Further work on default methods in traits.
And some trait-related code cleanup in typeck::collect.
This commit is contained in:
Lindsey Kuper
parent
a98407ee34
commit
fe2f3d210a
1 changed files with 62 additions and 39 deletions
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@ -177,33 +177,33 @@ fn ensure_trait_methods(ccx: @crate_ctxt, id: ast::node_id) {
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*
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* - impl_m: the method in the impl
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* - impl_tps: the type params declared on the impl itself (not the method!)
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* - if_m: the method in the trait
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* - if_substs: the substitutions used on the type of the trait
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* - trait_m: the method in the trait
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* - trait_substs: the substitutions used on the type of the trait
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* - self_ty: the self type of the impl
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*/
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fn compare_impl_method(tcx: ty::ctxt, sp: span,
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impl_m: ty::method, impl_tps: uint,
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if_m: ty::method, if_substs: ty::substs,
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trait_m: ty::method, trait_substs: ty::substs,
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self_ty: ty::t) {
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if impl_m.tps != if_m.tps {
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tcx.sess.span_err(sp, ~"method `" + *if_m.ident +
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if impl_m.tps != trait_m.tps {
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tcx.sess.span_err(sp, ~"method `" + *trait_m.ident +
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~"` has an incompatible set of type parameters");
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return;
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}
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if vec::len(impl_m.fty.inputs) != vec::len(if_m.fty.inputs) {
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if vec::len(impl_m.fty.inputs) != vec::len(trait_m.fty.inputs) {
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tcx.sess.span_err(sp,fmt!{"method `%s` has %u parameters \
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but the trait has %u",
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*if_m.ident,
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*trait_m.ident,
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vec::len(impl_m.fty.inputs),
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vec::len(if_m.fty.inputs)});
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vec::len(trait_m.fty.inputs)});
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return;
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}
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// Perform substitutions so that the trait/impl methods are expressed
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// in terms of the same set of type/region parameters:
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// - replace trait type parameters with those from `if_substs`
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// - replace trait type parameters with those from `trait_substs`
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// - replace method parameters on the trait with fresh, dummy parameters
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// that correspond to the parameters we will find on the impl
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// - replace self region with a fresh, dummy region
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@ -212,8 +212,8 @@ fn compare_impl_method(tcx: ty::ctxt, sp: span,
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let impl_fty = ty::mk_fn(tcx, impl_m.fty);
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replace_bound_self(tcx, impl_fty, dummy_self_r)
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};
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let if_fty = {
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let dummy_tps = do vec::from_fn((*if_m.tps).len()) |i| {
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let trait_fty = {
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let dummy_tps = do vec::from_fn((*trait_m.tps).len()) |i| {
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// hack: we don't know the def id of the impl tp, but it
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// is not important for unification
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ty::mk_param(tcx, i + impl_tps, {crate: 0, node: 0})
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@ -221,14 +221,14 @@ fn compare_impl_method(tcx: ty::ctxt, sp: span,
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let substs = {
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self_r: some(dummy_self_r),
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self_ty: some(self_ty),
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tps: vec::append(if_substs.tps, dummy_tps)
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tps: vec::append(trait_substs.tps, dummy_tps)
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};
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let if_fty = ty::mk_fn(tcx, if_m.fty);
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ty::subst(tcx, substs, if_fty)
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let trait_fty = ty::mk_fn(tcx, trait_m.fty);
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ty::subst(tcx, substs, trait_fty)
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};
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require_same_types(
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tcx, none, sp, impl_fty, if_fty,
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|| ~"method `" + *if_m.ident + ~"` has an incompatible type");
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tcx, none, sp, impl_fty, trait_fty,
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|| ~"method `" + *trait_m.ident + ~"` has an incompatible type");
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return;
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// Replaces bound references to the self region with `with_r`.
