diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index 44b8af3c1df98..68b080ccb95da 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -194,13 +194,12 @@ enum SelectionCandidate<'tcx> {
ProjectionCandidate,
/// Implementation of a `Fn`-family trait by one of the anonymous types
- /// generated for a `||` expression. The ty::ClosureKind informs the
- /// confirmation step what ClosureKind obligation to emit.
- ClosureCandidate(/* closure */ DefId, ty::ClosureSubsts<'tcx>, ty::ClosureKind),
+ /// generated for a `||` expression.
+ ClosureCandidate,
/// Implementation of a `Generator` trait by one of the anonymous types
/// generated for a generator.
- GeneratorCandidate(/* function / closure */ DefId, ty::ClosureSubsts<'tcx>),
+ GeneratorCandidate,
/// Implementation of a `Fn`-family trait by one of the anonymous
/// types generated for a fn pointer type (e.g., `fn(int)->int`)
@@ -229,20 +228,12 @@ impl<'a, 'tcx> ty::Lift<'tcx> for SelectionCandidate<'a> {
ObjectCandidate => ObjectCandidate,
BuiltinObjectCandidate => BuiltinObjectCandidate,
BuiltinUnsizeCandidate => BuiltinUnsizeCandidate,
+ ClosureCandidate => ClosureCandidate,
+ GeneratorCandidate => GeneratorCandidate,
ParamCandidate(ref trait_ref) => {
return tcx.lift(trait_ref).map(ParamCandidate);
}
- GeneratorCandidate(def_id, ref substs) => {
- return tcx.lift(substs).map(|substs| {
- GeneratorCandidate(def_id, substs)
- });
- }
- ClosureCandidate(def_id, ref substs, kind) => {
- return tcx.lift(substs).map(|substs| {
- ClosureCandidate(def_id, substs, kind)
- });
- }
})
}
}
@@ -1518,23 +1509,22 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
// touch bound regions, they just capture the in-scope
// type/region parameters
let self_ty = *obligation.self_ty().skip_binder();
- let (closure_def_id, substs) = match self_ty.sty {
- ty::TyGenerator(id, substs, _) => (id, substs),
+ match self_ty.sty {
+ ty::TyGenerator(..) => {
+ debug!("assemble_generator_candidates: self_ty={:?} obligation={:?}",
+ self_ty,
+ obligation);
+
+ candidates.vec.push(GeneratorCandidate);
+ Ok(())
+ }
ty::TyInfer(ty::TyVar(_)) => {
debug!("assemble_generator_candidates: ambiguous self-type");
candidates.ambiguous = true;
return Ok(());
}
_ => { return Ok(()); }
- };
-
- debug!("assemble_generator_candidates: self_ty={:?} obligation={:?}",
- self_ty,
- obligation);
-
- candidates.vec.push(GeneratorCandidate(closure_def_id, substs));
-
- Ok(())
+ }
}
/// Check for the artificial impl that the compiler will create for an obligation like `X :
@@ -1556,36 +1546,31 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
// ok to skip binder because the substs on closure types never
// touch bound regions, they just capture the in-scope
// type/region parameters
- let self_ty = *obligation.self_ty().skip_binder();
- let (closure_def_id, substs) = match self_ty.sty {
- ty::TyClosure(id, substs) => (id, substs),
+ match obligation.self_ty().skip_binder().sty {
+ ty::TyClosure(closure_def_id, _) => {
+ debug!("assemble_unboxed_candidates: kind={:?} obligation={:?}",
+ kind, obligation);
+ match self.infcx.closure_kind(closure_def_id) {
+ Some(closure_kind) => {
+ debug!("assemble_unboxed_candidates: closure_kind = {:?}", closure_kind);
+ if closure_kind.extends(kind) {
+ candidates.vec.push(ClosureCandidate);
+ }
+ }
+ None => {
+ debug!("assemble_unboxed_candidates: closure_kind not yet known");
+ candidates.vec.push(ClosureCandidate);
+ }
+ };
+ Ok(())
+ }
ty::TyInfer(ty::TyVar(_)) => {
debug!("assemble_unboxed_closure_candidates: ambiguous self-type");
candidates.ambiguous = true;
return Ok(());
}
_ => { return Ok(()); }
- };
-
- debug!("assemble_unboxed_candidates: self_ty={:?} kind={:?} obligation={:?}",
- self_ty,
- kind,
- obligation);
-
- match self.infcx.closure_kind(closure_def_id) {
- Some(closure_kind) => {
- debug!("assemble_unboxed_candidates: closure_kind = {:?}", closure_kind);
- if closure_kind.extends(kind) {
- candidates.vec.push(ClosureCandidate(closure_def_id, substs, kind));
- }
- }
- None => {
- debug!("assemble_unboxed_candidates: closure_kind not yet known");
- candidates.vec.push(ClosureCandidate(closure_def_id, substs, kind));
- }
}
-
- Ok(())
}
/// Implement one of the `Fn()` family for a fn pointer.
@@ -1902,8 +1887,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
when there are other valid candidates");
}
ImplCandidate(..) |
- ClosureCandidate(..) |
- GeneratorCandidate(..) |
+ ClosureCandidate |
+ GeneratorCandidate |
FnPointerCandidate |
BuiltinObjectCandidate |
BuiltinUnsizeCandidate |
@@ -2245,15 +2230,13 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
Ok(VtableImpl(self.confirm_impl_candidate(obligation, impl_def_id)))
}
- ClosureCandidate(closure_def_id, substs, kind) => {
- let vtable_closure =
- self.confirm_closure_candidate(obligation, closure_def_id, substs, kind)?;
+ ClosureCandidate => {
+ let vtable_closure = self.confirm_closure_candidate(obligation)?;
Ok(VtableClosure(vtable_closure))
}
- GeneratorCandidate(closure_def_id, substs) => {
- let vtable_generator =
- self.confirm_generator_candidate(obligation, closure_def_id, substs)?;
+ GeneratorCandidate => {
+ let vtable_generator = self.confirm_generator_candidate(obligation)?;
Ok(VtableGenerator(vtable_generator))
}
@@ -2590,21 +2573,34 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
}
fn confirm_generator_candidate(&mut self,
- obligation: &TraitObligation<'tcx>,
- closure_def_id: DefId,
- substs: ty::ClosureSubsts<'tcx>)
- -> Result<VtableGeneratorData<'tcx, PredicateObligation<'tcx>>,
+ obligation: &TraitObligation<'tcx>)
+ -> Result<VtableGeneratorData<'tcx, PredicateObligation<'tcx>>,
SelectionError<'tcx>>
{
+ // ok to skip binder because the substs on generator types never
+ // touch bound regions, they just capture the in-scope
+ // type/region parameters
+ let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
+ let (closure_def_id, substs) = match self_ty.sty {
+ ty::TyGenerator(id, substs, _) => (id, substs),
+ _ => bug!("closure candidate for non-closure {:?}", obligation)
+ };
+
debug!("confirm_generator_candidate({:?},{:?},{:?})",
obligation,
closure_def_id,
substs);
+ let trait_ref =
+ self.generator_trait_ref_unnormalized(obligation, closure_def_id, substs);
let Normalized {
value: trait_ref,
obligations
- } = self.generator_trait_ref(obligation, closure_def_id, substs);
+ } = normalize_with_depth(self,
+ obligation.param_env,
+ obligation.cause.clone(),
+ obligation.recursion_depth+1,
+ &trait_ref);
debug!("confirm_generator_candidate(closure_def_id={:?}, trait_ref={:?}, obligations={:?})",
closure_def_id,
@@ -2624,22 +2620,36 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
}
fn confirm_closure_candidate(&mut self,
- obligation: &TraitObligation<'tcx>,
- closure_def_id: DefId,
- substs: ty::ClosureSubsts<'tcx>,
- kind: ty::ClosureKind)
+ obligation: &TraitObligation<'tcx>)
-> Result<VtableClosureData<'tcx, PredicateObligation<'tcx>>,
SelectionError<'tcx>>
{
- debug!("confirm_closure_candidate({:?},{:?},{:?})",
- obligation,
- closure_def_id,
- substs);
+ debug!("confirm_closure_candidate({:?})", obligation);
+
+ let kind = match self.tcx().lang_items.fn_trait_kind(obligation.predicate.0.def_id()) {
+ Some(k) => k,
+ None => bug!("closure candidate for non-fn trait {:?}", obligation)
+ };
+
+ // ok to skip binder because the substs on closure types never
+ // touch bound regions, they just capture the in-scope
+ // type/region parameters
+ let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
+ let (closure_def_id, substs) = match self_ty.sty {
+ ty::TyClosure(id, substs) => (id, substs),
+ _ => bug!("closure candidate for non-closure {:?}", obligation)
+ };
+ let trait_ref =
+ self.closure_trait_ref_unnormalized(obligation, closure_def_id, substs);
let Normalized {
value: trait_ref,
mut obligations
- } = self.closure_trait_ref(obligation, closure_def_id, substs);
+ } = normalize_with_depth(self,
+ obligation.param_env,
+ obligation.cause.clone(),
+ obligation.recursion_depth+1,
+ &trait_ref);
debug!("confirm_closure_candidate(closure_def_id={:?}, trait_ref={:?}, obligations={:?})",
closure_def_id,
@@ -3106,24 +3116,6 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
ty::Binder(trait_ref)
}
- fn closure_trait_ref(&mut self,
- obligation: &TraitObligation<'tcx>,
- closure_def_id: DefId,
- substs: ty::ClosureSubsts<'tcx>)
- -> Normalized<'tcx, ty::PolyTraitRef<'tcx>>
- {
- let trait_ref = self.closure_trait_ref_unnormalized(
- obligation, closure_def_id, substs);
-
- // A closure signature can contain associated types which
- // must be normalized.
