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.
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.
15 Within the check phase of type check, we check each item one at a time
16 (bodies of function expressions are checked as part of the containing
17 function). Inference is used to supply types wherever they are
20 By far the most complex case is checking the body of a function. This
21 can be broken down into several distinct phases:
23 - gather: creates type variables to represent the type of each local
24 variable and pattern binding.
26 - main: the main pass does the lion's share of the work: it
27 determines the types of all expressions, resolves
28 methods, checks for most invalid conditions, and so forth. In
29 some cases, where a type is unknown, it may create a type or region
30 variable and use that as the type of an expression.
32 In the process of checking, various constraints will be placed on
33 these type variables through the subtyping relationships requested
34 through the `demand` module. The `infer` module is in charge
35 of resolving those constraints.
37 - regionck: after main is complete, the regionck pass goes over all
38 types looking for regions and making sure that they did not escape
39 into places they are not in scope. This may also influence the
40 final assignments of the various region variables if there is some
43 - vtable: find and records the impls to use for each trait bound that
44 appears on a type parameter.
46 - writeback: writes the final types within a function body, replacing
47 type variables with their final inferred types. These final types
48 are written into the `tcx.node_types` table, which should *never* contain
49 any reference to a type variable.
53 While type checking a function, the intermediate types for the
54 expressions, blocks, and so forth contained within the function are
55 stored in `fcx.node_types` and `fcx.item_substs`. These types
56 may contain unresolved type variables. After type checking is
57 complete, the functions in the writeback module are used to take the
58 types from this table, resolve them, and then write them into their
59 permanent home in the type context `ccx.tcx`.
61 This means that during inferencing you should use `fcx.write_ty()`
62 and `fcx.expr_ty()` / `fcx.node_ty()` to write/obtain the types of
63 nodes within the function.
65 The types of top-level items, which never contain unbound type
66 variables, are stored directly into the `tcx` tables.
68 n.b.: A type variable is not the same thing as a type parameter. A
69 type variable is rather an "instance" of a type parameter: that is,
70 given a generic function `fn foo<T>(t: T)`: while checking the
71 function `foo`, the type `ty_param(0)` refers to the type `T`, which
72 is treated in abstract. When `foo()` is called, however, `T` will be
73 substituted for a fresh type variable `N`. This variable will
74 eventually be resolved to some concrete type (which might itself be
79 pub use self::LvaluePreference::*;
80 pub use self::Expectation::*;
81 pub use self::compare_method::{compare_impl_method, compare_const_impl};
82 use self::TupleArgumentsFlag::*;
84 use astconv::{self, ast_region_to_region, ast_ty_to_ty, AstConv, PathParamMode};
85 use check::_match::pat_ctxt;
86 use fmt_macros::{Parser, Piece, Position};
87 use middle::astconv_util::{check_path_args, NO_TPS, NO_REGIONS};
90 use middle::infer::type_variable;
91 use middle::pat_util::{self, pat_id_map};
92 use middle::privacy::{AllPublic, LastMod};
93 use middle::region::{self, CodeExtent};
94 use middle::subst::{self, Subst, Substs, VecPerParamSpace, ParamSpace, TypeSpace};
95 use middle::traits::{self, report_fulfillment_errors};
96 use middle::ty::{FnSig, GenericPredicates, TypeScheme};
97 use middle::ty::{Disr, ParamTy, ParameterEnvironment};
98 use middle::ty::{self, HasTypeFlags, RegionEscape, ToPolyTraitRef, Ty};
99 use middle::ty::{MethodCall, MethodCallee};
100 use middle::ty_fold::{TypeFolder, TypeFoldable};
101 use require_c_abi_if_variadic;
102 use rscope::{ElisionFailureInfo, RegionScope};
103 use session::Session;
104 use {CrateCtxt, lookup_full_def, require_same_types};
107 use util::common::{block_query, ErrorReported, indenter, loop_query};
108 use util::nodemap::{DefIdMap, FnvHashMap, NodeMap};
109 use util::lev_distance::lev_distance;
111 use std::cell::{Cell, Ref, RefCell};
112 use std::collections::HashSet;
113 use std::mem::replace;
115 use syntax::{self, abi, attr};
116 use syntax::attr::AttrMetaMethods;
117 use syntax::ast::{self, DefId, Visibility};
118 use syntax::ast_util::{self, local_def};
119 use syntax::codemap::{self, Span};
120 use syntax::feature_gate::emit_feature_err;
121 use syntax::owned_slice::OwnedSlice;
122 use syntax::parse::token::{self, InternedString};
123 use syntax::print::pprust;
125 use syntax::visit::{self, Visitor};
143 /// closures defined within the function. For example:
146 /// bar(move|| { ... })
149 /// Here, the function `foo()` and the closure passed to
150 /// `bar()` will each have their own `FnCtxt`, but they will
151 /// share the inherited fields.
152 pub struct Inherited<'a, 'tcx: 'a> {
153 infcx: infer::InferCtxt<'a, 'tcx>,
154 locals: RefCell<NodeMap<Ty<'tcx>>>,
156 tables: &'a RefCell<ty::Tables<'tcx>>,
158 // A mapping from each fn's id to its signature, with all bound
159 // regions replaced with free ones. Unlike the other tables, this
160 // one is never copied into the tcx: it is only used by regionck.
161 fn_sig_map: RefCell<NodeMap<Vec<Ty<'tcx>>>>,
163 // When we process a call like `c()` where `c` is a closure type,
164 // we may not have decided yet whether `c` is a `Fn`, `FnMut`, or
165 // `FnOnce` closure. In that case, we defer full resolution of the
166 // call until upvar inference can kick in and make the
167 // decision. We keep these deferred resolutions grouped by the
168 // def-id of the closure, so that once we decide, we can easily go
169 // back and process them.
170 deferred_call_resolutions: RefCell<DefIdMap<Vec<DeferredCallResolutionHandler<'tcx>>>>,
172 deferred_cast_checks: RefCell<Vec<cast::CastCheck<'tcx>>>,
175 trait DeferredCallResolution<'tcx> {
176 fn resolve<'a>(&mut self, fcx: &FnCtxt<'a,'tcx>);
179 type DeferredCallResolutionHandler<'tcx> = Box<DeferredCallResolution<'tcx>+'tcx>;
181 /// When type-checking an expression, we propagate downward
182 /// whatever type hint we are able in the form of an `Expectation`.
183 #[derive(Copy, Clone, Debug)]
184 pub enum Expectation<'tcx> {
185 /// We know nothing about what type this expression should have.
188 /// This expression should have the type given (or some subtype)
189 ExpectHasType(Ty<'tcx>),
191 /// This expression will be cast to the `Ty`
192 ExpectCastableToType(Ty<'tcx>),
194 /// This rvalue expression will be wrapped in `&` or `Box` and coerced
195 /// to `&Ty` or `Box<Ty>`, respectively. `Ty` is `[A]` or `Trait`.
196 ExpectRvalueLikeUnsized(Ty<'tcx>),
199 impl<'tcx> Expectation<'tcx> {
200 // Disregard "castable to" expectations because they
201 // can lead us astray. Consider for example `if cond
202 // {22} else {c} as u8` -- if we propagate the
203 // "castable to u8" constraint to 22, it will pick the
204 // type 22u8, which is overly constrained (c might not
205 // be a u8). In effect, the problem is that the
206 // "castable to" expectation is not the tightest thing
207 // we can say, so we want to drop it in this case.
208 // The tightest thing we can say is "must unify with
209 // else branch". Note that in the case of a "has type"
210 // constraint, this limitation does not hold.
212 // If the expected type is just a type variable, then don't use
213 // an expected type. Otherwise, we might write parts of the type
214 // when checking the 'then' block which are incompatible with the
216 fn adjust_for_branches<'a>(&self, fcx: &FnCtxt<'a, 'tcx>) -> Expectation<'tcx> {
218 ExpectHasType(ety) => {
219 let ety = fcx.infcx().shallow_resolve(ety);
220 if !ety.is_ty_var() {
226 ExpectRvalueLikeUnsized(ety) => {
227 ExpectRvalueLikeUnsized(ety)
234 #[derive(Copy, Clone)]
235 pub struct UnsafetyState {
236 pub def: ast::NodeId,
237 pub unsafety: ast::Unsafety,
238 pub unsafe_push_count: u32,
243 pub fn function(unsafety: ast::Unsafety, def: ast::NodeId) -> UnsafetyState {
244 UnsafetyState { def: def, unsafety: unsafety, unsafe_push_count: 0, from_fn: true }
247 pub fn recurse(&mut self, blk: &ast::Block) -> UnsafetyState {
248 match self.unsafety {
249 // If this unsafe, then if the outer function was already marked as
250 // unsafe we shouldn't attribute the unsafe'ness to the block. This
251 // way the block can be warned about instead of ignoring this
252 // extraneous block (functions are never warned about).
253 ast::Unsafety::Unsafe if self.from_fn => *self,
256 let (unsafety, def, count) = match blk.rules {
257 ast::PushUnsafeBlock(..) =>
258 (unsafety, blk.id, self.unsafe_push_count.checked_add(1).unwrap()),
259 ast::PopUnsafeBlock(..) =>
260 (unsafety, blk.id, self.unsafe_push_count.checked_sub(1).unwrap()),
261 ast::UnsafeBlock(..) =>
262 (ast::Unsafety::Unsafe, blk.id, self.unsafe_push_count),
264 (unsafety, self.def, self.unsafe_push_count),
266 UnsafetyState{ def: def,
268 unsafe_push_count: count,
276 pub struct FnCtxt<'a, 'tcx: 'a> {
277 body_id: ast::NodeId,
279 // This flag is set to true if, during the writeback phase, we encounter
280 // a type error in this function.
281 writeback_errors: Cell<bool>,
283 // Number of errors that had been reported when we started
284 // checking this function. On exit, if we find that *more* errors
285 // have been reported, we will skip regionck and other work that
286 // expects the types within the function to be consistent.
287 err_count_on_creation: usize,
289 ret_ty: ty::FnOutput<'tcx>,
291 ps: RefCell<UnsafetyState>,
293 inh: &'a Inherited<'a, 'tcx>,
295 ccx: &'a CrateCtxt<'a, 'tcx>,
298 impl<'a, 'tcx> Inherited<'a, 'tcx> {
299 fn new(tcx: &'a ty::ctxt<'tcx>,
300 tables: &'a RefCell<ty::Tables<'tcx>>,
301 param_env: ty::ParameterEnvironment<'a, 'tcx>)
302 -> Inherited<'a, 'tcx> {
305 infcx: infer::new_infer_ctxt(tcx, tables, Some(param_env), true),
306 locals: RefCell::new(NodeMap()),
308 fn_sig_map: RefCell::new(NodeMap()),
309 deferred_call_resolutions: RefCell::new(DefIdMap()),
310 deferred_cast_checks: RefCell::new(Vec::new()),
314 fn normalize_associated_types_in<T>(&self,
316 body_id: ast::NodeId,
319 where T : TypeFoldable<'tcx> + HasTypeFlags
321 let mut fulfillment_cx = self.infcx.fulfillment_cx.borrow_mut();
322 assoc::normalize_associated_types_in(&self.infcx,
331 // Used by check_const and check_enum_variants
332 pub fn blank_fn_ctxt<'a, 'tcx>(ccx: &'a CrateCtxt<'a, 'tcx>,
333 inh: &'a Inherited<'a, 'tcx>,
334 rty: ty::FnOutput<'tcx>,
335 body_id: ast::NodeId)
336 -> FnCtxt<'a, 'tcx> {
339 writeback_errors: Cell::new(false),
340 err_count_on_creation: ccx.tcx.sess.err_count(),
342 ps: RefCell::new(UnsafetyState::function(ast::Unsafety::Normal, 0)),
348 fn static_inherited_fields<'a, 'tcx>(ccx: &'a CrateCtxt<'a, 'tcx>,
349 tables: &'a RefCell<ty::Tables<'tcx>>)
350 -> Inherited<'a, 'tcx> {
351 // It's kind of a kludge to manufacture a fake function context
352 // and statement context, but we might as well do write the code only once
353 let param_env = ccx.tcx.empty_parameter_environment();
354 Inherited::new(ccx.tcx, &tables, param_env)
357 struct CheckItemTypesVisitor<'a, 'tcx: 'a> { ccx: &'a CrateCtxt<'a, 'tcx> }
358 struct CheckItemBodiesVisitor<'a, 'tcx: 'a> { ccx: &'a CrateCtxt<'a, 'tcx> }
360 impl<'a, 'tcx> Visitor<'tcx> for CheckItemTypesVisitor<'a, 'tcx> {
361 fn visit_item(&mut self, i: &'tcx ast::Item) {
362 check_item_type(self.ccx, i);
363 visit::walk_item(self, i);
366 fn visit_ty(&mut self, t: &'tcx ast::Ty) {
368 ast::TyFixedLengthVec(_, ref expr) => {
369 check_const_in_type(self.ccx, &**expr, self.ccx.tcx.types.usize);
374 visit::walk_ty(self, t);
378 impl<'a, 'tcx> Visitor<'tcx> for CheckItemBodiesVisitor<'a, 'tcx> {
379 fn visit_item(&mut self, i: &'tcx ast::Item) {
380 check_item_body(self.ccx, i);
381 visit::walk_item(self, i);
385 pub fn check_item_types(ccx: &CrateCtxt) {
386 let krate = ccx.tcx.map.krate();
387 let mut visit = wf::CheckTypeWellFormedVisitor::new(ccx);
388 visit::walk_crate(&mut visit, krate);
390 // If types are not well-formed, it leads to all manner of errors
391 // downstream, so stop reporting errors at this point.
392 ccx.tcx.sess.abort_if_errors();
394 let mut visit = CheckItemTypesVisitor { ccx: ccx };
395 visit::walk_crate(&mut visit, krate);
397 ccx.tcx.sess.abort_if_errors();
399 let mut visit = CheckItemBodiesVisitor { ccx: ccx };
400 visit::walk_crate(&mut visit, krate);
402 ccx.tcx.sess.abort_if_errors();
404 for drop_method_did in ccx.tcx.destructors.borrow().iter() {
405 if drop_method_did.krate == ast::LOCAL_CRATE {
406 let drop_impl_did = ccx.tcx.map.get_parent_did(drop_method_did.node);
407 match dropck::check_drop_impl(ccx.tcx, drop_impl_did) {
410 assert!(ccx.tcx.sess.has_errors());
416 ccx.tcx.sess.abort_if_errors();
419 fn check_bare_fn<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
420 decl: &'tcx ast::FnDecl,
421 body: &'tcx ast::Block,
425 param_env: ty::ParameterEnvironment<'a, 'tcx>)
428 ty::TyBareFn(_, ref fn_ty) => {
429 let tables = RefCell::new(ty::Tables::empty());
430 let inh = Inherited::new(ccx.tcx, &tables, param_env);
432 // Compute the fty from point of view of inside fn.
434 fn_ty.sig.subst(ccx.tcx, &inh.infcx.parameter_environment.free_substs);
436 ccx.tcx.liberate_late_bound_regions(region::DestructionScopeData::new(body.id),
439 inh.normalize_associated_types_in(body.span,
443 let fcx = check_fn(ccx, fn_ty.unsafety, fn_id, &fn_sig,
444 decl, fn_id, body, &inh);
446 fcx.select_all_obligations_and_apply_defaults();
447 upvar::closure_analyze_fn(&fcx, fn_id, decl, body);
448 fcx.select_all_obligations_or_error();
451 fcx.select_all_obligations_or_error(); // Casts can introduce new obligations.
453 regionck::regionck_fn(&fcx, fn_id, fn_span, decl, body);
454 writeback::resolve_type_vars_in_fn(&fcx, decl, body);
456 _ => ccx.tcx.sess.impossible_case(body.span,
457 "check_bare_fn: function type expected")
461 struct GatherLocalsVisitor<'a, 'tcx: 'a> {
462 fcx: &'a FnCtxt<'a, 'tcx>
465 impl<'a, 'tcx> GatherLocalsVisitor<'a, 'tcx> {
466 fn assign(&mut self, _span: Span, nid: ast::NodeId, ty_opt: Option<Ty<'tcx>>) -> Ty<'tcx> {
469 // infer the variable's type
470 let var_ty = self.fcx.infcx().next_ty_var();
471 self.fcx.inh.locals.borrow_mut().insert(nid, var_ty);
475 // take type that the user specified
476 self.fcx.inh.locals.borrow_mut().insert(nid, typ);
483 impl<'a, 'tcx> Visitor<'tcx> for GatherLocalsVisitor<'a, 'tcx> {
484 // Add explicitly-declared locals.
485 fn visit_local(&mut self, local: &'tcx ast::Local) {
486 let o_ty = match local.ty {
487 Some(ref ty) => Some(self.fcx.to_ty(&**ty)),
490 self.assign(local.span, local.id, o_ty);
491 debug!("Local variable {:?} is assigned type {}",
493 self.fcx.infcx().ty_to_string(
494 self.fcx.inh.locals.borrow().get(&local.id).unwrap().clone()));
495 visit::walk_local(self, local);
498 // Add pattern bindings.
499 fn visit_pat(&mut self, p: &'tcx ast::Pat) {
500 if let ast::PatIdent(_, ref path1, _) = p.node {
501 if pat_util::pat_is_binding(&self.fcx.ccx.tcx.def_map, p) {
502 let var_ty = self.assign(p.span, p.id, None);
504 self.fcx.require_type_is_sized(var_ty, p.span,
505 traits::VariableType(p.id));
507 debug!("Pattern binding {} is assigned to {} with type {:?}",
509 self.fcx.infcx().ty_to_string(
510 self.fcx.inh.locals.borrow().get(&p.id).unwrap().clone()),
514 visit::walk_pat(self, p);
517 fn visit_block(&mut self, b: &'tcx ast::Block) {
518 // non-obvious: the `blk` variable maps to region lb, so
519 // we have to keep this up-to-date. This
520 // is... unfortunate. It'd be nice to not need this.
521 visit::walk_block(self, b);
524 // Since an expr occurs as part of the type fixed size arrays we
525 // need to record the type for that node
526 fn visit_ty(&mut self, t: &'tcx ast::Ty) {
528 ast::TyFixedLengthVec(ref ty, ref count_expr) => {
529 self.visit_ty(&**ty);
530 check_expr_with_hint(self.fcx, &**count_expr, self.fcx.tcx().types.usize);
532 _ => visit::walk_ty(self, t)
536 // Don't descend into fns and items
537 fn visit_fn(&mut self, _: visit::FnKind<'tcx>, _: &'tcx ast::FnDecl,
538 _: &'tcx ast::Block, _: Span, _: ast::NodeId) { }
539 fn visit_item(&mut self, _: &ast::Item) { }
543 /// Helper used by check_bare_fn and check_expr_fn. Does the grungy work of checking a function
544 /// body and returns the function context used for that purpose, since in the case of a fn item
545 /// there is still a bit more to do.
548 /// * inherited: other fields inherited from the enclosing fn (if any)
549 fn check_fn<'a, 'tcx>(ccx: &'a CrateCtxt<'a, 'tcx>,
550 unsafety: ast::Unsafety,
551 unsafety_id: ast::NodeId,
552 fn_sig: &ty::FnSig<'tcx>,
553 decl: &'tcx ast::FnDecl,
555 body: &'tcx ast::Block,
556 inherited: &'a Inherited<'a, 'tcx>)
560 let err_count_on_creation = tcx.sess.err_count();
562 let arg_tys = &fn_sig.inputs;
563 let ret_ty = fn_sig.output;
565 debug!("check_fn(arg_tys={:?}, ret_ty={:?}, fn_id={})",
570 // Create the function context. This is either derived from scratch or,
571 // in the case of function expressions, based on the outer context.
574 writeback_errors: Cell::new(false),
575 err_count_on_creation: err_count_on_creation,
577 ps: RefCell::new(UnsafetyState::function(unsafety, unsafety_id)),
582 // Remember return type so that regionck can access it later.
583 let mut fn_sig_tys: Vec<Ty> =
588 if let ty::FnConverging(ret_ty) = ret_ty {
589 fcx.require_type_is_sized(ret_ty, decl.output.span(), traits::ReturnType);
590 fn_sig_tys.push(ret_ty);
593 debug!("fn-sig-map: fn_id={} fn_sig_tys={:?}",
597 inherited.fn_sig_map.borrow_mut().insert(fn_id, fn_sig_tys);
600 let mut visit = GatherLocalsVisitor { fcx: &fcx, };
602 // Add formal parameters.
603 for (arg_ty, input) in arg_tys.iter().zip(&decl.inputs) {
604 // Create type variables for each argument.
605 pat_util::pat_bindings(
608 |_bm, pat_id, sp, _path| {
609 let var_ty = visit.assign(sp, pat_id, None);
610 fcx.require_type_is_sized(var_ty, sp,
611 traits::VariableType(pat_id));
614 // Check the pattern.
617 map: pat_id_map(&tcx.def_map, &*input.pat),
619 _match::check_pat(&pcx, &*input.pat, *arg_ty);
622 visit.visit_block(body);
625 check_block_with_expected(&fcx, body, match ret_ty {
626 ty::FnConverging(result_type) => ExpectHasType(result_type),
627 ty::FnDiverging => NoExpectation
630 for (input, arg) in decl.inputs.iter().zip(arg_tys) {
631 fcx.write_ty(input.id, arg);
637 pub fn check_struct(ccx: &CrateCtxt, id: ast::NodeId, span: Span) {
640 check_representable(tcx, span, id, "struct");
641 check_instantiable(tcx, span, id);
643 if tcx.lookup_simd(local_def(id)) {
644 check_simd(tcx, span, id);
648 pub fn check_item_type<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, it: &'tcx ast::Item) {
649 debug!("check_item_type(it.id={}, it.ident={})",
651 ccx.tcx.item_path_str(local_def(it.id)));
652 let _indenter = indenter();
654 // Consts can play a role in type-checking, so they are included here.
