>,
}
// Reexports of the form `pub use foo as bar;` where `foo` is `extern crate foo;`
// are permitted for backward-compatibility under a deprecation lint.
fn pub_use_of_private_extern_crate_hack(
import: Import<'_>,
binding: NameBinding<'_>,
) -> Option<NodeId> {
match (&import.kind, &binding.kind) {
(ImportKind::Single { .. }, NameBindingKind::Import { import: binding_import, .. })
if let ImportKind::ExternCrate { id, .. } = binding_import.kind
&& import.vis.is_public() =>
{
Some(id)
}
_ => None,
}
}
impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
/// Given a binding and an import that resolves to it,
/// return the corresponding binding defined by the import.
pub(crate) fn import(
&self,
binding: NameBinding<'ra>,
import: Import<'ra>,
) -> NameBinding<'ra> {
let import_vis = import.vis.to_def_id();
let vis = if binding.vis.is_at_least(import_vis, self.tcx)
|| pub_use_of_private_extern_crate_hack(import, binding).is_some()
{
import_vis
} else {
binding.vis
};
if let ImportKind::Glob { ref max_vis, .. } = import.kind {
if vis == import_vis
|| max_vis.get().map_or(true, |max_vis| vis.is_at_least(max_vis, self.tcx))
{
max_vis.set(Some(vis.expect_local()))
}
}
self.arenas.alloc_name_binding(NameBindingData {
kind: NameBindingKind::Import { binding, import },
ambiguity: None,
warn_ambiguity: false,
span: import.span,
vis,
expansion: import.parent_scope.expansion,
})
}
/// Define the name or return the existing binding if there is a collision.
/// `update` indicates if the definition is a redefinition of an existing binding.
pub(crate) fn try_define(
&mut self,
module: Module<'ra>,
key: BindingKey,
binding: NameBinding<'ra>,
warn_ambiguity: bool,
) -> Result<(), NameBinding<'ra>> {
let res = binding.res();
self.check_reserved_macro_name(key.ident, res);
self.set_binding_parent_module(binding, module);
self.update_resolution(module, key, warn_ambiguity, |this, resolution| {
if let Some(old_binding) = resolution.binding {
if res == Res::Err && old_binding.res() != Res::Err {
// Do not override real bindings with `Res::Err`s from error recovery.
return Ok(());
}
match (old_binding.is_glob_import(), binding.is_glob_import()) {
(true, true) => {
// FIXME: remove `!binding.is_ambiguity_recursive()` after delete the warning ambiguity.
if !binding.is_ambiguity_recursive()
&& let NameBindingKind::Import { import: old_import, .. } =
old_binding.kind
&& let NameBindingKind::Import { import, .. } = binding.kind
&& old_import == import
{
// We should replace the `old_binding` with `binding` regardless
// of whether they has same resolution or not when they are
// imported from the same glob-import statement.
resolution.binding = Some(binding);
} else if res != old_binding.res() {
resolution.binding = Some(this.new_ambiguity_binding(
AmbiguityKind::GlobVsGlob,
old_binding,
binding,
warn_ambiguity,
));
} else if !old_binding.vis.is_at_least(binding.vis, this.tcx) {
// We are glob-importing the same item but with greater visibility.
resolution.binding = Some(binding);
} else if binding.is_ambiguity_recursive() {
resolution.binding = Some(this.new_warn_ambiguity_binding(binding));
}
}
(old_glob @ true, false) | (old_glob @ false, true) => {
let (glob_binding, nonglob_binding) =
if old_glob { (old_binding, binding) } else { (binding, old_binding) };
if key.ns == MacroNS
&& nonglob_binding.expansion != LocalExpnId::ROOT
&& glob_binding.res() != nonglob_binding.res()
{
resolution.binding = Some(this.new_ambiguity_binding(
AmbiguityKind::GlobVsExpanded,
nonglob_binding,
glob_binding,
false,
));
} else {
resolution.binding = Some(nonglob_binding);
}
if let Some(old_shadowed_glob) = resolution.shadowed_glob {
assert!(old_shadowed_glob.is_glob_import());
if glob_binding.res() != old_shadowed_glob.res() {
resolution.shadowed_glob = Some(this.new_ambiguity_binding(
AmbiguityKind::GlobVsGlob,
old_shadowed_glob,
glob_binding,
false,
));
} else if !old_shadowed_glob.vis.is_at_least(binding.vis, this.tcx) {
resolution.shadowed_glob = Some(glob_binding);
}
} else {
resolution.shadowed_glob = Some(glob_binding);
}
}
(false, false) => {
return Err(old_binding);
}
}
} else {
resolution.binding = Some(binding);
}
Ok(())
})
}
fn new_ambiguity_binding(
&self,
ambiguity_kind: AmbiguityKind,
primary_binding: NameBinding<'ra>,
secondary_binding: NameBinding<'ra>,
warn_ambiguity: bool,
) -> NameBinding<'ra> {
let ambiguity = Some((secondary_binding, ambiguity_kind));
let data = NameBindingData { ambiguity, warn_ambiguity, ..*primary_binding };
self.arenas.alloc_name_binding(data)
}
fn new_warn_ambiguity_binding(&self, binding: NameBinding<'ra>) -> NameBinding<'ra> {
assert!(binding.is_ambiguity_recursive());
self.arenas.alloc_name_binding(NameBindingData { warn_ambiguity: true, ..*binding })
}
// Use `f` to mutate the resolution of the name in the module.