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@ -245,36 +245,59 @@ fn check_methods_against_trait(ccx: @crate_ctxt,
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rp: bool,
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selfty: ty::t,
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a_trait_ty: @ast::trait_ref,
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ms: ~[converted_method]) {
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impl_ms: ~[converted_method]) {
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let tcx = ccx.tcx;
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let (did, tpt) = instantiate_trait_ref(ccx, a_trait_ty, rp);
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if did.crate == ast::local_crate {
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ensure_trait_methods(ccx, did.node);
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}
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for vec::each(*ty::trait_methods(tcx, did)) |if_m| {
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alt vec::find(ms, |m| if_m.ident == m.mty.ident) {
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some({mty: m, id, span}) {
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if m.purity != if_m.purity {
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for vec::each(*ty::trait_methods(tcx, did)) |trait_m| {
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alt vec::find(impl_ms, |impl_m| trait_m.ident == impl_m.mty.ident) {
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some({mty: impl_m, id, span}) {
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if impl_m.purity != trait_m.purity {
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ccx.tcx.sess.span_err(
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span, fmt!{"method `%s`'s purity does \
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not match the trait method's \
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purity", *m.ident});
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purity", *impl_m.ident});
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}
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compare_impl_method(
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ccx.tcx, span, m, vec::len(tps),
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if_m, tpt.substs, selfty);
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ccx.tcx, span, impl_m, vec::len(tps),
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trait_m, tpt.substs, selfty);
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}
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none {
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// FIXME (#2794): if there's a default impl in the trait,
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// use that.
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// If we couldn't find an implementation for trait_m in
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// the impl, then see if there was a default
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// implementation in the trait itself. If not, raise a
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// "missing method" error.
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tcx.sess.span_err(
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a_trait_ty.path.span,
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fmt!{"missing method `%s`", *if_m.ident});
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alt tcx.items.get(did.node) {
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ast_map::node_item(
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@{node: ast::item_trait(_, _, trait_methods), _}, _) {
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let (_, provided_methods) =
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split_trait_methods(trait_methods);
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alt vec::find(provided_methods, |provided_method|
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provided_method.ident == trait_m.ident) {
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some(m) {
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// If there's a provided method with the name we
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// want, then we're fine; nothing else to do.
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}
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none {
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tcx.sess.span_err(
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a_trait_ty.path.span,
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fmt!{"missing method `%s`", *trait_m.ident});
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}
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}
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}
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_ {
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tcx.sess.bug(~"check_methods_against_trait(): trait_ref \
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didn't refer to a trait");
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}
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}
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}
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} // alt
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} // |if_m|
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} // |trait_m|
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} // fn
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fn convert_field(ccx: @crate_ctxt,
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@ -324,7 +347,7 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
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write_ty_to_tcx(tcx, it.id, tpt.ty);
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get_enum_variant_types(ccx, tpt.ty, variants, ty_params, rp);
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}
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ast::item_impl(tps, trt, selfty, ms) {
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ast::item_impl(tps, trait_ref, selfty, ms) {
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let i_bounds = ty_param_bounds(ccx, tps);
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let selfty = ccx.to_ty(type_rscope(rp), selfty);
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write_ty_to_tcx(tcx, it.id, selfty);
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@ -334,7 +357,7 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
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ty: selfty});
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let cms = convert_methods(ccx, ms, rp, i_bounds, selfty);
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for trt.each |t| {
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for trait_ref.each |t| {
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check_methods_against_trait(ccx, tps, rp, selfty, t, cms);
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}
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}
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@ -351,11 +374,11 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
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let _cms = convert_methods(ccx, provided_methods, rp, bounds, selfty);
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// FIXME (#2616): something like this, when we start having
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// trait inheritance?
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// for trt.each |t| {
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// for trait_ref.each |t| {
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// check_methods_against_trait(ccx, tps, rp, selfty, t, cms);
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// }
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}
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ast::item_class(tps, traits, members, m_ctor, m_dtor) {
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ast::item_class(tps, trait_refs, members, m_ctor, m_dtor) {
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// Write the class type
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let tpt = ty_of_item(ccx, it);
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write_ty_to_tcx(tcx, it.id, tpt.ty);
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@ -405,11 +428,11 @@ fn convert(ccx: @crate_ctxt, it: @ast::item) {
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let {bounds, substs} = mk_substs(ccx, tps, rp);
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let selfty = ty::mk_class(tcx, local_def(it.id), substs);
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let cms = convert_methods(ccx, methods, rp, bounds, selfty);
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for traits.each |trt| {
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check_methods_against_trait(ccx, tps, rp, selfty, trt, cms);
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// trt.impl_id represents (class, trait) pair
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write_ty_to_tcx(tcx, trt.impl_id, tpt.ty);
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tcx.tcache.insert(local_def(trt.impl_id), tpt);
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for trait_refs.each |trait_ref| {
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check_methods_against_trait(ccx, tps, rp, selfty, trait_ref, cms);
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// trait_ref.impl_id represents (class, trait) pair
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write_ty_to_tcx(tcx, trait_ref.impl_id, tpt.ty);
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tcx.tcache.insert(local_def(trait_ref.impl_id), tpt);
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}
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}
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_ {
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