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Mention missing constructor when complaining about inexhaustive top-level pattern

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It previously, uselessly, only pointed out the constructor when the
inexhaustive pattern was nested in some other pattern.

Closes #2337
This commit is contained in:
Marijn Haverbeke 2012-05-03 17:35:12 +02:00
parent f1129635ee
commit d0d71838cd
2 changed files with 30 additions and 11 deletions
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38
src/rustc/middle/check_alt.rs
View file

@ -122,7 +122,8 @@ fn is_useful(tcx: ty::ctxt, m: matrix, v: [@pat]) -> useful {
alt pat_ctor_id(tcx, v[0]) {
none {
if is_complete(tcx, m, left_ty) {
alt missing_ctor(tcx, m, left_ty) {
none {
alt ty::get(left_ty).struct {
ty::ty_bool {
alt is_useful_specialized(tcx, m, v, val(const_int(1i64)),
@ -149,9 +150,14 @@ fn is_useful(tcx: ty::ctxt, m: matrix, v: [@pat]) -> useful {
is_useful_specialized(tcx, m, v, single, arity, left_ty)
}
}
} else {
is_useful(tcx, vec::filter_map(m, {|r| default(tcx, r)}),
vec::tail(v))
}
some(ctor) {
alt is_useful(tcx, vec::filter_map(m, {|r| default(tcx, r)}),
vec::tail(v)) {
useful_ { useful(left_ty, ctor) }
u { u }
}
}
}
}
some(v0_ctor) {
@ -202,13 +208,13 @@ fn is_wild(tcx: ty::ctxt, p: @pat) -> bool {
}
}
fn is_complete(tcx: ty::ctxt, m: matrix, left_ty: ty::t) -> bool {
fn missing_ctor(tcx: ty::ctxt, m: matrix, left_ty: ty::t) -> option<ctor> {
alt ty::get(left_ty).struct {
ty::ty_box(_) | ty::ty_uniq(_) | ty::ty_tup(_) | ty::ty_rec(_) {
for m.each {|r|
if !is_wild(tcx, r[0]) { ret true; }
if !is_wild(tcx, r[0]) { ret none; }
}
ret false;
ret some(single);
}
ty::ty_enum(eid, _) {
let mut found = [];
@ -217,9 +223,17 @@ fn is_complete(tcx: ty::ctxt, m: matrix, left_ty: ty::t) -> bool {
if !vec::contains(found, id) { found += [id]; }
}
}
found.len() == (*ty::enum_variants(tcx, eid)).len()
let variants = ty::enum_variants(tcx, eid);
if found.len() != (*variants).len() {
for vec::each(*variants) {|v|
if !found.contains(variant(v.id)) {
ret some(variant(v.id));
}
}
fail;
} else { none }
}
ty::ty_nil { true }
ty::ty_nil { none }
ty::ty_bool {
let mut true_found = false, false_found = false;
for m.each {|r|
@ -229,9 +243,11 @@ fn is_complete(tcx: ty::ctxt, m: matrix, left_ty: ty::t) -> bool {
some(val(const_int(0i64))) { false_found = true; }
}
}
true_found && false_found
if true_found && false_found { none }
else if true_found { some(val(const_int(0i64))) }
else { some(val(const_int(1i64))) }
}
_ { false }
_ { some(single) }
}
}

3
src/test/compile-fail/non-exhaustive-match.rs
View file

@ -16,6 +16,9 @@ fn main() {
(a, b) {}
(b, a) {}
}
alt a { //! ERROR b not covered
a {}
}
// This is exhaustive, though the algorithm got it wrong at one point
alt (a, b) {
(a, _) {}