// If the resolution becomes a success, define it in the module's glob importers.
fn update_resolution<T, F>(
&mut self,
module: Module<'ra>,
key: BindingKey,
warn_ambiguity: bool,
f: F,
) -> T
where
F: FnOnce(&mut Resolver<'ra, 'tcx>, &mut NameResolution<'ra>) -> T,
{
// Ensure that `resolution` isn't borrowed when defining in the module's glob importers,
// during which the resolution might end up getting re-defined via a glob cycle.
let (binding, t, warn_ambiguity) = {
let resolution = &mut *self.resolution(module, key).borrow_mut();
let old_binding = resolution.binding();
let t = f(self, resolution);
if let Some(binding) = resolution.binding()
&& old_binding != Some(binding)
{
(binding, t, warn_ambiguity || old_binding.is_some())
} else {
return t;
}
};
let Ok(glob_importers) = module.glob_importers.try_borrow_mut() else {
return t;
};
// Define or update `binding` in `module`s glob importers.
for import in glob_importers.iter() {
let mut ident = key.ident;
let scope = match ident.span.reverse_glob_adjust(module.expansion, import.span) {
Some(Some(def)) => self.expn_def_scope(def),
Some(None) => import.parent_scope.module,
None => continue,
};
if self.is_accessible_from(binding.vis, scope) {
let imported_binding = self.import(binding, *import);
let key = BindingKey { ident, ..key };
let _ = self.try_define(
import.parent_scope.module,
key,
imported_binding,
warn_ambiguity,
);
}
}
t
}
// Define a dummy resolution containing a `Res::Err` as a placeholder for a failed
// or indeterminate resolution, also mark such failed imports as used to avoid duplicate diagnostics.
fn import_dummy_binding(&mut self, import: Import<'ra>, is_indeterminate: bool) {
if let ImportKind::Single { target, ref target_bindings, .. } = import.kind {
if !(is_indeterminate || target_bindings.iter().all(|binding| binding.get().is_none()))
{
return; // Has resolution, do not create the dummy binding
}
let dummy_binding = self.dummy_binding;
let dummy_binding = self.import(dummy_binding, import);
self.per_ns(|this, ns| {
let key = BindingKey::new(target, ns);
let _ = this.try_define(import.parent_scope.module, key, dummy_binding, false);
this.update_resolution(import.parent_scope.module, key, false, |_, resolution| {
resolution.single_imports.remove(&import);
})
});
self.record_use(target, dummy_binding, Used::Other);
} else if import.imported_module.get().is_none() {
self.import_use_map.insert(import, Used::Other);
if let Some(id) = import.id() {
self.used_imports.insert(id);
}
}
}
// Import resolution
//
// This is a fixed-point algorithm. We resolve imports until our efforts
// are stymied by an unresolved import; then we bail out of the current
// module and continue. We terminate successfully once no more imports
// remain or unsuccessfully when no forward progress in resolving imports
// is made.
/// Resolves all imports for the crate. This method performs the fixed-
/// point iteration.
pub(crate) fn resolve_imports(&mut self) {
let mut prev_indeterminate_count = usize::MAX;
let mut indeterminate_count = self.indeterminate_imports.len() * 3;
while indeterminate_count < prev_indeterminate_count {
prev_indeterminate_count = indeterminate_count;
indeterminate_count = 0;
for import in mem::take(&mut self.indeterminate_imports) {
let import_indeterminate_count = self.resolve_import(import);
indeterminate_count += import_indeterminate_count;
match import_indeterminate_count {
0 => self.determined_imports.push(import),
_ => self.indeterminate_imports.push(import),
}
}
}
}
pub(crate) fn finalize_imports(&mut self) {
for module in self.arenas.local_modules().iter() {
self.finalize_resolutions_in(*module);
}
let mut seen_spans = FxHashSet::default();
let mut errors = vec![];
let mut prev_root_id: NodeId = NodeId::ZERO;
let determined_imports = mem::take(&mut self.determined_imports);
let indeterminate_imports = mem::take(&mut self.indeterminate_imports);
let mut glob_error = false;
for (is_indeterminate, import) in determined_imports
.iter()
.map(|i| (false, i))
.chain(indeterminate_imports.iter().map(|i| (true, i)))
{
let unresolved_import_error = self.finalize_import(*import);
// If this import is unresolved then create a dummy import
// resolution for it so that later resolve stages won't complain.