- normalize_with_depth(self,
- obligation.param_env,
- obligation.cause.clone(),
- obligation.recursion_depth+1,
- &trait_ref)
- }
-
fn generator_trait_ref_unnormalized(&mut self,
obligation: &TraitObligation<'tcx>,
closure_def_id: DefId,
@@ -3145,24 +3137,6 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
ty::Binder(trait_ref)
}
- fn generator_trait_ref(&mut self,
- obligation: &TraitObligation<'tcx>,
- closure_def_id: DefId,
- substs: ty::ClosureSubsts<'tcx>)
- -> Normalized<'tcx, ty::PolyTraitRef<'tcx>>
- {
- let trait_ref = self.generator_trait_ref_unnormalized(
- obligation, closure_def_id, substs);
-
- // A generator signature can contain associated types which
- // must be normalized.
- normalize_with_depth(self,
- obligation.param_env,
- obligation.cause.clone(),
- obligation.recursion_depth+1,
- &trait_ref)
- }
-
/// Returns the obligations that are implied by instantiating an
/// impl or trait. The obligations are substituted and fully
/// normalized. This is used when confirming an impl or default
diff --git a/src/librustc_typeck/check/method/confirm.rs b/src/librustc_typeck/check/method/confirm.rs
index db383b6305b4a..08ec3bf74a71d 100644
--- a/src/librustc_typeck/check/method/confirm.rs
+++ b/src/librustc_typeck/check/method/confirm.rs
@@ -232,24 +232,6 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
})
}
- probe::ExtensionImplPick(impl_def_id) => {
- // The method being invoked is the method as defined on the trait,
- // so return the substitutions from the trait. Consider:
- //
- // impl<A,B,C> Trait<A,B> for Foo<C> { ... }
- //
- // If we instantiate A, B, and C with $A, $B, and $C
- // respectively, then we want to return the type
- // parameters from the trait ([$A,$B]), not those from
- // the impl ([$A,$B,$C]) not the receiver type ([$C]).
- let impl_polytype = self.impl_self_ty(self.span, impl_def_id);
- let impl_trait_ref =
- self.instantiate_type_scheme(self.span,
- impl_polytype.substs,
- &self.tcx.impl_trait_ref(impl_def_id).unwrap());
- impl_trait_ref.substs
- }
-
probe::TraitPick => {
let trait_def_id = pick.item.container.id();
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 819f48a1b57e8..31ceed5b965bf 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -52,10 +52,6 @@ pub enum MethodError<'tcx> {
// Multiple methods might apply.
Ambiguity(Vec<CandidateSource>),
- // Using a `Fn`/`FnMut`/etc method on a raw closure type before we have inferred its kind.
- ClosureAmbiguity(// DefId of fn trait
- DefId),
-
// Found an applicable method, but it is not visible. The second argument contains a list of
// not-in-scope traits which may work.
PrivateMatch(Def, Vec<DefId>),
@@ -63,6 +59,9 @@ pub enum MethodError<'tcx> {
// Found a `Self: Sized` bound where `Self` is a trait object, also the caller may have
// forgotten to import a trait.
IllegalSizedBound(Vec<DefId>),
+
+ // Found a match, but the return type is wrong
+ BadReturnType,
}
// Contains a list of static methods that may apply, a list of unsatisfied trait predicates which
@@ -113,9 +112,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
Ok(..) => true,
Err(NoMatch(..)) => false,
Err(Ambiguity(..)) => true,
- Err(ClosureAmbiguity(..)) => true,
Err(PrivateMatch(..)) => allow_private,
Err(IllegalSizedBound(..)) => true,
+ Err(BadReturnType) => {
+ bug!("no return type expectations but got BadReturnType")
+ }
+
}
}
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 5e5a27f2ba137..228b6c88f24db 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -18,7 +18,7 @@ use hir::def_id::DefId;
use hir::def::Def;
use rustc::ty::subst::{Subst, Substs};
use rustc::traits::{self, ObligationCause};
-use rustc::ty::{self, Ty, ToPolyTraitRef, TraitRef, TypeFoldable};
+use rustc::ty::{self, Ty, ToPolyTraitRef, ToPredicate, TraitRef, TypeFoldable};
use rustc::infer::type_variable::TypeVariableOrigin;
use rustc::util::nodemap::FxHashSet;
use rustc::infer::{self, InferOk};
@@ -32,15 +32,6 @@ use std::rc::Rc;
use self::CandidateKind::*;
pub use self::PickKind::*;
-pub enum LookingFor<'tcx> {
- /// looking for methods with the given name; this is the normal case
- MethodName(ast::Name),
-
- /// looking for methods that return a given type; this is used to
- /// assemble suggestions
- ReturnType(Ty<'tcx>),
-}
-
/// Boolean flag used to indicate if this search is for a suggestion
/// or not. If true, we can allow ambiguity and so forth.
