src/librustc/ty/maps.rs

   1 // Copyright 2012-2015 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.
   4 //
   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.
  10
  11 use dep_graph::{DepConstructor, DepNode, DepNodeIndex};
  12 use errors::{Diagnostic, DiagnosticBuilder};
  13 use hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
  14 use hir::def::Def;
  15 use hir;
  16 use lint;
  17 use middle::const_val;
  18 use middle::cstore::{ExternCrate, LinkagePreference};
  19 use middle::privacy::AccessLevels;
  20 use middle::region::RegionMaps;
  21 use mir;
  22 use mir::transform::{MirSuite, MirPassIndex};
  23 use session::CompileResult;
  24 use traits::specialization_graph;
  25 use ty::{self, CrateInherentImpls, Ty, TyCtxt};
  26 use ty::layout::{Layout, LayoutError};
  27 use ty::item_path;
  28 use ty::steal::Steal;
  29 use ty::subst::Substs;
  30 use ty::fast_reject::SimplifiedType;
  31 use util::nodemap::{DefIdSet, NodeSet};
  32 use util::common::{profq_msg, ProfileQueriesMsg};
  33
  34 use rustc_data_structures::indexed_vec::IndexVec;
  35 use rustc_data_structures::fx::FxHashMap;
  36 use std::cell::{RefCell, RefMut, Cell};
  37 use std::fmt::Debug;
  38 use std::hash::Hash;
  39 use std::marker::PhantomData;
  40 use std::mem;
  41 use std::collections::BTreeMap;
  42 use std::ops::Deref;
  43 use std::rc::Rc;
  44 use syntax_pos::{Span, DUMMY_SP};
  45 use syntax::attr;
  46 use syntax::ast;
  47 use syntax::symbol::Symbol;
  48
  49 pub trait Key: Clone + Hash + Eq + Debug {
  50     fn map_crate(&self) -> CrateNum;
  51     fn default_span(&self, tcx: TyCtxt) -> Span;
  52 }
  53
  54 impl<'tcx> Key for ty::InstanceDef<'tcx> {
  55     fn map_crate(&self) -> CrateNum {
  56         LOCAL_CRATE
  57     }
  58
  59     fn default_span(&self, tcx: TyCtxt) -> Span {
  60         tcx.def_span(self.def_id())
  61     }
  62 }
  63
  64 impl<'tcx> Key for ty::Instance<'tcx> {
  65     fn map_crate(&self) -> CrateNum {
  66         LOCAL_CRATE
  67     }
  68
  69     fn default_span(&self, tcx: TyCtxt) -> Span {
  70         tcx.def_span(self.def_id())
  71     }
  72 }
  73
  74 impl Key for CrateNum {
  75     fn map_crate(&self) -> CrateNum {
  76         *self
  77     }
  78     fn default_span(&self, _: TyCtxt) -> Span {
  79         DUMMY_SP
  80     }
  81 }
  82
  83 impl Key for DefId {
  84     fn map_crate(&self) -> CrateNum {
  85         self.krate
  86     }
  87     fn default_span(&self, tcx: TyCtxt) -> Span {
  88         tcx.def_span(*self)
  89     }
  90 }
  91
  92 impl Key for (DefId, DefId) {
  93     fn map_crate(&self) -> CrateNum {
  94         self.0.krate
  95     }
  96     fn default_span(&self, tcx: TyCtxt) -> Span {
  97         self.1.default_span(tcx)
  98     }
  99 }
 100
 101 impl Key for (CrateNum, DefId) {
 102     fn map_crate(&self) -> CrateNum {
 103         self.0
 104     }
 105     fn default_span(&self, tcx: TyCtxt) -> Span {
 106         self.1.default_span(tcx)
 107     }
 108 }
 109
 110 impl Key for (DefId, SimplifiedType) {
 111     fn map_crate(&self) -> CrateNum {
 112         self.0.krate
 113     }
 114     fn default_span(&self, tcx: TyCtxt) -> Span {
 115         self.0.default_span(tcx)
 116     }
 117 }
 118
 119 impl<'tcx> Key for (DefId, &'tcx Substs<'tcx>) {
 120     fn map_crate(&self) -> CrateNum {
 121         self.0.krate
 122     }
 123     fn default_span(&self, tcx: TyCtxt) -> Span {
 124         self.0.default_span(tcx)
 125     }
 126 }
 127
 128 impl Key for (MirSuite, DefId) {
 129     fn map_crate(&self) -> CrateNum {
 130         self.1.map_crate()
 131     }
 132     fn default_span(&self, tcx: TyCtxt) -> Span {
 133         self.1.default_span(tcx)
 134     }
 135 }
 136
 137 impl Key for (MirSuite, MirPassIndex, DefId) {
 138     fn map_crate(&self) -> CrateNum {
 139         self.2.map_crate()
 140     }
 141     fn default_span(&self, tcx: TyCtxt) -> Span {
 142         self.2.default_span(tcx)
 143     }
 144 }
 145
 146 impl<'tcx, T: Clone + Hash + Eq + Debug> Key for ty::ParamEnvAnd<'tcx, T> {
 147     fn map_crate(&self) -> CrateNum {
 148         LOCAL_CRATE
 149     }
 150     fn default_span(&self, _: TyCtxt) -> Span {
 151         DUMMY_SP
 152     }
 153 }
 154
 155 trait Value<'tcx>: Sized {
 156     fn from_cycle_error<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Self;
 157 }
 158
 159 impl<'tcx, T> Value<'tcx> for T {
 160     default fn from_cycle_error<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> T {
 161         tcx.sess.abort_if_errors();
 162         bug!("Value::from_cycle_error called without errors");
 163     }
 164 }
 165
 166 impl<'tcx, T: Default> Value<'tcx> for T {
 167     default fn from_cycle_error<'a>(_: TyCtxt<'a, 'tcx, 'tcx>) -> T {
 168         T::default()
 169     }
 170 }
 171
 172 impl<'tcx> Value<'tcx> for Ty<'tcx> {
 173     fn from_cycle_error<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Ty<'tcx> {
 174         tcx.types.err
 175     }
 176 }
 177
 178 impl<'tcx> Value<'tcx> for ty::DtorckConstraint<'tcx> {
 179     fn from_cycle_error<'a>(_: TyCtxt<'a, 'tcx, 'tcx>) -> Self {
 180         Self::empty()
 181     }
 182 }
 183
 184 impl<'tcx> Value<'tcx> for ty::SymbolName {
 185     fn from_cycle_error<'a>(_: TyCtxt<'a, 'tcx, 'tcx>) -> Self {
 186         ty::SymbolName { name: Symbol::intern("<error>").as_str() }
 187     }
 188 }
 189
 190 struct QueryMap<D: QueryDescription> {
 191     phantom: PhantomData<D>,
 192     map: FxHashMap<D::Key, QueryValue<D::Value>>,
 193 }
 194
 195 struct QueryValue<T> {
 196     value: T,
 197     index: DepNodeIndex,
 198     diagnostics: Option<Box<QueryDiagnostics>>,
 199 }
 200
 201 struct QueryDiagnostics {
