squiid/rust
1
0
Fork 0
Code Issues Pull requests Projects Activity

Auto merge of #23438 - nikomatsakis:issue-23435-default-methods-with-where-clauses, r=nrc

Browse source 
Fixes #23435
This commit is contained in:
bors 2015-03-18 00:51:03 +00:00
commit 1ae32decb8
5 changed files with 171 additions and 49 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
src/librustc/util/ppaux.rs
View file

@ -1053,10 +1053,11 @@ impl<'tcx> Repr<'tcx> for ty::Variance {
impl<'tcx> Repr<'tcx> for ty::Method<'tcx> {
fn repr(&self, tcx: &ctxt<'tcx>) -> String {
format!("method(name: {}, generics: {}, fty: {}, \
format!("method(name: {}, generics: {}, predicates: {}, fty: {}, \
explicit_self: {}, vis: {}, def_id: {})",
self.name.repr(tcx),
self.generics.repr(tcx),
self.predicates.repr(tcx),
self.fty.repr(tcx),
self.explicit_self.repr(tcx),
self.vis.repr(tcx),

67
src/librustc_trans/trans/common.rs
View file

@ -46,6 +46,7 @@ use arena::TypedArena;
use libc::{c_uint, c_char};
use std::ffi::CString;
use std::cell::{Cell, RefCell};
use std::result::Result as StdResult;
use std::vec::Vec;
use syntax::ast::Ident;
use syntax::ast;
@ -997,9 +998,9 @@ pub fn expr_ty_adjusted<'blk, 'tcx>(bcx: &BlockS<'blk, 'tcx>, ex: &ast::Expr) ->
/// do not (necessarily) resolve all nested obligations on the impl. Note that type check should
/// guarantee to us that all nested obligations *could be* resolved if we wanted to.
pub fn fulfill_obligation<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
span: Span,
trait_ref: ty::PolyTraitRef<'tcx>)
-> traits::Vtable<'tcx, ()>
span: Span,
trait_ref: ty::PolyTraitRef<'tcx>)
-> traits::Vtable<'tcx, ()>
{
let tcx = ccx.tcx();
@ -1058,7 +1059,7 @@ pub fn fulfill_obligation<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
let vtable = selection.map_move_nested(|predicate| {
fulfill_cx.register_predicate_obligation(&infcx, predicate);
});
let vtable = drain_fulfillment_cx(span, &infcx, &mut fulfill_cx, &vtable);
let vtable = drain_fulfillment_cx_or_panic(span, &infcx, &mut fulfill_cx, &vtable);
info!("Cache miss: {}", trait_ref.repr(ccx.tcx()));
ccx.trait_cache().borrow_mut().insert(trait_ref,
@ -1067,6 +1068,22 @@ pub fn fulfill_obligation<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
vtable
}
pub fn predicates_hold<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
predicates: Vec<ty::Predicate<'tcx>>)
-> bool
{
debug!("predicates_hold(predicates={})",
predicates.repr(ccx.tcx()));
let infcx = infer::new_infer_ctxt(ccx.tcx());
let mut fulfill_cx = traits::FulfillmentContext::new();
for predicate in predicates {