655 ast::ItemStatic(_, _, ref e) |
656 ast::ItemConst(_, ref e) => check_const(ccx, it.span, &**e, it.id),
657 ast::ItemEnum(ref enum_definition, _) => {
658 check_enum_variants(ccx,
660 &enum_definition.variants,
663 ast::ItemFn(..) => {} // entirely within check_item_body
664 ast::ItemImpl(_, _, _, _, _, ref impl_items) => {
665 debug!("ItemImpl {} with id {}", it.ident, it.id);
666 match ccx.tcx.impl_trait_ref(local_def(it.id)) {
667 Some(impl_trait_ref) => {
668 check_impl_items_against_trait(ccx,
676 ast::ItemTrait(_, ref generics, _, _) => {
677 check_trait_on_unimplemented(ccx, generics, it);
679 ast::ItemStruct(..) => {
680 check_struct(ccx, it.id, it.span);
682 ast::ItemTy(ref t, ref generics) => {
683 let pty_ty = ccx.tcx.node_id_to_type(it.id);
684 check_bounds_are_used(ccx, t.span, &generics.ty_params, pty_ty);
686 ast::ItemForeignMod(ref m) => {
687 if m.abi == abi::RustIntrinsic {
688 for item in &m.items {
689 check_intrinsic_type(ccx, &**item);
692 for item in &m.items {
693 let pty = ccx.tcx.lookup_item_type(local_def(item.id));
694 if !pty.generics.types.is_empty() {
695 span_err!(ccx.tcx.sess, item.span, E0044,
696 "foreign items may not have type parameters");
699 if let ast::ForeignItemFn(ref fn_decl, _) = item.node {
700 require_c_abi_if_variadic(ccx.tcx, fn_decl, m.abi, item.span);
705 _ => {/* nothing to do */ }
709 pub fn check_item_body<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>, it: &'tcx ast::Item) {
710 debug!("check_item_body(it.id={}, it.ident={})",
712 ccx.tcx.item_path_str(local_def(it.id)));
713 let _indenter = indenter();
715 ast::ItemFn(ref decl, _, _, _, _, ref body) => {
716 let fn_pty = ccx.tcx.lookup_item_type(ast_util::local_def(it.id));
717 let param_env = ParameterEnvironment::for_item(ccx.tcx, it.id);
718 check_bare_fn(ccx, &**decl, &**body, it.id, it.span, fn_pty.ty, param_env);
720 ast::ItemImpl(_, _, _, _, _, ref impl_items) => {
721 debug!("ItemImpl {} with id {}", it.ident, it.id);
723 let impl_pty = ccx.tcx.lookup_item_type(ast_util::local_def(it.id));
725 for impl_item in impl_items {
726 match impl_item.node {
727 ast::ConstImplItem(_, ref expr) => {
728 check_const(ccx, impl_item.span, &*expr, impl_item.id)
730 ast::MethodImplItem(ref sig, ref body) => {
731 check_method_body(ccx, &impl_pty.generics, sig, body,
732 impl_item.id, impl_item.span);
734 ast::TypeImplItem(_) |
735 ast::MacImplItem(_) => {
736 // Nothing to do here.
741 ast::ItemTrait(_, _, _, ref trait_items) => {
742 let trait_def = ccx.tcx.lookup_trait_def(local_def(it.id));
743 for trait_item in trait_items {
744 match trait_item.node {
745 ast::ConstTraitItem(_, Some(ref expr)) => {
746 check_const(ccx, trait_item.span, &*expr, trait_item.id)
748 ast::MethodTraitItem(ref sig, Some(ref body)) => {
749 check_trait_fn_not_const(ccx, trait_item.span, sig.constness);
751 check_method_body(ccx, &trait_def.generics, sig, body,
752 trait_item.id, trait_item.span);
754 ast::MethodTraitItem(ref sig, None) => {
755 check_trait_fn_not_const(ccx, trait_item.span, sig.constness);
757 ast::ConstTraitItem(_, None) |
758 ast::TypeTraitItem(..) => {
764 _ => {/* nothing to do */ }
768 fn check_trait_fn_not_const<'a,'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
770 constness: ast::Constness)
773 ast::Constness::NotConst => {
776 ast::Constness::Const => {
777 span_err!(ccx.tcx.sess, span, E0379, "trait fns cannot be declared const");
782 fn check_trait_on_unimplemented<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
783 generics: &ast::Generics,
785 if let Some(ref attr) = item.attrs.iter().find(|a| {
786 a.check_name("rustc_on_unimplemented")
788 if let Some(ref istring) = attr.value_str() {
789 let parser = Parser::new(&istring);
790 let types = &*generics.ty_params;
791 for token in parser {
793 Piece::String(_) => (), // Normal string, no need to check it
794 Piece::NextArgument(a) => match a.position {
795 // `{Self}` is allowed
796 Position::ArgumentNamed(s) if s == "Self" => (),
797 // So is `{A}` if A is a type parameter
798 Position::ArgumentNamed(s) => match types.iter().find(|t| {
803 span_err!(ccx.tcx.sess, attr.span, E0230,
804 "there is no type parameter \
809 // `{:1}` and `{}` are not to be used
810 Position::ArgumentIs(_) | Position::ArgumentNext => {
811 span_err!(ccx.tcx.sess, attr.span, E0231,
812 "only named substitution \
813 parameters are allowed");
819 span_err!(ccx.tcx.sess, attr.span, E0232,
820 "this attribute must have a value, \
821 eg `#[rustc_on_unimplemented = \"foo\"]`")
826 /// Type checks a method body.
830 /// * `item_generics`: generics defined on the impl/trait that contains
832 /// * `self_bound`: bound for the `Self` type parameter, if any
833 /// * `method`: the method definition
834 fn check_method_body<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
835 item_generics: &ty::Generics<'tcx>,
836 sig: &'tcx ast::MethodSig,
837 body: &'tcx ast::Block,
838 id: ast::NodeId, span: Span) {
839 debug!("check_method_body(item_generics={:?}, id={})",
841 let param_env = ParameterEnvironment::for_item(ccx.tcx, id);
843 let fty = ccx.tcx.node_id_to_type(id);
844 debug!("check_method_body: fty={:?}", fty);
846 check_bare_fn(ccx, &sig.decl, body, id, span, fty, param_env);
849 fn check_impl_items_against_trait<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
851 impl_trait_ref: &ty::TraitRef<'tcx>,
852 impl_items: &[P<ast::ImplItem>]) {
853 // Locate trait methods
855 let trait_items = tcx.trait_items(impl_trait_ref.def_id);
856 let mut overridden_associated_type = None;
858 // Check existing impl methods to see if they are both present in trait
859 // and compatible with trait signature
860 for impl_item in impl_items {
861 let ty_impl_item = ccx.tcx.impl_or_trait_item(local_def(impl_item.id));
862 let ty_trait_item = trait_items.iter()
863 .find(|ac| ac.name() == ty_impl_item.name())
865 // This is checked by resolve
866 tcx.sess.span_bug(impl_item.span,
867 &format!("impl-item `{}` is not a member of `{:?}`",
871 match impl_item.node {
872 ast::ConstImplItem(..) => {
873 let impl_const = match ty_impl_item {
874 ty::ConstTraitItem(ref cti) => cti,
875 _ => tcx.sess.span_bug(impl_item.span, "non-const impl-item for const")
878 // Find associated const definition.
879 if let &ty::ConstTraitItem(ref trait_const) = ty_trait_item {
880 compare_const_impl(ccx.tcx,
886 span_err!(tcx.sess, impl_item.span, E0323,
887 "item `{}` is an associated const, \
888 which doesn't match its trait `{:?}`",
893 ast::MethodImplItem(ref sig, ref body) => {
894 check_trait_fn_not_const(ccx, impl_item.span, sig.constness);
896 let impl_method = match ty_impl_item {
897 ty::MethodTraitItem(ref mti) => mti,
898 _ => tcx.sess.span_bug(impl_item.span, "non-method impl-item for method")
901 if let &ty::MethodTraitItem(ref trait_method) = ty_trait_item {
902 compare_impl_method(ccx.tcx,
909 span_err!(tcx.sess, impl_item.span, E0324,
910 "item `{}` is an associated method, \
911 which doesn't match its trait `{:?}`",
916 ast::TypeImplItem(_) => {
917 let impl_type = match ty_impl_item {
918 ty::TypeTraitItem(ref tti) => tti,
919 _ => tcx.sess.span_bug(impl_item.span, "non-type impl-item for type")
922 if let &ty::TypeTraitItem(ref at) = ty_trait_item {
923 if let Some(_) = at.ty {
924 overridden_associated_type = Some(impl_item);
927 span_err!(tcx.sess, impl_item.span, E0325,
928 "item `{}` is an associated type, \
929 which doesn't match its trait `{:?}`",
934 ast::MacImplItem(_) => tcx.sess.span_bug(impl_item.span,
939 // Check for missing items from trait
940 let provided_methods = tcx.provided_trait_methods(impl_trait_ref.def_id);
941 let associated_consts = tcx.associated_consts(impl_trait_ref.def_id);
942 let mut missing_items = Vec::new();
943 let mut invalidated_items = Vec::new();
944 let associated_type_overridden = overridden_associated_type.is_some();
945 for trait_item in trait_items.iter() {
947 ty::ConstTraitItem(ref associated_const) => {
948 let is_implemented = impl_items.iter().any(|ii| {
950 ast::ConstImplItem(..) => {
951 ii.ident.name == associated_const.name
957 associated_consts.iter().any(|ac| ac.default.is_some() &&
958 ac.name == associated_const.name);
961 missing_items.push(associated_const.name);
962 } else if associated_type_overridden {
963 invalidated_items.push(associated_const.name);
967 ty::MethodTraitItem(ref trait_method) => {
969 impl_items.iter().any(|ii| {
971 ast::MethodImplItem(..) => {
972 ii.ident.name == trait_method.name
978 provided_methods.iter().any(|m| m.name == trait_method.name);
981 missing_items.push(trait_method.name);
982 } else if associated_type_overridden {
983 invalidated_items.push(trait_method.name);
987 ty::TypeTraitItem(ref associated_type) => {
988 let is_implemented = impl_items.iter().any(|ii| {
990 ast::TypeImplItem(_) => {
991 ii.ident.name == associated_type.name
996 let is_provided = associated_type.ty.is_some();
999 missing_items.push(associated_type.name);
1000 } else if associated_type_overridden {
1001 invalidated_items.push(associated_type.name);
1008 if !missing_items.is_empty() {
1009 span_err!(tcx.sess, impl_span, E0046,
1010 "not all trait items implemented, missing: `{}`",
1011 missing_items.iter()
1012 .map(|name| name.to_string())
1013 .collect::<Vec<_>>().join("`, `"))
1016 if !invalidated_items.is_empty() {
1017 let invalidator = overridden_associated_type.unwrap();
1018 span_err!(tcx.sess, invalidator.span, E0399,
1019 "the following trait items need to be reimplemented \
1020 as `{}` was overridden: `{}`",
1022 invalidated_items.iter()
1023 .map(|name| name.to_string())
1024 .collect::<Vec<_>>().join("`, `"))
1028 fn report_cast_to_unsized_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
1035 let tstr = fcx.infcx().ty_to_string(t_cast);
1036 fcx.type_error_message(span, |actual| {
1037 format!("cast to unsized type: `{}` as `{}`", actual, tstr)
1040 ty::TyRef(_, ty::TypeAndMut { mutbl: mt, .. }) => {
1041 let mtstr = match mt {
1042 ast::MutMutable => "mut ",
1043 ast::MutImmutable => ""
1045 if t_cast.is_trait() {
1046 match fcx.tcx().sess.codemap().span_to_snippet(t_span) {
1048 fcx.tcx().sess.span_suggestion(t_span,
1049 "try casting to a reference instead:",
1050 format!("&{}{}", mtstr, s));
1053 span_help!(fcx.tcx().sess, t_span,
1054 "did you mean `&{}{}`?", mtstr, tstr),
1057 span_help!(fcx.tcx().sess, span,
1058 "consider using an implicit coercion to `&{}{}` instead",
1063 match fcx.tcx().sess.codemap().span_to_snippet(t_span) {
1065 fcx.tcx().sess.span_suggestion(t_span,
1066 "try casting to a `Box` instead:",
1067 format!("Box<{}>", s));
1070 span_help!(fcx.tcx().sess, t_span, "did you mean `Box<{}>`?", tstr),
1074 span_help!(fcx.tcx().sess, e_span,
1075 "consider using a box or reference as appropriate");
1078 fcx.write_error(id);
1082 impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
1083 fn tcx(&self) -> &ty::ctxt<'tcx> { self.ccx.tcx }
1085 fn get_item_type_scheme(&self, _: Span, id: ast::DefId)
1086 -> Result<ty::TypeScheme<'tcx>, ErrorReported>
1088 Ok(self.tcx().lookup_item_type(id))
1091 fn get_trait_def(&self, _: Span, id: ast::DefId)
1092 -> Result<&'tcx ty::TraitDef<'tcx>, ErrorReported>
1094 Ok(self.tcx().lookup_trait_def(id))
1097 fn ensure_super_predicates(&self, _: Span, _: ast::DefId) -> Result<(), ErrorReported> {
1098 // all super predicates are ensured during collect pass
1102 fn get_free_substs(&self) -> Option<&Substs<'tcx>> {
1103 Some(&self.inh.infcx.parameter_environment.free_substs)
1106 fn get_type_parameter_bounds(&self,
1108 node_id: ast::NodeId)
1109 -> Result<Vec<ty::PolyTraitRef<'tcx>>, ErrorReported>
1111 let def = self.tcx().type_parameter_def(node_id);
1112 let r = self.inh.infcx.parameter_environment
1115 .filter_map(|predicate| {
1117 ty::Predicate::Trait(ref data) => {
1118 if data.0.self_ty().is_param(def.space, def.index) {
1119 Some(data.to_poly_trait_ref())
1133 fn trait_defines_associated_type_named(&self,
1134 trait_def_id: ast::DefId,
1135 assoc_name: ast::Name)
1138 let trait_def = self.ccx.tcx.lookup_trait_def(trait_def_id);
1139 trait_def.associated_type_names.contains(&assoc_name)
1143 ty_param_def: Option<ty::TypeParameterDef<'tcx>>,
1144 substs: Option<&mut subst::Substs<'tcx>>,
1145 space: Option<subst::ParamSpace>,
1146 span: Span) -> Ty<'tcx> {
1147 // Grab the default doing subsitution
1148 let default = ty_param_def.and_then(|def| {
1149 def.default.map(|ty| type_variable::Default {
1150 ty: ty.subst_spanned(self.tcx(), substs.as_ref().unwrap(), Some(span)),
1152 def_id: def.default_def_id
1156 let ty_var = self.infcx().next_ty_var_with_default(default);
1158 // Finally we add the type variable to the substs
1161 Some(substs) => { substs.types.push(space.unwrap(), ty_var); ty_var }
1165 fn projected_ty_from_poly_trait_ref(&self,
1167 poly_trait_ref: ty::PolyTraitRef<'tcx>,
1168 item_name: ast::Name)
1171 let (trait_ref, _) =
1172 self.infcx().replace_late_bound_regions_with_fresh_var(
1174 infer::LateBoundRegionConversionTime::AssocTypeProjection(item_name),
1177 self.normalize_associated_type(span, trait_ref, item_name)
1180 fn projected_ty(&self,
1182 trait_ref: ty::TraitRef<'tcx>,
1183 item_name: ast::Name)
1186 self.normalize_associated_type(span, trait_ref, item_name)
1190 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
1191 fn tcx(&self) -> &ty::ctxt<'tcx> { self.ccx.tcx }
1193 pub fn infcx(&self) -> &infer::InferCtxt<'a,'tcx> {
1197 pub fn param_env(&self) -> &ty::ParameterEnvironment<'a,'tcx> {
1198 &self.inh.infcx.parameter_environment
1201 pub fn sess(&self) -> &Session {
1205 pub fn err_count_since_creation(&self) -> usize {
1206 self.ccx.tcx.sess.err_count() - self.err_count_on_creation
1209 /// Resolves type variables in `ty` if possible. Unlike the infcx
1210 /// version, this version will also select obligations if it seems
1211 /// useful, in an effort to get more type information.
1212 fn resolve_type_vars_if_possible(&self, mut ty: Ty<'tcx>) -> Ty<'tcx> {
1213 debug!("resolve_type_vars_if_possible(ty={:?})", ty);
1215 // No TyInfer()? Nothing needs doing.
1216 if !ty.has_infer_types() {
1217 debug!("resolve_type_vars_if_possible: ty={:?}", ty);
1221 // If `ty` is a type variable, see whether we already know what it is.
1222 ty = self.infcx().resolve_type_vars_if_possible(&ty);
1223 if !ty.has_infer_types() {
1224 debug!("resolve_type_vars_if_possible: ty={:?}", ty);
1228 // If not, try resolving any new fcx obligations that have cropped up.
1229 self.select_new_obligations();
1230 ty = self.infcx().resolve_type_vars_if_possible(&ty);
1231 if !ty.has_infer_types() {
1232 debug!("resolve_type_vars_if_possible: ty={:?}", ty);
1236 // If not, try resolving *all* pending obligations as much as
1237 // possible. This can help substantially when there are
1238 // indirect dependencies that don't seem worth tracking
1240 self.select_obligations_where_possible();
1241 ty = self.infcx().resolve_type_vars_if_possible(&ty);
1243 debug!("resolve_type_vars_if_possible: ty={:?}", ty);
1247 fn record_deferred_call_resolution(&self,
1248 closure_def_id: ast::DefId,
1249 r: DeferredCallResolutionHandler<'tcx>) {
1250 let mut deferred_call_resolutions = self.inh.deferred_call_resolutions.borrow_mut();
1251 deferred_call_resolutions.entry(closure_def_id).or_insert(vec![]).push(r);
1254 fn remove_deferred_call_resolutions(&self,
1255 closure_def_id: ast::DefId)
1256 -> Vec<DeferredCallResolutionHandler<'tcx>>
1258 let mut deferred_call_resolutions = self.inh.deferred_call_resolutions.borrow_mut();
1259 deferred_call_resolutions.remove(&closure_def_id).unwrap_or(Vec::new())
1262 pub fn tag(&self) -> String {
1263 let self_ptr: *const FnCtxt = self;
1264 format!("{:?}", self_ptr)
1267 pub fn local_ty(&self, span: Span, nid: ast::NodeId) -> Ty<'tcx> {
1268 match self.inh.locals.borrow().get(&nid) {
1271 self.tcx().sess.span_err(
1273 &format!("no type for local variable {}", nid));
1274 self.tcx().types.err
1280 pub fn write_ty(&self, node_id: ast::NodeId, ty: Ty<'tcx>) {
1281 debug!("write_ty({}, {:?}) in fcx {}",
1282 node_id, ty, self.tag());
1283 self.inh.tables.borrow_mut().node_types.insert(node_id, ty);
1286 pub fn write_substs(&self, node_id: ast::NodeId, substs: ty::ItemSubsts<'tcx>) {
1287 if !substs.substs.is_noop() {
1288 debug!("write_substs({}, {:?}) in fcx {}",
1293 self.inh.tables.borrow_mut().item_substs.insert(node_id, substs);
1297 pub fn write_autoderef_adjustment(&self,
1298 node_id: ast::NodeId,
1300 self.write_adjustment(
1302 ty::AdjustDerefRef(ty::AutoDerefRef {
1310 pub fn write_adjustment(&self,
1311 node_id: ast::NodeId,
1312 adj: ty::AutoAdjustment<'tcx>) {
1313 debug!("write_adjustment(node_id={}, adj={:?})", node_id, adj);
1315 if adj.is_identity() {
1319 self.inh.tables.borrow_mut().adjustments.insert(node_id, adj);
1322 /// Basically whenever we are converting from a type scheme into
1323 /// the fn body space, we always want to normalize associated
1324 /// types as well. This function combines the two.
1325 fn instantiate_type_scheme<T>(&self,
1327 substs: &Substs<'tcx>,
1330 where T : TypeFoldable<'tcx> + HasTypeFlags
1332 let value = value.subst(self.tcx(), substs);
1333 let result = self.normalize_associated_types_in(span, &value);
1334 debug!("instantiate_type_scheme(value={:?}, substs={:?}) = {:?}",
1341 /// As `instantiate_type_scheme`, but for the bounds found in a
1342 /// generic type scheme.