pub struct IsSuggestion(pub bool);
@@ -49,9 +40,9 @@ struct ProbeContext<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
span: Span,
mode: Mode,
- looking_for: LookingFor<'tcx>,
+ method_name: Option<ast::Name>,
+ return_type: Option<Ty<'tcx>>,
steps: Rc<Vec<CandidateStep<'tcx>>>,
- opt_simplified_steps: Option<Vec<ty::fast_reject::SimplifiedType>>,
inherent_candidates: Vec<Candidate<'tcx>>,
extension_candidates: Vec<Candidate<'tcx>>,
impl_dups: FxHashSet<DefId>,
@@ -85,6 +76,7 @@ struct CandidateStep<'tcx> {
#[derive(Debug)]
struct Candidate<'tcx> {
xform_self_ty: Ty<'tcx>,
+ xform_ret_ty: Option<Ty<'tcx>>,
item: ty::AssociatedItem,
kind: CandidateKind<'tcx>,
import_id: Option<ast::NodeId>,
@@ -95,17 +87,19 @@ enum CandidateKind<'tcx> {
InherentImplCandidate(&'tcx Substs<'tcx>,
// Normalize obligations
Vec<traits::PredicateObligation<'tcx>>),
- ExtensionImplCandidate(// Impl
- DefId,
- &'tcx Substs<'tcx>,
- // Normalize obligations
- Vec<traits::PredicateObligation<'tcx>>),
ObjectCandidate,
- TraitCandidate,
+ TraitCandidate(ty::TraitRef<'tcx>),
WhereClauseCandidate(// Trait
ty::PolyTraitRef<'tcx>),
}
+#[derive(Debug, PartialEq, Eq, Copy, Clone)]
+enum ProbeResult {
+ NoMatch,
+ BadReturnType,
+ Match,
+}
+
#[derive(Debug, PartialEq, Eq, Clone)]
pub struct Pick<'tcx> {
pub item: ty::AssociatedItem,
@@ -133,8 +127,6 @@ pub struct Pick<'tcx> {
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum PickKind<'tcx> {
InherentImplPick,
- ExtensionImplPick(// Impl
- DefId),
ObjectPick,
TraitPick,
WhereClausePick(// Trait
@@ -183,19 +175,19 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
return_type,
scope_expr_id);
let method_names =
- self.probe_op(span, mode, LookingFor::ReturnType(return_type), IsSuggestion(true),
+ self.probe_op(span, mode, None, Some(return_type), IsSuggestion(true),
self_ty, scope_expr_id, ProbeScope::TraitsInScope,
|probe_cx| Ok(probe_cx.candidate_method_names()))
.unwrap_or(vec![]);
- method_names
- .iter()
- .flat_map(|&method_name| {
- match self.probe_for_name(span, mode, method_name, IsSuggestion(true), self_ty,
- scope_expr_id, ProbeScope::TraitsInScope) {
- Ok(pick) => Some(pick.item),
- Err(_) => None,
- }
- })
+ method_names
+ .iter()
+ .flat_map(|&method_name| {
+ self.probe_op(
+ span, mode, Some(method_name), Some(return_type),
+ IsSuggestion(true), self_ty, scope_expr_id,
+ ProbeScope::TraitsInScope, |probe_cx| probe_cx.pick()
+ ).ok().map(|pick| pick.item)
+ })
.collect()
}
@@ -214,7 +206,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
scope_expr_id);
self.probe_op(span,
mode,
- LookingFor::MethodName(item_name),
+ Some(item_name),
+ None,
is_suggestion,
self_ty,
scope_expr_id,
@@ -225,7 +218,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
fn probe_op<OP,R>(&'a self,
span: Span,
mode: Mode,
- looking_for: LookingFor<'tcx>,
+ method_name: Option<ast::Name>,
+ return_type: Option<Ty<'tcx>>,
is_suggestion: IsSuggestion,
self_ty: Ty<'tcx>,
scope_expr_id: ast::NodeId,
@@ -259,24 +253,6 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}]
};
- // Create a list of simplified self types, if we can.
- let mut simplified_steps = Vec::new();
- for step in &steps {
- match ty::fast_reject::simplify_type(self.tcx, step.self_ty, true) {
- None => {
- break;
- }
- Some(simplified_type) => {
- simplified_steps.push(simplified_type);
- }
- }
- }
- let opt_simplified_steps = if simplified_steps.len() < steps.len() {
- None // failed to convert at least one of the steps
- } else {
- Some(simplified_steps)
- };
-
debug!("ProbeContext: steps for self_ty={:?} are {:?}",
self_ty,
steps);
@@ -285,8 +261,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// that we create during the probe process are removed later
self.probe(|_| {
let mut probe_cx =
- ProbeContext::new(self, span, mode, looking_for,
- steps, opt_simplified_steps);
+ ProbeContext::new(self, span, mode, method_name, return_type, steps);
probe_cx.assemble_inherent_candidates();
match scope {
@@ -356,20 +331,20 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
fn new(fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
span: Span,
mode: Mode,
- looking_for: LookingFor<'tcx>,
- steps: Vec<CandidateStep<'tcx>>,
- opt_simplified_steps: Option<Vec<ty::fast_reject::SimplifiedType>>)
+ method_name: Option<ast::Name>,
+ return_type: Option<Ty<'tcx>>,
+ steps: Vec<CandidateStep<'tcx>>)
-> ProbeContext<'a, 'gcx, 'tcx> {
ProbeContext {
fcx,
span,
mode,
- looking_for,
+ method_name,
+ return_type,
inherent_candidates: Vec::new(),
extension_candidates: Vec::new(),
impl_dups: FxHashSet(),
steps: Rc::new(steps),
- opt_simplified_steps,
static_candidates: Vec::new(),
private_candidate: None,
unsatisfied_predicates: Vec::new(),
@@ -387,33 +362,25 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
///////////////////////////////////////////////////////////////////////////
// CANDIDATE ASSEMBLY
- fn push_inherent_candidate(&mut self, xform_self_ty: Ty<'tcx>, item: ty::AssociatedItem,
- kind: CandidateKind<'tcx>, import_id: Option<ast::NodeId>) {
- let is_accessible = if let LookingFor::MethodName(name) = self.looking_for {
- let def_scope = self.tcx.adjust(name, item.container.id(), self.body_id).1;
- item.vis.is_accessible_from(def_scope, self.tcx)
- } else {
- true
- };
- if is_accessible {
- self.inherent_candidates.push(Candidate { xform_self_ty, item, kind, import_id });
- } else if self.private_candidate.is_none() {
- self.private_candidate = Some(item.def());
- }
- }
-
- fn push_extension_candidate(&mut self, xform_self_ty: Ty<'tcx>, item: ty::AssociatedItem,
- kind: CandidateKind<'tcx>, import_id: Option<ast::NodeId>) {
- let is_accessible = if let LookingFor::MethodName(name) = self.looking_for {
+ fn push_candidate(&mut self,
+ candidate: Candidate<'tcx>,
+ is_inherent: bool)
+ {
+ let is_accessible = if let Some(name) = self.method_name {
+ let item = candidate.item;
let def_scope = self.tcx.adjust(name, item.container.id(), self.body_id).1;
item.vis.is_accessible_from(def_scope, self.tcx)
} else {
true
};
if is_accessible {
- self.extension_candidates.push(Candidate { xform_self_ty, item, kind, import_id });
+ if is_inherent {
+ self.inherent_candidates.push(candidate);
+ } else {
+ self.extension_candidates.push(candidate);
+ }
} else if self.private_candidate.is_none() {
- self.private_candidate = Some(item.def());
+ self.private_candidate = Some(candidate.item.def());
}
}
@@ -551,19 +518,22 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
let impl_ty = impl_ty.subst(self.tcx, impl_substs);
// Determine the receiver type that the method itself expects.
- let xform_self_ty = self.xform_self_ty(&item, impl_ty, impl_substs);
+ let xform_tys = self.xform_self_ty(&item, impl_ty, impl_substs);
// We can't use normalize_associated_types_in as it will pollute the
// fcx's fulfillment context after this probe is over.
let cause = traits::ObligationCause::misc(self.span, self.body_id);
let selcx = &mut traits::SelectionContext::new(self.fcx);
- let traits::Normalized { value: xform_self_ty, obligations } =
- traits::normalize(selcx, self.param_env, cause, &xform_self_ty);
- debug!("assemble_inherent_impl_probe: xform_self_ty = {:?}",
- xform_self_ty);
-
- self.push_inherent_candidate(xform_self_ty, item,
- InherentImplCandidate(impl_substs, obligations), None);
+ let traits::Normalized { value: (xform_self_ty, xform_ret_ty), obligations } =
+ traits::normalize(selcx, self.param_env, cause, &xform_tys);
+ debug!("assemble_inherent_impl_probe: xform_self_ty = {:?}/{:?}",
+ xform_self_ty, xform_ret_ty);
+
+ self.push_candidate(Candidate {
+ xform_self_ty, xform_ret_ty, item,
+ kind: InherentImplCandidate(impl_substs, obligations),
+ import_id: None
+ }, true);
}
}
@@ -584,10 +554,13 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
self.elaborate_bounds(&[trait_ref], |this, new_trait_ref, item| {
let new_trait_ref = this.erase_late_bound_regions(&new_trait_ref);
- let xform_self_ty =
+ let (xform_self_ty, xform_ret_ty) =
this.xform_self_ty(&item, new_trait_ref.self_ty(), new_trait_ref.substs);
-
- this.push_inherent_candidate(xform_self_ty, item, ObjectCandidate, None);
+ this.push_candidate(Candidate {
+ xform_self_ty, xform_ret_ty, item,
+ kind: ObjectCandidate,
+ import_id: None
+ }, true);
});
}
@@ -624,7 +597,8 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
self.elaborate_bounds(&bounds, |this, poly_trait_ref, item| {
let trait_ref = this.erase_late_bound_regions(&poly_trait_ref);
- let xform_self_ty = this.xform_self_ty(&item, trait_ref.self_ty(), trait_ref.substs);
+ let (xform_self_ty, xform_ret_ty) =
+ this.xform_self_ty(&item, trait_ref.self_ty(), trait_ref.substs);
// Because this trait derives from a where-clause, it
// should not contain any inference variables or other
@@ -633,8 +607,11 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
// `WhereClausePick`.
