Remove support for multiple traits in a single impl
There was half-working support for them, but they were never fully implemented or even approved. Remove them altogether. Closes #3410
This commit is contained in:
Tim Chevalier
parent
62ab9d70f4
commit
f5093dff7b
9 changed files with 44 additions and 35 deletions
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@ -1267,7 +1267,7 @@ enum item_ {
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item_class(@struct_def, ~[ty_param]),
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item_trait(~[ty_param], ~[@trait_ref], ~[trait_method]),
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item_impl(~[ty_param],
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~[@trait_ref], /* traits this impl implements */
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Option<@trait_ref>, /* (optional) trait this impl implements */
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@ty, /* self */
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~[@method]),
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item_mac(mac),
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@ -2571,11 +2571,11 @@ struct parser {
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// Parse traits, if necessary.
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let traits = if self.token == token::COLON {
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let opt_trait = if self.token == token::COLON {
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self.bump();
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self.parse_trait_ref_list(token::LBRACE)
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Some(self.parse_trait_ref())
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} else {
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~[]
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None
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};
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let mut meths = ~[];
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@ -2584,7 +2584,7 @@ struct parser {
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let vis = self.parse_visibility();
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vec::push(meths, self.parse_method(vis));
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}
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(ident, item_impl(tps, traits, ty, meths), None)
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(ident, item_impl(tps, opt_trait, ty, meths), None)
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}
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// Instantiates ident <i> with references to <typarams> as arguments.
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@ -499,7 +499,7 @@ fn print_item(s: ps, &&item: @ast::item) {
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print_struct(s, struct_def, tps, item.ident, item.span);
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}
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ast::item_impl(tps, traits, ty, methods) => {
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ast::item_impl(tps, opt_trait, ty, methods) => {
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head(s, ~"impl");
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if tps.is_not_empty() {
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print_type_params(s, tps);
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@ -507,12 +507,13 @@ fn print_item(s: ps, &&item: @ast::item) {
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}
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print_type(s, ty);
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if vec::len(traits) != 0u {
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match opt_trait {
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Some(t) => {
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word_space(s, ~":");
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do commasep(s, inconsistent, traits) |s, p| {
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print_path(s, p.path, false);
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}
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print_path(s, t.path, false);
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}
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None => ()
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};
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space(s.s);
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bopen(s);
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@ -699,7 +699,7 @@ fn encode_info_for_item(ecx: @encode_ctxt, ebml_w: ebml::Writer, item: @item,
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else { None }, tps);
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}
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}
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item_impl(tps, traits, _, methods) => {
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item_impl(tps, opt_trait, _, methods) => {
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add_to_index();
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ebml_w.start_tag(tag_items_data_item);
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encode_def_id(ebml_w, local_def(item.id));
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@ -714,10 +714,7 @@ fn encode_info_for_item(ecx: @encode_ctxt, ebml_w: ebml::Writer, item: @item,
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ebml_w.writer.write(str::to_bytes(def_to_str(local_def(m.id))));
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ebml_w.end_tag();
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}
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if traits.len() > 1 {
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fail ~"multiple traits!!";
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}
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for traits.each |associated_trait| {
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do opt_trait.iter() |associated_trait| {
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encode_trait_ref(ebml_w, ecx, associated_trait)
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}
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encode_path(ecx, ebml_w, path, ast_map::path_name(item.ident));
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@ -3532,7 +3532,7 @@ struct Resolver {
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fn resolve_implementation(id: node_id,
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span: span,
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type_parameters: ~[ty_param],
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trait_references: ~[@trait_ref],
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opt_trait_reference: Option<@trait_ref>,
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self_type: @ty,
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methods: ~[@method],
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visitor: ResolveVisitor) {
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@ -3549,9 +3549,9 @@ struct Resolver {
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// Resolve the trait reference, if necessary.
