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rustc: Push type parameters down through alt tag patterns; add a test

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This commit is contained in:
Patrick Walton 2011-02-25 12:37:03 -08:00
parent 081c3aa76d
commit 7a1d01effc
2 changed files with 68 additions and 6 deletions
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55
src/comp/middle/typeck.rs
View file

@ -919,9 +919,42 @@ fn demand_pat(&@fn_ctxt fcx, @ty.t expected, @ast.pat pat) -> @ast.pat {
// acquire here with the type parameters provided to us by
// "expected".
// Grab the values for the type parameters of the tag from the
// expected type.
let vec[@ty.t] typaram_bindings = vec(); // FIXME: typestate botch
alt (expected.struct) {
case (ty.ty_tag(_, ?tps)) { typaram_bindings = tps; }
case (_) {
log "tag pattern didn't have tag type?!";
fail;
}
}
// Get the item corresponding to the tag and its type.
auto vdef = option.get[ast.variant_def](vdef_opt);
auto variant_ty = fcx.ccx.item_types.get(vdef._1);
// FIXME: typestate botch
let option.t[@ast.item] item_opt = none[@ast.item];
alt (fcx.ccx.item_items.get(vdef._0)) {
case (any_item_rust(?it)) { item_opt = some[@ast.item](it); }
case (_) {
log "tag item isn't a Rust item?!";
fail;
}
}
let @ast.item item = option.get[@ast.item](item_opt);
// Get the IDs of the type parameters from that item.
let vec[ast.ty_param] ty_params = vec(); // FIXME: typestate botch
alt (item.node) {
case (ast.item_tag(_, _, ?tps, _)) { ty_params = tps; }
case (_) {
log "tag's corresponding item isn't a tag?!";
fail;
}
}
auto subpats_len = _vec.len[@ast.pat](subpats);
alt (variant_ty.struct) {
case (ty.ty_tag(_, _)) {
@ -930,10 +963,14 @@ fn demand_pat(&@fn_ctxt fcx, @ty.t expected, @ast.pat pat) -> @ast.pat {
p_1 = ast.pat_tag(id, subpats, vdef_opt, ast.ann_type(t));
}
case (ty.ty_fn(_, ?args, ?tag_ty)) {
// N-ary tag variant.
let vec[@ast.pat] new_subpats = vec();
auto i = 0u;
for (arg a in args) {
auto new_subpat = demand_pat(fcx, a.ty, subpats.(i));
auto arg_ty = ty.substitute_ty_params(ty_params,
typaram_bindings, a.ty);
auto new_subpat = demand_pat(fcx, arg_ty,
subpats.(i));
new_subpats += vec(new_subpat);
i += 1u;
}
@ -1260,14 +1297,13 @@ fn check_pat(&@fn_ctxt fcx, @ast.pat pat) -> @ast.pat {
new_subpats += vec(check_pat(fcx, subpat));
}
auto ann = ast.ann_type(tag_ty);
auto tag_ty_g = generalize_ty(fcx.ccx, tag_ty);
auto ann = ast.ann_type(tag_ty_g);
new_pat = ast.pat_tag(p, new_subpats, vdef_opt, ann);
}
// Nullary variants have tag types.
case (ty.ty_tag(?tid, _)) {
// TODO: ty params
case (ty.ty_tag(?tid, ?tps)) {
auto subpats_len = _vec.len[@ast.pat](subpats);
if (subpats_len > 0u) {
// TODO: pluralize properly
@ -1281,7 +1317,14 @@ fn check_pat(&@fn_ctxt fcx, @ast.pat pat) -> @ast.pat {
fail; // TODO: recover
}
let vec[@ty.t] tys = vec(); // FIXME
// Add the appropriate number of type variables.
let vec[@ty.t] tys = vec();
auto i = 0u;
while (i < _vec.len[@ty.t](tps)) {
tys += vec(next_ty_var(fcx.ccx));
i += 1u;
}
auto ann = ast.ann_type(plain_ty(ty.ty_tag(tid, tys)));
new_pat = ast.pat_tag(p, subpats, vdef_opt, ann);
}

19
src/test/run-pass/generic-tag-box-alt.rs Normal file
View file

@ -0,0 +1,19 @@
tag foo[T] {
arm(@T);
}
fn altfoo[T](foo[T] f) {
auto hit = false;
alt (f) {
case (arm[T](?x)) {
log "in arm";
hit = true;
}
}
check (hit);
}
fn main() {
altfoo[int](arm[int](@10));
}