1343 fn instantiate_bounds(&self,
1345 substs: &Substs<'tcx>,
1346 bounds: &ty::GenericPredicates<'tcx>)
1347 -> ty::InstantiatedPredicates<'tcx>
1349 ty::InstantiatedPredicates {
1350 predicates: self.instantiate_type_scheme(span, substs, &bounds.predicates)
1355 fn normalize_associated_types_in<T>(&self, span: Span, value: &T) -> T
1356 where T : TypeFoldable<'tcx> + HasTypeFlags
1358 self.inh.normalize_associated_types_in(span, self.body_id, value)
1361 fn normalize_associated_type(&self,
1363 trait_ref: ty::TraitRef<'tcx>,
1364 item_name: ast::Name)
1367 let cause = traits::ObligationCause::new(span,
1369 traits::ObligationCauseCode::MiscObligation);
1374 .normalize_projection_type(self.infcx(),
1376 trait_ref: trait_ref,
1377 item_name: item_name,
1382 /// Returns the type of `def_id` with all generics replaced by by fresh type/region variables.
1383 /// Also returns the substitution from the type parameters on `def_id` to the fresh variables.
1384 /// Registers any trait obligations specified on `def_id` at the same time.
1386 /// Note that function is only intended to be used with types (notably, not fns). This is
1387 /// because it doesn't do any instantiation of late-bound regions.
1388 pub fn instantiate_type(&self,
1391 -> TypeAndSubsts<'tcx>
1394 self.tcx().lookup_item_type(def_id);
1395 let type_predicates =
1396 self.tcx().lookup_predicates(def_id);
1398 self.infcx().fresh_substs_for_generics(
1400 &type_scheme.generics);
1402 self.instantiate_bounds(span, &substs, &type_predicates);
1403 self.add_obligations_for_parameters(
1404 traits::ObligationCause::new(
1407 traits::ItemObligation(def_id)),
1410 self.instantiate_type_scheme(span, &substs, &type_scheme.ty);
1418 /// Returns the type that this AST path refers to. If the path has no type
1419 /// parameters and the corresponding type has type parameters, fresh type
1420 /// and/or region variables are substituted.
1422 /// This is used when checking the constructor in struct literals.
1423 fn instantiate_struct_literal_ty(&self,
1426 -> TypeAndSubsts<'tcx>
1428 let tcx = self.tcx();
1430 let ty::TypeScheme { generics, ty: decl_ty } =
1431 tcx.lookup_item_type(did);
1433 let substs = astconv::ast_path_substs_for_ty(self, self,
1435 PathParamMode::Optional,
1437 path.segments.last().unwrap());
1439 let ty = self.instantiate_type_scheme(path.span, &substs, &decl_ty);
1441 TypeAndSubsts { substs: substs, ty: ty }
1444 pub fn write_nil(&self, node_id: ast::NodeId) {
1445 self.write_ty(node_id, self.tcx().mk_nil());
1447 pub fn write_error(&self, node_id: ast::NodeId) {
1448 self.write_ty(node_id, self.tcx().types.err);
1451 pub fn require_type_meets(&self,
1454 code: traits::ObligationCauseCode<'tcx>,
1455 bound: ty::BuiltinBound)
1457 self.register_builtin_bound(
1460 traits::ObligationCause::new(span, self.body_id, code));
1463 pub fn require_type_is_sized(&self,
1466 code: traits::ObligationCauseCode<'tcx>)
1468 self.require_type_meets(ty, span, code, ty::BoundSized);
1471 pub fn require_expr_have_sized_type(&self,
1473 code: traits::ObligationCauseCode<'tcx>)
1475 self.require_type_is_sized(self.expr_ty(expr), expr.span, code);
1478 pub fn type_is_known_to_be_sized(&self,
1483 traits::type_known_to_meet_builtin_bound(self.infcx(),
1489 pub fn register_builtin_bound(&self,
1491 builtin_bound: ty::BuiltinBound,
1492 cause: traits::ObligationCause<'tcx>)
1494 self.inh.infcx.fulfillment_cx.borrow_mut()
1495 .register_builtin_bound(self.infcx(), ty, builtin_bound, cause);
1498 pub fn register_predicate(&self,
1499 obligation: traits::PredicateObligation<'tcx>)
1501 debug!("register_predicate({:?})",
1503 self.inh.infcx.fulfillment_cx
1505 .register_predicate_obligation(self.infcx(), obligation);
1508 pub fn to_ty(&self, ast_t: &ast::Ty) -> Ty<'tcx> {
1509 let t = ast_ty_to_ty(self, self, ast_t);
1511 let mut bounds_checker = wf::BoundsChecker::new(self,
1514 bounds_checker.check_ty(t, ast_t.span);
1519 pub fn expr_ty(&self, ex: &ast::Expr) -> Ty<'tcx> {
1520 match self.inh.tables.borrow().node_types.get(&ex.id) {
1523 self.tcx().sess.bug(&format!("no type for expr in fcx {}",
1529 /// Apply `adjustment` to the type of `expr`
1530 pub fn adjust_expr_ty(&self,
1532 adjustment: Option<&ty::AutoAdjustment<'tcx>>)
1535 let raw_ty = self.expr_ty(expr);
1536 let raw_ty = self.infcx().shallow_resolve(raw_ty);
1537 let resolve_ty = |ty: Ty<'tcx>| self.infcx().resolve_type_vars_if_possible(&ty);
1538 raw_ty.adjust(self.tcx(), expr.span, expr.id, adjustment, |method_call| {
1539 self.inh.tables.borrow().method_map.get(&method_call)
1540 .map(|method| resolve_ty(method.ty))
1544 pub fn node_ty(&self, id: ast::NodeId) -> Ty<'tcx> {
1545 match self.inh.tables.borrow().node_types.get(&id) {
1547 None if self.err_count_since_creation() != 0 => self.tcx().types.err,
1549 self.tcx().sess.bug(
1550 &format!("no type for node {}: {} in fcx {}",
1551 id, self.tcx().map.node_to_string(id),
1557 pub fn item_substs(&self) -> Ref<NodeMap<ty::ItemSubsts<'tcx>>> {
1558 // NOTE: @jroesch this is hack that appears to be fixed on nightly, will monitor if
1559 // it changes when we upgrade the snapshot compiler
1560 fn project_item_susbts<'a, 'tcx>(tables: &'a ty::Tables<'tcx>)
1561 -> &'a NodeMap<ty::ItemSubsts<'tcx>> {
1565 Ref::map(self.inh.tables.borrow(), project_item_susbts)
1568 pub fn opt_node_ty_substs<F>(&self,
1571 F: FnOnce(&ty::ItemSubsts<'tcx>),
1573 match self.inh.tables.borrow().item_substs.get(&id) {
1579 pub fn mk_subty(&self,
1580 a_is_expected: bool,
1581 origin: infer::TypeOrigin,
1584 -> Result<(), ty::TypeError<'tcx>> {
1585 infer::mk_subty(self.infcx(), a_is_expected, origin, sub, sup)
1588 pub fn mk_eqty(&self,
1589 a_is_expected: bool,
1590 origin: infer::TypeOrigin,
1593 -> Result<(), ty::TypeError<'tcx>> {
1594 infer::mk_eqty(self.infcx(), a_is_expected, origin, sub, sup)
1597 pub fn mk_subr(&self,
1598 origin: infer::SubregionOrigin<'tcx>,
1601 infer::mk_subr(self.infcx(), origin, sub, sup)
1604 pub fn type_error_message<M>(&self,
1607 actual_ty: Ty<'tcx>,
1608 err: Option<&ty::TypeError<'tcx>>) where
1609 M: FnOnce(String) -> String,
1611 self.infcx().type_error_message(sp, mk_msg, actual_ty, err);
1614 pub fn report_mismatched_types(&self,
1618 err: &ty::TypeError<'tcx>) {
1619 self.infcx().report_mismatched_types(sp, e, a, err)
1622 /// Registers an obligation for checking later, during regionck, that the type `ty` must
1623 /// outlive the region `r`.
1624 pub fn register_region_obligation(&self,
1627 cause: traits::ObligationCause<'tcx>)
1629 let mut fulfillment_cx = self.inh.infcx.fulfillment_cx.borrow_mut();
1630 fulfillment_cx.register_region_obligation(ty, region, cause);
1633 pub fn add_default_region_param_bounds(&self,
1634 substs: &Substs<'tcx>,
1637 for &ty in &substs.types {
1638 let default_bound = ty::ReScope(CodeExtent::from_node_id(expr.id));
1639 let cause = traits::ObligationCause::new(expr.span, self.body_id,
1640 traits::MiscObligation);
1641 self.register_region_obligation(ty, default_bound, cause);
1645 /// Given a fully substituted set of bounds (`generic_bounds`), and the values with which each
1646 /// type/region parameter was instantiated (`substs`), creates and registers suitable
1647 /// trait/region obligations.
1649 /// For example, if there is a function:
1652 /// fn foo<'a,T:'a>(...)
1655 /// and a reference:
1661 /// Then we will create a fresh region variable `'$0` and a fresh type variable `$1` for `'a`
1662 /// and `T`. This routine will add a region obligation `$1:'$0` and register it locally.
1663 pub fn add_obligations_for_parameters(&self,
1664 cause: traits::ObligationCause<'tcx>,
1665 predicates: &ty::InstantiatedPredicates<'tcx>)
1667 assert!(!predicates.has_escaping_regions());
1669 debug!("add_obligations_for_parameters(predicates={:?})",
1672 for obligation in traits::predicates_for_generics(cause, predicates) {
1673 self.register_predicate(obligation);
1677 // Only for fields! Returns <none> for methods>
1678 // Indifferent to privacy flags
1679 pub fn lookup_field_ty(&self,
1681 class_id: ast::DefId,
1682 items: &[ty::FieldTy],
1683 fieldname: ast::Name,
1684 substs: &subst::Substs<'tcx>)
1687 let o_field = items.iter().find(|f| f.name == fieldname);
1688 o_field.map(|f| self.tcx().lookup_field_type(class_id, f.id, substs))
1689 .map(|t| self.normalize_associated_types_in(span, &t))
1692 pub fn lookup_tup_field_ty(&self,
1694 class_id: ast::DefId,
1695 items: &[ty::FieldTy],
1697 substs: &subst::Substs<'tcx>)
1700 let o_field = if idx < items.len() { Some(&items[idx]) } else { None };
1701 o_field.map(|f| self.tcx().lookup_field_type(class_id, f.id, substs))
1702 .map(|t| self.normalize_associated_types_in(span, &t))
1705 fn check_casts(&self) {
1706 let mut deferred_cast_checks = self.inh.deferred_cast_checks.borrow_mut();
1707 for cast in deferred_cast_checks.drain(..) {
1712 /// Apply "fallbacks" to some types
1713 /// ! gets replaced with (), unconstrained ints with i32, and unconstrained floats with f64.
1714 fn default_type_parameters(&self) {
1715 use middle::ty::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat, Neither};
1716 for ty in &self.infcx().unsolved_variables() {
1717 let resolved = self.infcx().resolve_type_vars_if_possible(ty);
1718 if self.infcx().type_var_diverges(resolved) {
1719 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1721 match self.infcx().type_is_unconstrained_numeric(resolved) {
1722 UnconstrainedInt => {
1723 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1725 UnconstrainedFloat => {
1726 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1734 fn select_all_obligations_and_apply_defaults(&self) {
1735 if self.tcx().sess.features.borrow().default_type_parameter_fallback {
1736 self.new_select_all_obligations_and_apply_defaults();
1738 self.old_select_all_obligations_and_apply_defaults();
1742 // Implements old type inference fallback algorithm
1743 fn old_select_all_obligations_and_apply_defaults(&self) {
1744 self.select_obligations_where_possible();
1745 self.default_type_parameters();
1746 self.select_obligations_where_possible();
1749 fn new_select_all_obligations_and_apply_defaults(&self) {
1750 use middle::ty::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat, Neither};
1752 // For the time being this errs on the side of being memory wasteful but provides better
1754 // let type_variables = self.infcx().type_variables.clone();
1756 // There is a possibility that this algorithm will have to run an arbitrary number of times
1757 // to terminate so we bound it by the compiler's recursion limit.
1758 for _ in (0..self.tcx().sess.recursion_limit.get()) {
1759 // First we try to solve all obligations, it is possible that the last iteration
1760 // has made it possible to make more progress.
1761 self.select_obligations_where_possible();
1763 let mut conflicts = Vec::new();
1765 // Collect all unsolved type, integral and floating point variables.
1766 let unsolved_variables = self.inh.infcx.unsolved_variables();
1768 // We must collect the defaults *before* we do any unification. Because we have
1769 // directly attached defaults to the type variables any unification that occurs
1770 // will erase defaults causing conflicting defaults to be completely ignored.
1771 let default_map: FnvHashMap<_, _> =
1774 .filter_map(|t| self.infcx().default(t).map(|d| (t, d)))
1777 let mut unbound_tyvars = HashSet::new();
1779 debug!("select_all_obligations_and_apply_defaults: defaults={:?}", default_map);
1781 // We loop over the unsolved variables, resolving them and if they are
1782 // and unconstrainted numberic type we add them to the set of unbound
1783 // variables. We do this so we only apply literal fallback to type
1784 // variables without defaults.
1785 for ty in &unsolved_variables {
1786 let resolved = self.infcx().resolve_type_vars_if_possible(ty);
1787 if self.infcx().type_var_diverges(resolved) {
1788 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1790 match self.infcx().type_is_unconstrained_numeric(resolved) {
1791 UnconstrainedInt | UnconstrainedFloat => {
1792 unbound_tyvars.insert(resolved);
1799 // We now remove any numeric types that also have defaults, and instead insert
1800 // the type variable with a defined fallback.
1801 for ty in &unsolved_variables {
1802 if let Some(_default) = default_map.get(ty) {
1803 let resolved = self.infcx().resolve_type_vars_if_possible(ty);
1805 debug!("select_all_obligations_and_apply_defaults: ty: {:?} with default: {:?}",
1808 match resolved.sty {
1809 ty::TyInfer(ty::TyVar(_)) => {
1810 unbound_tyvars.insert(ty);
1813 ty::TyInfer(ty::IntVar(_)) | ty::TyInfer(ty::FloatVar(_)) => {
1814 unbound_tyvars.insert(ty);
1815 if unbound_tyvars.contains(resolved) {
1816 unbound_tyvars.remove(resolved);
1825 // If there are no more fallbacks to apply at this point we have applied all possible
1826 // defaults and type inference will procede as normal.
1827 if unbound_tyvars.is_empty() {
1831 // Finally we go through each of the unbound type variables and unify them with
1832 // the proper fallback, reporting a conflicting default error if any of the
1833 // unifications fail. We know it must be a conflicting default because the
1834 // variable would only be in `unbound_tyvars` and have a concrete value if
1835 // it had been solved by previously applying a default.
1837 // We wrap this in a transaction for error reporting, if we detect a conflict
1838 // we will rollback the inference context to its prior state so we can probe
1839 // for conflicts and correctly report them.
1842 let _ = self.infcx().commit_if_ok(|_: &infer::CombinedSnapshot| {
1843 for ty in &unbound_tyvars {
1844 if self.infcx().type_var_diverges(ty) {
1845 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1847 match self.infcx().type_is_unconstrained_numeric(ty) {
1848 UnconstrainedInt => {
1849 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1851 UnconstrainedFloat => {
1852 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1855 if let Some(default) = default_map.get(ty) {
1856 let default = default.clone();
1857 match infer::mk_eqty(self.infcx(), false,
1858 infer::Misc(default.origin_span),
1862 conflicts.push((*ty, default));
1871 // If there are conflicts we rollback, otherwise commit
1872 if conflicts.len() > 0 {
1879 if conflicts.len() > 0 {
1880 // Loop through each conflicting default, figuring out the default that caused
1881 // a unification failure and then report an error for each.
1882 for (conflict, default) in conflicts {
1883 let conflicting_default =
1884 self.find_conflicting_default(&unbound_tyvars, &default_map, conflict)
1885 .unwrap_or(type_variable::Default {
1886 ty: self.infcx().next_ty_var(),
1887 origin_span: codemap::DUMMY_SP,
1888 def_id: local_def(0) // what do I put here?
1891 // This is to ensure that we elimnate any non-determinism from the error
1892 // reporting by fixing an order, it doesn't matter what order we choose
1893 // just that it is consistent.
1894 let (first_default, second_default) =
1895 if default.def_id < conflicting_default.def_id {
1896 (default, conflicting_default)
1898 (conflicting_default, default)
1902 self.infcx().report_conflicting_default_types(
1903 first_default.origin_span,
1910 self.select_obligations_where_possible();
1913 // For use in error handling related to default type parameter fallback. We explicitly
1914 // apply the default that caused conflict first to a local version of the type variable
1915 // table then apply defaults until we find a conflict. That default must be the one
1916 // that caused conflict earlier.
1917 fn find_conflicting_default(&self,
1918 unbound_vars: &HashSet<Ty<'tcx>>,
1919 default_map: &FnvHashMap<&Ty<'tcx>, type_variable::Default<'tcx>>,
1921 -> Option<type_variable::Default<'tcx>> {
1922 use middle::ty::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat, Neither};
1924 // Ensure that we apply the conflicting default first
1925 let mut unbound_tyvars = Vec::with_capacity(unbound_vars.len() + 1);
1926 unbound_tyvars.push(conflict);
1927 unbound_tyvars.extend(unbound_vars.iter());
1929 let mut result = None;
1930 // We run the same code as above applying defaults in order, this time when
1931 // we find the conflict we just return it for error reporting above.
1933 // We also run this inside snapshot that never commits so we can do error
1934 // reporting for more then one conflict.
1935 for ty in &unbound_tyvars {
1936 if self.infcx().type_var_diverges(ty) {
1937 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().mk_nil());
1939 match self.infcx().type_is_unconstrained_numeric(ty) {
1940 UnconstrainedInt => {
1941 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.i32)
1943 UnconstrainedFloat => {
1944 demand::eqtype(self, codemap::DUMMY_SP, *ty, self.tcx().types.f64)
1947 if let Some(default) = default_map.get(ty) {
1948 let default = default.clone();
1949 match infer::mk_eqty(self.infcx(), false,
1950 infer::Misc(default.origin_span),
1954 result = Some(default);
1966 fn select_all_obligations_or_error(&self) {
1967 debug!("select_all_obligations_or_error");
1969 // upvar inference should have ensured that all deferred call
1970 // resolutions are handled by now.
1971 assert!(self.inh.deferred_call_resolutions.borrow().is_empty());
1973 self.select_all_obligations_and_apply_defaults();
1975 let mut fulfillment_cx = self.inh.infcx.fulfillment_cx.borrow_mut();
1976 match fulfillment_cx.select_all_or_error(self.infcx()) {
1978 Err(errors) => { report_fulfillment_errors(self.infcx(), &errors); }
1982 /// Select as many obligations as we can at present.
1983 fn select_obligations_where_possible(&self) {
1985 self.inh.infcx.fulfillment_cx
1987 .select_where_possible(self.infcx())
1990 Err(errors) => { report_fulfillment_errors(self.infcx(), &errors); }
1994 /// Try to select any fcx obligation that we haven't tried yet, in an effort
1995 /// to improve inference. You could just call
1996 /// `select_obligations_where_possible` except that it leads to repeated
1998 fn select_new_obligations(&self) {
2000 self.inh.infcx.fulfillment_cx
2002 .select_new_obligations(self.infcx())
2005 Err(errors) => { report_fulfillment_errors(self.infcx(), &errors); }
2011 impl<'a, 'tcx> RegionScope for FnCtxt<'a, 'tcx> {
2012 fn object_lifetime_default(&self, span: Span) -> Option<ty::Region> {
2013 Some(self.base_object_lifetime_default(span))
2016 fn base_object_lifetime_default(&self, span: Span) -> ty::Region {
2017 // RFC #599 specifies that object lifetime defaults take
2018 // precedence over other defaults. But within a fn body we
2019 // don't have a *default* region, rather we use inference to
2020 // find the *correct* region, which is strictly more general
2021 // (and anyway, within a fn body the right region may not even
2022 // be something the user can write explicitly, since it might
2023 // be some expression).
2024 self.infcx().next_region_var(infer::MiscVariable(span))
2027 fn anon_regions(&self, span: Span, count: usize)
2028 -> Result<Vec<ty::Region>, Option<Vec<ElisionFailureInfo>>> {
2029 Ok((0..count).map(|_| {
2030 self.infcx().next_region_var(infer::MiscVariable(span))
2035 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2036 pub enum LvaluePreference {
2041 impl LvaluePreference {
2042 pub fn from_mutbl(m: ast::Mutability) -> Self {
2044 ast::MutMutable => PreferMutLvalue,
2045 ast::MutImmutable => NoPreference,
2050 /// Whether `autoderef` requires types to resolve.
2051 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
2052 pub enum UnresolvedTypeAction {
2053 /// Produce an error and return `TyError` whenever a type cannot
2054 /// be resolved (i.e. it is `TyInfer`).
2056 /// Go on without emitting any errors, and return the unresolved
2057 /// type. Useful for probing, e.g. in coercions.
2061 /// Executes an autoderef loop for the type `t`. At each step, invokes `should_stop` to decide
2062 /// whether to terminate the loop. Returns the final type and number of derefs that it performed.
2064 /// Note: this method does not modify the adjustments table. The caller is responsible for
2065 /// inserting an AutoAdjustment record into the `fcx` using one of the suitable methods.