self.import_dummy_binding(*import, is_indeterminate);
if let Some(err) = unresolved_import_error {
glob_error |= import.is_glob();
if let ImportKind::Single { source, ref source_bindings, .. } = import.kind {
if source.name == kw::SelfLower {
// Silence `unresolved import` error if E0429 is already emitted
if let Err(Determined) = source_bindings.value_ns.get() {
continue;
}
}
}
if prev_root_id != NodeId::ZERO
&& prev_root_id != import.root_id
&& !errors.is_empty()
{
// In the case of a new import line, throw a diagnostic message
// for the previous line.
self.throw_unresolved_import_error(errors, glob_error);
errors = vec![];
}
if seen_spans.insert(err.span) {
errors.push((*import, err));
prev_root_id = import.root_id;
}
}
}
if !errors.is_empty() {
self.throw_unresolved_import_error(errors, glob_error);
return;
}
for import in &indeterminate_imports {
let path = import_path_to_string(
&import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
&import.kind,
import.span,
);
// FIXME: there should be a better way of doing this than
// formatting this as a string then checking for `::`
if path.contains("::") {
let err = UnresolvedImportError {
span: import.span,
label: None,
note: None,
suggestion: None,
candidates: None,
segment: None,
module: None,
};
errors.push((*import, err))
}
}
self.throw_unresolved_import_error(errors, glob_error);
}
pub(crate) fn check_hidden_glob_reexports(
&mut self,
exported_ambiguities: FxHashSet<NameBinding<'ra>>,
) {
for module in self.arenas.local_modules().iter() {
for (key, resolution) in self.resolutions(*module).borrow().iter() {
let resolution = resolution.borrow();
if let Some(binding) = resolution.binding {
if let NameBindingKind::Import { import, .. } = binding.kind
&& let Some((amb_binding, _)) = binding.ambiguity
&& binding.res() != Res::Err
&& exported_ambiguities.contains(&binding)
{
self.lint_buffer.buffer_lint(
AMBIGUOUS_GLOB_REEXPORTS,
import.root_id,
import.root_span,
BuiltinLintDiag::AmbiguousGlobReexports {
name: key.ident.to_string(),
namespace: key.ns.descr().to_string(),
first_reexport_span: import.root_span,
duplicate_reexport_span: amb_binding.span,
},
);
}
if let Some(glob_binding) = resolution.shadowed_glob {
let binding_id = match binding.kind {
NameBindingKind::Res(res) => {
Some(self.def_id_to_node_id[res.def_id().expect_local()])
}
NameBindingKind::Module(module) => {
Some(self.def_id_to_node_id[module.def_id().expect_local()])
}
NameBindingKind::Import { import, .. } => import.id(),
};
if binding.res() != Res::Err
&& glob_binding.res() != Res::Err
&& let NameBindingKind::Import { import: glob_import, .. } =
glob_binding.kind
&& let Some(binding_id) = binding_id
&& let Some(glob_import_id) = glob_import.id()
&& let glob_import_def_id = self.local_def_id(glob_import_id)
&& self.effective_visibilities.is_exported(glob_import_def_id)
&& glob_binding.vis.is_public()
&& !binding.vis.is_public()
{
self.lint_buffer.buffer_lint(
HIDDEN_GLOB_REEXPORTS,
binding_id,
binding.span,
BuiltinLintDiag::HiddenGlobReexports {
name: key.ident.name.to_string(),
namespace: key.ns.descr().to_owned(),
glob_reexport_span: glob_binding.span,
private_item_span: binding.span,
},
);
}
}
}
}
}
}
fn throw_unresolved_import_error(
&mut self,
mut errors: Vec<(Import<'_>, UnresolvedImportError)>,
glob_error: bool,
) {
errors.retain(|(_import, err)| match err.module {
// Skip `use` errors for `use foo::Bar;` if `foo.rs` has unrecovered parse errors.
