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Abort on arity mismatch

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As this can cause panics on array accesses later.
This commit is contained in:
Nadrieril 2024-03-04 19:35:33 +01:00
parent 516b6162a2
commit 2af01a2fef
1 changed files with 15 additions and 7 deletions
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22
compiler/rustc_pattern_analysis/src/usefulness.rs
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@ -1001,19 +1001,26 @@ impl<'p, Cx: TypeCx> PatStack<'p, Cx> {
/// Only call if `ctor.is_covered_by(self.head().ctor())` is true.
fn pop_head_constructor(
&self,
cx: &Cx,
ctor: &Constructor<Cx>,
ctor_arity: usize,
ctor_is_relevant: bool,
) -> PatStack<'p, Cx> {
) -> Result<PatStack<'p, Cx>, Cx::Error> {
// We pop the head pattern and push the new fields extracted from the arguments of
// `self.head()`.
let mut new_pats = self.head().specialize(ctor, ctor_arity);
if new_pats.len() != ctor_arity {
return Err(cx.bug(format_args!(
"uncaught type error: pattern {:?} has inconsistent arity (expected arity {ctor_arity})",
self.head().as_pat().unwrap()
)));
}
new_pats.extend_from_slice(&self.pats[1..]);
// `ctor` is relevant for this row if it is the actual constructor of this row, or if the
// row has a wildcard and `ctor` is relevant for wildcards.
let ctor_is_relevant =
!matches!(self.head().ctor(), Constructor::Wildcard) || ctor_is_relevant;
PatStack { pats: new_pats, relevant: self.relevant && ctor_is_relevant }
Ok(PatStack { pats: new_pats, relevant: self.relevant && ctor_is_relevant })
}
}
@ -1083,18 +1090,19 @@ impl<'p, Cx: TypeCx> MatrixRow<'p, Cx> {
/// Only call if `ctor.is_covered_by(self.head().ctor())` is true.
fn pop_head_constructor(
&self,
cx: &Cx,
ctor: &Constructor<Cx>,
ctor_arity: usize,
ctor_is_relevant: bool,
parent_row: usize,
) -> MatrixRow<'p, Cx> {
MatrixRow {
pats: self.pats.pop_head_constructor(ctor, ctor_arity, ctor_is_relevant),
) -> Result<MatrixRow<'p, Cx>, Cx::Error> {
Ok(MatrixRow {
pats: self.pats.pop_head_constructor(cx, ctor, ctor_arity, ctor_is_relevant)?,
parent_row,
is_under_guard: self.is_under_guard,
useful: false,
intersects: BitSet::new_empty(0), // Initialized in `Matrix::expand_and_push`.
}
})
}
}
@ -1217,7 +1225,7 @@ impl<'p, Cx: TypeCx> Matrix<'p, Cx> {
};
for (i, row) in self.rows().enumerate() {
if ctor.is_covered_by(pcx.cx, row.head().ctor())? {
let new_row = row.pop_head_constructor(ctor, arity, ctor_is_relevant, i);
let new_row = row.pop_head_constructor(pcx.cx, ctor, arity, ctor_is_relevant, i)?;
matrix.expand_and_push(new_row);
}
}