 202     diagnostics: Vec<Diagnostic>,
 203     emitted_diagnostics: Cell<bool>,
 204 }
 205
 206 impl<M: QueryDescription> QueryMap<M> {
 207     fn new() -> QueryMap<M> {
 208         QueryMap {
 209             phantom: PhantomData,
 210             map: FxHashMap(),
 211         }
 212     }
 213 }
 214
 215 struct CycleError<'a, 'tcx: 'a> {
 216     span: Span,
 217     cycle: RefMut<'a, [(Span, Query<'tcx>)]>,
 218 }
 219
 220 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 221     fn report_cycle(self, CycleError { span, cycle }: CycleError)
 222         -> DiagnosticBuilder<'a>
 223     {
 224         // Subtle: release the refcell lock before invoking `describe()`
 225         // below by dropping `cycle`.
 226         let stack = cycle.to_vec();
 227         mem::drop(cycle);
 228
 229         assert!(!stack.is_empty());
 230
 231         // Disable naming impls with types in this path, since that
 232         // sometimes cycles itself, leading to extra cycle errors.
 233         // (And cycle errors around impls tend to occur during the
 234         // collect/coherence phases anyhow.)
 235         item_path::with_forced_impl_filename_line(|| {
 236             let mut err =
 237                 struct_span_err!(self.sess, span, E0391,
 238                                  "unsupported cyclic reference between types/traits detected");
 239             err.span_label(span, "cyclic reference");
 240
 241             err.span_note(stack[0].0, &format!("the cycle begins when {}...",
 242                                                stack[0].1.describe(self)));
 243
 244             for &(span, ref query) in &stack[1..] {
 245                 err.span_note(span, &format!("...which then requires {}...",
 246                                              query.describe(self)));
 247             }
 248
 249             err.note(&format!("...which then again requires {}, completing the cycle.",
 250                               stack[0].1.describe(self)));
 251
 252             return err
 253         })
 254     }
 255
 256     fn cycle_check<F, R>(self, span: Span, query: Query<'gcx>, compute: F)
 257                          -> Result<R, CycleError<'a, 'gcx>>
 258         where F: FnOnce() -> R
 259     {
 260         {
 261             let mut stack = self.maps.query_stack.borrow_mut();
 262             if let Some((i, _)) = stack.iter().enumerate().rev()
 263                                        .find(|&(_, &(_, ref q))| *q == query) {
 264                 return Err(CycleError {
 265                     span,
 266                     cycle: RefMut::map(stack, |stack| &mut stack[i..])
 267                 });
 268             }
 269             stack.push((span, query));
 270         }
 271
 272         let result = compute();
 273
 274         self.maps.query_stack.borrow_mut().pop();
 275
 276         Ok(result)
 277     }
 278 }
 279
 280 pub trait QueryConfig {
 281     type Key: Eq + Hash + Clone;
 282     type Value;
 283 }
 284
 285 trait QueryDescription: QueryConfig {
 286     fn describe(tcx: TyCtxt, key: Self::Key) -> String;
 287 }
 288
 289 impl<M: QueryConfig<Key=DefId>> QueryDescription for M {
 290     default fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 291         format!("processing `{}`", tcx.item_path_str(def_id))
 292     }
 293 }
 294
 295 impl<'tcx> QueryDescription for queries::is_copy_raw<'tcx> {
 296     fn describe(_tcx: TyCtxt, env: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> String {
 297         format!("computing whether `{}` is `Copy`", env.value)
 298     }
 299 }
 300
 301 impl<'tcx> QueryDescription for queries::is_sized_raw<'tcx> {
 302     fn describe(_tcx: TyCtxt, env: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> String {
 303         format!("computing whether `{}` is `Sized`", env.value)
 304     }
 305 }
 306
 307 impl<'tcx> QueryDescription for queries::is_freeze_raw<'tcx> {
 308     fn describe(_tcx: TyCtxt, env: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> String {
 309         format!("computing whether `{}` is freeze", env.value)
 310     }
 311 }
 312
 313 impl<'tcx> QueryDescription for queries::needs_drop_raw<'tcx> {
 314     fn describe(_tcx: TyCtxt, env: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> String {
 315         format!("computing whether `{}` needs drop", env.value)
 316     }
 317 }
 318
 319 impl<'tcx> QueryDescription for queries::layout_raw<'tcx> {
 320     fn describe(_tcx: TyCtxt, env: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> String {
 321         format!("computing layout of `{}`", env.value)
 322     }
 323 }
 324
 325 impl<'tcx> QueryDescription for queries::super_predicates_of<'tcx> {
 326     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 327         format!("computing the supertraits of `{}`",
 328                 tcx.item_path_str(def_id))
 329     }
 330 }
 331
 332 impl<'tcx> QueryDescription for queries::type_param_predicates<'tcx> {
 333     fn describe(tcx: TyCtxt, (_, def_id): (DefId, DefId)) -> String {
 334         let id = tcx.hir.as_local_node_id(def_id).unwrap();
 335         format!("computing the bounds for type parameter `{}`",
 336                 tcx.hir.ty_param_name(id))
 337     }
 338 }
 339
 340 impl<'tcx> QueryDescription for queries::coherent_trait<'tcx> {
 341     fn describe(tcx: TyCtxt, (_, def_id): (CrateNum, DefId)) -> String {
 342         format!("coherence checking all impls of trait `{}`",
 343                 tcx.item_path_str(def_id))
 344     }
 345 }
 346
 347 impl<'tcx> QueryDescription for queries::crate_inherent_impls<'tcx> {
 348     fn describe(_: TyCtxt, k: CrateNum) -> String {
 349         format!("all inherent impls defined in crate `{:?}`", k)