Some(def_id) if self.mods_with_parse_errors.contains(&def_id) => false,
_ => true,
});
if errors.is_empty() {
return;
}
/// Upper limit on the number of `span_label` messages.
const MAX_LABEL_COUNT: usize = 10;
let span = MultiSpan::from_spans(errors.iter().map(|(_, err)| err.span).collect());
let paths = errors
.iter()
.map(|(import, err)| {
let path = import_path_to_string(
&import.module_path.iter().map(|seg| seg.ident).collect::<Vec<_>>(),
&import.kind,
err.span,
);
format!("`{path}`")
})
.collect::<Vec<_>>();
let msg = format!("unresolved import{} {}", pluralize!(paths.len()), paths.join(", "),);
let mut diag = struct_span_code_err!(self.dcx(), span, E0432, "{msg}");
if let Some((_, UnresolvedImportError { note: Some(note), .. })) = errors.iter().last() {
diag.note(note.clone());
}
for (import, err) in errors.into_iter().take(MAX_LABEL_COUNT) {
if let Some(label) = err.label {
diag.span_label(err.span, label);
}
if let Some((suggestions, msg, applicability)) = err.suggestion {
if suggestions.is_empty() {
diag.help(msg);
continue;
}
diag.multipart_suggestion(msg, suggestions, applicability);
}
if let Some(candidates) = &err.candidates {
match &import.kind {
ImportKind::Single { nested: false, source, target, .. } => import_candidates(
self.tcx,
&mut diag,
Some(err.span),
candidates,
DiagMode::Import { append: false },
(source != target)
.then(|| format!(" as {target}"))
.as_deref()
.unwrap_or(""),
),
ImportKind::Single { nested: true, source, target, .. } => {
import_candidates(
self.tcx,
&mut diag,
None,
candidates,
DiagMode::Normal,
(source != target)
.then(|| format!(" as {target}"))
.as_deref()
.unwrap_or(""),
);
}
_ => {}
}
}
if matches!(import.kind, ImportKind::Single { .. })
&& let Some(segment) = err.segment
&& let Some(module) = err.module
{
self.find_cfg_stripped(&mut diag, &segment, module)
}
}
let guar = diag.emit();
if glob_error {
self.glob_error = Some(guar);
}
}
/// Attempts to resolve the given import, returning:
/// - `0` means its resolution is determined.
/// - Other values mean that indeterminate exists under certain namespaces.
///
/// Meanwhile, if resolve successful, the resolved bindings are written
/// into the module.
fn resolve_import(&mut self, import: Import<'ra>) -> usize {
debug!(
"(resolving import for module) resolving import `{}::...` in `{}`",
Segment::names_to_string(&import.module_path),
module_to_string(import.parent_scope.module).unwrap_or_else(|| "???".to_string()),
);
let module = if let Some(module) = import.imported_module.get() {
module
} else {
let path_res = self.maybe_resolve_path(
&import.module_path,
None,
&import.parent_scope,
Some(import),
);
match path_res {
PathResult::Module(module) => module,
PathResult::Indeterminate => return 3,
PathResult::NonModule(..) | PathResult::Failed { .. } => return 0,
}
};
import.imported_module.set(Some(module));
let (source, target, source_bindings, target_bindings, type_ns_only) = match import.kind {
ImportKind::Single {
source,
target,
ref source_bindings,
ref target_bindings,
type_ns_only,
..
} => (source, target, source_bindings, target_bindings, type_ns_only),
ImportKind::Glob { .. } => {
self.resolve_glob_import(import);
return 0;
}
_ => unreachable!(),
};
let mut indeterminate_count = 0;
self.per_ns(|this, ns| {
if !type_ns_only || ns == TypeNS {
if let Err(Undetermined) = source_bindings[ns].get() {
let binding = this.maybe_resolve_ident_in_module(
module,
source,
ns,
&import.parent_scope,
Some(import),
);
source_bindings[ns].set(binding);
} else {
return;
};
let parent = import.parent_scope.module;
match source_bindings[ns].get() {
Err(Undetermined) => indeterminate_count += 1,
// Don't update the resolution, because it was never added.
Err(Determined) if target.name == kw::Underscore => {}
Ok(binding) if binding.is_importable() => {
let imported_binding = this.import(binding, import);
target_bindings[ns].set(Some(imported_binding));
this.define(parent, target, ns, imported_binding);
}
source_binding @ (Ok(..) | Err(Determined)) => {
if source_binding.is_ok() {
this.dcx()
.create_err(IsNotDirectlyImportable { span: import.span, target })
.emit();
}
let key = BindingKey::new(target, ns);
this.update_resolution(parent, key, false, |_, resolution| {
resolution.single_imports.remove(&import);
});
}
}
}
});
indeterminate_count
}
/// Performs final import resolution, consistency checks and error reporting.