assert!(!trait_ref.substs.needs_infer());
- this.push_inherent_candidate(xform_self_ty, item,
- WhereClauseCandidate(poly_trait_ref), None);
+ this.push_candidate(Candidate {
+ xform_self_ty, xform_ret_ty, item,
+ kind: WhereClauseCandidate(poly_trait_ref),
+ import_id: None
+ }, true);
});
}
@@ -687,17 +664,27 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
Ok(())
}
- pub fn matches_return_type(&self, method: &ty::AssociatedItem,
- expected: ty::Ty<'tcx>) -> bool {
+ pub fn matches_return_type(&self,
+ method: &ty::AssociatedItem,
+ self_ty: Option<Ty<'tcx>>,
+ expected: Ty<'tcx>) -> bool {
match method.def() {
Def::Method(def_id) => {
let fty = self.tcx.fn_sig(def_id);
self.probe(|_| {
let substs = self.fresh_substs_for_item(self.span, method.def_id);
- let output = fty.output().subst(self.tcx, substs);
- let (output, _) = self.replace_late_bound_regions_with_fresh_var(
- self.span, infer::FnCall, &output);
- self.can_sub(self.param_env, output, expected).is_ok()
+ let fty = fty.subst(self.tcx, substs);
+ let (fty, _) = self.replace_late_bound_regions_with_fresh_var(
+ self.span, infer::FnCall, &fty);
+
+ if let Some(self_ty) = self_ty {
+ if let Err(_) = self.at(&ObligationCause::dummy(), self.param_env)
+ .sup(fty.inputs()[0], self_ty)
+ {
+ return false
+ }
+ }
+ self.can_sub(self.param_env, fty.output(), expected).is_ok()
})
}
_ => false,
@@ -710,6 +697,8 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
-> Result<(), MethodError<'tcx>> {
debug!("assemble_extension_candidates_for_trait(trait_def_id={:?})",
trait_def_id);
+ let trait_substs = self.fresh_item_substs(trait_def_id);
+ let trait_ref = ty::TraitRef::new(trait_def_id, trait_substs);
for item in self.impl_or_trait_item(trait_def_id) {
// Check whether `trait_def_id` defines a method with suitable name:
@@ -719,326 +708,31 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
continue;
}
- self.assemble_builtin_candidates(import_id, trait_def_id, item.clone());
-
- self.assemble_extension_candidates_for_trait_impls(import_id, trait_def_id,
- item.clone());
-
- self.assemble_closure_candidates(import_id, trait_def_id, item.clone())?;
-
- self.assemble_generator_candidates(import_id, trait_def_id, item.clone())?;
-
- self.assemble_projection_candidates(import_id, trait_def_id, item.clone());
-
- self.assemble_where_clause_candidates(import_id, trait_def_id, item.clone());
- }
-
- Ok(())
- }
-
- fn assemble_builtin_candidates(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem) {
- if Some(trait_def_id) == self.tcx.lang_items.clone_trait() {
- self.assemble_builtin_clone_candidates(import_id, trait_def_id, item);
- }
- }
-
- fn assemble_builtin_clone_candidates(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem) {
- for step in Rc::clone(&self.steps).iter() {
- match step.self_ty.sty {
- ty::TyInfer(ty::IntVar(_)) | ty::TyInfer(ty::FloatVar(_)) |
- ty::TyUint(_) | ty::TyInt(_) | ty::TyBool | ty::TyFloat(_) |
- ty::TyFnDef(..) | ty::TyFnPtr(_) | ty::TyChar |
- ty::TyRawPtr(..) | ty::TyError | ty::TyNever |
- ty::TyRef(_, ty::TypeAndMut { ty: _, mutbl: hir::MutImmutable }) |
- ty::TyArray(..) | ty::TyTuple(..) => {
- ()
- }
-
- _ => continue,
- };
-
- let substs = Substs::for_item(self.tcx,
- trait_def_id,
- |def, _| self.region_var_for_def(self.span, def),
- |def, substs| {
- if def.index == 0 {
- step.self_ty
- } else {
- self.type_var_for_def(self.span, def, substs)
- }
- });
-
- let xform_self_ty = self.xform_self_ty(&item, step.self_ty, substs);
- self.push_inherent_candidate(xform_self_ty, item, TraitCandidate, import_id);
- }
- }
-
- fn assemble_extension_candidates_for_trait_impls(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem) {
- // FIXME(arielb1): can we use for_each_relevant_impl here?
- self.tcx.for_each_impl(trait_def_id, |impl_def_id| {
- debug!("assemble_extension_candidates_for_trait_impl: trait_def_id={:?} \
- impl_def_id={:?}",
- trait_def_id,
- impl_def_id);
-
- if !self.impl_can_possibly_match(impl_def_id) {
- return;
- }
-
- let (_, impl_substs) = self.impl_ty_and_substs(impl_def_id);
-
- debug!("impl_substs={:?}", impl_substs);
-
- let impl_trait_ref = self.tcx.impl_trait_ref(impl_def_id)
- .unwrap() // we know this is a trait impl
- .subst(self.tcx, impl_substs);
-
- debug!("impl_trait_ref={:?}", impl_trait_ref);
-
- // Determine the receiver type that the method itself expects.
- let xform_self_ty =
- self.xform_self_ty(&item, impl_trait_ref.self_ty(), impl_trait_ref.substs);
-
- // Normalize the receiver. We can't use normalize_associated_types_in
- // as it will pollute the fcx's fulfillment context after this probe
- // is over.
- let cause = traits::ObligationCause::misc(self.span, self.body_id);
- let selcx = &mut traits::SelectionContext::new(self.fcx);
- let traits::Normalized { value: xform_self_ty, obligations } =
- traits::normalize(selcx, self.param_env, cause, &xform_self_ty);
-
- debug!("xform_self_ty={:?}", xform_self_ty);
-
- self.push_extension_candidate(xform_self_ty, item,
- ExtensionImplCandidate(impl_def_id, impl_substs, obligations), import_id);
- });
- }
-
- fn impl_can_possibly_match(&self, impl_def_id: DefId) -> bool {
- let simplified_steps = match self.opt_simplified_steps {
- Some(ref simplified_steps) => simplified_steps,
- None => {
- return true;
- }
- };
-
- let impl_type = self.tcx.type_of(impl_def_id);
- let impl_simplified_type =
- match ty::fast_reject::simplify_type(self.tcx, impl_type, false) {
- Some(simplified_type) => simplified_type,
- None => {
- return true;
- }
- };
-
- simplified_steps.contains(&impl_simplified_type)
- }
-
- fn assemble_closure_candidates(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem)
- -> Result<(), MethodError<'tcx>> {
- // Check if this is one of the Fn,FnMut,FnOnce traits.
- let tcx = self.tcx;
- let kind = if Some(trait_def_id) == tcx.lang_items.fn_trait() {
- ty::ClosureKind::Fn
- } else if Some(trait_def_id) == tcx.lang_items.fn_mut_trait() {
- ty::ClosureKind::FnMut
- } else if Some(trait_def_id) == tcx.lang_items.fn_once_trait() {
- ty::ClosureKind::FnOnce
- } else {
- return Ok(());
- };
-
- // Check if there is an unboxed-closure self-type in the list of receivers.
- // If so, add "synthetic impls".