 350     }
 351 }
 352
 353 impl<'tcx> QueryDescription for queries::crate_inherent_impls_overlap_check<'tcx> {
 354     fn describe(_: TyCtxt, _: CrateNum) -> String {
 355         format!("check for overlap between inherent impls defined in this crate")
 356     }
 357 }
 358
 359 impl<'tcx> QueryDescription for queries::crate_variances<'tcx> {
 360     fn describe(_tcx: TyCtxt, _: CrateNum) -> String {
 361         format!("computing the variances for items in this crate")
 362     }
 363 }
 364
 365 impl<'tcx> QueryDescription for queries::mir_shims<'tcx> {
 366     fn describe(tcx: TyCtxt, def: ty::InstanceDef<'tcx>) -> String {
 367         format!("generating MIR shim for `{}`",
 368                 tcx.item_path_str(def.def_id()))
 369     }
 370 }
 371
 372 impl<'tcx> QueryDescription for queries::privacy_access_levels<'tcx> {
 373     fn describe(_: TyCtxt, _: CrateNum) -> String {
 374         format!("privacy access levels")
 375     }
 376 }
 377
 378 impl<'tcx> QueryDescription for queries::typeck_item_bodies<'tcx> {
 379     fn describe(_: TyCtxt, _: CrateNum) -> String {
 380         format!("type-checking all item bodies")
 381     }
 382 }
 383
 384 impl<'tcx> QueryDescription for queries::reachable_set<'tcx> {
 385     fn describe(_: TyCtxt, _: CrateNum) -> String {
 386         format!("reachability")
 387     }
 388 }
 389
 390 impl<'tcx> QueryDescription for queries::const_eval<'tcx> {
 391     fn describe(tcx: TyCtxt, key: ty::ParamEnvAnd<'tcx, (DefId, &'tcx Substs<'tcx>)>) -> String {
 392         format!("const-evaluating `{}`", tcx.item_path_str(key.value.0))
 393     }
 394 }
 395
 396 impl<'tcx> QueryDescription for queries::mir_keys<'tcx> {
 397     fn describe(_: TyCtxt, _: CrateNum) -> String {
 398         format!("getting a list of all mir_keys")
 399     }
 400 }
 401
 402 impl<'tcx> QueryDescription for queries::symbol_name<'tcx> {
 403     fn describe(_tcx: TyCtxt, instance: ty::Instance<'tcx>) -> String {
 404         format!("computing the symbol for `{}`", instance)
 405     }
 406 }
 407
 408 impl<'tcx> QueryDescription for queries::describe_def<'tcx> {
 409     fn describe(_: TyCtxt, _: DefId) -> String {
 410         bug!("describe_def")
 411     }
 412 }
 413
 414 impl<'tcx> QueryDescription for queries::def_span<'tcx> {
 415     fn describe(_: TyCtxt, _: DefId) -> String {
 416         bug!("def_span")
 417     }
 418 }
 419
 420
 421 impl<'tcx> QueryDescription for queries::stability<'tcx> {
 422     fn describe(_: TyCtxt, _: DefId) -> String {
 423         bug!("stability")
 424     }
 425 }
 426
 427 impl<'tcx> QueryDescription for queries::deprecation<'tcx> {
 428     fn describe(_: TyCtxt, _: DefId) -> String {
 429         bug!("deprecation")
 430     }
 431 }
 432
 433 impl<'tcx> QueryDescription for queries::item_attrs<'tcx> {
 434     fn describe(_: TyCtxt, _: DefId) -> String {
 435         bug!("item_attrs")
 436     }
 437 }
 438
 439 impl<'tcx> QueryDescription for queries::is_exported_symbol<'tcx> {
 440     fn describe(_: TyCtxt, _: DefId) -> String {
 441         bug!("is_exported_symbol")
 442     }
 443 }
 444
 445 impl<'tcx> QueryDescription for queries::fn_arg_names<'tcx> {
 446     fn describe(_: TyCtxt, _: DefId) -> String {
 447         bug!("fn_arg_names")
 448     }
 449 }
 450
 451 impl<'tcx> QueryDescription for queries::impl_parent<'tcx> {
 452     fn describe(_: TyCtxt, _: DefId) -> String {
 453         bug!("impl_parent")
 454     }
 455 }
 456
 457 impl<'tcx> QueryDescription for queries::trait_of_item<'tcx> {
 458     fn describe(_: TyCtxt, _: DefId) -> String {
 459         bug!("trait_of_item")
 460     }
 461 }
 462
 463 impl<'tcx> QueryDescription for queries::item_body_nested_bodies<'tcx> {
 464     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 465         format!("nested item bodies of `{}`", tcx.item_path_str(def_id))
 466     }
 467 }
 468
 469 impl<'tcx> QueryDescription for queries::const_is_rvalue_promotable_to_static<'tcx> {
 470     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 471         format!("const checking if rvalue is promotable to static `{}`",
 472             tcx.item_path_str(def_id))
 473     }
 474 }
 475
 476 impl<'tcx> QueryDescription for queries::is_mir_available<'tcx> {
 477     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 478         format!("checking if item is mir available: `{}`",
 479             tcx.item_path_str(def_id))
 480     }
 481 }
 482
 483 impl<'tcx> QueryDescription for queries::trait_impls_of<'tcx> {
 484     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 485         format!("trait impls of `{}`", tcx.item_path_str(def_id))
 486     }
 487 }
 488
 489 impl<'tcx> QueryDescription for queries::is_object_safe<'tcx> {
 490     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 491         format!("determine object safety of trait `{}`", tcx.item_path_str(def_id))
 492     }
 493 }
 494
 495 impl<'tcx> QueryDescription for queries::is_const_fn<'tcx> {
 496     fn describe(tcx: TyCtxt, def_id: DefId) -> String {
 497         format!("checking if item is const fn: `{}`", tcx.item_path_str(def_id))
 498     }
 499 }
 500
 501 impl<'tcx> QueryDescription for queries::dylib_dependency_formats<'tcx> {
 502     fn describe(_: TyCtxt, _: DefId) -> String {
 503         "dylib dependency formats of crate".to_string()
 504     }
 505 }
 506
 507 impl<'tcx> QueryDescription for queries::is_allocator<'tcx> {
 508     fn describe(_: TyCtxt, _: DefId) -> String {
 509         "checking if the crate is_allocator".to_string()
 510     }
 511 }
 512
 513 impl<'tcx> QueryDescription for queries::is_panic_runtime<'tcx> {
 514     fn describe(_: TyCtxt, _: DefId) -> String {