///
/// Optionally returns an unresolved import error. This error is buffered and used to
/// consolidate multiple unresolved import errors into a single diagnostic.
fn finalize_import(&mut self, import: Import<'ra>) -> Option<UnresolvedImportError> {
let ignore_binding = match &import.kind {
ImportKind::Single { target_bindings, .. } => target_bindings[TypeNS].get(),
_ => None,
};
let ambiguity_errors_len =
|errors: &Vec<AmbiguityError<'_>>| errors.iter().filter(|error| !error.warning).count();
let prev_ambiguity_errors_len = ambiguity_errors_len(&self.ambiguity_errors);
let finalize = Finalize::with_root_span(import.root_id, import.span, import.root_span);
// We'll provide more context to the privacy errors later, up to `len`.
let privacy_errors_len = self.privacy_errors.len();
let path_res = self.resolve_path(
&import.module_path,
None,
&import.parent_scope,
Some(finalize),
ignore_binding,
Some(import),
);
let no_ambiguity =
ambiguity_errors_len(&self.ambiguity_errors) == prev_ambiguity_errors_len;
let module = match path_res {
PathResult::Module(module) => {
// Consistency checks, analogous to `finalize_macro_resolutions`.
if let Some(initial_module) = import.imported_module.get() {
if module != initial_module && no_ambiguity {
span_bug!(import.span, "inconsistent resolution for an import");
}
} else if self.privacy_errors.is_empty() {
self.dcx()
.create_err(CannotDetermineImportResolution { span: import.span })
.emit();
}
module
}
PathResult::Failed {
is_error_from_last_segment: false,
span,
segment_name,
label,
suggestion,
module,
error_implied_by_parse_error: _,
} => {
if no_ambiguity {
assert!(import.imported_module.get().is_none());
self.report_error(span, ResolutionError::FailedToResolve {
segment: Some(segment_name),
label,
suggestion,
module,
});
}
return None;
}
PathResult::Failed {
is_error_from_last_segment: true,
span,
label,
suggestion,
module,
segment_name,
..
} => {
if no_ambiguity {
assert!(import.imported_module.get().is_none());
let module = if let Some(ModuleOrUniformRoot::Module(m)) = module {
m.opt_def_id()
} else {
None
};
let err = match self.make_path_suggestion(
span,
import.module_path.clone(),
&import.parent_scope,
) {
Some((suggestion, note)) => UnresolvedImportError {
span,
label: None,
note,
suggestion: Some((
vec![(span, Segment::names_to_string(&suggestion))],
String::from("a similar path exists"),
Applicability::MaybeIncorrect,
)),
candidates: None,
segment: Some(segment_name),
module,
},
None => UnresolvedImportError {
span,
label: Some(label),
note: None,
suggestion,
candidates: None,
segment: Some(segment_name),
module,
},
};
return Some(err);
}
return None;
}
PathResult::NonModule(partial_res) => {
if no_ambiguity && partial_res.full_res() != Some(Res::Err) {
// Check if there are no ambiguities and the result is not dummy.
assert!(import.imported_module.get().is_none());
}
// The error was already reported earlier.
return None;
}
PathResult::Indeterminate => unreachable!(),
};
let (ident, target, source_bindings, target_bindings, type_ns_only, import_id) =
match import.kind {
ImportKind::Single {
source,
target,
ref source_bindings,
ref target_bindings,
type_ns_only,
id,
..
} => (source, target, source_bindings, target_bindings, type_ns_only, id),
ImportKind::Glob { is_prelude, ref max_vis, id } => {
if import.module_path.len() <= 1 {
// HACK(eddyb) `lint_if_path_starts_with_module` needs at least
// 2 segments, so the `resolve_path` above won't trigger it.
let mut full_path = import.module_path.clone();
full_path.push(Segment::from_ident(Ident::empty()));
self.lint_if_path_starts_with_module(Some(finalize), &full_path, None);
}
if let ModuleOrUniformRoot::Module(module) = module {
if module == import.parent_scope.module {
// Importing a module into itself is not allowed.
return Some(UnresolvedImportError {
span: import.span,
label: Some(String::from(
"cannot glob-import a module into itself",
)),
note: None,
suggestion: None,
candidates: None,
segment: None,
module: None,
});
}
}
if !is_prelude
&& let Some(max_vis) = max_vis.get()
&& !max_vis.is_at_least(import.vis, self.tcx)
{
let def_id = self.local_def_id(id);
self.lint_buffer.buffer_lint(
UNUSED_IMPORTS,
id,
import.span,
BuiltinLintDiag::RedundantImportVisibility {
max_vis: max_vis.to_string(def_id, self.tcx),
import_vis: import.vis.to_string(def_id, self.tcx),
span: import.span,
},
);
}
return None;
}
_ => unreachable!(),
};
if self.privacy_errors.len() != privacy_errors_len {
// Get the Res for the last element, so that we can point to alternative ways of
// importing it if available.