- let steps = self.steps.clone();
- for step in steps.iter() {
- let closure_id = match step.self_ty.sty {
- ty::TyClosure(def_id, _) => {
- if let Some(id) = self.tcx.hir.as_local_node_id(def_id) {
- self.tcx.hir.node_to_hir_id(id)
- } else {
- continue;
- }
- }
- _ => continue,
- };
-
- let closure_kind = {
- match self.tables.borrow().closure_kinds().get(closure_id) {
- Some(&(k, _)) => k,
- None => {
- return Err(MethodError::ClosureAmbiguity(trait_def_id));
- }
- }
- };
-
- // this closure doesn't implement the right kind of `Fn` trait
- if !closure_kind.extends(kind) {
- continue;
- }
-
- // create some substitutions for the argument/return type;
- // for the purposes of our method lookup, we only take
- // receiver type into account, so we can just substitute
- // fresh types here to use during substitution and subtyping.
- let substs = Substs::for_item(self.tcx,
- trait_def_id,
- |def, _| self.region_var_for_def(self.span, def),
- |def, substs| {
- if def.index == 0 {
- step.self_ty
- } else {
- self.type_var_for_def(self.span, def, substs)
- }
- });
-
- let xform_self_ty = self.xform_self_ty(&item, step.self_ty, substs);
- self.push_inherent_candidate(xform_self_ty, item, TraitCandidate, import_id);
- }
-
- Ok(())
- }
-
- fn assemble_generator_candidates(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem)
- -> Result<(), MethodError<'tcx>> {
- // Check if this is the Generator trait.
- let tcx = self.tcx;
- if Some(trait_def_id) != tcx.lang_items.gen_trait() {
- return Ok(());
- }
-
- // Check if there is an generator self-type in the list of receivers.
- // If so, add "synthetic impls".
- let steps = self.steps.clone();
- for step in steps.iter() {
- match step.self_ty.sty {
- ty::TyGenerator(..) => (),
- _ => continue,
- };
-
- // create some substitutions for the argument/return type;
- // for the purposes of our method lookup, we only take
- // receiver type into account, so we can just substitute
- // fresh types here to use during substitution and subtyping.
- let substs = Substs::for_item(self.tcx,
- trait_def_id,
- |def, _| self.region_var_for_def(self.span, def),
- |def, substs| {
- if def.index == 0 {
- step.self_ty
- } else {
- self.type_var_for_def(self.span, def, substs)
- }
- });
-
- let xform_self_ty = self.xform_self_ty(&item, step.self_ty, substs);
- self.push_inherent_candidate(xform_self_ty, item, TraitCandidate, import_id);
+ let (xform_self_ty, xform_ret_ty) =
+ self.xform_self_ty(&item, trait_ref.self_ty(), trait_substs);
+ self.push_candidate(Candidate {
+ xform_self_ty, xform_ret_ty, item, import_id,
+ kind: TraitCandidate(trait_ref),
+ }, false);
}
-
Ok(())
}
- fn assemble_projection_candidates(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem) {
- debug!("assemble_projection_candidates(\
- trait_def_id={:?}, \
- item={:?})",
- trait_def_id,
- item);
-
- for step in Rc::clone(&self.steps).iter() {
- debug!("assemble_projection_candidates: step={:?}", step);
-
- let (def_id, substs) = match step.self_ty.sty {
- ty::TyProjection(ref data) => {
- let trait_ref = data.trait_ref(self.tcx);
- (trait_ref.def_id, trait_ref.substs)
- },
- ty::TyAnon(def_id, substs) => (def_id, substs),
- _ => continue,
- };
-
- debug!("assemble_projection_candidates: def_id={:?} substs={:?}",
- def_id,
- substs);
-
- let trait_predicates = self.tcx.predicates_of(def_id);
- let bounds = trait_predicates.instantiate(self.tcx, substs);
- let predicates = bounds.predicates;
- debug!("assemble_projection_candidates: predicates={:?}",
- predicates);
- for poly_bound in traits::elaborate_predicates(self.tcx, predicates)
- .filter_map(|p| p.to_opt_poly_trait_ref())
- .filter(|b| b.def_id() == trait_def_id) {
- let bound = self.erase_late_bound_regions(&poly_bound);
-
- debug!("assemble_projection_candidates: def_id={:?} substs={:?} bound={:?}",
- def_id,
- substs,
- bound);
-
- if self.can_eq(self.param_env, step.self_ty, bound.self_ty()).is_ok() {
- let xform_self_ty = self.xform_self_ty(&item, bound.self_ty(), bound.substs);
-
- debug!("assemble_projection_candidates: bound={:?} xform_self_ty={:?}",
- bound,
- xform_self_ty);
-
- self.push_extension_candidate(xform_self_ty, item, TraitCandidate, import_id);
- }
- }
- }
- }
-
- fn assemble_where_clause_candidates(&mut self,
- import_id: Option<ast::NodeId>,
- trait_def_id: DefId,
- item: ty::AssociatedItem) {
- debug!("assemble_where_clause_candidates(trait_def_id={:?})",
- trait_def_id);
-
- let caller_predicates = self.param_env.caller_bounds.to_vec();
- for poly_bound in traits::elaborate_predicates(self.tcx, caller_predicates)
- .filter_map(|p| p.to_opt_poly_trait_ref())
- .filter(|b| b.def_id() == trait_def_id) {
- let bound = self.erase_late_bound_regions(&poly_bound);
- let xform_self_ty = self.xform_self_ty(&item, bound.self_ty(), bound.substs);
-
- debug!("assemble_where_clause_candidates: bound={:?} xform_self_ty={:?}",
- bound,
- xform_self_ty);
-
- self.push_extension_candidate(xform_self_ty, item,
- WhereClauseCandidate(poly_bound), import_id);
- }
- }
-
fn candidate_method_names(&self) -> Vec<ast::Name> {
let mut set = FxHashSet();
- let mut names: Vec<_> =
- self.inherent_candidates
- .iter()
- .chain(&self.extension_candidates)
- .map(|candidate| candidate.item.name)
- .filter(|&name| set.insert(name))
- .collect();
+ let mut names: Vec<_> = self.inherent_candidates
+ .iter()
+ .chain(&self.extension_candidates)
+ .filter(|candidate| {
+ if let Some(return_ty) = self.return_type {
+ self.matches_return_type(&candidate.item, None, return_ty)
+ } else {
+ true
+ }
+ })
+ .map(|candidate| candidate.item.name)
+ .filter(|&name| set.insert(name))
+ .collect();
// sort them by the name so we have a stable result
names.sort_by_key(|n| n.as_str());
@@ -1049,10 +743,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
// THE ACTUAL SEARCH
fn pick(mut self) -> PickResult<'tcx> {
- assert!(match self.looking_for {
- LookingFor::MethodName(_) => true,
- LookingFor::ReturnType(_) => false,
- });
+ assert!(self.method_name.is_some());
if let Some(r) = self.pick_core() {
return r;
@@ -1095,10 +786,6 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
assert!(others.is_empty());
vec![]
}
- Some(Err(MethodError::ClosureAmbiguity(..))) => {
- // this error only occurs when assembling candidates
- span_bug!(span, "encountered ClosureAmbiguity from pick_core");
- }
_ => vec![],
};
@@ -1116,21 +803,17 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
let steps = self.steps.clone();
// find the first step that works
- steps.iter().filter_map(|step| self.pick_step(step)).next()
- }
-
- fn pick_step(&mut self, step: &CandidateStep<'tcx>) -> Option<PickResult<'tcx>> {
- debug!("pick_step: step={:?}", step);
-
- if step.self_ty.references_error() {
- return None;
- }
-
- if let Some(result) = self.pick_by_value_method(step) {
- return Some(result);
- }
-
- self.pick_autorefd_method(step)
+ steps
+ .iter()
+ .filter(|step| {
+ debug!("pick_core: step={:?}", step);
+ !step.self_ty.references_error()
+ }).flat_map(|step| {
+ self.pick_by_value_method(step).or_else(|| {
+ self.pick_autorefd_method(step, hir::MutImmutable).or_else(|| {
+ self.pick_autorefd_method(step, hir::MutMutable)
+ })})})
+ .next()
}
fn pick_by_value_method(&mut self, step: &CandidateStep<'tcx>) -> Option<PickResult<'tcx>> {
@@ -1161,36 +844,30 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
})
}
- fn pick_autorefd_method(&mut self, step: &CandidateStep<'tcx>) -> Option<PickResult<'tcx>> {
+ fn pick_autorefd_method(&mut self, step: &CandidateStep<'tcx>, mutbl: hir::Mutability)
+ -> Option<PickResult<'tcx>> {
let tcx = self.tcx;
// In general, during probing we erase regions. See
// `impl_self_ty()` for an explanation.