 515         "checking if the crate is_panic_runtime".to_string()
 516     }
 517 }
 518
 519 impl<'tcx> QueryDescription for queries::is_compiler_builtins<'tcx> {
 520     fn describe(_: TyCtxt, _: DefId) -> String {
 521         "checking if the crate is_compiler_builtins".to_string()
 522     }
 523 }
 524
 525 impl<'tcx> QueryDescription for queries::has_global_allocator<'tcx> {
 526     fn describe(_: TyCtxt, _: DefId) -> String {
 527         "checking if the crate has_global_allocator".to_string()
 528     }
 529 }
 530
 531 impl<'tcx> QueryDescription for queries::extern_crate<'tcx> {
 532     fn describe(_: TyCtxt, _: DefId) -> String {
 533         "getting crate's ExternCrateData".to_string()
 534     }
 535 }
 536
 537 impl<'tcx> QueryDescription for queries::lint_levels<'tcx> {
 538     fn describe(_tcx: TyCtxt, _: CrateNum) -> String {
 539         format!("computing the lint levels for items in this crate")
 540     }
 541 }
 542
 543 // If enabled, send a message to the profile-queries thread
 544 macro_rules! profq_msg {
 545     ($tcx:expr, $msg:expr) => {
 546         if cfg!(debug_assertions) {
 547             if  $tcx.sess.profile_queries() {
 548                 profq_msg($msg)
 549             }
 550         }
 551     }
 552 }
 553
 554 // If enabled, format a key using its debug string, which can be
 555 // expensive to compute (in terms of time).
 556 macro_rules! profq_key {
 557     ($tcx:expr, $key:expr) => {
 558         if cfg!(debug_assertions) {
 559             if $tcx.sess.profile_queries_and_keys() {
 560                 Some(format!("{:?}", $key))
 561             } else { None }
 562         } else { None }
 563     }
 564 }
 565
 566 macro_rules! define_maps {
 567     (<$tcx:tt>
 568      $($(#[$attr:meta])*
 569        [$($modifiers:tt)*] $name:ident: $node:ident($K:ty) -> $V:ty,)*) => {
 570         define_map_struct! {
 571             tcx: $tcx,
 572             input: ($(([$($modifiers)*] [$($attr)*] [$name]))*)
 573         }
 574
 575         impl<$tcx> Maps<$tcx> {
 576             pub fn new(providers: IndexVec<CrateNum, Providers<$tcx>>)
 577                        -> Self {
 578                 Maps {
 579                     providers,
 580                     query_stack: RefCell::new(vec![]),
 581                     $($name: RefCell::new(QueryMap::new())),*
 582                 }
 583             }
 584         }
 585
 586         #[allow(bad_style)]
 587         #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 588         pub enum Query<$tcx> {
 589             $($(#[$attr])* $name($K)),*
 590         }
 591
 592         #[allow(bad_style)]
 593         #[derive(Clone, Debug, PartialEq, Eq)]
 594         pub enum QueryMsg {
 595             $($name(Option<String>)),*
 596         }
 597
 598         impl<$tcx> Query<$tcx> {
 599             pub fn describe(&self, tcx: TyCtxt) -> String {
 600                 match *self {
 601                     $(Query::$name(key) => queries::$name::describe(tcx, key)),*
 602                 }
 603             }
 604         }
 605
 606         pub mod queries {
 607             use std::marker::PhantomData;
 608
 609             $(#[allow(bad_style)]
 610             pub struct $name<$tcx> {
 611                 data: PhantomData<&$tcx ()>
 612             })*
 613         }
 614
 615         $(impl<$tcx> QueryConfig for queries::$name<$tcx> {
 616             type Key = $K;
 617             type Value = $V;
 618         }
 619
 620         impl<'a, $tcx, 'lcx> queries::$name<$tcx> {
 621             #[allow(unused)]
 622             fn to_dep_node(tcx: TyCtxt<'a, $tcx, 'lcx>, key: &$K) -> DepNode {
 623                 use dep_graph::DepConstructor::*;
 624
 625                 DepNode::new(tcx, $node(*key))
 626             }
 627
 628             fn try_get_with<F, R>(tcx: TyCtxt<'a, $tcx, 'lcx>,
 629                                   mut span: Span,
 630                                   key: $K,
 631                                   f: F)
 632                                   -> Result<R, CycleError<'a, $tcx>>
 633                 where F: FnOnce(&$V) -> R
 634             {
 635                 debug!("ty::queries::{}::try_get_with(key={:?}, span={:?})",
 636                        stringify!($name),
 637                        key,
 638                        span);
 639
 640                 profq_msg!(tcx,
 641                     ProfileQueriesMsg::QueryBegin(
 642                         span.clone(),
 643                         QueryMsg::$name(profq_key!(tcx, key))
 644                     )
 645                 );
 646
 647                 if let Some(value) = tcx.maps.$name.borrow().map.get(&key) {
 648                     if let Some(ref d) = value.diagnostics {
 649                         if !d.emitted_diagnostics.get() {
 650                             d.emitted_diagnostics.set(true);
 651                             let handle = tcx.sess.diagnostic();
 652                             for diagnostic in d.diagnostics.iter() {
 653                                 DiagnosticBuilder::new_diagnostic(handle, diagnostic.clone())
 654                                     .emit();
 655                             }
 656                         }
 657                     }
 658                     profq_msg!(tcx, ProfileQueriesMsg::CacheHit);
 659                     tcx.dep_graph.read_index(value.index);
 660                     return Ok(f(&value.value));
 661                 }
 662                 // else, we are going to run the provider:
 663                 profq_msg!(tcx, ProfileQueriesMsg::ProviderBegin);
 664
 665                 // FIXME(eddyb) Get more valid Span's on queries.