let mut path = import.module_path.clone();
path.push(Segment::from_ident(ident));
if let PathResult::Module(ModuleOrUniformRoot::Module(module)) = self.resolve_path(
&path,
None,
&import.parent_scope,
Some(finalize),
ignore_binding,
None,
) {
let res = module.res().map(|r| (r, ident));
for error in &mut self.privacy_errors[privacy_errors_len..] {
error.outermost_res = res;
}
}
}
let mut all_ns_err = true;
self.per_ns(|this, ns| {
if !type_ns_only || ns == TypeNS {
let binding = this.resolve_ident_in_module(
module,
ident,
ns,
&import.parent_scope,
Some(Finalize { report_private: false, ..finalize }),
target_bindings[ns].get(),
Some(import),
);
match binding {
Ok(binding) => {
// Consistency checks, analogous to `finalize_macro_resolutions`.
let initial_res = source_bindings[ns].get().map(|initial_binding| {
all_ns_err = false;
if let Some(target_binding) = target_bindings[ns].get() {
if target.name == kw::Underscore
&& initial_binding.is_extern_crate()
&& !initial_binding.is_import()
{
let used = if import.module_path.is_empty() {
Used::Scope
} else {
Used::Other
};
this.record_use(ident, target_binding, used);
}
}
initial_binding.res()
});
let res = binding.res();
let has_ambiguity_error =
this.ambiguity_errors.iter().any(|error| !error.warning);
if res == Res::Err || has_ambiguity_error {
this.dcx()
.span_delayed_bug(import.span, "some error happened for an import");
return;
}
if let Ok(initial_res) = initial_res {
if res != initial_res {
span_bug!(import.span, "inconsistent resolution for an import");
}
} else if this.privacy_errors.is_empty() {
this.dcx()
.create_err(CannotDetermineImportResolution { span: import.span })
.emit();
}
}
Err(..) => {
// FIXME: This assert may fire if public glob is later shadowed by a private
// single import (see test `issue-55884-2.rs`). In theory single imports should
// always block globs, even if they are not yet resolved, so that this kind of
// self-inconsistent resolution never happens.
// Re-enable the assert when the issue is fixed.
// assert!(result[ns].get().is_err());
}
}
}
});
if all_ns_err {
let mut all_ns_failed = true;
self.per_ns(|this, ns| {
if !type_ns_only || ns == TypeNS {
let binding = this.resolve_ident_in_module(
module,
ident,
ns,
&import.parent_scope,
Some(finalize),
None,
None,
);
if binding.is_ok() {
all_ns_failed = false;
}
}
});
return if all_ns_failed {
let resolutions = match module {
ModuleOrUniformRoot::Module(module) => Some(self.resolutions(module).borrow()),
_ => None,
};
let resolutions = resolutions.as_ref().into_iter().flat_map(|r| r.iter());
let names = resolutions
.filter_map(|(BindingKey { ident: i, .. }, resolution)| {
if i.name == ident.name {
return None;
} // Never suggest the same name
match *resolution.borrow() {
NameResolution { binding: Some(name_binding), .. } => {
match name_binding.kind {
NameBindingKind::Import { binding, .. } => {
match binding.kind {
// Never suggest the name that has binding error
// i.e., the name that cannot be previously resolved
NameBindingKind::Res(Res::Err) => None,
_ => Some(i.name),
}
}
_ => Some(i.name),
}
}
NameResolution { ref single_imports, .. }
if single_imports.is_empty() =>
{
None
}
_ => Some(i.name),
}
})
.collect::<Vec<Symbol>>();
let lev_suggestion =
find_best_match_for_name(&names, ident.name, None).map(|suggestion| {
(
vec![(ident.span, suggestion.to_string())],
String::from("a similar name exists in the module"),
Applicability::MaybeIncorrect,
)
});
let (suggestion, note) =
match self.check_for_module_export_macro(import, module, ident) {
Some((suggestion, note)) => (suggestion.or(lev_suggestion), note),
_ => (lev_suggestion, None),
};
let label = match module {
ModuleOrUniformRoot::Module(module) => {
let module_str = module_to_string(module);
if let Some(module_str) = module_str {
format!("no `{ident}` in `{module_str}`")
} else {
format!("no `{ident}` in the root")
}
}
_ => {
if !ident.is_path_segment_keyword() {
format!("no external crate `{ident}`")
} else {
// HACK(eddyb) this shows up for `self` & `super`, which
// should work instead - for now keep the same error message.
format!("no `{ident}` in the root")
}
}
};
let parent_suggestion =
self.lookup_import_candidates(ident, TypeNS, &import.parent_scope, |_| true);
Some(UnresolvedImportError {
span: import.span,
label: Some(label),
note,
suggestion,
candidates: if !parent_suggestion.is_empty() {
Some(parent_suggestion)
} else {
None
},
module: import.imported_module.get().and_then(|module| {
if let ModuleOrUniformRoot::Module(m) = module {
m.opt_def_id()
} else {
None
}
}),
segment: Some(ident.name),
})
} else {
// `resolve_ident_in_module` reported a privacy error.