let region = tcx.types.re_erased;
- // Search through mutabilities in order to find one where pick works:
- [hir::MutImmutable, hir::MutMutable]
- .iter()
- .filter_map(|&m| {
- let autoref_ty = tcx.mk_ref(region,
- ty::TypeAndMut {
- ty: step.self_ty,
- mutbl: m,
- });
- self.pick_method(autoref_ty).map(|r| {
- r.map(|mut pick| {
- pick.autoderefs = step.autoderefs;
- pick.autoref = Some(m);
- pick.unsize = if step.unsize {
- Some(step.self_ty)
- } else {
- None
- };
- pick
- })
- })
+ let autoref_ty = tcx.mk_ref(region,
+ ty::TypeAndMut {
+ ty: step.self_ty, mutbl
+ });
+ self.pick_method(autoref_ty).map(|r| {
+ r.map(|mut pick| {
+ pick.autoderefs = step.autoderefs;
+ pick.autoref = Some(mutbl);
+ pick.unsize = if step.unsize {
+ Some(step.self_ty)
+ } else {
+ None
+ };
+ pick
})
- .nth(0)
+ })
}
fn pick_method(&mut self, self_ty: Ty<'tcx>) -> Option<PickResult<'tcx>> {
@@ -1221,7 +898,10 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
possibly_unsatisfied_predicates: &mut Vec<TraitRef<'tcx>>)
-> Option<PickResult<'tcx>> {
let mut applicable_candidates: Vec<_> = probes.iter()
- .filter(|&probe| self.consider_probe(self_ty, probe, possibly_unsatisfied_predicates))
+ .map(|probe| {
+ (probe, self.consider_probe(self_ty, probe, possibly_unsatisfied_predicates))
+ })
+ .filter(|&(_, status)| status != ProbeResult::NoMatch)
.collect();
debug!("applicable_candidates: {:?}", applicable_candidates);
@@ -1236,18 +916,60 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
}
if applicable_candidates.len() > 1 {
- let sources = probes.iter().map(|p| p.to_source()).collect();
+ let sources = probes.iter()
+ .map(|p| self.candidate_source(p, self_ty))
+ .collect();
return Some(Err(MethodError::Ambiguity(sources)));
}
- applicable_candidates.pop().map(|probe| Ok(probe.to_unadjusted_pick()))
+ applicable_candidates.pop().map(|(probe, status)| {
+ if status == ProbeResult::Match {
+ Ok(probe.to_unadjusted_pick())
+ } else {
+ Err(MethodError::BadReturnType)
+ }
+ })
+ }
+
+ fn select_trait_candidate(&self, trait_ref: ty::TraitRef<'tcx>)
+ -> traits::SelectionResult<'tcx, traits::Selection<'tcx>>
+ {
+ let cause = traits::ObligationCause::misc(self.span, self.body_id);
+ let predicate =
+ trait_ref.to_poly_trait_ref().to_poly_trait_predicate();
+ let obligation = traits::Obligation::new(cause, self.param_env, predicate);
+ traits::SelectionContext::new(self).select(&obligation)
+ }
+
+ fn candidate_source(&self, candidate: &Candidate<'tcx>, self_ty: Ty<'tcx>)
+ -> CandidateSource
+ {
+ match candidate.kind {
+ InherentImplCandidate(..) => ImplSource(candidate.item.container.id()),
+ ObjectCandidate |
+ WhereClauseCandidate(_) => TraitSource(candidate.item.container.id()),
+ TraitCandidate(trait_ref) => self.probe(|_| {
+ let _ = self.at(&ObligationCause::dummy(), self.param_env)
+ .sup(candidate.xform_self_ty, self_ty);
+ match self.select_trait_candidate(trait_ref) {
+ Ok(Some(traits::Vtable::VtableImpl(ref impl_data))) => {
+ // If only a single impl matches, make the error message point
+ // to that impl.
+ ImplSource(impl_data.impl_def_id)
+ }
+ _ => {
+ TraitSource(candidate.item.container.id())
+ }
+ }
+ })
+ }
}
fn consider_probe(&self,
self_ty: Ty<'tcx>,
probe: &Candidate<'tcx>,
possibly_unsatisfied_predicates: &mut Vec<TraitRef<'tcx>>)
- -> bool {
+ -> ProbeResult {
debug!("consider_probe: self_ty={:?} probe={:?}", self_ty, probe);
self.probe(|_| {
@@ -1257,60 +979,102 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
Ok(InferOk { obligations, value: () }) => obligations,
Err(_) => {
debug!("--> cannot relate self-types");
- return false;
+ return ProbeResult::NoMatch;
}
};
+ let mut result = ProbeResult::Match;
+ let selcx = &mut traits::SelectionContext::new(self);
+ let cause = traits::ObligationCause::misc(self.span, self.body_id);
+
// If so, impls may carry other conditions (e.g., where
// clauses) that must be considered. Make sure that those
// match as well (or at least may match, sometimes we
// don't have enough information to fully evaluate).
- let (impl_def_id, substs, ref_obligations) = match probe.kind {
+ let candidate_obligations : Vec<_> = match probe.kind {
InherentImplCandidate(ref substs, ref ref_obligations) => {
- (probe.item.container.id(), substs, ref_obligations)
- }
-
- ExtensionImplCandidate(impl_def_id, ref substs, ref ref_obligations) => {
- (impl_def_id, substs, ref_obligations)
+ // Check whether the impl imposes obligations we have to worry about.
+ let impl_def_id = probe.item.container.id();
+ let impl_bounds = self.tcx.predicates_of(impl_def_id);
+ let impl_bounds = impl_bounds.instantiate(self.tcx, substs);
+ let traits::Normalized { value: impl_bounds, obligations: norm_obligations } =
+ traits::normalize(selcx, self.param_env, cause.clone(), &impl_bounds);
+
+ // Convert the bounds into obligations.
+ let impl_obligations = traits::predicates_for_generics(
+ cause.clone(), self.param_env, &impl_bounds);
+
+ debug!("impl_obligations={:?}", impl_obligations);
+ impl_obligations.into_iter()
+ .chain(norm_obligations.into_iter())
+ .chain(ref_obligations.iter().cloned())
+ .collect()
}
ObjectCandidate |
- TraitCandidate |
WhereClauseCandidate(..) => {
// These have no additional conditions to check.
- return true;
+ vec![]
}
- };
- let selcx = &mut traits::SelectionContext::new(self);
- let cause = traits::ObligationCause::misc(self.span, self.body_id);
-
- // Check whether the impl imposes obligations we have to worry about.
- let impl_bounds = self.tcx.predicates_of(impl_def_id);
- let impl_bounds = impl_bounds.instantiate(self.tcx, substs);
- let traits::Normalized { value: impl_bounds, obligations: norm_obligations } =
- traits::normalize(selcx, self.param_env, cause.clone(), &impl_bounds);
+ TraitCandidate(trait_ref) => {
+ let predicate = trait_ref.to_predicate();
+ let obligation =
+ traits::Obligation::new(cause.clone(), self.param_env, predicate);
+ if !selcx.evaluate_obligation(&obligation) {
+ if self.probe(|_| self.select_trait_candidate(trait_ref).is_err()) {
+ // This candidate's primary obligation doesn't even
+ // select - don't bother registering anything in
+ // `potentially_unsatisfied_predicates`.
+ return ProbeResult::NoMatch;
+ } else {
+ // Some nested subobligation of this predicate
+ // failed.
+ //
+ // FIXME: try to find the exact nested subobligation
+ // and point at it rather than reporting the entire
+ // trait-ref?