2066 pub fn autoderef<'a, 'tcx, T, F>(fcx: &FnCtxt<'a, 'tcx>,
2069 opt_expr: Option<&ast::Expr>,
2070 unresolved_type_action: UnresolvedTypeAction,
2071 mut lvalue_pref: LvaluePreference,
2073 -> (Ty<'tcx>, usize, Option<T>)
2074 where F: FnMut(Ty<'tcx>, usize) -> Option<T>,
2076 debug!("autoderef(base_ty={:?}, opt_expr={:?}, lvalue_pref={:?})",
2081 let mut t = base_ty;
2082 for autoderefs in 0..fcx.tcx().sess.recursion_limit.get() {
2083 let resolved_t = match unresolved_type_action {
2084 UnresolvedTypeAction::Error => {
2085 structurally_resolved_type(fcx, sp, t)
2087 UnresolvedTypeAction::Ignore => {
2088 // We can continue even when the type cannot be resolved
2089 // (i.e. it is an inference variable) because `Ty::builtin_deref`
2090 // and `try_overloaded_deref` both simply return `None`
2091 // in such a case without producing spurious errors.
2092 fcx.resolve_type_vars_if_possible(t)
2095 if resolved_t.references_error() {
2096 return (resolved_t, autoderefs, None);
2099 match should_stop(resolved_t, autoderefs) {
2100 Some(x) => return (resolved_t, autoderefs, Some(x)),
2104 // Otherwise, deref if type is derefable:
2105 let mt = match resolved_t.builtin_deref(false) {
2106 Some(mt) => Some(mt),
2109 opt_expr.map(|expr| MethodCall::autoderef(expr.id, autoderefs as u32));
2111 // Super subtle: it might seem as though we should
2112 // pass `opt_expr` to `try_overloaded_deref`, so that
2113 // the (implicit) autoref of using an overloaded deref
2114 // would get added to the adjustment table. However we
2115 // do not do that, because it's kind of a
2116 // "meta-adjustment" -- instead, we just leave it
2117 // unrecorded and know that there "will be" an
2118 // autoref. regionck and other bits of the code base,
2119 // when they encounter an overloaded autoderef, have
2120 // to do some reconstructive surgery. This is a pretty
2121 // complex mess that is begging for a proper MIR.
2122 try_overloaded_deref(fcx, sp, method_call, None, resolved_t, lvalue_pref)
2128 if mt.mutbl == ast::MutImmutable {
2129 lvalue_pref = NoPreference;
2132 None => return (resolved_t, autoderefs, None)
2136 // We've reached the recursion limit, error gracefully.
2137 span_err!(fcx.tcx().sess, sp, E0055,
2138 "reached the recursion limit while auto-dereferencing {:?}",
2140 (fcx.tcx().types.err, 0, None)
2143 fn try_overloaded_deref<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2145 method_call: Option<MethodCall>,
2146 base_expr: Option<&ast::Expr>,
2148 lvalue_pref: LvaluePreference)
2149 -> Option<ty::TypeAndMut<'tcx>>
2151 // Try DerefMut first, if preferred.
2152 let method = match (lvalue_pref, fcx.tcx().lang_items.deref_mut_trait()) {
2153 (PreferMutLvalue, Some(trait_did)) => {
2154 method::lookup_in_trait(fcx, span, base_expr,
2155 token::intern("deref_mut"), trait_did,
2161 // Otherwise, fall back to Deref.
2162 let method = match (method, fcx.tcx().lang_items.deref_trait()) {
2163 (None, Some(trait_did)) => {
2164 method::lookup_in_trait(fcx, span, base_expr,
2165 token::intern("deref"), trait_did,
2168 (method, _) => method
2171 make_overloaded_lvalue_return_type(fcx, method_call, method)
2174 /// For the overloaded lvalue expressions (`*x`, `x[3]`), the trait returns a type of `&T`, but the
2175 /// actual type we assign to the *expression* is `T`. So this function just peels off the return
2176 /// type by one layer to yield `T`. It also inserts the `method-callee` into the method map.
2177 fn make_overloaded_lvalue_return_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2178 method_call: Option<MethodCall>,
2179 method: Option<MethodCallee<'tcx>>)
2180 -> Option<ty::TypeAndMut<'tcx>>
2184 // extract method method return type, which will be &T;
2185 // all LB regions should have been instantiated during method lookup
2186 let ret_ty = method.ty.fn_ret();
2187 let ret_ty = fcx.tcx().no_late_bound_regions(&ret_ty).unwrap().unwrap();
2189 if let Some(method_call) = method_call {
2190 fcx.inh.tables.borrow_mut().method_map.insert(method_call, method);
2193 // method returns &T, but the type as visible to user is T, so deref
2194 ret_ty.builtin_deref(true)
2200 fn lookup_indexing<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2202 base_expr: &'tcx ast::Expr,
2205 lvalue_pref: LvaluePreference)
2206 -> Option<(/*index type*/ Ty<'tcx>, /*element type*/ Ty<'tcx>)>
2208 // FIXME(#18741) -- this is almost but not quite the same as the
2209 // autoderef that normal method probing does. They could likely be
2212 let (ty, autoderefs, final_mt) = autoderef(fcx,
2216 UnresolvedTypeAction::Error,
2219 try_index_step(fcx, MethodCall::expr(expr.id), expr, base_expr,
2220 adj_ty, idx, false, lvalue_pref, idx_ty)
2223 if final_mt.is_some() {
2227 // After we have fully autoderef'd, if the resulting type is [T; n], then
2228 // do a final unsized coercion to yield [T].
2229 if let ty::TyArray(element_ty, _) = ty.sty {
2230 let adjusted_ty = fcx.tcx().mk_slice(element_ty);
2231 try_index_step(fcx, MethodCall::expr(expr.id), expr, base_expr,
2232 adjusted_ty, autoderefs, true, lvalue_pref, idx_ty)
2238 /// To type-check `base_expr[index_expr]`, we progressively autoderef (and otherwise adjust)
2239 /// `base_expr`, looking for a type which either supports builtin indexing or overloaded indexing.
2240 /// This loop implements one step in that search; the autoderef loop is implemented by
2241 /// `lookup_indexing`.
2242 fn try_index_step<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2243 method_call: MethodCall,
2245 base_expr: &'tcx ast::Expr,
2246 adjusted_ty: Ty<'tcx>,
2249 lvalue_pref: LvaluePreference,
2251 -> Option<(/*index type*/ Ty<'tcx>, /*element type*/ Ty<'tcx>)>
2253 let tcx = fcx.tcx();
2254 debug!("try_index_step(expr={:?}, base_expr.id={:?}, adjusted_ty={:?}, \
2255 autoderefs={}, unsize={}, index_ty={:?})",
2263 let input_ty = fcx.infcx().next_ty_var();
2265 // First, try built-in indexing.
2266 match (adjusted_ty.builtin_index(), &index_ty.sty) {
2267 (Some(ty), &ty::TyUint(ast::TyUs)) | (Some(ty), &ty::TyInfer(ty::IntVar(_))) => {
2268 debug!("try_index_step: success, using built-in indexing");
2269 // If we had `[T; N]`, we should've caught it before unsizing to `[T]`.
2271 fcx.write_autoderef_adjustment(base_expr.id, autoderefs);
2272 return Some((tcx.types.usize, ty));
2277 // Try `IndexMut` first, if preferred.
2278 let method = match (lvalue_pref, tcx.lang_items.index_mut_trait()) {
2279 (PreferMutLvalue, Some(trait_did)) => {
2280 method::lookup_in_trait_adjusted(fcx,
2283 token::intern("index_mut"),
2288 Some(vec![input_ty]))
2293 // Otherwise, fall back to `Index`.
2294 let method = match (method, tcx.lang_items.index_trait()) {
2295 (None, Some(trait_did)) => {
2296 method::lookup_in_trait_adjusted(fcx,
2299 token::intern("index"),
2304 Some(vec![input_ty]))
2306 (method, _) => method,
2309 // If some lookup succeeds, write callee into table and extract index/element
2310 // type from the method signature.
2311 // If some lookup succeeded, install method in table
2312 method.and_then(|method| {
2313 debug!("try_index_step: success, using overloaded indexing");
2314 make_overloaded_lvalue_return_type(fcx, Some(method_call), Some(method)).
2315 map(|ret| (input_ty, ret.ty))
2319 fn check_method_argument_types<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2321 method_fn_ty: Ty<'tcx>,
2322 callee_expr: &'tcx ast::Expr,
2323 args_no_rcvr: &'tcx [P<ast::Expr>],
2324 tuple_arguments: TupleArgumentsFlag,
2325 expected: Expectation<'tcx>)
2326 -> ty::FnOutput<'tcx> {
2327 if method_fn_ty.references_error() {
2328 let err_inputs = err_args(fcx.tcx(), args_no_rcvr.len());
2330 let err_inputs = match tuple_arguments {
2331 DontTupleArguments => err_inputs,
2332 TupleArguments => vec![fcx.tcx().mk_tup(err_inputs)],
2335 check_argument_types(fcx,
2342 ty::FnConverging(fcx.tcx().types.err)
2344 match method_fn_ty.sty {
2345 ty::TyBareFn(_, ref fty) => {
2346 // HACK(eddyb) ignore self in the definition (see above).
2347 let expected_arg_tys = expected_types_for_fn_args(fcx,
2351 &fty.sig.0.inputs[1..]);
2352 check_argument_types(fcx,
2354 &fty.sig.0.inputs[1..],
2355 &expected_arg_tys[..],
2362 fcx.tcx().sess.span_bug(callee_expr.span,
2363 "method without bare fn type");
2369 /// Generic function that factors out common logic from function calls, method calls and overloaded
2371 fn check_argument_types<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2373 fn_inputs: &[Ty<'tcx>],
2374 expected_arg_tys: &[Ty<'tcx>],
2375 args: &'tcx [P<ast::Expr>],
2377 tuple_arguments: TupleArgumentsFlag) {
2378 let tcx = fcx.ccx.tcx;
2380 // Grab the argument types, supplying fresh type variables
2381 // if the wrong number of arguments were supplied
2382 let supplied_arg_count = if tuple_arguments == DontTupleArguments {
2388 let mut expected_arg_tys = expected_arg_tys;
2389 let expected_arg_count = fn_inputs.len();
2390 let formal_tys = if tuple_arguments == TupleArguments {
2391 let tuple_type = structurally_resolved_type(fcx, sp, fn_inputs[0]);
2392 match tuple_type.sty {
2393 ty::TyTuple(ref arg_types) => {
2394 if arg_types.len() != args.len() {
2395 span_err!(tcx.sess, sp, E0057,
2396 "this function takes {} parameter{} but {} parameter{} supplied",
2398 if arg_types.len() == 1 {""} else {"s"},
2400 if args.len() == 1 {" was"} else {"s were"});
2401 expected_arg_tys = &[];
2402 err_args(fcx.tcx(), args.len())
2404 expected_arg_tys = match expected_arg_tys.get(0) {
2405 Some(&ty) => match ty.sty {
2406 ty::TyTuple(ref tys) => &**tys,
2411 (*arg_types).clone()
2415 span_err!(tcx.sess, sp, E0059,
2416 "cannot use call notation; the first type parameter \
2417 for the function trait is neither a tuple nor unit");
2418 expected_arg_tys = &[];
2419 err_args(fcx.tcx(), args.len())
2422 } else if expected_arg_count == supplied_arg_count {
2424 } else if variadic {
2425 if supplied_arg_count >= expected_arg_count {
2428 span_err!(tcx.sess, sp, E0060,
2429 "this function takes at least {} parameter{} \
2430 but {} parameter{} supplied",
2432 if expected_arg_count == 1 {""} else {"s"},
2434 if supplied_arg_count == 1 {" was"} else {"s were"});
2435 expected_arg_tys = &[];
2436 err_args(fcx.tcx(), supplied_arg_count)
2439 span_err!(tcx.sess, sp, E0061,
2440 "this function takes {} parameter{} but {} parameter{} supplied",
2442 if expected_arg_count == 1 {""} else {"s"},
2444 if supplied_arg_count == 1 {" was"} else {"s were"});
2445 expected_arg_tys = &[];
2446 err_args(fcx.tcx(), supplied_arg_count)
2449 debug!("check_argument_types: formal_tys={:?}",
2450 formal_tys.iter().map(|t| fcx.infcx().ty_to_string(*t)).collect::<Vec<String>>());
2452 // Check the arguments.
2453 // We do this in a pretty awful way: first we typecheck any arguments
2454 // that are not anonymous functions, then we typecheck the anonymous
2455 // functions. This is so that we have more information about the types
2456 // of arguments when we typecheck the functions. This isn't really the
2457 // right way to do this.
2458 let xs = [false, true];
2459 for check_blocks in &xs {
2460 let check_blocks = *check_blocks;
2461 debug!("check_blocks={}", check_blocks);
2463 // More awful hacks: before we check argument types, try to do
2464 // an "opportunistic" vtable resolution of any trait bounds on
2465 // the call. This helps coercions.
2467 fcx.select_new_obligations();
2470 // For variadic functions, we don't have a declared type for all of
2471 // the arguments hence we only do our usual type checking with
2472 // the arguments who's types we do know.
2473 let t = if variadic {
2475 } else if tuple_arguments == TupleArguments {
2480 for (i, arg) in args.iter().take(t).enumerate() {
2481 let is_block = match arg.node {
2482 ast::ExprClosure(..) => true,
2486 if is_block == check_blocks {
2487 debug!("checking the argument");
2488 let formal_ty = formal_tys[i];
2490 // The special-cased logic below has three functions:
2491 // 1. Provide as good of an expected type as possible.
2492 let expected = expected_arg_tys.get(i).map(|&ty| {
2493 Expectation::rvalue_hint(fcx.tcx(), ty)
2496 check_expr_with_unifier(fcx, &**arg,
2497 expected.unwrap_or(ExpectHasType(formal_ty)),
2499 // 2. Coerce to the most detailed type that could be coerced
2500 // to, which is `expected_ty` if `rvalue_hint` returns an
2501 // `ExprHasType(expected_ty)`, or the `formal_ty` otherwise.
2502 let coerce_ty = expected.and_then(|e| e.only_has_type(fcx));
2503 demand::coerce(fcx, arg.span, coerce_ty.unwrap_or(formal_ty), &**arg);
2505 // 3. Relate the expected type and the formal one,
2506 // if the expected type was used for the coercion.
2507 coerce_ty.map(|ty| demand::suptype(fcx, arg.span, formal_ty, ty));
2513 // We also need to make sure we at least write the ty of the other
2514 // arguments which we skipped above.
2516 for arg in args.iter().skip(expected_arg_count) {
2517 check_expr(fcx, &**arg);
2519 // There are a few types which get autopromoted when passed via varargs
2520 // in C but we just error out instead and require explicit casts.
2521 let arg_ty = structurally_resolved_type(fcx, arg.span,
2522 fcx.expr_ty(&**arg));
2524 ty::TyFloat(ast::TyF32) => {
2525 fcx.type_error_message(arg.span,
2527 format!("can't pass an {} to variadic \
2528 function, cast to c_double", t)
2531 ty::TyInt(ast::TyI8) | ty::TyInt(ast::TyI16) | ty::TyBool => {
2532 fcx.type_error_message(arg.span, |t| {
2533 format!("can't pass {} to variadic \
2534 function, cast to c_int",
2538 ty::TyUint(ast::TyU8) | ty::TyUint(ast::TyU16) => {
2539 fcx.type_error_message(arg.span, |t| {
2540 format!("can't pass {} to variadic \
2541 function, cast to c_uint",
2551 // FIXME(#17596) Ty<'tcx> is incorrectly invariant w.r.t 'tcx.
2552 fn err_args<'tcx>(tcx: &ty::ctxt<'tcx>, len: usize) -> Vec<Ty<'tcx>> {
2553 (0..len).map(|_| tcx.types.err).collect()
2556 fn write_call<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2557 call_expr: &ast::Expr,
2558 output: ty::FnOutput<'tcx>) {
2559 fcx.write_ty(call_expr.id, match output {
2560 ty::FnConverging(output_ty) => output_ty,
2561 ty::FnDiverging => fcx.infcx().next_diverging_ty_var()
2565 // AST fragment checking
2566 fn check_lit<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2568 expected: Expectation<'tcx>)
2571 let tcx = fcx.ccx.tcx;
2574 ast::LitStr(..) => tcx.mk_static_str(),
2575 ast::LitBinary(ref v) => {
2576 tcx.mk_imm_ref(tcx.mk_region(ty::ReStatic),
2577 tcx.mk_array(tcx.types.u8, v.len()))
2579 ast::LitByte(_) => tcx.types.u8,
2580 ast::LitChar(_) => tcx.types.char,
2581 ast::LitInt(_, ast::SignedIntLit(t, _)) => tcx.mk_mach_int(t),
2582 ast::LitInt(_, ast::UnsignedIntLit(t)) => tcx.mk_mach_uint(t),
2583 ast::LitInt(_, ast::UnsuffixedIntLit(_)) => {
2584 let opt_ty = expected.to_option(fcx).and_then(|ty| {
2586 ty::TyInt(_) | ty::TyUint(_) => Some(ty),
2587 ty::TyChar => Some(tcx.types.u8),
2588 ty::TyRawPtr(..) => Some(tcx.types.usize),
2589 ty::TyBareFn(..) => Some(tcx.types.usize),
2593 opt_ty.unwrap_or_else(
2594 || tcx.mk_int_var(fcx.infcx().next_int_var_id()))
2596 ast::LitFloat(_, t) => tcx.mk_mach_float(t),
2597 ast::LitFloatUnsuffixed(_) => {
2598 let opt_ty = expected.to_option(fcx).and_then(|ty| {
2600 ty::TyFloat(_) => Some(ty),
2604 opt_ty.unwrap_or_else(
2605 || tcx.mk_float_var(fcx.infcx().next_float_var_id()))
2607 ast::LitBool(_) => tcx.types.bool
2611 pub fn check_expr_has_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2612 expr: &'tcx ast::Expr,
2613 expected: Ty<'tcx>) {
2614 check_expr_with_unifier(
2615 fcx, expr, ExpectHasType(expected), NoPreference,
2616 || demand::suptype(fcx, expr.span, expected, fcx.expr_ty(expr)));
2619 fn check_expr_coercable_to_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2620 expr: &'tcx ast::Expr,
2621 expected: Ty<'tcx>) {
2622 check_expr_with_unifier(
2623 fcx, expr, ExpectHasType(expected), NoPreference,
2624 || demand::coerce(fcx, expr.span, expected, expr));
2627 fn check_expr_with_hint<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>, expr: &'tcx ast::Expr,
2628 expected: Ty<'tcx>) {
2629 check_expr_with_unifier(
2630 fcx, expr, ExpectHasType(expected), NoPreference,
2634 fn check_expr_with_expectation<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2635 expr: &'tcx ast::Expr,
2636 expected: Expectation<'tcx>) {
2637 check_expr_with_unifier(
2638 fcx, expr, expected, NoPreference,
2642 fn check_expr_with_expectation_and_lvalue_pref<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2643 expr: &'tcx ast::Expr,
2644 expected: Expectation<'tcx>,
2645 lvalue_pref: LvaluePreference)
2647 check_expr_with_unifier(fcx, expr, expected, lvalue_pref, || ())
2650 fn check_expr<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>, expr: &'tcx ast::Expr) {
2651 check_expr_with_unifier(fcx, expr, NoExpectation, NoPreference, || ())
2654 fn check_expr_with_lvalue_pref<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>, expr: &'tcx ast::Expr,
2655 lvalue_pref: LvaluePreference) {
2656 check_expr_with_unifier(fcx, expr, NoExpectation, lvalue_pref, || ())
2659 // determine the `self` type, using fresh variables for all variables
2660 // declared on the impl declaration e.g., `impl<A,B> for Vec<(A,B)>`
2661 // would return ($0, $1) where $0 and $1 are freshly instantiated type
2663 pub fn impl_self_ty<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2664 span: Span, // (potential) receiver for this impl
2666 -> TypeAndSubsts<'tcx> {
2667 let tcx = fcx.tcx();
2669 let ity = tcx.lookup_item_type(did);
2670 let (tps, rps, raw_ty) =
2671 (ity.generics.types.get_slice(subst::TypeSpace),
2672 ity.generics.regions.get_slice(subst::TypeSpace),
2675 debug!("impl_self_ty: tps={:?} rps={:?} raw_ty={:?}", tps, rps, raw_ty);
2677 let rps = fcx.inh.infcx.region_vars_for_defs(span, rps);
2678 let mut substs = subst::Substs::new(
2679 VecPerParamSpace::empty(),
2680 VecPerParamSpace::new(rps, Vec::new(), Vec::new()));
2681 fcx.inh.infcx.type_vars_for_defs(span, ParamSpace::TypeSpace, &mut substs, tps);
2682 let substd_ty = fcx.instantiate_type_scheme(span, &substs, &raw_ty);
2684 TypeAndSubsts { substs: substs, ty: substd_ty }
2687 /// Controls whether the arguments are tupled. This is used for the call
2690 /// Tupling means that all call-side arguments are packed into a tuple and
2691 /// passed as a single parameter. For example, if tupling is enabled, this
2694 /// fn f(x: (isize, isize))
2696 /// Can be called as:
2703 #[derive(Clone, Eq, PartialEq)]
2704 enum TupleArgumentsFlag {
2709 /// Unifies the return type with the expected type early, for more coercions
2710 /// and forward type information on the argument expressions.
2711 fn expected_types_for_fn_args<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2713 expected_ret: Expectation<'tcx>,
2714 formal_ret: ty::FnOutput<'tcx>,
2715 formal_args: &[Ty<'tcx>])
2717 let expected_args = expected_ret.only_has_type(fcx).and_then(|ret_ty| {
2718 if let ty::FnConverging(formal_ret_ty) = formal_ret {
2719 fcx.infcx().commit_regions_if_ok(|| {
2720 // Attempt to apply a subtyping relationship between the formal
2721 // return type (likely containing type variables if the function
2722 // is polymorphic) and the expected return type.