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let original_trait_refs = self.current_trait_refs;
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if trait_references.len() >= 1 {
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let mut new_trait_refs = @DVec();
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for trait_references.each |trait_reference| {
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match opt_trait_reference {
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Some(trait_reference) => {
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let new_trait_refs = @DVec();
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match self.resolve_path(
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trait_reference.path, TypeNS, true, visitor) {
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None => {
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@ -3566,11 +3566,11 @@ struct Resolver {
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(*new_trait_refs).push(def_id_of_def(def));
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}
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}
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}
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// Record the current set of trait references.
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self.current_trait_refs = Some(new_trait_refs);
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}
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None => ()
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}
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// Resolve the self type.
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self.resolve_type(self_type, visitor);
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@ -3121,12 +3121,12 @@ fn impl_traits(cx: ctxt, id: ast::def_id) -> ~[t] {
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debug!("(impl_traits) searching for trait impl %?", id);
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match cx.items.find(id.node) {
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Some(ast_map::node_item(@{
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node: ast::item_impl(_, trait_refs, _, _),
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node: ast::item_impl(_, opt_trait, _, _),
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_},
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_)) => {
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do vec::map(trait_refs) |trait_ref| {
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node_id_to_type(cx, trait_ref.ref_id)
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do option::map_default(opt_trait, ~[]) |trait_ref| {
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~[node_id_to_type(cx, trait_ref.ref_id)]
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}
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}
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Some(ast_map::node_item(@{node: ast::item_class(sd,_),
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@ -231,8 +231,8 @@ struct CoherenceChecker {
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self.crate_context.tcx.sess.str_of(item.ident));
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match item.node {
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item_impl(_, associated_traits, _, _) => {
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self.check_implementation(item, associated_traits);
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item_impl(_, opt_trait, _, _) => {
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self.check_implementation(item, opt_trait.to_vec());
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}
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item_class(struct_def, _) => {
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self.check_implementation(item, struct_def.traits);
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@ -432,7 +432,7 @@ struct CoherenceChecker {
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// Then visit the module items.
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visit_mod(module_, item.span, item.id, (), visitor);
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}
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item_impl(_, associated_traits, _, _) => {
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item_impl(_, opt_trait, _, _) => {
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match self.base_type_def_ids.find(
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local_def(item.id)) {
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@ -453,7 +453,8 @@ struct CoherenceChecker {
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// if the traits are defined in the same
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// crate.
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if associated_traits.len() == 0 {
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match opt_trait {
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None => {
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// There is no trait to implement, so
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// this is an error.
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@ -470,8 +471,10 @@ struct CoherenceChecker {
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or new type \
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instead");
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}
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_ => ()
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}
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for associated_traits.each |trait_ref| {
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do opt_trait.iter() |trait_ref| {
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// This is OK if and only if the
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// trait was defined in this
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// crate.
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@ -243,10 +243,10 @@ fn fold_impl(
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let (trait_types, self_ty) = do astsrv::exec(srv) |ctxt| {
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match ctxt.ast_map.get(doc.id()) {
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ast_map::node_item(@{
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node: ast::item_impl(_, trait_types, self_ty, _), _
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node: ast::item_impl(_, opt_trait_type, self_ty, _), _
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}, _) => {
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let trait_types = vec::map(trait_types, |p| {
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pprust::path_to_str(p.path, extract::interner())
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let trait_types = opt_trait_type.map_default(~[], |p| {
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~[pprust::path_to_str(p.path, extract::interner())]
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});
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(trait_types, Some(pprust::ty_to_str(self_ty,
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extract::interner())))
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8
src/test/compile-fail/multitrait.rs
Normal file
8
src/test/compile-fail/multitrait.rs
Normal file
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@ -0,0 +1,8 @@
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struct S {
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y: int;
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}
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impl S: Cmp, ToStr { //~ ERROR: expected `{` but found `,`
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fn eq(&&other: S) { false }
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fn to_str() -> ~str { ~"hi" }
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}
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