+ result = ProbeResult::NoMatch;
+ let trait_ref = self.resolve_type_vars_if_possible(&trait_ref);
+ possibly_unsatisfied_predicates.push(trait_ref);
+ }
+ }
+ vec![]
+ }
+ };
- // Convert the bounds into obligations.
- let obligations = traits::predicates_for_generics(cause.clone(),
- self.param_env,
- &impl_bounds);
- debug!("impl_obligations={:?}", obligations);
+ debug!("consider_probe - candidate_obligations={:?} sub_obligations={:?}",
+ candidate_obligations, sub_obligations);
// Evaluate those obligations to see if they might possibly hold.
- let mut all_true = true;
- for o in obligations.iter()
- .chain(sub_obligations.iter())
- .chain(norm_obligations.iter())
- .chain(ref_obligations.iter()) {
- if !selcx.evaluate_obligation(o) {
- all_true = false;
+ for o in candidate_obligations.into_iter().chain(sub_obligations) {
+ let o = self.resolve_type_vars_if_possible(&o);
+ if !selcx.evaluate_obligation(&o) {
+ result = ProbeResult::NoMatch;
if let &ty::Predicate::Trait(ref pred) = &o.predicate {
possibly_unsatisfied_predicates.push(pred.0.trait_ref);
}
}
}
- all_true
+
+ if let ProbeResult::Match = result {
+ if let (Some(return_ty), Some(xform_ret_ty)) =
+ (self.return_type, probe.xform_ret_ty)
+ {
+ let xform_ret_ty = self.resolve_type_vars_if_possible(&xform_ret_ty);
+ debug!("comparing return_ty {:?} with xform ret ty {:?}",
+ return_ty,
+ probe.xform_ret_ty);
+ if self.at(&ObligationCause::dummy(), self.param_env)
+ .sup(return_ty, xform_ret_ty)
+ .is_err()
+ {
+ return ProbeResult::BadReturnType;
+ }
+ }
+ }
+
+ result
})
}
@@ -1331,22 +1095,25 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
///
/// Now imagine the receiver is `Vec<_>`. It doesn't really matter at this time which impl we
/// use, so it's ok to just commit to "using the method from the trait Foo".
- fn collapse_candidates_to_trait_pick(&self, probes: &[&Candidate<'tcx>]) -> Option<Pick<'tcx>> {
+ fn collapse_candidates_to_trait_pick(&self, probes: &[(&Candidate<'tcx>, ProbeResult)])
+ -> Option<Pick<'tcx>>
+ {
// Do all probes correspond to the same trait?
- let container = probes[0].item.container;
+ let container = probes[0].0.item.container;
match container {
ty::TraitContainer(_) => {}
ty::ImplContainer(_) => return None,
}
- if probes[1..].iter().any(|p| p.item.container != container) {
+ if probes[1..].iter().any(|&(p, _)| p.item.container != container) {
return None;
}
+ // FIXME: check the return type here somehow.
// If so, just use this trait and call it a day.
Some(Pick {
- item: probes[0].item.clone(),
+ item: probes[0].0.item.clone(),
kind: TraitPick,
- import_id: probes[0].import_id,
+ import_id: probes[0].0.import_id,
autoderefs: 0,
autoref: None,
unsize: None,
@@ -1384,23 +1151,23 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
item: &ty::AssociatedItem,
impl_ty: Ty<'tcx>,
substs: &Substs<'tcx>)
- -> Ty<'tcx> {
+ -> (Ty<'tcx>, Option<Ty<'tcx>>) {
if item.kind == ty::AssociatedKind::Method && self.mode == Mode::MethodCall {
- self.xform_method_self_ty(item.def_id, impl_ty, substs)
+ let sig = self.xform_method_sig(item.def_id, substs);
+ (sig.inputs()[0], Some(sig.output()))
} else {
- impl_ty
+ (impl_ty, None)
}
}
- fn xform_method_self_ty(&self,
- method: DefId,
- impl_ty: Ty<'tcx>,
- substs: &Substs<'tcx>)
- -> Ty<'tcx> {
- let self_ty = self.tcx.fn_sig(method).input(0);
- debug!("xform_self_ty(impl_ty={:?}, self_ty={:?}, substs={:?})",
- impl_ty,
- self_ty,
+ fn xform_method_sig(&self,
+ method: DefId,
+ substs: &Substs<'tcx>)
+ -> ty::FnSig<'tcx>
+ {
+ let fn_sig = self.tcx.fn_sig(method);
+ debug!("xform_self_ty(fn_sig={:?}, substs={:?})",
+ fn_sig,
substs);
assert!(!substs.has_escaping_regions());
@@ -1416,10 +1183,10 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
// Erase any late-bound regions from the method and substitute
// in the values from the substitution.
- let xform_self_ty = self.erase_late_bound_regions(&self_ty);
+ let xform_fn_sig = self.erase_late_bound_regions(&fn_sig);
if generics.types.is_empty() && generics.regions.is_empty() {
- xform_self_ty.subst(self.tcx, substs)
+ xform_fn_sig.subst(self.tcx, substs)
} else {
let substs = Substs::for_item(self.tcx, method, |def, _| {
let i = def.index as usize;
@@ -1438,22 +1205,22 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
self.type_var_for_def(self.span, def, cur_substs)
}
});
- xform_self_ty.subst(self.tcx, substs)
+ xform_fn_sig.subst(self.tcx, substs)
}
}
/// Get the type of an impl and generate substitutions with placeholders.
fn impl_ty_and_substs(&self, impl_def_id: DefId) -> (Ty<'tcx>, &'tcx Substs<'tcx>) {
- let impl_ty = self.tcx.type_of(impl_def_id);
-
- let substs = Substs::for_item(self.tcx,
- impl_def_id,
- |_, _| self.tcx.types.re_erased,
- |_, _| self.next_ty_var(
- TypeVariableOrigin::SubstitutionPlaceholder(
- self.tcx.def_span(impl_def_id))));
+ (self.tcx.type_of(impl_def_id), self.fresh_item_substs(impl_def_id))
+ }
- (impl_ty, substs)
+ fn fresh_item_substs(&self, def_id: DefId) -> &'tcx Substs<'tcx> {
+ Substs::for_item(self.tcx,
+ def_id,
+ |_, _| self.tcx.types.re_erased,
+ |_, _| self.next_ty_var(
+ TypeVariableOrigin::SubstitutionPlaceholder(
+ self.tcx.def_span(def_id))))
}
/// Replace late-bound-regions bound by `value` with `'static` using
@@ -1482,17 +1249,10 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
/// Find the method with the appropriate name (or return type, as the case may be).