2723 // No argument expectations are produced if unification fails.
2724 let origin = infer::Misc(call_span);
2725 let ures = fcx.infcx().sub_types(false, origin, formal_ret_ty, ret_ty);
2726 // FIXME(#15760) can't use try! here, FromError doesn't default
2727 // to identity so the resulting type is not constrained.
2728 if let Err(e) = ures {
2732 // Record all the argument types, with the substitutions
2733 // produced from the above subtyping unification.
2734 Ok(formal_args.iter().map(|ty| {
2735 fcx.infcx().resolve_type_vars_if_possible(ty)
2741 }).unwrap_or(vec![]);
2742 debug!("expected_types_for_fn_args(formal={:?} -> {:?}, expected={:?} -> {:?})",
2743 formal_args, formal_ret,
2744 expected_args, expected_ret);
2749 /// If an expression has any sub-expressions that result in a type error,
2750 /// inspecting that expression's type with `ty.references_error()` will return
2751 /// true. Likewise, if an expression is known to diverge, inspecting its
2752 /// type with `ty::type_is_bot` will return true (n.b.: since Rust is
2753 /// strict, _|_ can appear in the type of an expression that does not,
2754 /// itself, diverge: for example, fn() -> _|_.)
2755 /// Note that inspecting a type's structure *directly* may expose the fact
2756 /// that there are actually multiple representations for `TyError`, so avoid
2757 /// that when err needs to be handled differently.
2758 fn check_expr_with_unifier<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>,
2759 expr: &'tcx ast::Expr,
2760 expected: Expectation<'tcx>,
2761 lvalue_pref: LvaluePreference,
2765 debug!(">> typechecking: expr={:?} expected={:?}",
2768 // Checks a method call.
2769 fn check_method_call<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2770 expr: &'tcx ast::Expr,
2771 method_name: ast::SpannedIdent,
2772 args: &'tcx [P<ast::Expr>],
2774 expected: Expectation<'tcx>,
2775 lvalue_pref: LvaluePreference) {
2776 let rcvr = &*args[0];
2777 check_expr_with_lvalue_pref(fcx, &*rcvr, lvalue_pref);
2779 // no need to check for bot/err -- callee does that
2780 let expr_t = structurally_resolved_type(fcx,
2782 fcx.expr_ty(&*rcvr));
2784 let tps = tps.iter().map(|ast_ty| fcx.to_ty(&**ast_ty)).collect::<Vec<_>>();
2785 let fn_ty = match method::lookup(fcx,
2787 method_name.node.name,
2793 let method_ty = method.ty;
2794 let method_call = MethodCall::expr(expr.id);
2795 fcx.inh.tables.borrow_mut().method_map.insert(method_call, method);
2799 method::report_error(fcx, method_name.span, expr_t,
2800 method_name.node.name, Some(rcvr), error);
2801 fcx.write_error(expr.id);
2806 // Call the generic checker.
2807 let ret_ty = check_method_argument_types(fcx,
2815 write_call(fcx, expr, ret_ty);
2818 // A generic function for checking the then and else in an if
2820 fn check_then_else<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
2821 cond_expr: &'tcx ast::Expr,
2822 then_blk: &'tcx ast::Block,
2823 opt_else_expr: Option<&'tcx ast::Expr>,
2826 expected: Expectation<'tcx>) {
2827 check_expr_has_type(fcx, cond_expr, fcx.tcx().types.bool);
2829 let expected = expected.adjust_for_branches(fcx);
2830 check_block_with_expected(fcx, then_blk, expected);
2831 let then_ty = fcx.node_ty(then_blk.id);
2833 let branches_ty = match opt_else_expr {
2834 Some(ref else_expr) => {
2835 check_expr_with_expectation(fcx, &**else_expr, expected);
2836 let else_ty = fcx.expr_ty(&**else_expr);
2837 infer::common_supertype(fcx.infcx(),
2838 infer::IfExpression(sp),
2844 infer::common_supertype(fcx.infcx(),
2845 infer::IfExpressionWithNoElse(sp),
2852 let cond_ty = fcx.expr_ty(cond_expr);
2853 let if_ty = if cond_ty.references_error() {
2859 fcx.write_ty(id, if_ty);
2862 // Check field access expressions
2863 fn check_field<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
2864 expr: &'tcx ast::Expr,
2865 lvalue_pref: LvaluePreference,
2866 base: &'tcx ast::Expr,
2867 field: &ast::SpannedIdent) {
2868 let tcx = fcx.ccx.tcx;
2869 check_expr_with_lvalue_pref(fcx, base, lvalue_pref);
2870 let expr_t = structurally_resolved_type(fcx, expr.span,
2872 // FIXME(eddyb) #12808 Integrate privacy into this auto-deref loop.
2873 let (_, autoderefs, field_ty) = autoderef(fcx,
2877 UnresolvedTypeAction::Error,
2881 ty::TyStruct(base_id, substs) => {
2882 debug!("struct named {:?}", base_t);
2883 let fields = tcx.lookup_struct_fields(base_id);
2884 fcx.lookup_field_ty(expr.span, base_id, &fields[..],
2885 field.node.name, &(*substs))
2892 fcx.write_ty(expr.id, field_ty);
2893 fcx.write_autoderef_adjustment(base.id, autoderefs);
2899 if method::exists(fcx, field.span, field.node.name, expr_t, expr.id) {
2900 fcx.type_error_message(
2903 format!("attempted to take value of method `{}` on type \
2904 `{}`", field.node, actual)
2908 tcx.sess.fileline_help(field.span,
2909 "maybe a `()` to call it is missing? \
2910 If not, try an anonymous function");
2912 fcx.type_error_message(
2915 format!("attempted access of field `{}` on \
2916 type `{}`, but no field with that \
2922 if let ty::TyStruct(did, _) = expr_t.sty {
2923 suggest_field_names(did, field, tcx, vec![]);
2927 fcx.write_error(expr.id);
2930 // displays hints about the closest matches in field names
2931 fn suggest_field_names<'tcx>(id : DefId,
2932 field : &ast::SpannedIdent,
2933 tcx : &ty::ctxt<'tcx>,
2934 skip : Vec<InternedString>) {
2935 let name = field.node.name.as_str();
2936 // only find fits with at least one matching letter
2937 let mut best_dist = name.len();
2938 let fields = tcx.lookup_struct_fields(id);
2939 let mut best = None;
2940 for elem in &fields {
2941 let n = elem.name.as_str();
2942 // ignore already set fields
2943 if skip.iter().any(|x| *x == n) {
2946 // ignore private fields from non-local crates
2947 if id.krate != ast::LOCAL_CRATE && elem.vis != Visibility::Public {
2950 let dist = lev_distance(&n, &name);
2951 if dist < best_dist {
2956 if let Some(n) = best {
2957 tcx.sess.span_help(field.span,
2958 &format!("did you mean `{}`?", n));
2962 // Check tuple index expressions
2963 fn check_tup_field<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
2964 expr: &'tcx ast::Expr,
2965 lvalue_pref: LvaluePreference,
2966 base: &'tcx ast::Expr,
2967 idx: codemap::Spanned<usize>) {
2968 let tcx = fcx.ccx.tcx;
2969 check_expr_with_lvalue_pref(fcx, base, lvalue_pref);
2970 let expr_t = structurally_resolved_type(fcx, expr.span,
2972 let mut tuple_like = false;
2973 // FIXME(eddyb) #12808 Integrate privacy into this auto-deref loop.
2974 let (_, autoderefs, field_ty) = autoderef(fcx,
2978 UnresolvedTypeAction::Error,
2982 ty::TyStruct(base_id, substs) => {
2983 tuple_like = tcx.is_tuple_struct(base_id);
2985 debug!("tuple struct named {:?}", base_t);
2986 let fields = tcx.lookup_struct_fields(base_id);
2987 fcx.lookup_tup_field_ty(expr.span, base_id, &fields[..],
2988 idx.node, &(*substs))
2993 ty::TyTuple(ref v) => {
2995 if idx.node < v.len() { Some(v[idx.node]) } else { None }
3002 fcx.write_ty(expr.id, field_ty);
3003 fcx.write_autoderef_adjustment(base.id, autoderefs);
3008 fcx.type_error_message(
3012 format!("attempted out-of-bounds tuple index `{}` on \
3017 format!("attempted tuple index `{}` on type `{}`, but the \
3018 type was not a tuple or tuple struct",
3025 fcx.write_error(expr.id);
3028 fn check_struct_or_variant_fields<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
3029 struct_ty: Ty<'tcx>,
3031 class_id: ast::DefId,
3032 node_id: ast::NodeId,
3033 substitutions: &'tcx subst::Substs<'tcx>,
3034 field_types: &[ty::FieldTy],
3035 ast_fields: &'tcx [ast::Field],
3036 check_completeness: bool,
3037 enum_id_opt: Option<ast::DefId>) {
3038 let tcx = fcx.ccx.tcx;
3040 let mut class_field_map = FnvHashMap();
3041 let mut fields_found = 0;
3042 for field in field_types {
3043 class_field_map.insert(field.name, (field.id, false));
3046 let mut error_happened = false;
3048 // Typecheck each field.
3049 for field in ast_fields {
3050 let mut expected_field_type = tcx.types.err;
3052 let pair = class_field_map.get(&field.ident.node.name).cloned();
3055 fcx.type_error_message(
3057 |actual| match enum_id_opt {
3059 let variant_type = tcx.enum_variant_with_id(enum_id,
3061 format!("struct variant `{}::{}` has no field named `{}`",
3062 actual, variant_type.name.as_str(),
3066 format!("structure `{}` has no field named `{}`",
3073 // prevent all specified fields from being suggested
3074 let skip_fields = ast_fields.iter().map(|ref x| x.ident.node.name.as_str());
3075 let actual_id = match enum_id_opt {
3076 Some(_) => class_id,
3077 None => struct_ty.ty_to_def_id().unwrap()
3079 suggest_field_names(actual_id, &field.ident, tcx, skip_fields.collect());
3080 error_happened = true;
3082 Some((_, true)) => {
3083 span_err!(fcx.tcx().sess, field.ident.span, E0062,
3084 "field `{}` specified more than once",
3086 error_happened = true;
3088 Some((field_id, false)) => {
3089 expected_field_type =
3090 tcx.lookup_field_type(class_id, field_id, substitutions);
3091 expected_field_type =
3092 fcx.normalize_associated_types_in(
3093 field.span, &expected_field_type);
3094 class_field_map.insert(
3095 field.ident.node.name, (field_id, true));
3100 // Make sure to give a type to the field even if there's
3101 // an error, so we can continue typechecking
3102 check_expr_coercable_to_type(fcx, &*field.expr, expected_field_type);
3106 fcx.write_error(node_id);
3109 if check_completeness && !error_happened {
3110 // Make sure the programmer specified all the fields.
3111 assert!(fields_found <= field_types.len());
3112 if fields_found < field_types.len() {
3113 let mut missing_fields = Vec::new();
3114 for class_field in field_types {
3115 let name = class_field.name;
3116 let (_, seen) = *class_field_map.get(&name).unwrap();
3118 missing_fields.push(
3119 format!("`{}`", name))
3123 span_err!(tcx.sess, span, E0063,
3124 "missing field{}: {}",
3125 if missing_fields.len() == 1 {""} else {"s"},
3126 missing_fields.join(", "));
3130 if !error_happened {
3131 fcx.write_ty(node_id, fcx.ccx.tcx.mk_struct(class_id, substitutions));
3135 fn check_struct_constructor<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
3137 span: codemap::Span,
3138 class_id: ast::DefId,
3139 fields: &'tcx [ast::Field],
3140 base_expr: Option<&'tcx ast::Expr>) {
3141 let tcx = fcx.ccx.tcx;
3143 // Generate the struct type.
3145 ty: mut struct_type,
3146 substs: struct_substs
3147 } = fcx.instantiate_type(span, class_id);
3149 // Look up and check the fields.
3150 let class_fields = tcx.lookup_struct_fields(class_id);
3151 check_struct_or_variant_fields(fcx,
3156 fcx.ccx.tcx.mk_substs(struct_substs),
3159 base_expr.is_none(),
3161 if fcx.node_ty(id).references_error() {
3162 struct_type = tcx.types.err;
3165 // Check the base expression if necessary.
3168 Some(base_expr) => {
3169 check_expr_has_type(fcx, &*base_expr, struct_type);
3173 // Write in the resulting type.
3174 fcx.write_ty(id, struct_type);
3177 fn check_struct_enum_variant<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
3179 span: codemap::Span,
3180 enum_id: ast::DefId,
3181 variant_id: ast::DefId,
3182 fields: &'tcx [ast::Field]) {
3183 let tcx = fcx.ccx.tcx;
3185 // Look up the number of type parameters and the raw type, and
3186 // determine whether the enum is region-parameterized.
3189 substs: substitutions
3190 } = fcx.instantiate_type(span, enum_id);
3192 // Look up and check the enum variant fields.
3193 let variant_fields = tcx.lookup_struct_fields(variant_id);
3194 check_struct_or_variant_fields(fcx,
3199 fcx.ccx.tcx.mk_substs(substitutions),
3200 &variant_fields[..],
3204 fcx.write_ty(id, enum_type);
3207 fn check_struct_fields_on_error<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
3209 fields: &'tcx [ast::Field],
3210 base_expr: &'tcx Option<P<ast::Expr>>) {
3211 // Make sure to still write the types
3212 // otherwise we might ICE
3213 fcx.write_error(id);
3214 for field in fields {
3215 check_expr(fcx, &*field.expr);
3218 Some(ref base) => check_expr(fcx, &**base),
3223 type ExprCheckerWithTy = fn(&FnCtxt, &ast::Expr, Ty);
3225 let tcx = fcx.ccx.tcx;
3228 ast::ExprBox(ref opt_place, ref subexpr) => {
3229 opt_place.as_ref().map(|place|check_expr(fcx, &**place));
3230 check_expr(fcx, &**subexpr);
3232 let mut checked = false;
3233 opt_place.as_ref().map(|place| match place.node {
3234 ast::ExprPath(None, ref path) => {
3235 // FIXME(pcwalton): For now we hardcode the only permissible
3236 // place: the exchange heap.
3237 let definition = lookup_full_def(tcx, path.span, place.id);
3238 let def_id = definition.def_id();
3239 let referent_ty = fcx.expr_ty(&**subexpr);
3240 if tcx.lang_items.exchange_heap() == Some(def_id) {
3241 fcx.write_ty(id, tcx.mk_box(referent_ty));
3249 span_err!(tcx.sess, expr.span, E0066,
3250 "only the exchange heap is currently supported");
3251 fcx.write_ty(id, tcx.types.err);
3255 ast::ExprLit(ref lit) => {
3256 let typ = check_lit(fcx, &**lit, expected);
3257 fcx.write_ty(id, typ);
3259 ast::ExprBinary(op, ref lhs, ref rhs) => {
3260 op::check_binop(fcx, expr, op, lhs, rhs);
3262 ast::ExprAssignOp(op, ref lhs, ref rhs) => {
3263 op::check_binop_assign(fcx, expr, op, lhs, rhs);
3265 ast::ExprUnary(unop, ref oprnd) => {
3266 let expected_inner = expected.to_option(fcx).map_or(NoExpectation, |ty| {
3268 ast::UnUniq => match ty.sty {
3270 Expectation::rvalue_hint(tcx, ty)
3276 ast::UnNot | ast::UnNeg => {
3284 let lvalue_pref = match unop {
3285 ast::UnDeref => lvalue_pref,
3288 check_expr_with_expectation_and_lvalue_pref(
3289 fcx, &**oprnd, expected_inner, lvalue_pref);
3290 let mut oprnd_t = fcx.expr_ty(&**oprnd);
3292 if !oprnd_t.references_error() {
3295 oprnd_t = tcx.mk_box(oprnd_t);
3298 oprnd_t = structurally_resolved_type(fcx, expr.span, oprnd_t);
3299 oprnd_t = match oprnd_t.builtin_deref(true) {
3301 None => match try_overloaded_deref(fcx, expr.span,
3302 Some(MethodCall::expr(expr.id)),
3303 Some(&**oprnd), oprnd_t, lvalue_pref) {
3306 fcx.type_error_message(expr.span, |actual| {
3307 format!("type `{}` cannot be \
3308 dereferenced", actual)
3316 oprnd_t = structurally_resolved_type(fcx, oprnd.span,
3318 if !(oprnd_t.is_integral() || oprnd_t.sty == ty::TyBool) {
3319 oprnd_t = op::check_user_unop(fcx, "!", "not",
3320 tcx.lang_items.not_trait(),
3321 expr, &**oprnd, oprnd_t, unop);
3325 oprnd_t = structurally_resolved_type(fcx, oprnd.span,
3327 if !(oprnd_t.is_integral() || oprnd_t.is_fp()) {
3328 oprnd_t = op::check_user_unop(fcx, "-", "neg",
3329 tcx.lang_items.neg_trait(),
3330 expr, &**oprnd, oprnd_t, unop);
3335 fcx.write_ty(id, oprnd_t);
3337 ast::ExprAddrOf(mutbl, ref oprnd) => {
3338 let hint = expected.only_has_type(fcx).map_or(NoExpectation, |ty| {
3340 ty::TyRef(_, ref mt) | ty::TyRawPtr(ref mt) => {
3341 if fcx.tcx().expr_is_lval(&**oprnd) {
3342 // Lvalues may legitimately have unsized types.
3343 // For example, dereferences of a fat pointer and
3344 // the last field of a struct can be unsized.
3345 ExpectHasType(mt.ty)
3347 Expectation::rvalue_hint(tcx, mt.ty)
3353 let lvalue_pref = LvaluePreference::from_mutbl(mutbl);
3354 check_expr_with_expectation_and_lvalue_pref(fcx,
3359 let tm = ty::TypeAndMut { ty: fcx.expr_ty(&**oprnd), mutbl: mutbl };
3360 let oprnd_t = if tm.ty.references_error() {
3363 // Note: at this point, we cannot say what the best lifetime
3364 // is to use for resulting pointer. We want to use the
3365 // shortest lifetime possible so as to avoid spurious borrowck
3366 // errors. Moreover, the longest lifetime will depend on the
3367 // precise details of the value whose address is being taken
3368 // (and how long it is valid), which we don't know yet until type
3369 // inference is complete.
3371 // Therefore, here we simply generate a region variable. The
3372 // region inferencer will then select the ultimate value.
3373 // Finally, borrowck is charged with guaranteeing that the
3374 // value whose address was taken can actually be made to live
3375 // as long as it needs to live.
3376 let region = fcx.infcx().next_region_var(infer::AddrOfRegion(expr.span));
3377 tcx.mk_ref(tcx.mk_region(region), tm)
3379 fcx.write_ty(id, oprnd_t);
3381 ast::ExprPath(ref maybe_qself, ref path) => {
3382 let opt_self_ty = maybe_qself.as_ref().map(|qself| {
3383 fcx.to_ty(&qself.ty)
3386 let path_res = if let Some(&d) = tcx.def_map.borrow().get(&id) {
3388 } else if let Some(ast::QSelf { position: 0, .. }) = *maybe_qself {
3389 // Create some fake resolution that can't possibly be a type.
3390 def::PathResolution {
3391 base_def: def::DefMod(local_def(ast::CRATE_NODE_ID)),
3392 last_private: LastMod(AllPublic),
3393 depth: path.segments.len()
3396 tcx.sess.span_bug(expr.span,
3397 &format!("unbound path {:?}", expr))
3400 if let Some((opt_ty, segments, def)) =
3401 resolve_ty_and_def_ufcs(fcx, path_res, opt_self_ty, path,
3402 expr.span, expr.id) {
3403 let (scheme, predicates) = type_scheme_and_predicates_for_def(fcx,
3406 instantiate_path(fcx,
3416 // We always require that the type provided as the value for
3417 // a type parameter outlives the moment of instantiation.