None
};
}
let mut reexport_error = None;
let mut any_successful_reexport = false;
let mut crate_private_reexport = false;
self.per_ns(|this, ns| {
if let Ok(binding) = source_bindings[ns].get() {
if !binding.vis.is_at_least(import.vis, this.tcx) {
reexport_error = Some((ns, binding));
if let ty::Visibility::Restricted(binding_def_id) = binding.vis {
if binding_def_id.is_top_level_module() {
crate_private_reexport = true;
}
}
} else {
any_successful_reexport = true;
}
}
});
// All namespaces must be re-exported with extra visibility for an error to occur.
if !any_successful_reexport {
let (ns, binding) = reexport_error.unwrap();
if let Some(extern_crate_id) = pub_use_of_private_extern_crate_hack(import, binding) {
self.lint_buffer.buffer_lint(
PUB_USE_OF_PRIVATE_EXTERN_CRATE,
import_id,
import.span,
BuiltinLintDiag::PrivateExternCrateReexport {
source: ident,
extern_crate_span: self.tcx.source_span(self.local_def_id(extern_crate_id)),
},
);
} else if ns == TypeNS {
let err = if crate_private_reexport {
self.dcx()
.create_err(CannotBeReexportedCratePublicNS { span: import.span, ident })
} else {
self.dcx().create_err(CannotBeReexportedPrivateNS { span: import.span, ident })
};
err.emit();
} else {
let mut err = if crate_private_reexport {
self.dcx()
.create_err(CannotBeReexportedCratePublic { span: import.span, ident })
} else {
self.dcx().create_err(CannotBeReexportedPrivate { span: import.span, ident })
};
match binding.kind {
NameBindingKind::Res(Res::Def(DefKind::Macro(_), def_id))
// exclude decl_macro
if self.get_macro_by_def_id(def_id).macro_rules =>
{
err.subdiagnostic( ConsiderAddingMacroExport {
span: binding.span,
});
}
_ => {
err.subdiagnostic( ConsiderMarkingAsPub {
span: import.span,
ident,
});
}
}
err.emit();
}
}
if import.module_path.len() <= 1 {
// HACK(eddyb) `lint_if_path_starts_with_module` needs at least
// 2 segments, so the `resolve_path` above won't trigger it.
let mut full_path = import.module_path.clone();
full_path.push(Segment::from_ident(ident));
self.per_ns(|this, ns| {
if let Ok(binding) = source_bindings[ns].get() {
this.lint_if_path_starts_with_module(Some(finalize), &full_path, Some(binding));
}
});
}
// Record what this import resolves to for later uses in documentation,
// this may resolve to either a value or a type, but for documentation
// purposes it's good enough to just favor one over the other.
self.per_ns(|this, ns| {
if let Ok(binding) = source_bindings[ns].get() {
this.import_res_map.entry(import_id).or_default()[ns] = Some(binding.res());
}
});
debug!("(resolving single import) successfully resolved import");
None
}
pub(crate) fn check_for_redundant_imports(&mut self, import: Import<'ra>) -> bool {
// This function is only called for single imports.
let ImportKind::Single {
source, target, ref source_bindings, ref target_bindings, id, ..
} = import.kind
else {
unreachable!()
};
// Skip if the import is of the form `use source as target` and source != target.
if source != target {
return false;
}
// Skip if the import was produced by a macro.
if import.parent_scope.expansion != LocalExpnId::ROOT {
return false;
}
// Skip if we are inside a named module (in contrast to an anonymous
// module defined by a block).
// Skip if the import is public or was used through non scope-based resolution,
// e.g. through a module-relative path.