 666                 // def_span guard is necessary to prevent a recursive loop,
 667                 // default_span calls def_span query internally.
 668                 if span == DUMMY_SP && stringify!($name) != "def_span" {
 669                     span = key.default_span(tcx)
 670                 }
 671
 672                 let res = tcx.cycle_check(span, Query::$name(key), || {
 673                     let dep_node = Self::to_dep_node(tcx, &key);
 674
 675                     tcx.sess.diagnostic().track_diagnostics(|| {
 676                         if dep_node.kind.is_anon() {
 677                             tcx.dep_graph.with_anon_task(dep_node.kind, || {
 678                                 let provider = tcx.maps.providers[key.map_crate()].$name;
 679                                 provider(tcx.global_tcx(), key)
 680                             })
 681                         } else {
 682                             fn run_provider<'a, 'tcx, 'lcx>(tcx: TyCtxt<'a, 'tcx, 'lcx>,
 683                                                             key: $K)
 684                                                             -> $V {
 685                                 let provider = tcx.maps.providers[key.map_crate()].$name;
 686                                 provider(tcx.global_tcx(), key)
 687                             }
 688
 689                             tcx.dep_graph.with_task(dep_node, tcx, key, run_provider)
 690                         }
 691                     })
 692                 })?;
 693                 profq_msg!(tcx, ProfileQueriesMsg::ProviderEnd);
 694                 let ((result, dep_node_index), diagnostics) = res;
 695
 696                 tcx.dep_graph.read_index(dep_node_index);
 697
 698                 let value = QueryValue {
 699                     value: result,
 700                     index: dep_node_index,
 701                     diagnostics: if diagnostics.len() == 0 {
 702                         None
 703                     } else {
 704                         Some(Box::new(QueryDiagnostics {
 705                             diagnostics,
 706                             emitted_diagnostics: Cell::new(true),
 707                         }))
 708                     },
 709                 };
 710
 711                 Ok(f(&tcx.maps
 712                          .$name
 713                          .borrow_mut()
 714                          .map
 715                          .entry(key)
 716                          .or_insert(value)
 717                          .value))
 718             }
 719
 720             pub fn try_get(tcx: TyCtxt<'a, $tcx, 'lcx>, span: Span, key: $K)
 721                            -> Result<$V, DiagnosticBuilder<'a>> {
 722                 match Self::try_get_with(tcx, span, key, Clone::clone) {
 723                     Ok(e) => Ok(e),
 724                     Err(e) => Err(tcx.report_cycle(e)),
 725                 }
 726             }
 727
 728             pub fn force(tcx: TyCtxt<'a, $tcx, 'lcx>, span: Span, key: $K) {
 729                 // Ignore dependencies, since we not reading the computed value
 730                 let _task = tcx.dep_graph.in_ignore();
 731
 732                 match Self::try_get_with(tcx, span, key, |_| ()) {
 733                     Ok(()) => {}
 734                     Err(e) => tcx.report_cycle(e).emit(),
 735                 }
 736             }
 737         })*
 738
 739         #[derive(Copy, Clone)]
 740         pub struct TyCtxtAt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
 741             pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
 742             pub span: Span,
 743         }
 744
 745         impl<'a, 'gcx, 'tcx> Deref for TyCtxtAt<'a, 'gcx, 'tcx> {
 746             type Target = TyCtxt<'a, 'gcx, 'tcx>;
 747             fn deref(&self) -> &Self::Target {
 748                 &self.tcx
 749             }
 750         }
 751
 752         impl<'a, $tcx, 'lcx> TyCtxt<'a, $tcx, 'lcx> {
 753             /// Return a transparent wrapper for `TyCtxt` which uses
 754             /// `span` as the location of queries performed through it.
 755             pub fn at(self, span: Span) -> TyCtxtAt<'a, $tcx, 'lcx> {
 756                 TyCtxtAt {
 757                     tcx: self,
 758                     span
 759                 }
 760             }
 761
 762             $($(#[$attr])*
 763             pub fn $name(self, key: $K) -> $V {
 764                 self.at(DUMMY_SP).$name(key)
 765             })*
 766         }
 767
 768         impl<'a, $tcx, 'lcx> TyCtxtAt<'a, $tcx, 'lcx> {
 769             $($(#[$attr])*
 770             pub fn $name(self, key: $K) -> $V {
 771                 queries::$name::try_get(self.tcx, self.span, key).unwrap_or_else(|mut e| {
 772                     e.emit();
 773                     Value::from_cycle_error(self.global_tcx())
 774                 })
 775             })*
 776         }
 777
 778         define_provider_struct! {
 779             tcx: $tcx,
 780             input: ($(([$($modifiers)*] [$name] [$K] [$V]))*),
 781             output: ()
 782         }
 783
 784         impl<$tcx> Copy for Providers<$tcx> {}
 785         impl<$tcx> Clone for Providers<$tcx> {
 786             fn clone(&self) -> Self { *self }
 787         }
 788     }
 789 }
 790
 791 macro_rules! define_map_struct {
 792     // Initial state
 793     (tcx: $tcx:tt,
 794      input: $input:tt) => {
 795         define_map_struct! {
 796             tcx: $tcx,
 797             input: $input,
 798             output: ()
 799         }
 800     };
 801
 802     // Final output
 803     (tcx: $tcx:tt,
 804      input: (),
 805      output: ($($output:tt)*)) => {
 806         pub struct Maps<$tcx> {
 807             providers: IndexVec<CrateNum, Providers<$tcx>>,
 808             query_stack: RefCell<Vec<(Span, Query<$tcx>)>>,
 809             $($output)*
 810         }
 811     };
 812
 813     // Field recognized and ready to shift into the output
 814     (tcx: $tcx:tt,
 815      ready: ([$($pub:tt)*] [$($attr:tt)*] [$name:ident]),
 816      input: $input:tt,
 817      output: ($($output:tt)*)) => {
 818         define_map_struct! {
 819             tcx: $tcx,
 820             input: $input,
 821             output: ($($output)*
 822                      $(#[$attr])* $($pub)* $name: RefCell<QueryMap<queries::$name<$tcx>>>,)
 823         }
 824     };
 825
 826     // No modifiers left? This is a private item.