3418 constrain_path_type_parameters(fcx, expr);
3420 ast::ExprInlineAsm(ref ia) => {
3421 for &(_, ref input) in &ia.inputs {
3422 check_expr(fcx, &**input);
3424 for &(_, ref out, _) in &ia.outputs {
3425 check_expr(fcx, &**out);
3429 ast::ExprMac(_) => tcx.sess.bug("unexpanded macro"),
3430 ast::ExprBreak(_) => { fcx.write_ty(id, fcx.infcx().next_diverging_ty_var()); }
3431 ast::ExprAgain(_) => { fcx.write_ty(id, fcx.infcx().next_diverging_ty_var()); }
3432 ast::ExprRet(ref expr_opt) => {
3434 ty::FnConverging(result_type) => {
3437 if let Err(_) = fcx.mk_eqty(false, infer::Misc(expr.span),
3438 result_type, fcx.tcx().mk_nil()) {
3439 span_err!(tcx.sess, expr.span, E0069,
3440 "`return;` in a function whose return type is \
3444 check_expr_coercable_to_type(fcx, &**e, result_type);
3448 ty::FnDiverging => {
3449 if let Some(ref e) = *expr_opt {
3450 check_expr(fcx, &**e);
3452 span_err!(tcx.sess, expr.span, E0166,
3453 "`return` in a function declared as diverging");
3456 fcx.write_ty(id, fcx.infcx().next_diverging_ty_var());
3458 ast::ExprParen(ref a) => {
3459 check_expr_with_expectation_and_lvalue_pref(fcx,
3463 fcx.write_ty(id, fcx.expr_ty(&**a));
3465 ast::ExprAssign(ref lhs, ref rhs) => {
3466 check_expr_with_lvalue_pref(fcx, &**lhs, PreferMutLvalue);
3468 let tcx = fcx.tcx();
3469 if !tcx.expr_is_lval(&**lhs) {
3470 span_err!(tcx.sess, expr.span, E0070,
3471 "invalid left-hand side expression");
3474 let lhs_ty = fcx.expr_ty(&**lhs);
3475 check_expr_coercable_to_type(fcx, &**rhs, lhs_ty);
3476 let rhs_ty = fcx.expr_ty(&**rhs);
3478 fcx.require_expr_have_sized_type(&**lhs, traits::AssignmentLhsSized);
3480 if lhs_ty.references_error() || rhs_ty.references_error() {
3481 fcx.write_error(id);
3486 ast::ExprIf(ref cond, ref then_blk, ref opt_else_expr) => {
3487 check_then_else(fcx, &**cond, &**then_blk, opt_else_expr.as_ref().map(|e| &**e),
3488 id, expr.span, expected);
3490 ast::ExprIfLet(..) => {
3491 tcx.sess.span_bug(expr.span, "non-desugared ExprIfLet");
3493 ast::ExprWhile(ref cond, ref body, _) => {
3494 check_expr_has_type(fcx, &**cond, tcx.types.bool);
3495 check_block_no_value(fcx, &**body);
3496 let cond_ty = fcx.expr_ty(&**cond);
3497 let body_ty = fcx.node_ty(body.id);
3498 if cond_ty.references_error() || body_ty.references_error() {
3499 fcx.write_error(id);
3505 ast::ExprWhileLet(..) => {
3506 tcx.sess.span_bug(expr.span, "non-desugared ExprWhileLet");
3508 ast::ExprForLoop(..) => {
3509 tcx.sess.span_bug(expr.span, "non-desugared ExprForLoop");
3511 ast::ExprLoop(ref body, _) => {
3512 check_block_no_value(fcx, &**body);
3513 if !may_break(tcx, expr.id, &**body) {
3514 fcx.write_ty(id, fcx.infcx().next_diverging_ty_var());
3519 ast::ExprMatch(ref discrim, ref arms, match_src) => {
3520 _match::check_match(fcx, expr, &**discrim, arms, expected, match_src);
3522 ast::ExprClosure(capture, ref decl, ref body) => {
3523 closure::check_expr_closure(fcx, expr, capture, &**decl, &**body, expected);
3525 ast::ExprBlock(ref b) => {
3526 check_block_with_expected(fcx, &**b, expected);
3527 fcx.write_ty(id, fcx.node_ty(b.id));
3529 ast::ExprCall(ref callee, ref args) => {
3530 callee::check_call(fcx, expr, &**callee, &args[..], expected);
3532 ast::ExprMethodCall(ident, ref tps, ref args) => {
3533 check_method_call(fcx, expr, ident, &args[..], &tps[..], expected, lvalue_pref);
3534 let arg_tys = args.iter().map(|a| fcx.expr_ty(&**a));
3535 let args_err = arg_tys.fold(false,
3537 rest_err || a.references_error()});
3539 fcx.write_error(id);
3542 ast::ExprCast(ref e, ref t) => {
3543 if let ast::TyFixedLengthVec(_, ref count_expr) = t.node {
3544 check_expr_with_hint(fcx, &**count_expr, tcx.types.usize);
3547 // Find the type of `e`. Supply hints based on the type we are casting to,
3549 let t_cast = fcx.to_ty(t);
3550 let t_cast = structurally_resolved_type(fcx, expr.span, t_cast);
3551 check_expr_with_expectation(fcx, e, ExpectCastableToType(t_cast));
3552 let t_expr = fcx.expr_ty(e);
3554 // Eagerly check for some obvious errors.
3555 if t_expr.references_error() {
3556 fcx.write_error(id);
3557 } else if !fcx.type_is_known_to_be_sized(t_cast, expr.span) {
3558 report_cast_to_unsized_type(fcx, expr.span, t.span, e.span, t_cast, t_expr, id);
3560 // Write a type for the whole expression, assuming everything is going
3562 fcx.write_ty(id, t_cast);
3564 // Defer other checks until we're done type checking.
3565 let mut deferred_cast_checks = fcx.inh.deferred_cast_checks.borrow_mut();
3566 let cast_check = cast::CastCheck::new((**e).clone(), t_expr, t_cast, expr.span);
3567 deferred_cast_checks.push(cast_check);
3570 ast::ExprVec(ref args) => {
3571 let uty = expected.to_option(fcx).and_then(|uty| {
3573 ty::TyArray(ty, _) | ty::TySlice(ty) => Some(ty),
3578 let typ = match uty {
3581 check_expr_coercable_to_type(fcx, &**e, uty);
3586 let t: Ty = fcx.infcx().next_ty_var();
3588 check_expr_has_type(fcx, &**e, t);
3593 let typ = tcx.mk_array(typ, args.len());
3594 fcx.write_ty(id, typ);
3596 ast::ExprRepeat(ref element, ref count_expr) => {
3597 check_expr_has_type(fcx, &**count_expr, tcx.types.usize);
3598 let count = fcx.tcx().eval_repeat_count(&**count_expr);
3600 let uty = match expected {
3601 ExpectHasType(uty) => {
3603 ty::TyArray(ty, _) | ty::TySlice(ty) => Some(ty),
3610 let (element_ty, t) = match uty {
3612 check_expr_coercable_to_type(fcx, &**element, uty);
3616 let t: Ty = fcx.infcx().next_ty_var();
3617 check_expr_has_type(fcx, &**element, t);
3618 (fcx.expr_ty(&**element), t)
3623 // For [foo, ..n] where n > 1, `foo` must have
3625 fcx.require_type_meets(
3632 if element_ty.references_error() {
3633 fcx.write_error(id);
3635 let t = tcx.mk_array(t, count);
3636 fcx.write_ty(id, t);
3639 ast::ExprTup(ref elts) => {
3640 let flds = expected.only_has_type(fcx).and_then(|ty| {
3642 ty::TyTuple(ref flds) => Some(&flds[..]),
3646 let mut err_field = false;
3648 let elt_ts = elts.iter().enumerate().map(|(i, e)| {
3649 let t = match flds {
3650 Some(ref fs) if i < fs.len() => {
3652 check_expr_coercable_to_type(fcx, &**e, ety);
3656 check_expr_with_expectation(fcx, &**e, NoExpectation);
3660 err_field = err_field || t.references_error();
3664 fcx.write_error(id);
3666 let typ = tcx.mk_tup(elt_ts);
3667 fcx.write_ty(id, typ);
3670 ast::ExprStruct(ref path, ref fields, ref base_expr) => {
3671 // Resolve the path.
3672 let def = lookup_full_def(tcx, path.span, id);
3673 let struct_id = match def {
3674 def::DefVariant(enum_id, variant_id, true) => {
3675 if let &Some(ref base_expr) = base_expr {
3676 span_err!(tcx.sess, base_expr.span, E0436,
3677 "functional record update syntax requires a struct");
3678 fcx.write_error(base_expr.id);
3680 check_struct_enum_variant(fcx, id, expr.span, enum_id,
3681 variant_id, &fields[..]);
3684 def::DefTrait(def_id) => {
3685 span_err!(tcx.sess, path.span, E0159,
3686 "use of trait `{}` as a struct constructor",
3687 pprust::path_to_string(path));
3688 check_struct_fields_on_error(fcx,
3695 // Verify that this was actually a struct.
3696 let typ = fcx.ccx.tcx.lookup_item_type(def.def_id());
3698 ty::TyStruct(struct_did, _) => {
3699 check_struct_constructor(fcx,
3704 base_expr.as_ref().map(|e| &**e));
3707 span_err!(tcx.sess, path.span, E0071,
3708 "`{}` does not name a structure",
3709 pprust::path_to_string(path));
3710 check_struct_fields_on_error(fcx,
3721 // Turn the path into a type and verify that that type unifies with
3722 // the resulting structure type. This is needed to handle type
3723 // parameters correctly.
3724 let actual_structure_type = fcx.expr_ty(&*expr);
3725 if !actual_structure_type.references_error() {
3726 let type_and_substs = fcx.instantiate_struct_literal_ty(struct_id, path);
3727 match fcx.mk_subty(false,
3728 infer::Misc(path.span),
3729 actual_structure_type,
3730 type_and_substs.ty) {
3732 Err(type_error) => {
3733 span_err!(fcx.tcx().sess, path.span, E0235,
3734 "structure constructor specifies a \
3735 structure of type `{}`, but this \
3736 structure has type `{}`: {}",
3738 .ty_to_string(type_and_substs.ty),
3741 actual_structure_type),
3743 tcx.note_and_explain_type_err(&type_error, path.span);
3748 fcx.require_expr_have_sized_type(expr, traits::StructInitializerSized);
3750 ast::ExprField(ref base, ref field) => {
3751 check_field(fcx, expr, lvalue_pref, &**base, field);
3753 ast::ExprTupField(ref base, idx) => {
3754 check_tup_field(fcx, expr, lvalue_pref, &**base, idx);
3756 ast::ExprIndex(ref base, ref idx) => {
3757 check_expr_with_lvalue_pref(fcx, &**base, lvalue_pref);
3758 check_expr(fcx, &**idx);
3760 let base_t = fcx.expr_ty(&**base);
3761 let idx_t = fcx.expr_ty(&**idx);
3763 if base_t.references_error() {
3764 fcx.write_ty(id, base_t);
3765 } else if idx_t.references_error() {
3766 fcx.write_ty(id, idx_t);
3768 let base_t = structurally_resolved_type(fcx, expr.span, base_t);
3769 match lookup_indexing(fcx, expr, base, base_t, idx_t, lvalue_pref) {
3770 Some((index_ty, element_ty)) => {
3771 let idx_expr_ty = fcx.expr_ty(idx);
3772 demand::eqtype(fcx, expr.span, index_ty, idx_expr_ty);
3773 fcx.write_ty(id, element_ty);
3776 check_expr_has_type(fcx, &**idx, fcx.tcx().types.err);
3777 fcx.type_error_message(
3780 format!("cannot index a value of type `{}`",
3785 fcx.write_ty(id, fcx.tcx().types.err);
3790 ast::ExprRange(ref start, ref end) => {
3791 let t_start = start.as_ref().map(|e| {
3792 check_expr(fcx, &**e);
3795 let t_end = end.as_ref().map(|e| {
3796 check_expr(fcx, &**e);
3800 let idx_type = match (t_start, t_end) {
3801 (Some(ty), None) | (None, Some(ty)) => {
3804 (Some(t_start), Some(t_end)) if (t_start.references_error() ||
3805 t_end.references_error()) => {
3806 Some(fcx.tcx().types.err)
3808 (Some(t_start), Some(t_end)) => {
3809 Some(infer::common_supertype(fcx.infcx(),
3810 infer::RangeExpression(expr.span),
3818 // Note that we don't check the type of start/end satisfy any
3819 // bounds because right now the range structs do not have any. If we add
3820 // some bounds, then we'll need to check `t_start` against them here.
3822 let range_type = match idx_type {
3823 Some(idx_type) if idx_type.references_error() => {
3827 // Find the did from the appropriate lang item.
3828 let did = match (start, end) {
3829 (&Some(_), &Some(_)) => tcx.lang_items.range_struct(),
3830 (&Some(_), &None) => tcx.lang_items.range_from_struct(),
3831 (&None, &Some(_)) => tcx.lang_items.range_to_struct(),
3833 tcx.sess.span_bug(expr.span, "full range should be dealt with above")
3837 if let Some(did) = did {
3838 let predicates = tcx.lookup_predicates(did);
3839 let substs = Substs::new_type(vec![idx_type], vec![]);
3840 let bounds = fcx.instantiate_bounds(expr.span, &substs, &predicates);
3841 fcx.add_obligations_for_parameters(
3842 traits::ObligationCause::new(expr.span,
3844 traits::ItemObligation(did)),
3847 tcx.mk_struct(did, tcx.mk_substs(substs))
3849 span_err!(tcx.sess, expr.span, E0236, "no lang item for range syntax");
3854 // Neither start nor end => RangeFull
3855 if let Some(did) = tcx.lang_items.range_full_struct() {
3856 let substs = Substs::new_type(vec![], vec![]);
3857 tcx.mk_struct(did, tcx.mk_substs(substs))
3859 span_err!(tcx.sess, expr.span, E0237, "no lang item for range syntax");
3865 fcx.write_ty(id, range_type);
3870 debug!("type of expr({}) {} is...", expr.id,
3871 syntax::print::pprust::expr_to_string(expr));
3872 debug!("... {:?}, expected is {:?}",
3879 pub fn resolve_ty_and_def_ufcs<'a, 'b, 'tcx>(fcx: &FnCtxt<'b, 'tcx>,
3880 path_res: def::PathResolution,
3881 opt_self_ty: Option<Ty<'tcx>>,
3882 path: &'a ast::Path,
3884 node_id: ast::NodeId)
3885 -> Option<(Option<Ty<'tcx>>,
3886 &'a [ast::PathSegment],
3890 // Associated constants can't depend on generic types.
3891 fn have_disallowed_generic_consts<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
3895 node_id: ast::NodeId) -> bool {
3897 def::DefAssociatedConst(..) => {
3898 if ty.has_param_types() || ty.has_self_ty() {
3899 span_err!(fcx.sess(), span, E0329,
3900 "Associated consts cannot depend \
3901 on type parameters or Self.");
3902 fcx.write_error(node_id);
3911 // If fully resolved already, we don't have to do anything.
3912 if path_res.depth == 0 {
3913 if let Some(ty) = opt_self_ty {
3914 if have_disallowed_generic_consts(fcx, path_res.full_def(), ty,
3919 Some((opt_self_ty, &path.segments, path_res.base_def))
3921 let mut def = path_res.base_def;
3922 let ty_segments = path.segments.split_last().unwrap().1;
3923 let base_ty_end = path.segments.len() - path_res.depth;
3924 let ty = astconv::finish_resolving_def_to_ty(fcx, fcx, span,
3925 PathParamMode::Optional,
3928 &ty_segments[..base_ty_end],
3929 &ty_segments[base_ty_end..]);
3930 let item_segment = path.segments.last().unwrap();
3931 let item_name = item_segment.identifier.name;
3932 match method::resolve_ufcs(fcx, span, item_name, ty, node_id) {
3934 if have_disallowed_generic_consts(fcx, def, ty, span, node_id) {
3937 // Write back the new resolution.
3938 fcx.ccx.tcx.def_map.borrow_mut()
3939 .insert(node_id, def::PathResolution {
3941 last_private: path_res.last_private.or(lp),
3944 Some((Some(ty), slice::ref_slice(item_segment), def))
3947 method::report_error(fcx, span, ty,
3948 item_name, None, error);
3949 fcx.write_error(node_id);
3956 fn constrain_path_type_parameters(fcx: &FnCtxt,
3959 fcx.opt_node_ty_substs(expr.id, |item_substs| {
3960 fcx.add_default_region_param_bounds(&item_substs.substs, expr);
3964 impl<'tcx> Expectation<'tcx> {
3965 /// Provide an expectation for an rvalue expression given an *optional*
3966 /// hint, which is not required for type safety (the resulting type might
3967 /// be checked higher up, as is the case with `&expr` and `box expr`), but
3968 /// is useful in determining the concrete type.
3970 /// The primary use case is where the expected type is a fat pointer,
3971 /// like `&[isize]`. For example, consider the following statement:
3973 /// let x: &[isize] = &[1, 2, 3];
3975 /// In this case, the expected type for the `&[1, 2, 3]` expression is
3976 /// `&[isize]`. If however we were to say that `[1, 2, 3]` has the
3977 /// expectation `ExpectHasType([isize])`, that would be too strong --
3978 /// `[1, 2, 3]` does not have the type `[isize]` but rather `[isize; 3]`.
3979 /// It is only the `&[1, 2, 3]` expression as a whole that can be coerced
3980 /// to the type `&[isize]`. Therefore, we propagate this more limited hint,
3981 /// which still is useful, because it informs integer literals and the like.
3982 /// See the test case `test/run-pass/coerce-expect-unsized.rs` and #20169
3983 /// for examples of where this comes up,.
3984 fn rvalue_hint(tcx: &ty::ctxt<'tcx>, ty: Ty<'tcx>) -> Expectation<'tcx> {
3985 match tcx.struct_tail(ty).sty {
3986 ty::TySlice(_) | ty::TyTrait(..) => {
3987 ExpectRvalueLikeUnsized(ty)
3989 _ => ExpectHasType(ty)
3993 // Resolves `expected` by a single level if it is a variable. If
3994 // there is no expected type or resolution is not possible (e.g.,
3995 // no constraints yet present), just returns `None`.
3996 fn resolve<'a>(self, fcx: &FnCtxt<'a, 'tcx>) -> Expectation<'tcx> {
4001 ExpectCastableToType(t) => {
4002 ExpectCastableToType(
4003 fcx.infcx().resolve_type_vars_if_possible(&t))
4005 ExpectHasType(t) => {
4007 fcx.infcx().resolve_type_vars_if_possible(&t))
4009 ExpectRvalueLikeUnsized(t) => {
4010 ExpectRvalueLikeUnsized(
4011 fcx.infcx().resolve_type_vars_if_possible(&t))
4016 fn to_option<'a>(self, fcx: &FnCtxt<'a, 'tcx>) -> Option<Ty<'tcx>> {
4017 match self.resolve(fcx) {
4018 NoExpectation => None,
4019 ExpectCastableToType(ty) |
4021 ExpectRvalueLikeUnsized(ty) => Some(ty),
4025 fn only_has_type<'a>(self, fcx: &FnCtxt<'a, 'tcx>) -> Option<Ty<'tcx>> {
4026 match self.resolve(fcx) {
4027 ExpectHasType(ty) => Some(ty),
4033 pub fn check_decl_initializer<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
4034 local: &'tcx ast::Local,
4035 init: &'tcx ast::Expr)
4037 let ref_bindings = fcx.tcx().pat_contains_ref_binding(&local.pat);
4039 let local_ty = fcx.local_ty(init.span, local.id);
4040 if let Some(m) = ref_bindings {
4041 // Somewhat subtle: if we have a `ref` binding in the pattern,
4042 // we want to avoid introducing coercions for the RHS. This is
4043 // both because it helps preserve sanity and, in the case of
4044 // ref mut, for soundness (issue #23116). In particular, in
4045 // the latter case, we need to be clear that the type of the
4046 // referent for the reference that results is *equal to* the
4047 // type of the lvalue it is referencing, and not some
4048 // supertype thereof.
4049 check_expr_with_lvalue_pref(fcx, init, LvaluePreference::from_mutbl(m));
4050 let init_ty = fcx.expr_ty(init);
4051 demand::eqtype(fcx, init.span, init_ty, local_ty);
4053 check_expr_coercable_to_type(fcx, init, local_ty)
4057 pub fn check_decl_local<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>, local: &'tcx ast::Local) {
4058 let tcx = fcx.ccx.tcx;
4060 let t = fcx.local_ty(local.span, local.id);
4061 fcx.write_ty(local.id, t);
4063 if let Some(ref init) = local.init {
4064 check_decl_initializer(fcx, local, &**init);
4065 let init_ty = fcx.expr_ty(&**init);
4066 if init_ty.references_error() {
4067 fcx.write_ty(local.id, init_ty);
4071 let pcx = pat_ctxt {
4073 map: pat_id_map(&tcx.def_map, &*local.pat),
4075 _match::check_pat(&pcx, &*local.pat, t);
4076 let pat_ty = fcx.node_ty(local.pat.id);
4077 if pat_ty.references_error() {
4078 fcx.write_ty(local.id, pat_ty);
4082 pub fn check_stmt<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>, stmt: &'tcx ast::Stmt) {
4084 let mut saw_bot = false;
4085 let mut saw_err = false;
4087 ast::StmtDecl(ref decl, id) => {
4090 ast::DeclLocal(ref l) => {
4091 check_decl_local(fcx, &**l);
4092 let l_t = fcx.node_ty(l.id);
4093 saw_bot = saw_bot || fcx.infcx().type_var_diverges(l_t);
4094 saw_err = saw_err || l_t.references_error();
4096 ast::DeclItem(_) => {/* ignore for now */ }
4099 ast::StmtExpr(ref expr, id) => {
4101 // Check with expected type of ()
4102 check_expr_has_type(fcx, &**expr, fcx.tcx().mk_nil());
4103 let expr_ty = fcx.expr_ty(&**expr);
4104 saw_bot = saw_bot || fcx.infcx().type_var_diverges(expr_ty);
4105 saw_err = saw_err || expr_ty.references_error();
4107 ast::StmtSemi(ref expr, id) => {
4109 check_expr(fcx, &**expr);
4110 let expr_ty = fcx.expr_ty(&**expr);
4111 saw_bot |= fcx.infcx().type_var_diverges(expr_ty);
4112 saw_err |= expr_ty.references_error();
4114 ast::StmtMac(..) => fcx.ccx.tcx.sess.bug("unexpanded macro")
4117 fcx.write_ty(node_id, fcx.infcx().next_diverging_ty_var());
4120 fcx.write_error(node_id);
4123 fcx.write_nil(node_id)
4127 pub fn check_block_no_value<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>, blk: &'tcx ast::Block) {
4128 check_block_with_expected(fcx, blk, ExpectHasType(fcx.tcx().mk_nil()));
4129 let blkty = fcx.node_ty(blk.id);
4130 if blkty.references_error() {
4131 fcx.write_error(blk.id);
4133 let nilty = fcx.tcx().mk_nil();
4134 demand::suptype(fcx, blk.span, nilty, blkty);
4138 fn check_block_with_expected<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
4139 blk: &'tcx ast::Block,
4140 expected: Expectation<'tcx>) {
4142 let mut fcx_ps = fcx.ps.borrow_mut();
4143 let unsafety_state = fcx_ps.recurse(blk);
4144 replace(&mut *fcx_ps, unsafety_state)
4147 let mut warned = false;
4148 let mut any_diverges = false;
4149 let mut any_err = false;
4150 for s in &blk.stmts {
4151 check_stmt(fcx, &**s);
4152 let s_id = ast_util::stmt_id(&**s);
4153 let s_ty = fcx.node_ty(s_id);
4154 if any_diverges && !warned && match s.node {
4155 ast::StmtDecl(ref decl, _) => {
4157 ast::DeclLocal(_) => true,
4161 ast::StmtExpr(_, _) | ast::StmtSemi(_, _) => true,
4167 .add_lint(lint::builtin::UNREACHABLE_CODE,
4170 "unreachable statement".to_string());
4173 any_diverges = any_diverges || fcx.infcx().type_var_diverges(s_ty);
4174 any_err = any_err || s_ty.references_error();
4177 None => if any_err {
4178 fcx.write_error(blk.id);
4179 } else if any_diverges {
4180 fcx.write_ty(blk.id, fcx.infcx().next_diverging_ty_var());
4182 fcx.write_nil(blk.id);
4185 if any_diverges && !warned {
4189 .add_lint(lint::builtin::UNREACHABLE_CODE,
4192 "unreachable expression".to_string());
4194 let ety = match expected {
4195 ExpectHasType(ety) => {
4196 check_expr_coercable_to_type(fcx, &**e, ety);
4200 check_expr_with_expectation(fcx, &**e, expected);
4206 fcx.write_error(blk.id);
4207 } else if any_diverges {
4208 fcx.write_ty(blk.id, fcx.infcx().next_diverging_ty_var());
4210 fcx.write_ty(blk.id, ety);
4215 *fcx.ps.borrow_mut() = prev;
4218 /// Checks a constant appearing in a type. At the moment this is just the
4219 /// length expression in a fixed-length vector, but someday it might be
4220 /// extended to type-level numeric literals.