if self.import_use_map.get(&import) == Some(&Used::Other)
|| self.effective_visibilities.is_exported(self.local_def_id(id))
{
return false;
}
let mut is_redundant = true;
let mut redundant_span = PerNS { value_ns: None, type_ns: None, macro_ns: None };
self.per_ns(|this, ns| {
if is_redundant && let Ok(binding) = source_bindings[ns].get() {
if binding.res() == Res::Err {
return;
}
match this.early_resolve_ident_in_lexical_scope(
target,
ScopeSet::All(ns),
&import.parent_scope,
None,
false,
target_bindings[ns].get(),
None,
) {
Ok(other_binding) => {
is_redundant = binding.res() == other_binding.res()
&& !other_binding.is_ambiguity_recursive();
if is_redundant {
redundant_span[ns] =
Some((other_binding.span, other_binding.is_import()));
}
}
Err(_) => is_redundant = false,
}
}
});
if is_redundant && !redundant_span.is_empty() {
let mut redundant_spans: Vec<_> = redundant_span.present_items().collect();
redundant_spans.sort();
redundant_spans.dedup();
self.lint_buffer.buffer_lint(
REDUNDANT_IMPORTS,
id,
import.span,
BuiltinLintDiag::RedundantImport(redundant_spans, source),
);
return true;
}
false
}
fn resolve_glob_import(&mut self, import: Import<'ra>) {
// This function is only called for glob imports.
let ImportKind::Glob { id, is_prelude, .. } = import.kind else { unreachable!() };
let ModuleOrUniformRoot::Module(module) = import.imported_module.get().unwrap() else {
self.dcx().emit_err(CannotGlobImportAllCrates { span: import.span });
return;
};
if module.is_trait() {
self.dcx().emit_err(ItemsInTraitsAreNotImportable { span: import.span });
return;
} else if module == import.parent_scope.module {
return;
} else if is_prelude {
self.prelude = Some(module);
return;
}
// Add to module's glob_importers
module.glob_importers.borrow_mut().push(import);
// Ensure that `resolutions` isn't borrowed during `try_define`,
// since it might get updated via a glob cycle.
let bindings = self
.resolutions(module)
.borrow()
.iter()
.filter_map(|(key, resolution)| {
resolution.borrow().binding().map(|binding| (*key, binding))
})
.collect::<Vec<_>>();
for (mut key, binding) in bindings {
let scope = match key.ident.span.reverse_glob_adjust(module.expansion, import.span) {
Some(Some(def)) => self.expn_def_scope(def),
Some(None) => import.parent_scope.module,
None => continue,
};
if self.is_accessible_from(binding.vis, scope) {
let imported_binding = self.import(binding, import);
let warn_ambiguity = self
.resolution(import.parent_scope.module, key)
.borrow()
.binding()
.is_some_and(|binding| binding.warn_ambiguity_recursive());
let _ = self.try_define(
import.parent_scope.module,
key,
imported_binding,
warn_ambiguity,
);
}
}
// Record the destination of this import
self.record_partial_res(id, PartialRes::new(module.res().unwrap()));
}
// Miscellaneous post-processing, including recording re-exports,
// reporting conflicts, and reporting unresolved imports.
fn finalize_resolutions_in(&mut self, module: Module<'ra>) {
// Since import resolution is finished, globs will not define any more names.
*module.globs.borrow_mut() = Vec::new();
if let Some(def_id) = module.opt_def_id() {
let mut children = Vec::new();
module.for_each_child(self, |this, ident, _, binding| {
let res = binding.res().expect_non_local();
let error_ambiguity = binding.is_ambiguity_recursive() && !binding.warn_ambiguity;
if res != def::Res::Err && !error_ambiguity {
let mut reexport_chain = SmallVec::new();
let mut next_binding = binding;
while let NameBindingKind::Import { binding, import, .. } = next_binding.kind {
reexport_chain.push(import.simplify(this));
next_binding = binding;
}
children.push(ModChild { ident, res, vis: binding.vis, reexport_chain });
}
});
if !children.is_empty() {
// Should be fine because this code is only called for local modules.
self.module_children.insert(def_id.expect_local(), children);
}
}
}
}
fn import_path_to_string(names: &[Ident], import_kind: &ImportKind<'_>, span: Span) -> String {
let pos = names.iter().position(|p| span == p.span && p.name != kw::PathRoot);
let global = !names.is_empty() && names[0].name == kw::PathRoot;
if let Some(pos) = pos {
let names = if global { &names[1..pos + 1] } else { &names[..pos + 1] };
names_to_string(&names.iter().map(|ident| ident.name).collect::<Vec<_>>())
} else {
let names = if global { &names[1..] } else { names };
if names.is_empty() {
import_kind_to_string(import_kind)
} else {
format!(
"{}::{}",
names_to_string(&names.iter().map(|ident| ident.name).collect::<Vec<_>>()),
import_kind_to_string(import_kind),
)
}
}
}
fn import_kind_to_string(import_kind: &ImportKind<'_>) -> String {
match import_kind {
ImportKind::Single { source, .. } => source.to_string(),
ImportKind::Glob { .. } => "*".to_string(),
ImportKind::ExternCrate { .. } => "<extern crate>".to_string(),
ImportKind::MacroUse { .. } => "#[macro_use]".to_string(),
ImportKind::MacroExport => "#[macro_export]".to_string(),
}
}