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Make "cannot determine a type for this expression" non-fatal. Closes #621

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This commit is contained in:
Brian Anderson
2011-07-06 11:38:00 -07:00
parent c31472e845
commit 5c20a8aa9c
1 changed files with 37 additions and 17 deletions
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54
src/comp/middle/typeck.rs
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@@ -1027,28 +1027,45 @@ mod writeback {
export resolve_type_vars_in_block;
fn resolve_type_vars_in_type(&@fn_ctxt fcx, &span sp, ty::t typ) ->
ty::t {
if (!ty::type_contains_vars(fcx.ccx.tcx, typ)) { ret typ; }
option::t[ty::t] {
if (!ty::type_contains_vars(fcx.ccx.tcx, typ)) { ret some(typ); }
alt (ty::unify::fixup_vars(fcx.ccx.tcx, fcx.var_bindings, typ)) {
case (fix_ok(?new_type)) { ret new_type; }
case (fix_ok(?new_type)) { ret some(new_type); }
case (fix_err(?vid)) {
fcx.ccx.tcx.sess.span_fatal(sp,
fcx.ccx.tcx.sess.span_err(sp,
"cannot determine a type \
for this expression");
ret none;
}
}
}
fn resolve_type_vars_for_node(&@fn_ctxt fcx, &span sp, ast::node_id id) {
fn resolve_type_vars_for_node(&@wb_ctxt wbcx,
&span sp, ast::node_id id) {
auto fcx = wbcx.fcx;
auto tpot = ty::node_id_to_ty_param_substs_opt_and_ty
(fcx.ccx.tcx, id);
auto new_ty = resolve_type_vars_in_type(fcx, sp, tpot._1);
auto new_ty = alt (resolve_type_vars_in_type(fcx, sp, tpot._1)) {
case (some(?t)) { t }
case (none) {
wbcx.success = false;
ret
}
};
auto new_substs_opt;
alt (tpot._0) {
case (none[vec[ty::t]]) { new_substs_opt = none[vec[ty::t]]; }
case (some[vec[ty::t]](?substs)) {
let vec[ty::t] new_substs = [];
for (ty::t subst in substs) {
new_substs += [resolve_type_vars_in_type(fcx, sp, subst)];
alt (resolve_type_vars_in_type(fcx, sp, subst)) {
case (some(?t)) {
new_substs += [t];
}
case (none) {
wbcx.success = false;
ret;
}
}
}
new_substs_opt = some[vec[ty::t]](new_substs);
}
@@ -1058,19 +1075,20 @@ mod writeback {
type wb_ctxt = rec(@fn_ctxt fcx,
// A flag to ignore contained items and lambdas
mutable bool ignore);
mutable bool ignore,
mutable bool success);
fn visit_stmt_pre(@wb_ctxt wbcx, &@ast::stmt s) {
resolve_type_vars_for_node(wbcx.fcx, s.span, ty::stmt_node_id(s));
resolve_type_vars_for_node(wbcx, s.span, ty::stmt_node_id(s));
}
fn visit_expr_pre(@wb_ctxt wbcx, &@ast::expr e) {
resolve_type_vars_for_node(wbcx.fcx, e.span, e.id);
resolve_type_vars_for_node(wbcx, e.span, e.id);
}
fn visit_block_pre(@wb_ctxt wbcx, &ast::block b) {
resolve_type_vars_for_node(wbcx.fcx, b.span, b.node.id);
resolve_type_vars_for_node(wbcx, b.span, b.node.id);
}
fn visit_pat_pre(@wb_ctxt wbcx, &@ast::pat p) {
resolve_type_vars_for_node(wbcx.fcx, p.span, p.id);
resolve_type_vars_for_node(wbcx, p.span, p.id);
}
fn visit_local_pre(@wb_ctxt wbcx, &@ast::local l) {
auto var_id = lookup_local(wbcx.fcx, l.span, l.node.id);
@@ -1105,11 +1123,12 @@ mod writeback {
&ast::fn_ident i, ast::node_id d) {
wbcx.ignore = false;
}
fn keep_going(@wb_ctxt wbcx) -> bool { ret !wbcx.ignore; }
fn keep_going(@wb_ctxt wbcx) -> bool { !wbcx.ignore && wbcx.success }
fn resolve_type_vars_in_block(&@fn_ctxt fcx, &ast::block block) {
fn resolve_type_vars_in_block(&@fn_ctxt fcx, &ast::block block) -> bool {
auto wbcx = @rec(fcx = fcx,
mutable ignore = false);
mutable ignore = false,
mutable success = true);
auto visit =
rec(keep_going=bind keep_going(wbcx),
visit_item_pre=bind visit_item_pre(wbcx, _),
@@ -1123,6 +1142,7 @@ mod writeback {
visit_local_pre=bind visit_local_pre(wbcx, _)
with walk::default_visitor());
walk::walk_block(visit, block);
ret wbcx.success;
}
}
@@ -2482,9 +2502,9 @@ fn check_fn(&@crate_ctxt ccx, &ast::fn_decl decl, ast::proto proto,
case (_) { }
}
writeback::resolve_type_vars_in_block(fcx, body);
auto success = writeback::resolve_type_vars_in_block(fcx, body);
if (option::is_some(body.node.expr)) {
if (success && option::is_some(body.node.expr)) {
auto tail_expr = option::get(body.node.expr);
auto tail_expr_ty = expr_ty(ccx.tcx, tail_expr);
// Have to exclude ty_nil to allow functions to end in