4221 fn check_const_in_type<'a,'tcx>(ccx: &'a CrateCtxt<'a,'tcx>,
4222 expr: &'tcx ast::Expr,
4223 expected_type: Ty<'tcx>) {
4224 let tables = RefCell::new(ty::Tables::empty());
4225 let inh = static_inherited_fields(ccx, &tables);
4226 let fcx = blank_fn_ctxt(ccx, &inh, ty::FnConverging(expected_type), expr.id);
4227 check_const_with_ty(&fcx, expr.span, expr, expected_type);
4230 fn check_const<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
4234 let tables = RefCell::new(ty::Tables::empty());
4235 let inh = static_inherited_fields(ccx, &tables);
4236 let rty = ccx.tcx.node_id_to_type(id);
4237 let fcx = blank_fn_ctxt(ccx, &inh, ty::FnConverging(rty), e.id);
4238 let declty = fcx.ccx.tcx.lookup_item_type(local_def(id)).ty;
4239 check_const_with_ty(&fcx, sp, e, declty);
4242 fn check_const_with_ty<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
4246 // Gather locals in statics (because of block expressions).
4247 // This is technically unnecessary because locals in static items are forbidden,
4248 // but prevents type checking from blowing up before const checking can properly
4250 GatherLocalsVisitor { fcx: fcx }.visit_expr(e);
4252 check_expr_with_hint(fcx, e, declty);
4253 demand::coerce(fcx, e.span, declty, e);
4254 fcx.select_all_obligations_or_error();
4256 regionck::regionck_expr(fcx, e);
4257 writeback::resolve_type_vars_in_expr(fcx, e);
4260 /// Checks whether a type can be represented in memory. In particular, it
4261 /// identifies types that contain themselves without indirection through a
4262 /// pointer, which would mean their size is unbounded.
4263 pub fn check_representable(tcx: &ty::ctxt,
4265 item_id: ast::NodeId,
4266 designation: &str) -> bool {
4267 let rty = tcx.node_id_to_type(item_id);
4269 // Check that it is possible to represent this type. This call identifies
4270 // (1) types that contain themselves and (2) types that contain a different
4271 // recursive type. It is only necessary to throw an error on those that
4272 // contain themselves. For case 2, there must be an inner type that will be
4273 // caught by case 1.
4274 match rty.is_representable(tcx, sp) {
4275 ty::SelfRecursive => {
4276 span_err!(tcx.sess, sp, E0072, "invalid recursive {} type", designation);
4277 tcx.sess.fileline_help(sp, "wrap the inner value in a box to make it representable");
4280 ty::Representable | ty::ContainsRecursive => (),
4285 /// Checks whether a type can be constructed at runtime without
4286 /// an existing instance of that type.
4287 pub fn check_instantiable(tcx: &ty::ctxt,
4289 item_id: ast::NodeId) {
4290 let item_ty = tcx.node_id_to_type(item_id);
4291 if !item_ty.is_instantiable(tcx) &&
4292 !tcx.sess.features.borrow().static_recursion {
4293 emit_feature_err(&tcx.sess.parse_sess.span_diagnostic,
4296 "this type cannot be instantiated at runtime \
4297 without an instance of itself");
4301 pub fn check_simd(tcx: &ty::ctxt, sp: Span, id: ast::NodeId) {
4302 let t = tcx.node_id_to_type(id);
4303 if t.needs_subst() {
4304 span_err!(tcx.sess, sp, E0074, "SIMD vector cannot be generic");
4308 ty::TyStruct(did, substs) => {
4309 let fields = tcx.lookup_struct_fields(did);
4310 if fields.is_empty() {
4311 span_err!(tcx.sess, sp, E0075, "SIMD vector cannot be empty");
4314 let e = tcx.lookup_field_type(did, fields[0].id, substs);
4315 if !fields.iter().all(
4316 |f| tcx.lookup_field_type(did, f.id, substs) == e) {
4317 span_err!(tcx.sess, sp, E0076, "SIMD vector should be homogeneous");
4320 if !e.is_machine() {
4321 span_err!(tcx.sess, sp, E0077,
4322 "SIMD vector element type should be machine type");
4330 pub fn check_enum_variants<'a,'tcx>(ccx: &CrateCtxt<'a,'tcx>,
4332 vs: &'tcx [P<ast::Variant>],
4335 fn disr_in_range(ccx: &CrateCtxt,
4337 disr: ty::Disr) -> bool {
4338 fn uint_in_range(ccx: &CrateCtxt, ty: ast::UintTy, disr: ty::Disr) -> bool {
4340 ast::TyU8 => disr as u8 as Disr == disr,
4341 ast::TyU16 => disr as u16 as Disr == disr,
4342 ast::TyU32 => disr as u32 as Disr == disr,
4343 ast::TyU64 => disr as u64 as Disr == disr,
4344 ast::TyUs => uint_in_range(ccx, ccx.tcx.sess.target.uint_type, disr)
4347 fn int_in_range(ccx: &CrateCtxt, ty: ast::IntTy, disr: ty::Disr) -> bool {
4349 ast::TyI8 => disr as i8 as Disr == disr,
4350 ast::TyI16 => disr as i16 as Disr == disr,
4351 ast::TyI32 => disr as i32 as Disr == disr,
4352 ast::TyI64 => disr as i64 as Disr == disr,
4353 ast::TyIs => int_in_range(ccx, ccx.tcx.sess.target.int_type, disr)
4357 attr::UnsignedInt(ty) => uint_in_range(ccx, ty, disr),
4358 attr::SignedInt(ty) => int_in_range(ccx, ty, disr)
4362 fn do_check<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
4363 vs: &'tcx [P<ast::Variant>],
4365 hint: attr::ReprAttr) {
4366 #![allow(trivial_numeric_casts)]
4368 let rty = ccx.tcx.node_id_to_type(id);
4369 let mut disr_vals: Vec<ty::Disr> = Vec::new();
4371 let tables = RefCell::new(ty::Tables::empty());
4372 let inh = static_inherited_fields(ccx, &tables);
4373 let fcx = blank_fn_ctxt(ccx, &inh, ty::FnConverging(rty), id);
4375 let (_, repr_type_ty) = ccx.tcx.enum_repr_type(Some(&hint));
4377 if let Some(ref e) = v.node.disr_expr {
4378 check_const_with_ty(&fcx, e.span, e, repr_type_ty);
4382 let def_id = local_def(id);
4384 // ty::enum_variants guards against discriminant overflows, so
4385 // we need not check for that.
4386 let variants = ccx.tcx.enum_variants(def_id);
4388 for (v, variant) in vs.iter().zip(variants.iter()) {
4389 let current_disr_val = variant.disr_val;
4391 // Check for duplicate discriminant values
4392 match disr_vals.iter().position(|&x| x == current_disr_val) {
4394 span_err!(ccx.tcx.sess, v.span, E0081,
4395 "discriminant value `{}` already exists", disr_vals[i]);
4396 span_note!(ccx.tcx.sess, ccx.tcx.map.span(variants[i].id.node),
4397 "conflicting discriminant here")
4401 // Check for unrepresentable discriminant values
4403 attr::ReprAny | attr::ReprExtern => (),
4404 attr::ReprInt(sp, ity) => {
4405 if !disr_in_range(ccx, ity, current_disr_val) {
4406 span_err!(ccx.tcx.sess, v.span, E0082,
4407 "discriminant value outside specified type");
4408 span_note!(ccx.tcx.sess, sp,
4409 "discriminant type specified here");
4412 attr::ReprPacked => {
4413 ccx.tcx.sess.bug("range_to_inttype: found ReprPacked on an enum");
4416 disr_vals.push(current_disr_val);
4420 let hint = *ccx.tcx.lookup_repr_hints(ast::DefId { krate: ast::LOCAL_CRATE, node: id })
4421 .get(0).unwrap_or(&attr::ReprAny);
4423 if hint != attr::ReprAny && vs.len() <= 1 {
4425 span_err!(ccx.tcx.sess, sp, E0083,
4426 "unsupported representation for univariant enum");
4428 span_err!(ccx.tcx.sess, sp, E0084,
4429 "unsupported representation for zero-variant enum");
4433 do_check(ccx, vs, id, hint);
4435 check_representable(ccx.tcx, sp, id, "enum");
4436 check_instantiable(ccx.tcx, sp, id);
4439 // Returns the type parameter count and the type for the given definition.
4440 fn type_scheme_and_predicates_for_def<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
4443 -> (TypeScheme<'tcx>, GenericPredicates<'tcx>) {
4445 def::DefLocal(nid) | def::DefUpvar(nid, _) => {
4446 let typ = fcx.local_ty(sp, nid);
4447 (ty::TypeScheme { generics: ty::Generics::empty(), ty: typ },
4448 ty::GenericPredicates::empty())
4450 def::DefFn(id, _) | def::DefMethod(id, _) |
4451 def::DefStatic(id, _) | def::DefVariant(_, id, _) |
4452 def::DefStruct(id) | def::DefConst(id) | def::DefAssociatedConst(id, _) => {
4453 (fcx.tcx().lookup_item_type(id), fcx.tcx().lookup_predicates(id))
4457 def::DefAssociatedTy(..) |
4459 def::DefTyParam(..) |
4461 def::DefForeignMod(..) |
4463 def::DefRegion(..) |
4465 def::DefSelfTy(..) => {
4466 fcx.ccx.tcx.sess.span_bug(sp, &format!("expected value, found {:?}", defn));
4471 // Instantiates the given path, which must refer to an item with the given
4472 // number of type parameters and type.
4473 pub fn instantiate_path<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
4474 segments: &[ast::PathSegment],
4475 type_scheme: TypeScheme<'tcx>,
4476 type_predicates: &ty::GenericPredicates<'tcx>,
4477 opt_self_ty: Option<Ty<'tcx>>,
4480 node_id: ast::NodeId) {
4481 debug!("instantiate_path(path={:?}, def={:?}, node_id={}, type_scheme={:?})",
4487 // We need to extract the type parameters supplied by the user in
4488 // the path `path`. Due to the current setup, this is a bit of a
4489 // tricky-process; the problem is that resolve only tells us the
4490 // end-point of the path resolution, and not the intermediate steps.
4491 // Luckily, we can (at least for now) deduce the intermediate steps
4492 // just from the end-point.
4494 // There are basically four cases to consider:
4496 // 1. Reference to a *type*, such as a struct or enum:
4498 // mod a { struct Foo<T> { ... } }
4500 // Because we don't allow types to be declared within one
4501 // another, a path that leads to a type will always look like
4502 // `a::b::Foo<T>` where `a` and `b` are modules. This implies
4503 // that only the final segment can have type parameters, and
4504 // they are located in the TypeSpace.
4506 // *Note:* Generally speaking, references to types don't
4507 // actually pass through this function, but rather the
4508 // `ast_ty_to_ty` function in `astconv`. However, in the case
4509 // of struct patterns (and maybe literals) we do invoke
4510 // `instantiate_path` to get the general type of an instance of
4511 // a struct. (In these cases, there are actually no type
4512 // parameters permitted at present, but perhaps we will allow
4513 // them in the future.)
4515 // 1b. Reference to a enum variant or tuple-like struct:
4517 // struct foo<T>(...)
4518 // enum E<T> { foo(...) }
4520 // In these cases, the parameters are declared in the type
4523 // 2. Reference to a *fn item*:
4527 // In this case, the path will again always have the form
4528 // `a::b::foo::<T>` where only the final segment should have
4529 // type parameters. However, in this case, those parameters are
4530 // declared on a value, and hence are in the `FnSpace`.
4532 // 3. Reference to a *method*:
4534 // impl<A> SomeStruct<A> {
4538 // Here we can have a path like
4539 // `a::b::SomeStruct::<A>::foo::<B>`, in which case parameters
4540 // may appear in two places. The penultimate segment,
4541 // `SomeStruct::<A>`, contains parameters in TypeSpace, and the
4542 // final segment, `foo::<B>` contains parameters in fn space.
4544 // 4. Reference to an *associated const*:
4546 // impl<A> AnotherStruct<A> {
4547 // const FOO: B = BAR;
4550 // The path in this case will look like
4551 // `a::b::AnotherStruct::<A>::FOO`, so the penultimate segment
4552 // only will have parameters in TypeSpace.
4554 // The first step then is to categorize the segments appropriately.
4556 assert!(!segments.is_empty());
4558 let mut ufcs_method = None;
4559 let mut segment_spaces: Vec<_>;
4561 // Case 1 and 1b. Reference to a *type* or *enum variant*.
4562 def::DefSelfTy(..) |
4563 def::DefStruct(..) |
4564 def::DefVariant(..) |
4566 def::DefAssociatedTy(..) |
4568 def::DefPrimTy(..) |
4569 def::DefTyParam(..) => {
4570 // Everything but the final segment should have no
4571 // parameters at all.
4572 segment_spaces = vec![None; segments.len() - 1];
4573 segment_spaces.push(Some(subst::TypeSpace));
4576 // Case 2. Reference to a top-level value.
4579 def::DefStatic(..) => {
4580 segment_spaces = vec![None; segments.len() - 1];
4581 segment_spaces.push(Some(subst::FnSpace));
4584 // Case 3. Reference to a method.
4585 def::DefMethod(_, provenance) => {
4587 def::FromTrait(trait_did) => {
4588 callee::check_legal_trait_for_method_call(fcx.ccx, span, trait_did)
4590 def::FromImpl(_) => {}
4593 if segments.len() >= 2 {
4594 segment_spaces = vec![None; segments.len() - 2];
4595 segment_spaces.push(Some(subst::TypeSpace));
4596 segment_spaces.push(Some(subst::FnSpace));
4598 // `<T>::method` will end up here, and so can `T::method`.
4599 let self_ty = opt_self_ty.expect("UFCS sugared method missing Self");
4600 segment_spaces = vec![Some(subst::FnSpace)];
4601 ufcs_method = Some((provenance, self_ty));
4605 def::DefAssociatedConst(_, provenance) => {
4607 def::FromTrait(trait_did) => {
4608 callee::check_legal_trait_for_method_call(fcx.ccx, span, trait_did)
4610 def::FromImpl(_) => {}
4613 if segments.len() >= 2 {
4614 segment_spaces = vec![None; segments.len() - 2];
4615 segment_spaces.push(Some(subst::TypeSpace));
4616 segment_spaces.push(None);
4618 segment_spaces = vec![None];
4622 // Other cases. Various nonsense that really shouldn't show up
4623 // here. If they do, an error will have been reported
4624 // elsewhere. (I hope)
4626 def::DefForeignMod(..) |
4629 def::DefRegion(..) |
4631 def::DefUpvar(..) => {
4632 segment_spaces = vec![None; segments.len()];
4635 assert_eq!(segment_spaces.len(), segments.len());
4637 // In `<T as Trait<A, B>>::method`, `A` and `B` are mandatory, but
4638 // `opt_self_ty` can also be Some for `Foo::method`, where Foo's
4639 // type parameters are not mandatory.
4640 let require_type_space = opt_self_ty.is_some() && ufcs_method.is_none();
4642 debug!("segment_spaces={:?}", segment_spaces);
4644 // Next, examine the definition, and determine how many type
4645 // parameters we expect from each space.
4646 let type_defs = &type_scheme.generics.types;
4647 let region_defs = &type_scheme.generics.regions;
4649 // Now that we have categorized what space the parameters for each
4650 // segment belong to, let's sort out the parameters that the user
4651 // provided (if any) into their appropriate spaces. We'll also report
4652 // errors if type parameters are provided in an inappropriate place.
4653 let mut substs = Substs::empty();
4654 for (opt_space, segment) in segment_spaces.iter().zip(segments) {
4657 check_path_args(fcx.tcx(), slice::ref_slice(segment),
4658 NO_TPS | NO_REGIONS);
4662 push_explicit_parameters_from_segment_to_substs(fcx,
4672 if let Some(self_ty) = opt_self_ty {
4673 if type_defs.len(subst::SelfSpace) == 1 {
4674 substs.types.push(subst::SelfSpace, self_ty);
4678 // Now we have to compare the types that the user *actually*
4679 // provided against the types that were *expected*. If the user
4680 // did not provide any types, then we want to substitute inference
4681 // variables. If the user provided some types, we may still need
4682 // to add defaults. If the user provided *too many* types, that's
4684 for &space in &[subst::SelfSpace, subst::TypeSpace, subst::FnSpace] {
4685 adjust_type_parameters(fcx, span, space, type_defs,
4686 require_type_space, &mut substs);
4687 assert_eq!(substs.types.len(space), type_defs.len(space));
4689 adjust_region_parameters(fcx, span, space, region_defs, &mut substs);
4690 assert_eq!(substs.regions().len(space), region_defs.len(space));
4693 // The things we are substituting into the type should not contain
4694 // escaping late-bound regions, and nor should the base type scheme.
4695 assert!(!substs.has_regions_escaping_depth(0));
4696 assert!(!type_scheme.has_escaping_regions());
4698 // Add all the obligations that are required, substituting and
4699 // normalized appropriately.
4700 let bounds = fcx.instantiate_bounds(span, &substs, &type_predicates);
4701 fcx.add_obligations_for_parameters(
4702 traits::ObligationCause::new(span, fcx.body_id, traits::ItemObligation(def.def_id())),
4705 // Substitute the values for the type parameters into the type of
4706 // the referenced item.
4707 let ty_substituted = fcx.instantiate_type_scheme(span, &substs, &type_scheme.ty);
4710 if let Some((def::FromImpl(impl_def_id), self_ty)) = ufcs_method {
4711 // In the case of `Foo<T>::method` and `<Foo<T>>::method`, if `method`
4712 // is inherent, there is no `Self` parameter, instead, the impl needs
4713 // type parameters, which we can infer by unifying the provided `Self`
4714 // with the substituted impl type.
4715 let impl_scheme = fcx.tcx().lookup_item_type(impl_def_id);
4716 assert_eq!(substs.types.len(subst::TypeSpace),
4717 impl_scheme.generics.types.len(subst::TypeSpace));
4718 assert_eq!(substs.regions().len(subst::TypeSpace),
4719 impl_scheme.generics.regions.len(subst::TypeSpace));
4721 let impl_ty = fcx.instantiate_type_scheme(span, &substs, &impl_scheme.ty);
4722 if fcx.mk_subty(false, infer::Misc(span), self_ty, impl_ty).is_err() {
4723 fcx.tcx().sess.span_bug(span,
4725 "instantiate_path: (UFCS) {:?} was a subtype of {:?} but now is not?",
4731 fcx.write_ty(node_id, ty_substituted);
4732 fcx.write_substs(node_id, ty::ItemSubsts { substs: substs });
4735 /// Finds the parameters that the user provided and adds them to `substs`. If too many
4736 /// parameters are provided, then reports an error and clears the output vector.
4738 /// We clear the output vector because that will cause the `adjust_XXX_parameters()` later to
4739 /// use inference variables. This seems less likely to lead to derived errors.
