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Auto merge of #100502 - chenyukang:fix-100478, r=jackh726

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Avoid infinite loop in function arguments checking

Fixes #100478
Fixes #101097
This commit is contained in:
bors 2022-09-12 06:05:32 +00:00
commit 56e7678ca9
5 changed files with 330 additions and 9 deletions
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25
compiler/rustc_typeck/src/check/fn_ctxt/arg_matrix.rs
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@ -130,14 +130,17 @@ impl<'tcx> ArgMatrix<'tcx> {
let ai = &self.expected_indices;
let ii = &self.provided_indices;
// Issue: 100478, when we end the iteration,
// `next_unmatched_idx` will point to the index of the first unmatched
let mut next_unmatched_idx = 0;
for i in 0..cmp::max(ai.len(), ii.len()) {
// If we eliminate the last row, any left-over inputs are considered missing
// If we eliminate the last row, any left-over arguments are considered missing
if i >= mat.len() {
return Some(Issue::Missing(i));
return Some(Issue::Missing(next_unmatched_idx));
}
// If we eliminate the last column, any left-over arguments are extra
// If we eliminate the last column, any left-over inputs are extra
if mat[i].len() == 0 {
return Some(Issue::Extra(i));
return Some(Issue::Extra(next_unmatched_idx));
}
// Make sure we don't pass the bounds of our matrix
@ -145,6 +148,7 @@ impl<'tcx> ArgMatrix<'tcx> {
let is_input = i < ii.len();
if is_arg && is_input && matches!(mat[i][i], Compatibility::Compatible) {
// This is a satisfied input, so move along
next_unmatched_idx += 1;
continue;
}
@ -163,7 +167,7 @@ impl<'tcx> ArgMatrix<'tcx> {
if is_input {
for j in 0..ai.len() {
// If we find at least one argument that could satisfy this input
// this argument isn't useless
// this input isn't useless
if matches!(mat[i][j], Compatibility::Compatible) {
useless = false;
break;
@ -232,8 +236,8 @@ impl<'tcx> ArgMatrix<'tcx> {
if matches!(c, Compatibility::Compatible) { Some(i) } else { None }
})
.collect();
if compat.len() != 1 {
// this could go into multiple slots, don't bother exploring both
if compat.len() < 1 {
// try to find a cycle even when this could go into multiple slots, see #101097
is_cycle = false;
break;
}
@ -309,7 +313,8 @@ impl<'tcx> ArgMatrix<'tcx> {
}
while !self.provided_indices.is_empty() || !self.expected_indices.is_empty() {
match self.find_issue() {
let res = self.find_issue();
match res {
Some(Issue::Invalid(idx)) => {
let compatibility = self.compatibility_matrix[idx][idx].clone();
let input_idx = self.provided_indices[idx];
@ -364,7 +369,9 @@ impl<'tcx> ArgMatrix<'tcx> {
None => {
// We didn't find any issues, so we need to push the algorithm forward
// First, eliminate any arguments that currently satisfy their inputs
for (inp, arg) in self.eliminate_satisfied() {
let eliminated = self.eliminate_satisfied();
assert!(!eliminated.is_empty(), "didn't eliminated any indice in this round");
for (inp, arg) in eliminated {
matched_inputs[arg] = Some(inp);
}
}