let obligation = traits::Obligation::new(traits::ObligationCause::dummy(), predicate);
fulfill_cx.register_predicate_obligation(&infcx, obligation);
}
drain_fulfillment_cx(DUMMY_SP, &infcx, &mut fulfill_cx, &()).is_ok()
}
pub struct NormalizingClosureTyper<'a,'tcx:'a> {
param_env: ty::ParameterEnvironment<'a, 'tcx>
}
@ -1114,11 +1131,36 @@ impl<'a,'tcx> ty::ClosureTyper<'tcx> for NormalizingClosureTyper<'a,'tcx> {
}
}
pub fn drain_fulfillment_cx_or_panic<'a,'tcx,T>(span: Span,
infcx: &infer::InferCtxt<'a,'tcx>,
fulfill_cx: &mut traits::FulfillmentContext<'tcx>,
result: &T)
-> T
where T : TypeFoldable<'tcx> + Repr<'tcx>
{
match drain_fulfillment_cx(span, infcx, fulfill_cx, result) {
Ok(v) => v,
Err(errors) => {
infcx.tcx.sess.span_bug(
span,
&format!("Encountered errors `{}` fulfilling during trans",
errors.repr(infcx.tcx)));
}
}
}
/// Finishes processes any obligations that remain in the fulfillment
/// context, and then "freshens" and returns `result`. This is
/// primarily used during normalization and other cases where
/// processing the obligations in `fulfill_cx` may cause type
/// inference variables that appear in `result` to be unified, and
/// hence we need to process those obligations to get the complete
/// picture of the type.
pub fn drain_fulfillment_cx<'a,'tcx,T>(span: Span,
infcx: &infer::InferCtxt<'a,'tcx>,
fulfill_cx: &mut traits::FulfillmentContext<'tcx>,
result: &T)
-> T
infcx: &infer::InferCtxt<'a,'tcx>,
fulfill_cx: &mut traits::FulfillmentContext<'tcx>,
result: &T)
-> StdResult<T,Vec<traits::FulfillmentError<'tcx>>>
where T : TypeFoldable<'tcx> + Repr<'tcx>
{
debug!("drain_fulfillment_cx(result={})",
@ -1131,16 +1173,13 @@ pub fn drain_fulfillment_cx<'a,'tcx,T>(span: Span,
match fulfill_cx.select_all_or_error(infcx, &typer) {
Ok(()) => { }
Err(errors) => {
// We always want to surface any overflow errors, no matter what.
if errors.iter().all(|e| e.is_overflow()) {
// See Ok(None) case above.
infcx.tcx.sess.span_fatal(
span,
"reached the recursion limit during monomorphization");
} else {
infcx.tcx.sess.span_bug(
span,
&format!("Encountered errors `{}` fulfilling during trans",
errors.repr(infcx.tcx)));
return Err(errors);
}
}
}
@ -1150,7 +1189,7 @@ pub fn drain_fulfillment_cx<'a,'tcx,T>(span: Span,
// sort of overkill because we do not expect there to be any
// unbound type variables, hence no `TyFresh` types should ever be
// inserted.
result.fold_with(&mut infcx.freshener())
Ok(result.fold_with(&mut infcx.freshener()))
}
// Key used to lookup values supplied for type parameters in an expr.