4741 /// Note that we *do not* check for *too few* parameters here. Due to the presence of defaults
4742 /// etc that is more complicated. I wanted however to do the reporting of *too many* parameters
4743 /// here because we can easily use the precise span of the N+1'th parameter.
4744 fn push_explicit_parameters_from_segment_to_substs<'a, 'tcx>(
4745 fcx: &FnCtxt<'a, 'tcx>,
4746 space: subst::ParamSpace,
4748 type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>,
4749 region_defs: &VecPerParamSpace<ty::RegionParameterDef>,
4750 segment: &ast::PathSegment,
4751 substs: &mut Substs<'tcx>)
4753 match segment.parameters {
4754 ast::AngleBracketedParameters(ref data) => {
4755 push_explicit_angle_bracketed_parameters_from_segment_to_substs(
4756 fcx, space, type_defs, region_defs, data, substs);
4759 ast::ParenthesizedParameters(ref data) => {
4760 span_err!(fcx.tcx().sess, span, E0238,
4761 "parenthesized parameters may only be used with a trait");
4762 push_explicit_parenthesized_parameters_from_segment_to_substs(
4763 fcx, space, span, type_defs, data, substs);
4768 fn push_explicit_angle_bracketed_parameters_from_segment_to_substs<'a, 'tcx>(
4769 fcx: &FnCtxt<'a, 'tcx>,
4770 space: subst::ParamSpace,
4771 type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>,
4772 region_defs: &VecPerParamSpace<ty::RegionParameterDef>,
4773 data: &ast::AngleBracketedParameterData,
4774 substs: &mut Substs<'tcx>)
4777 let type_count = type_defs.len(space);
4778 assert_eq!(substs.types.len(space), 0);
4779 for (i, typ) in data.types.iter().enumerate() {
4780 let t = fcx.to_ty(&**typ);
4782 substs.types.push(space, t);
4783 } else if i == type_count {
4784 span_err!(fcx.tcx().sess, typ.span, E0087,
4785 "too many type parameters provided: \
4786 expected at most {} parameter{}, \
4787 found {} parameter{}",
4789 if type_count == 1 {""} else {"s"},
4791 if data.types.len() == 1 {""} else {"s"});
4792 substs.types.truncate(space, 0);
4798 if !data.bindings.is_empty() {
4799 span_err!(fcx.tcx().sess, data.bindings[0].span, E0182,
4800 "unexpected binding of associated item in expression path \
4801 (only allowed in type paths)");
4805 let region_count = region_defs.len(space);
4806 assert_eq!(substs.regions().len(space), 0);
4807 for (i, lifetime) in data.lifetimes.iter().enumerate() {
4808 let r = ast_region_to_region(fcx.tcx(), lifetime);
4809 if i < region_count {
4810 substs.mut_regions().push(space, r);
4811 } else if i == region_count {
4812 span_err!(fcx.tcx().sess, lifetime.span, E0088,
4813 "too many lifetime parameters provided: \
4814 expected {} parameter{}, found {} parameter{}",
4816 if region_count == 1 {""} else {"s"},
4817 data.lifetimes.len(),
4818 if data.lifetimes.len() == 1 {""} else {"s"});
4819 substs.mut_regions().truncate(space, 0);
4827 /// `push_explicit_angle_bracketed_parameters_from_segment_to_substs`,
4828 /// but intended for `Foo(A,B) -> C` form. This expands to
4829 /// roughly the same thing as `Foo<(A,B),C>`. One important
4830 /// difference has to do with the treatment of anonymous
4831 /// regions, which are translated into bound regions (NYI).
4832 fn push_explicit_parenthesized_parameters_from_segment_to_substs<'a, 'tcx>(
4833 fcx: &FnCtxt<'a, 'tcx>,
4834 space: subst::ParamSpace,
4836 type_defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>,
4837 data: &ast::ParenthesizedParameterData,
4838 substs: &mut Substs<'tcx>)
4840 let type_count = type_defs.len(space);
4842 span_err!(fcx.tcx().sess, span, E0167,
4843 "parenthesized form always supplies 2 type parameters, \
4844 but only {} parameter(s) were expected",
4848 let input_tys: Vec<Ty> =
4849 data.inputs.iter().map(|ty| fcx.to_ty(&**ty)).collect();
4851 let tuple_ty = fcx.tcx().mk_tup(input_tys);
4853 if type_count >= 1 {
4854 substs.types.push(space, tuple_ty);
4857 let output_ty: Option<Ty> =
4858 data.output.as_ref().map(|ty| fcx.to_ty(&**ty));
4861 output_ty.unwrap_or(fcx.tcx().mk_nil());
4863 if type_count >= 2 {
4864 substs.types.push(space, output_ty);
4868 fn adjust_type_parameters<'a, 'tcx>(
4869 fcx: &FnCtxt<'a, 'tcx>,
4872 defs: &VecPerParamSpace<ty::TypeParameterDef<'tcx>>,
4873 require_type_space: bool,
4874 substs: &mut Substs<'tcx>)
4876 let provided_len = substs.types.len(space);
4877 let desired = defs.get_slice(space);
4878 let required_len = desired.iter()
4879 .take_while(|d| d.default.is_none())
4882 debug!("adjust_type_parameters(space={:?}, \
4891 // Enforced by `push_explicit_parameters_from_segment_to_substs()`.
4892 assert!(provided_len <= desired.len());
4894 // Nothing specified at all: supply inference variables for
4896 if provided_len == 0 && !(require_type_space && space == subst::TypeSpace) {
4897 substs.types.replace(space, Vec::new());
4898 fcx.infcx().type_vars_for_defs(span, space, substs, &desired[..]);
4902 // Too few parameters specified: report an error and use Err
4904 if provided_len < required_len {
4906 if desired.len() != required_len { "at least " } else { "" };
4907 span_err!(fcx.tcx().sess, span, E0089,
4908 "too few type parameters provided: expected {}{} parameter{}, \
4909 found {} parameter{}",
4910 qualifier, required_len,
4911 if required_len == 1 {""} else {"s"},
4913 if provided_len == 1 {""} else {"s"});
4914 substs.types.replace(space, vec![fcx.tcx().types.err; desired.len()]);
4918 // Otherwise, add in any optional parameters that the user
4919 // omitted. The case of *too many* parameters is handled
4921 // push_explicit_parameters_from_segment_to_substs(). Note
4922 // that the *default* type are expressed in terms of all prior
4923 // parameters, so we have to substitute as we go with the
4924 // partial substitution that we have built up.
4925 for i in provided_len..desired.len() {
4926 let default = desired[i].default.unwrap();
4927 let default = default.subst_spanned(fcx.tcx(), substs, Some(span));
4928 substs.types.push(space, default);
4930 assert_eq!(substs.types.len(space), desired.len());
4932 debug!("Final substs: {:?}", substs);
4935 fn adjust_region_parameters(
4939 defs: &VecPerParamSpace<ty::RegionParameterDef>,
4940 substs: &mut Substs)
4942 let provided_len = substs.mut_regions().len(space);
4943 let desired = defs.get_slice(space);
4945 // Enforced by `push_explicit_parameters_from_segment_to_substs()`.
4946 assert!(provided_len <= desired.len());
4948 // If nothing was provided, just use inference variables.
4949 if provided_len == 0 {
4950 substs.mut_regions().replace(
4952 fcx.infcx().region_vars_for_defs(span, desired));
4956 // If just the right number were provided, everybody is happy.
4957 if provided_len == desired.len() {
4961 // Otherwise, too few were provided. Report an error and then
4962 // use inference variables.
4963 span_err!(fcx.tcx().sess, span, E0090,
4964 "too few lifetime parameters provided: expected {} parameter{}, \
4965 found {} parameter{}",
4967 if desired.len() == 1 {""} else {"s"},
4969 if provided_len == 1 {""} else {"s"});
4971 substs.mut_regions().replace(
4973 fcx.infcx().region_vars_for_defs(span, desired));
4977 fn structurally_resolve_type_or_else<'a, 'tcx, F>(fcx: &FnCtxt<'a, 'tcx>,
4981 where F: Fn() -> Ty<'tcx>
4983 let mut ty = fcx.resolve_type_vars_if_possible(ty);
4986 let alternative = f();
4989 if alternative.is_ty_var() || alternative.references_error() {
4990 fcx.type_error_message(sp, |_actual| {
4991 "the type of this value must be known in this context".to_string()
4993 demand::suptype(fcx, sp, fcx.tcx().types.err, ty);
4994 ty = fcx.tcx().types.err;
4996 demand::suptype(fcx, sp, alternative, ty);
5004 // Resolves `typ` by a single level if `typ` is a type variable. If no
5005 // resolution is possible, then an error is reported.
5006 pub fn structurally_resolved_type<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
5011 structurally_resolve_type_or_else(fcx, sp, ty, || {
5016 // Returns true if b contains a break that can exit from b
5017 pub fn may_break(cx: &ty::ctxt, id: ast::NodeId, b: &ast::Block) -> bool {
5018 // First: is there an unlabeled break immediately
5020 (loop_query(&*b, |e| {
5022 ast::ExprBreak(None) => true,
5026 // Second: is there a labeled break with label
5027 // <id> nested anywhere inside the loop?
5028 (block_query(b, |e| {
5029 if let ast::ExprBreak(Some(_)) = e.node {
5030 lookup_full_def(cx, e.span, e.id) == def::DefLabel(id)
5037 pub fn check_bounds_are_used<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
5039 tps: &OwnedSlice<ast::TyParam>,
5041 debug!("check_bounds_are_used(n_tps={}, ty={:?})",
5044 // make a vector of booleans initially false, set to true when used
5045 if tps.is_empty() { return; }
5046 let mut tps_used = vec![false; tps.len()];
5048 for leaf_ty in ty.walk() {
5049 if let ty::TyParam(ParamTy {idx, ..}) = leaf_ty.sty {
5050 debug!("Found use of ty param num {}", idx);
5051 tps_used[idx as usize] = true;
5055 for (i, b) in tps_used.iter().enumerate() {
5057 span_err!(ccx.tcx.sess, span, E0091,
5058 "type parameter `{}` is unused",
5064 /// Remember to add all intrinsics here, in librustc_trans/trans/intrinsic.rs,
5065 /// and in libcore/intrinsics.rs
5066 pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &ast::ForeignItem) {
5067 fn param<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>, n: u32) -> Ty<'tcx> {
5068 let name = token::intern(&format!("P{}", n));
5069 ccx.tcx.mk_param(subst::FnSpace, n, name)
5073 let name = it.ident.name.as_str();
5074 let (n_tps, inputs, output) = if name.starts_with("atomic_") {
5075 let split : Vec<&str> = name.split('_').collect();
5076 assert!(split.len() >= 2, "Atomic intrinsic not correct format");
5078 //We only care about the operation here
5079 let (n_tps, inputs, output) = match split[1] {
5080 "cxchg" => (1, vec!(tcx.mk_mut_ptr(param(ccx, 0)),
5084 "load" => (1, vec!(tcx.mk_imm_ptr(param(ccx, 0))),
5086 "store" => (1, vec!(tcx.mk_mut_ptr(param(ccx, 0)), param(ccx, 0)),
5089 "xchg" | "xadd" | "xsub" | "and" | "nand" | "or" | "xor" | "max" |
5090 "min" | "umax" | "umin" => {
5091 (1, vec!(tcx.mk_mut_ptr(param(ccx, 0)), param(ccx, 0)),
5094 "fence" | "singlethreadfence" => {
5095 (0, Vec::new(), tcx.mk_nil())
5098 span_err!(tcx.sess, it.span, E0092,
5099 "unrecognized atomic operation function: `{}`", op);
5103 (n_tps, inputs, ty::FnConverging(output))
5104 } else if &name[..] == "abort" || &name[..] == "unreachable" {
5105 (0, Vec::new(), ty::FnDiverging)
5107 let (n_tps, inputs, output) = match &name[..] {
5108 "breakpoint" => (0, Vec::new(), tcx.mk_nil()),
5110 "pref_align_of" | "min_align_of" => (1, Vec::new(), ccx.tcx.types.usize),
5111 "size_of_val" | "min_align_of_val" => {
5113 tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::new(1),
5116 ], ccx.tcx.types.usize)
5118 "init" | "init_dropped" => (1, Vec::new(), param(ccx, 0)),
5119 "uninit" => (1, Vec::new(), param(ccx, 0)),
5120 "forget" => (1, vec!( param(ccx, 0) ), tcx.mk_nil()),
5121 "transmute" => (2, vec!( param(ccx, 0) ), param(ccx, 1)),
5122 "move_val_init" => {
5125 tcx.mk_mut_ptr(param(ccx, 0)),
5130 "drop_in_place" => {
5131 (1, vec![tcx.mk_mut_ptr(param(ccx, 0))], tcx.mk_nil())
5133 "needs_drop" => (1, Vec::new(), ccx.tcx.types.bool),
5135 "type_name" => (1, Vec::new(), tcx.mk_static_str()),
5136 "type_id" => (1, Vec::new(), ccx.tcx.types.u64),
5137 "offset" | "arith_offset" => {
5140 tcx.mk_ptr(ty::TypeAndMut {
5142 mutbl: ast::MutImmutable
5146 tcx.mk_ptr(ty::TypeAndMut {
5148 mutbl: ast::MutImmutable
5151 "copy" | "copy_nonoverlapping" => {
5154 tcx.mk_ptr(ty::TypeAndMut {
5156 mutbl: ast::MutImmutable
5158 tcx.mk_ptr(ty::TypeAndMut {
5160 mutbl: ast::MutMutable
5166 "volatile_copy_memory" | "volatile_copy_nonoverlapping_memory" => {
5169 tcx.mk_ptr(ty::TypeAndMut {
5171 mutbl: ast::MutMutable
5173 tcx.mk_ptr(ty::TypeAndMut {
5175 mutbl: ast::MutImmutable
5181 "write_bytes" | "volatile_set_memory" => {
5184 tcx.mk_ptr(ty::TypeAndMut {
5186 mutbl: ast::MutMutable
5193 "sqrtf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5194 "sqrtf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5197 vec!( tcx.types.f32, tcx.types.i32 ),
5202 vec!( tcx.types.f64, tcx.types.i32 ),
5205 "sinf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5206 "sinf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5207 "cosf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5208 "cosf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5211 vec!( tcx.types.f32, tcx.types.f32 ),
5216 vec!( tcx.types.f64, tcx.types.f64 ),
5219 "expf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5220 "expf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5221 "exp2f32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5222 "exp2f64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5223 "logf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5224 "logf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5225 "log10f32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5226 "log10f64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5227 "log2f32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5228 "log2f64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5231 vec!( tcx.types.f32, tcx.types.f32, tcx.types.f32 ),
5236 vec!( tcx.types.f64, tcx.types.f64, tcx.types.f64 ),
5239 "fabsf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5240 "fabsf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5241 "copysignf32" => (0, vec!( tcx.types.f32, tcx.types.f32 ), tcx.types.f32),
5242 "copysignf64" => (0, vec!( tcx.types.f64, tcx.types.f64 ), tcx.types.f64),
5243 "floorf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5244 "floorf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5245 "ceilf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5246 "ceilf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5247 "truncf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5248 "truncf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5249 "rintf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5250 "rintf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5251 "nearbyintf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5252 "nearbyintf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5253 "roundf32" => (0, vec!( tcx.types.f32 ), tcx.types.f32),
5254 "roundf64" => (0, vec!( tcx.types.f64 ), tcx.types.f64),
5255 "ctpop8" => (0, vec!( tcx.types.u8 ), tcx.types.u8),
5256 "ctpop16" => (0, vec!( tcx.types.u16 ), tcx.types.u16),
5257 "ctpop32" => (0, vec!( tcx.types.u32 ), tcx.types.u32),
5258 "ctpop64" => (0, vec!( tcx.types.u64 ), tcx.types.u64),
5259 "ctlz8" => (0, vec!( tcx.types.u8 ), tcx.types.u8),
5260 "ctlz16" => (0, vec!( tcx.types.u16 ), tcx.types.u16),
5261 "ctlz32" => (0, vec!( tcx.types.u32 ), tcx.types.u32),
5262 "ctlz64" => (0, vec!( tcx.types.u64 ), tcx.types.u64),
5263 "cttz8" => (0, vec!( tcx.types.u8 ), tcx.types.u8),
5264 "cttz16" => (0, vec!( tcx.types.u16 ), tcx.types.u16),
5265 "cttz32" => (0, vec!( tcx.types.u32 ), tcx.types.u32),
5266 "cttz64" => (0, vec!( tcx.types.u64 ), tcx.types.u64),
5267 "bswap16" => (0, vec!( tcx.types.u16 ), tcx.types.u16),
5268 "bswap32" => (0, vec!( tcx.types.u32 ), tcx.types.u32),
5269 "bswap64" => (0, vec!( tcx.types.u64 ), tcx.types.u64),
5272 (1, vec!( tcx.mk_imm_ptr(param(ccx, 0)) ), param(ccx, 0)),
5274 (1, vec!( tcx.mk_mut_ptr(param(ccx, 0)), param(ccx, 0) ), tcx.mk_nil()),
5276 "i8_add_with_overflow" | "i8_sub_with_overflow" | "i8_mul_with_overflow" =>
5277 (0, vec!(tcx.types.i8, tcx.types.i8),
5278 tcx.mk_tup(vec!(tcx.types.i8, tcx.types.bool))),
5280 "i16_add_with_overflow" | "i16_sub_with_overflow" | "i16_mul_with_overflow" =>
5281 (0, vec!(tcx.types.i16, tcx.types.i16),
5282 tcx.mk_tup(vec!(tcx.types.i16, tcx.types.bool))),
5284 "i32_add_with_overflow" | "i32_sub_with_overflow" | "i32_mul_with_overflow" =>
5285 (0, vec!(tcx.types.i32, tcx.types.i32),
5286 tcx.mk_tup(vec!(tcx.types.i32, tcx.types.bool))),
5288 "i64_add_with_overflow" | "i64_sub_with_overflow" | "i64_mul_with_overflow" =>
5289 (0, vec!(tcx.types.i64, tcx.types.i64),
5290 tcx.mk_tup(vec!(tcx.types.i64, tcx.types.bool))),
5292 "u8_add_with_overflow" | "u8_sub_with_overflow" | "u8_mul_with_overflow" =>
5293 (0, vec!(tcx.types.u8, tcx.types.u8),
5294 tcx.mk_tup(vec!(tcx.types.u8, tcx.types.bool))),
5296 "u16_add_with_overflow" | "u16_sub_with_overflow" | "u16_mul_with_overflow" =>
5297 (0, vec!(tcx.types.u16, tcx.types.u16),
5298 tcx.mk_tup(vec!(tcx.types.u16, tcx.types.bool))),
5300 "u32_add_with_overflow" | "u32_sub_with_overflow" | "u32_mul_with_overflow"=>
5301 (0, vec!(tcx.types.u32, tcx.types.u32),
5302 tcx.mk_tup(vec!(tcx.types.u32, tcx.types.bool))),
5304 "u64_add_with_overflow" | "u64_sub_with_overflow" | "u64_mul_with_overflow" =>
5305 (0, vec!(tcx.types.u64, tcx.types.u64),
5306 tcx.mk_tup(vec!(tcx.types.u64, tcx.types.bool))),
5308 "unchecked_udiv" | "unchecked_sdiv" | "unchecked_urem" | "unchecked_srem" =>
5309 (1, vec![param(ccx, 0), param(ccx, 0)], param(ccx, 0)),
5311 "overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
5312 (1, vec![param(ccx, 0), param(ccx, 0)], param(ccx, 0)),
5314 "return_address" => (0, vec![], tcx.mk_imm_ptr(tcx.types.u8)),
5316 "assume" => (0, vec![tcx.types.bool], tcx.mk_nil()),
5318 "discriminant_value" => (1, vec![
5319 tcx.mk_imm_ref(tcx.mk_region(ty::ReLateBound(ty::DebruijnIndex::new(1),
5321 param(ccx, 0))], tcx.types.u64),
5324 let mut_u8 = tcx.mk_mut_ptr(tcx.types.u8);
5325 let fn_ty = ty::BareFnTy {
5326 unsafety: ast::Unsafety::Normal,
5328 sig: ty::Binder(FnSig {
5329 inputs: vec![mut_u8],
5330 output: ty::FnOutput::FnConverging(tcx.mk_nil()),
5334 let fn_ty = tcx.mk_bare_fn(fn_ty);
5335 (0, vec![tcx.mk_fn(None, fn_ty), mut_u8], mut_u8)
5339 span_err!(tcx.sess, it.span, E0093,
5340 "unrecognized intrinsic function: `{}`", *other);
5344 (n_tps, inputs, ty::FnConverging(output))
5346 let fty = tcx.mk_fn(None, tcx.mk_bare_fn(ty::BareFnTy {
5347 unsafety: ast::Unsafety::Unsafe,
5348 abi: abi::RustIntrinsic,
5349 sig: ty::Binder(FnSig {
5355 let i_ty = ccx.tcx.lookup_item_type(local_def(it.id));
5356 let i_n_tps = i_ty.generics.types.len(subst::FnSpace);
5357 if i_n_tps != n_tps {
5358 span_err!(tcx.sess, it.span, E0094,
5359 "intrinsic has wrong number of type \
5360 parameters: found {}, expected {}",
5363 require_same_types(tcx,
5370 format!("intrinsic has wrong type: expected `{}`",