 827     (tcx: $tcx:tt,
 828      input: (([] $attrs:tt $name:tt) $($input:tt)*),
 829      output: $output:tt) => {
 830         define_map_struct! {
 831             tcx: $tcx,
 832             ready: ([] $attrs $name),
 833             input: ($($input)*),
 834             output: $output
 835         }
 836     };
 837
 838     // Skip other modifiers
 839     (tcx: $tcx:tt,
 840      input: (([$other_modifier:tt $($modifiers:tt)*] $($fields:tt)*) $($input:tt)*),
 841      output: $output:tt) => {
 842         define_map_struct! {
 843             tcx: $tcx,
 844             input: (([$($modifiers)*] $($fields)*) $($input)*),
 845             output: $output
 846         }
 847     };
 848 }
 849
 850 macro_rules! define_provider_struct {
 851     // Initial state:
 852     (tcx: $tcx:tt, input: $input:tt) => {
 853         define_provider_struct! {
 854             tcx: $tcx,
 855             input: $input,
 856             output: ()
 857         }
 858     };
 859
 860     // Final state:
 861     (tcx: $tcx:tt,
 862      input: (),
 863      output: ($(([$name:ident] [$K:ty] [$R:ty]))*)) => {
 864         pub struct Providers<$tcx> {
 865             $(pub $name: for<'a> fn(TyCtxt<'a, $tcx, $tcx>, $K) -> $R,)*
 866         }
 867
 868         impl<$tcx> Default for Providers<$tcx> {
 869             fn default() -> Self {
 870                 $(fn $name<'a, $tcx>(_: TyCtxt<'a, $tcx, $tcx>, key: $K) -> $R {
 871                     bug!("tcx.maps.{}({:?}) unsupported by its crate",
 872                          stringify!($name), key);
 873                 })*
 874                 Providers { $($name),* }
 875             }
 876         }
 877     };
 878
 879     // Something ready to shift:
 880     (tcx: $tcx:tt,
 881      ready: ($name:tt $K:tt $V:tt),
 882      input: $input:tt,
 883      output: ($($output:tt)*)) => {
 884         define_provider_struct! {
 885             tcx: $tcx,
 886             input: $input,
 887             output: ($($output)* ($name $K $V))
 888         }
 889     };
 890
 891     // Regular queries produce a `V` only.
 892     (tcx: $tcx:tt,
 893      input: (([] $name:tt $K:tt $V:tt) $($input:tt)*),
 894      output: $output:tt) => {
 895         define_provider_struct! {
 896             tcx: $tcx,
 897             ready: ($name $K $V),
 898             input: ($($input)*),
 899             output: $output
 900         }
 901     };
 902
 903     // Skip modifiers.
 904     (tcx: $tcx:tt,
 905      input: (([$other_modifier:tt $($modifiers:tt)*] $($fields:tt)*) $($input:tt)*),
 906      output: $output:tt) => {
 907         define_provider_struct! {
 908             tcx: $tcx,
 909             input: (([$($modifiers)*] $($fields)*) $($input)*),
 910             output: $output
 911         }
 912     };
 913 }
 914
 915 // Each of these maps also corresponds to a method on a
 916 // `Provider` trait for requesting a value of that type,
 917 // and a method on `Maps` itself for doing that in a
 918 // a way that memoizes and does dep-graph tracking,
 919 // wrapping around the actual chain of providers that
 920 // the driver creates (using several `rustc_*` crates).
 921 define_maps! { <'tcx>
 922     /// Records the type of every item.
 923     [] type_of: TypeOfItem(DefId) -> Ty<'tcx>,
 924
 925     /// Maps from the def-id of an item (trait/struct/enum/fn) to its
 926     /// associated generics and predicates.
 927     [] generics_of: GenericsOfItem(DefId) -> &'tcx ty::Generics,
 928     [] predicates_of: PredicatesOfItem(DefId) -> ty::GenericPredicates<'tcx>,
 929
 930     /// Maps from the def-id of a trait to the list of
 931     /// super-predicates. This is a subset of the full list of
 932     /// predicates. We store these in a separate map because we must
 933     /// evaluate them even during type conversion, often before the
 934     /// full predicates are available (note that supertraits have
 935     /// additional acyclicity requirements).
 936     [] super_predicates_of: SuperPredicatesOfItem(DefId) -> ty::GenericPredicates<'tcx>,
 937
 938     /// To avoid cycles within the predicates of a single item we compute
 939     /// per-type-parameter predicates for resolving `T::AssocTy`.
 940     [] type_param_predicates: type_param_predicates((DefId, DefId))
 941         -> ty::GenericPredicates<'tcx>,
 942
 943     [] trait_def: TraitDefOfItem(DefId) -> &'tcx ty::TraitDef,
 944     [] adt_def: AdtDefOfItem(DefId) -> &'tcx ty::AdtDef,
 945     [] adt_destructor: AdtDestructor(DefId) -> Option<ty::Destructor>,
 946     [] adt_sized_constraint: SizedConstraint(DefId) -> &'tcx [Ty<'tcx>],
 947     [] adt_dtorck_constraint: DtorckConstraint(DefId) -> ty::DtorckConstraint<'tcx>,
 948
 949     /// True if this is a const fn
 950     [] is_const_fn: IsConstFn(DefId) -> bool,
 951
 952     /// True if this is a foreign item (i.e., linked via `extern { ... }`).