113
src/librustc_trans/trans/meth.rs
View file

@ -765,9 +765,15 @@ fn emit_vtable_methods<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
impl_id: ast::DefId,
substs: subst::Substs<'tcx>,
param_substs: &'tcx subst::Substs<'tcx>)
-> Vec<ValueRef> {
-> Vec<ValueRef>
{
let tcx = ccx.tcx();
debug!("emit_vtable_methods(impl_id={}, substs={}, param_substs={})",
impl_id.repr(tcx),
substs.repr(tcx),
param_substs.repr(tcx));
let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
Some(t_id) => t_id.def_id,
None => ccx.sess().bug("make_impl_vtable: don't know how to \
@ -777,41 +783,82 @@ fn emit_vtable_methods<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
ty::populate_implementations_for_trait_if_necessary(tcx, trt_id);
let trait_item_def_ids = ty::trait_item_def_ids(tcx, trt_id);
trait_item_def_ids.iter().flat_map(|method_def_id| {
let method_def_id = method_def_id.def_id();
let name = ty::impl_or_trait_item(tcx, method_def_id).name();
// The substitutions we have are on the impl, so we grab
// the method type from the impl to substitute into.
let m_id = method_with_name(ccx, impl_id, name);
let ti = ty::impl_or_trait_item(tcx, m_id);
match ti {
ty::MethodTraitItem(m) => {
debug!("(making impl vtable) emitting method {} at subst {}",
m.repr(tcx),
substs.repr(tcx));
if m.generics.has_type_params(subst::FnSpace) ||
ty::type_has_self(ty::mk_bare_fn(tcx, None, tcx.mk_bare_fn(m.fty.clone())))
{
debug!("(making impl vtable) method has self or type \
params: {}",
token::get_name(name));
Some(C_null(Type::nil(ccx).ptr_to())).into_iter()
} else {
let fn_ref = trans_fn_ref_with_substs(
ccx,
m_id,
ExprId(0),
param_substs,
substs.clone()).val;
trait_item_def_ids
.iter()
Some(fn_ref).into_iter()
// Filter out the associated types.
.filter_map(|item_def_id| {
match *item_def_id {
ty::MethodTraitItemId(def_id) => Some(def_id),
ty::TypeTraitItemId(_) => None,
}
})
// Now produce pointers for each remaining method. If the
// method could never be called from this object, just supply
// null.
.map(|trait_method_def_id| {
debug!("emit_vtable_methods: trait_method_def_id={}",
trait_method_def_id.repr(tcx));
let trait_method_type = match ty::impl_or_trait_item(tcx, trait_method_def_id) {
ty::MethodTraitItem(m) => m,
ty::TypeTraitItem(_) => ccx.sess().bug("should be a method, not assoc type")
};
let name = trait_method_type.name;
debug!("emit_vtable_methods: trait_method_type={}",
trait_method_type.repr(tcx));
// The substitutions we have are on the impl, so we grab
// the method type from the impl to substitute into.
let impl_method_def_id = method_with_name(ccx, impl_id, name);
let impl_method_type = match ty::impl_or_trait_item(tcx, impl_method_def_id) {
ty::MethodTraitItem(m) => m,
ty::TypeTraitItem(_) => ccx.sess().bug("should be a method, not assoc type")
};
debug!("emit_vtable_methods: m={}",
impl_method_type.repr(tcx));
let nullptr = C_null(Type::nil(ccx).ptr_to());
if impl_method_type.generics.has_type_params(subst::FnSpace) {
debug!("emit_vtable_methods: generic");
return nullptr;
}
let bare_fn_ty =
ty::mk_bare_fn(tcx, None, tcx.mk_bare_fn(impl_method_type.fty.clone()));
if ty::type_has_self(bare_fn_ty) {
debug!("emit_vtable_methods: type_has_self {}",
bare_fn_ty.repr(tcx));
return nullptr;
}
// If this is a default method, it's possible that it
// relies on where clauses that do not hold for this
// particular set of type parameters. Note that this
// method could then never be called, so we do not want to
// try and trans it, in that case. Issue #23435.
if ty::provided_source(tcx, impl_method_def_id).is_some() {
let predicates =
monomorphize::apply_param_substs(tcx,
&substs,
&impl_method_type.predicates.predicates);
if !predicates_hold(ccx, predicates.into_vec()) {
debug!("emit_vtable_methods: predicates do not hold");
return nullptr;
}
}
ty::TypeTraitItem(_) => {
None.into_iter()
}
}
}).collect()
trans_fn_ref_with_substs(ccx,
impl_method_def_id,
ExprId(0),
param_substs,
substs.clone()).val
})
.collect()
}
/// Generates the code to convert from a pointer (`Box<T>`, `&T`, etc) into an object

2
src/librustc_trans/trans/monomorphize.rs
View file

@ -339,7 +339,7 @@ pub fn normalize_associated_type<'tcx,T>(tcx: &ty::ctxt<'tcx>, value: &T) -> T
for obligation in obligations {
fulfill_cx.register_predicate_obligation(&infcx, obligation);
}
let result = drain_fulfillment_cx(DUMMY_SP, &infcx, &mut fulfill_cx, &result);
let result = drain_fulfillment_cx_or_panic(DUMMY_SP, &infcx, &mut fulfill_cx, &result);
result
}

35
src/test/run-pass/issue-23435.rs Normal file
View file

@ -0,0 +1,35 @@
// Copyright 2015 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.
// Test that we do not ICE when a default method implementation has
// requirements (in this case, `Self : Baz`) that do not hold for some
// specific impl (in this case, `Foo : Bar`). This causes problems
// only when building a vtable, because that goes along and
// instantiates all the methods, even those that could not otherwise
// be called.
struct Foo {
x: i32
}
trait Bar {
fn bar(&self) where Self : Baz { self.baz(); }
}
trait Baz {
fn baz(&self);
}
impl Bar for Foo {
}
fn main() {
let x: &Bar = &Foo { x: 22 };
}