fn impl_or_trait_item(&self, def_id: DefId) -> Vec<ty::AssociatedItem> {
- match self.looking_for {
- LookingFor::MethodName(name) => {
- self.fcx.associated_item(def_id, name).map_or(Vec::new(), |x| vec![x])
- }
- LookingFor::ReturnType(return_ty) => {
- self.tcx
- .associated_items(def_id)
- .map(|did| self.tcx.associated_item(did.def_id))
- .filter(|m| self.matches_return_type(m, return_ty))
- .collect()
- }
+ if let Some(name) = self.method_name {
+ self.fcx.associated_item(def_id, name).map_or(Vec::new(), |x| vec![x])
+ } else {
+ self.tcx.associated_items(def_id).collect()
}
}
}
@@ -1503,9 +1263,8 @@ impl<'tcx> Candidate<'tcx> {
item: self.item.clone(),
kind: match self.kind {
InherentImplCandidate(..) => InherentImplPick,
- ExtensionImplCandidate(def_id, ..) => ExtensionImplPick(def_id),
ObjectCandidate => ObjectPick,
- TraitCandidate => TraitPick,
+ TraitCandidate(_) => TraitPick,
WhereClauseCandidate(ref trait_ref) => {
// Only trait derived from where-clauses should
// appear here, so they should not contain any
@@ -1523,14 +1282,4 @@ impl<'tcx> Candidate<'tcx> {
unsize: None,
}
}
-
- fn to_source(&self) -> CandidateSource {
- match self.kind {
- InherentImplCandidate(..) => ImplSource(self.item.container.id()),
- ExtensionImplCandidate(def_id, ..) => ImplSource(def_id),
- ObjectCandidate |
- TraitCandidate |
- WhereClauseCandidate(_) => TraitSource(self.item.container.id()),
- }
- }
}
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index c8b828f3a434d..f2d7842e473f6 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -296,22 +296,6 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
err.emit();
}
- MethodError::ClosureAmbiguity(trait_def_id) => {
- let msg = format!("the `{}` method from the `{}` trait cannot be explicitly \
- invoked on this closure as we have not yet inferred what \
- kind of closure it is",
- item_name,
- self.tcx.item_path_str(trait_def_id));
- let msg = if let Some(callee) = rcvr_expr {
- format!("{}; use overloaded call notation instead (e.g., `{}()`)",
- msg,
- self.tcx.hir.node_to_pretty_string(callee.id))
- } else {
- msg
- };
- self.sess().span_err(span, &msg);
- }
-
MethodError::PrivateMatch(def, out_of_scope_traits) => {
let mut err = struct_span_err!(self.tcx.sess, span, E0624,
"{} `{}` is private", def.kind_name(), item_name);
@@ -337,6 +321,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
err.emit();
}
+
+ MethodError::BadReturnType => {
+ bug!("no return type expectations but got BadReturnType")
+ }
}
}
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 0427727269607..e937770bb0161 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -2818,6 +2818,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
formal_ret: Ty<'tcx>,
formal_args: &[Ty<'tcx>])
-> Vec<Ty<'tcx>> {
+ let formal_ret = self.resolve_type_vars_with_obligations(formal_ret);
let expected_args = expected_ret.only_has_type(self).and_then(|ret_ty| {
self.fudge_regions_if_ok(&RegionVariableOrigin::Coercion(call_span), || {
// Attempt to apply a subtyping relationship between the formal
@@ -3978,6 +3979,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
hir::ExprTup(ref elts) => {
let flds = expected.only_has_type(self).and_then(|ty| {
+ let ty = self.resolve_type_vars_with_obligations(ty);
match ty.sty {
ty::TyTuple(ref flds, _) => Some(&flds[..]),
_ => None
diff --git a/src/test/run-pass/method-argument-inference-associated-type.rs b/src/test/run-pass/method-argument-inference-associated-type.rs
new file mode 100644
index 0000000000000..76b8cf92329d1
--- /dev/null
+++ b/src/test/run-pass/method-argument-inference-associated-type.rs
@@ -0,0 +1,37 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub struct ClientMap;
+pub struct ClientMap2;
+
+pub trait Service {
+ type Request;
+ fn call(&self, _req: Self::Request);
+}
+
+pub struct S<T>(T);
+
+impl Service for ClientMap {
+ type Request = S<Box<Fn(i32)>>;
+ fn call(&self, _req: Self::Request) {}
+}
+
+
+impl Service for ClientMap2 {
+ type Request = (Box<Fn(i32)>,);
+ fn call(&self, _req: Self::Request) {}
+}
+
+
+fn main() {
+ ClientMap.call(S { 0: Box::new(|_msgid| ()) });
+ ClientMap.call(S(Box::new(|_msgid| ())));
+ ClientMap2.call((Box::new(|_msgid| ()),));
+}
diff --git a/src/test/compile-fail/unboxed-closures-infer-explicit-call-too-early.rs b/src/test/run-pass/unboxed-closures-infer-explicit-call-early.rs
similarity index 79%
rename from src/test/compile-fail/unboxed-closures-infer-explicit-call-too-early.rs
rename to src/test/run-pass/unboxed-closures-infer-explicit-call-early.rs
index 62f6ee56ca5de..028f2e9375b3c 100644
--- a/src/test/compile-fail/unboxed-closures-infer-explicit-call-too-early.rs
+++ b/src/test/run-pass/unboxed-closures-infer-explicit-call-early.rs
@@ -8,8 +8,10 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
+#![feature(fn_traits)]
+
fn main() {
- let mut zero = || {};
- let () = zero.call_mut(());
- //~^ ERROR we have not yet inferred what kind of closure it is
+ let mut zero = || 0;
+ let x = zero.call_mut(());
+ assert_eq!(x, 0);
}
diff --git a/src/test/ui/impl-trait/no-method-suggested-traits.stderr b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
index fc441f9484273..23f115858cd5e 100644
--- a/src/test/ui/impl-trait/no-method-suggested-traits.stderr
+++ b/src/test/ui/impl-trait/no-method-suggested-traits.stderr
@@ -8,6 +8,8 @@ error[E0599]: no method named `method` found for type `u32` in the current scope
= note: the following traits are implemented but not in scope, perhaps add a `use` for one of them:
candidate #1: `use foo::Bar;`
candidate #2: `use no_method_suggested_traits::foo::PubPub;`
+ candidate #3: `use no_method_suggested_traits::qux::PrivPub;`
+ candidate #4: `use no_method_suggested_traits::Reexported;`
error[E0599]: no method named `method` found for type `std::rc::Rc<&mut std::boxed::Box<&u32>>` in the current scope
--> $DIR/no-method-suggested-traits.rs:38:44
@@ -19,6 +21,8 @@ error[E0599]: no method named `method` found for type `std::rc::Rc<&mut std::box
= note: the following traits are implemented but not in scope, perhaps add a `use` for one of them:
candidate #1: `use foo::Bar;`
candidate #2: `use no_method_suggested_traits::foo::PubPub;`
+ candidate #3: `use no_method_suggested_traits::qux::PrivPub;`
+ candidate #4: `use no_method_suggested_traits::Reexported;`
error[E0599]: no method named `method` found for type `char` in the current scope
--> $DIR/no-method-suggested-traits.rs:44:9
diff --git a/src/test/ui/mismatched_types/issue-36053-2.stderr b/src/test/ui/mismatched_types/issue-36053-2.stderr
index 174f7dfa0d0f5..e2e2019307f34 100644
--- a/src/test/ui/mismatched_types/issue-36053-2.stderr
+++ b/src/test/ui/mismatched_types/issue-36053-2.stderr
@@ -5,8 +5,8 @@ error[E0599]: no method named `count` found for type `std::iter::Filter<std::ite
| ^^^^^
|
= note: the method `count` exists but the following trait bounds were not satisfied:
- `[closure@$DIR/issue-36053-2.rs:17:39: 17:53] : std::ops::FnMut<(&_,)>`
`std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
+ `&mut std::iter::Filter<std::iter::Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:17:39: 17:53]> : std::iter::Iterator`
error[E0281]: type mismatch: `[closure@$DIR/issue-36053-2.rs:17:39: 17:53]` implements the trait `for<'r> std::ops::FnMut<(&'r str,)>`, but the trait `for<'r> std::ops::FnMut<(&'r &str,)>` is required
--> $DIR/issue-36053-2.rs:17:32
diff --git a/src/test/ui/suggestions/issue-43420-no-over-suggest.rs b/src/test/ui/suggestions/issue-43420-no-over-suggest.rs
new file mode 100644
index 0000000000000..d504b7cae28c4
--- /dev/null
+++ b/src/test/ui/suggestions/issue-43420-no-over-suggest.rs
@@ -0,0 +1,19 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// check that we substitute type parameters before we suggest anything - otherwise
+// we would suggest function such as `as_slice` for the `&[u16]`.
+
+fn foo(b: &[u16]) {}
+
+fn main() {
+ let a: Vec<u8> = Vec::new();
+ foo(&a);
+}
diff --git a/src/test/ui/suggestions/issue-43420-no-over-suggest.stderr b/src/test/ui/suggestions/issue-43420-no-over-suggest.stderr
new file mode 100644
index 0000000000000..bcad9ce56c65e
--- /dev/null
+++ b/src/test/ui/suggestions/issue-43420-no-over-suggest.stderr
@@ -0,0 +1,11 @@
+error[E0308]: mismatched types
+ --> $DIR/issue-43420-no-over-suggest.rs:18:9
+ |
+18 | foo(&a);
+ | ^^ expected slice, found struct `std::vec::Vec`
+ |
+ = note: expected type `&[u16]`
+ found type `&std::vec::Vec<u8>`
+
+error: aborting due to previous error
+