 953     [] is_foreign_item: IsForeignItem(DefId) -> bool,
 954
 955     /// True if this is a default impl (aka impl Foo for ..)
 956     [] is_default_impl: IsDefaultImpl(DefId) -> bool,
 957
 958     /// Get a map with the variance of every item; use `item_variance`
 959     /// instead.
 960     [] crate_variances: crate_variances(CrateNum) -> Rc<ty::CrateVariancesMap>,
 961
 962     /// Maps from def-id of a type or region parameter to its
 963     /// (inferred) variance.
 964     [] variances_of: ItemVariances(DefId) -> Rc<Vec<ty::Variance>>,
 965
 966     /// Maps from an impl/trait def-id to a list of the def-ids of its items
 967     [] associated_item_def_ids: AssociatedItemDefIds(DefId) -> Rc<Vec<DefId>>,
 968
 969     /// Maps from a trait item to the trait item "descriptor"
 970     [] associated_item: AssociatedItems(DefId) -> ty::AssociatedItem,
 971
 972     [] impl_trait_ref: ImplTraitRef(DefId) -> Option<ty::TraitRef<'tcx>>,
 973     [] impl_polarity: ImplPolarity(DefId) -> hir::ImplPolarity,
 974
 975     /// Maps a DefId of a type to a list of its inherent impls.
 976     /// Contains implementations of methods that are inherent to a type.
 977     /// Methods in these implementations don't need to be exported.
 978     [] inherent_impls: InherentImpls(DefId) -> Rc<Vec<DefId>>,
 979
 980     /// Set of all the def-ids in this crate that have MIR associated with
 981     /// them. This includes all the body owners, but also things like struct
 982     /// constructors.
 983     [] mir_keys: mir_keys(CrateNum) -> Rc<DefIdSet>,
 984
 985     /// Maps DefId's that have an associated Mir to the result
 986     /// of the MIR qualify_consts pass. The actual meaning of
 987     /// the value isn't known except to the pass itself.
 988     [] mir_const_qualif: MirConstQualif(DefId) -> u8,
 989
 990     /// Fetch the MIR for a given def-id up till the point where it is
 991     /// ready for const evaluation.
 992     ///
 993     /// See the README for the `mir` module for details.
 994     [] mir_const: MirConst(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
 995
 996     [] mir_validated: MirValidated(DefId) -> &'tcx Steal<mir::Mir<'tcx>>,
 997
 998     /// MIR after our optimization passes have run. This is MIR that is ready
 999     /// for trans. This is also the only query that can fetch non-local MIR, at present.
1000     [] optimized_mir: MirOptimized(DefId) -> &'tcx mir::Mir<'tcx>,
1001
1002     /// Type of each closure. The def ID is the ID of the
1003     /// expression defining the closure.
1004     [] closure_kind: ClosureKind(DefId) -> ty::ClosureKind,
1005
1006     /// The signature of functions and closures.
1007     [] fn_sig: FnSignature(DefId) -> ty::PolyFnSig<'tcx>,
1008
1009     /// Caches CoerceUnsized kinds for impls on custom types.
1010     [] coerce_unsized_info: CoerceUnsizedInfo(DefId)
1011         -> ty::adjustment::CoerceUnsizedInfo,
1012
1013     [] typeck_item_bodies: typeck_item_bodies_dep_node(CrateNum) -> CompileResult,
1014
1015     [] typeck_tables_of: TypeckTables(DefId) -> &'tcx ty::TypeckTables<'tcx>,
1016
1017     [] has_typeck_tables: HasTypeckTables(DefId) -> bool,
1018
1019     [] coherent_trait: coherent_trait_dep_node((CrateNum, DefId)) -> (),
1020
1021     [] borrowck: BorrowCheck(DefId) -> (),
1022     // FIXME: shouldn't this return a `Result<(), BorrowckErrors>` instead?
1023     [] mir_borrowck: MirBorrowCheck(DefId) -> (),
1024
1025     /// Gets a complete map from all types to their inherent impls.
1026     /// Not meant to be used directly outside of coherence.
1027     /// (Defined only for LOCAL_CRATE)
1028     [] crate_inherent_impls: crate_inherent_impls_dep_node(CrateNum) -> CrateInherentImpls,
1029
1030     /// Checks all types in the krate for overlap in their inherent impls. Reports errors.
1031     /// Not meant to be used directly outside of coherence.
1032     /// (Defined only for LOCAL_CRATE)
1033     [] crate_inherent_impls_overlap_check: inherent_impls_overlap_check_dep_node(CrateNum) -> (),
1034
1035     /// Results of evaluating const items or constants embedded in
1036     /// other items (such as enum variant explicit discriminants).
1037     [] const_eval: const_eval_dep_node(ty::ParamEnvAnd<'tcx, (DefId, &'tcx Substs<'tcx>)>)
1038         -> const_val::EvalResult<'tcx>,
1039
1040     /// Performs the privacy check and computes "access levels".
1041     [] privacy_access_levels: PrivacyAccessLevels(CrateNum) -> Rc<AccessLevels>,
1042
1043     [] reachable_set: reachability_dep_node(CrateNum) -> Rc<NodeSet>,
1044
1045     /// Per-function `RegionMaps`. The `DefId` should be the owner-def-id for the fn body;
1046     /// in the case of closures or "inline" expressions, this will be redirected to the enclosing
1047     /// fn item.
1048     [] region_maps: RegionMaps(DefId) -> Rc<RegionMaps>,
1049
1050     [] mir_shims: mir_shim_dep_node(ty::InstanceDef<'tcx>) -> &'tcx mir::Mir<'tcx>,
1051
1052     [] def_symbol_name: SymbolName(DefId) -> ty::SymbolName,
1053     [] symbol_name: symbol_name_dep_node(ty::Instance<'tcx>) -> ty::SymbolName,
1054
1055     [] describe_def: DescribeDef(DefId) -> Option<Def>,
1056     [] def_span: DefSpan(DefId) -> Span,
1057     [] stability: Stability(DefId) -> Option<attr::Stability>,
1058     [] deprecation: Deprecation(DefId) -> Option<attr::Deprecation>,
1059     [] item_attrs: ItemAttrs(DefId) -> Rc<[ast::Attribute]>,
1060     [] fn_arg_names: FnArgNames(DefId) -> Vec<ast::Name>,
1061     [] impl_parent: ImplParent(DefId) -> Option<DefId>,
1062     [] trait_of_item: TraitOfItem(DefId) -> Option<DefId>,
1063     [] is_exported_symbol: IsExportedSymbol(DefId) -> bool,
1064     [] item_body_nested_bodies: ItemBodyNestedBodies(DefId) -> Rc<BTreeMap<hir::BodyId, hir::Body>>,
1065     [] const_is_rvalue_promotable_to_static: ConstIsRvaluePromotableToStatic(DefId) -> bool,
1066     [] is_mir_available: IsMirAvailable(DefId) -> bool,
1067
1068     [] trait_impls_of: TraitImpls(DefId) -> Rc<ty::trait_def::TraitImpls>,
1069     [] specialization_graph_of: SpecializationGraph(DefId) -> Rc<specialization_graph::Graph>,
1070     [] is_object_safe: ObjectSafety(DefId) -> bool,
1071
1072     // Get the ParameterEnvironment for a given item; this environment
1073     // will be in "user-facing" mode, meaning that it is suitabe for
1074     // type-checking etc, and it does not normalize specializable
1075     // associated types. This is almost always what you want,
1076     // unless you are doing MIR optimizations, in which case you
1077     // might want to use `reveal_all()` method to change modes.
1078     [] param_env: ParamEnv(DefId) -> ty::ParamEnv<'tcx>,
1079
1080     // Trait selection queries. These are best used by invoking `ty.moves_by_default()`,
1081     // `ty.is_copy()`, etc, since that will prune the environment where possible.
1082     [] is_copy_raw: is_copy_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
1083     [] is_sized_raw: is_sized_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
1084     [] is_freeze_raw: is_freeze_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
1085     [] needs_drop_raw: needs_drop_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> bool,
1086     [] layout_raw: layout_dep_node(ty::ParamEnvAnd<'tcx, Ty<'tcx>>)
1087                                   -> Result<&'tcx Layout, LayoutError<'tcx>>,
1088
1089     [] dylib_dependency_formats: DylibDepFormats(DefId)
1090                                     -> Rc<Vec<(CrateNum, LinkagePreference)>>,
1091
1092     [] is_allocator: IsAllocator(DefId) -> bool,
1093     [] is_panic_runtime: IsPanicRuntime(DefId) -> bool,
1094     [] is_compiler_builtins: IsCompilerBuiltins(DefId) -> bool,
1095     [] has_global_allocator: HasGlobalAllocator(DefId) -> bool,
1096
1097     [] extern_crate: ExternCrate(DefId) -> Rc<Option<ExternCrate>>,
1098
1099     [] lint_levels: lint_levels(CrateNum) -> Rc<lint::LintLevelMap>,
1100 }
1101
1102 fn type_param_predicates<'tcx>((item_id, param_id): (DefId, DefId)) -> DepConstructor<'tcx> {
1103     DepConstructor::TypeParamPredicates {
1104         item_id,
1105         param_id
1106     }
1107 }
1108
1109 fn coherent_trait_dep_node<'tcx>((_, def_id): (CrateNum, DefId)) -> DepConstructor<'tcx> {
1110     DepConstructor::CoherenceCheckTrait(def_id)
1111 }
1112
1113 fn crate_inherent_impls_dep_node<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1114     DepConstructor::Coherence
1115 }
1116
1117 fn inherent_impls_overlap_check_dep_node<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1118     DepConstructor::CoherenceInherentImplOverlapCheck
1119 }
1120
1121 fn reachability_dep_node<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1122     DepConstructor::Reachability
1123 }
1124
1125 fn mir_shim_dep_node<'tcx>(instance_def: ty::InstanceDef<'tcx>) -> DepConstructor<'tcx> {
1126     DepConstructor::MirShim {
1127         instance_def
1128     }
1129 }
1130
1131 fn symbol_name_dep_node<'tcx>(instance: ty::Instance<'tcx>) -> DepConstructor<'tcx> {
1132     DepConstructor::InstanceSymbolName { instance }
1133 }
1134
1135 fn typeck_item_bodies_dep_node<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1136     DepConstructor::TypeckBodiesKrate
1137 }
1138
1139 fn const_eval_dep_node<'tcx>(_: ty::ParamEnvAnd<'tcx, (DefId, &'tcx Substs<'tcx>)>)
1140                              -> DepConstructor<'tcx> {
1141     DepConstructor::ConstEval
1142 }
1143
1144 fn mir_keys<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1145     DepConstructor::MirKeys
1146 }
1147
1148 fn crate_variances<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1149     DepConstructor::CrateVariances
1150 }
1151
1152 fn is_copy_dep_node<'tcx>(_: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> DepConstructor<'tcx> {
1153     DepConstructor::IsCopy
1154 }
1155
1156 fn is_sized_dep_node<'tcx>(_: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> DepConstructor<'tcx> {
1157     DepConstructor::IsSized
1158 }
1159
1160 fn is_freeze_dep_node<'tcx>(_: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> DepConstructor<'tcx> {
1161     DepConstructor::IsFreeze
1162 }
1163
1164 fn needs_drop_dep_node<'tcx>(_: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> DepConstructor<'tcx> {
1165     DepConstructor::NeedsDrop
1166 }
1167
1168 fn layout_dep_node<'tcx>(_: ty::ParamEnvAnd<'tcx, Ty<'tcx>>) -> DepConstructor<'tcx> {
1169     DepConstructor::Layout
1170 }
1171
1172 fn lint_levels<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
1173     DepConstructor::LintLevels
1174 }