When I run the pcg on the following example (not at all minimised), the match at the let value = match e { line results in an incorrect pcg result.
pub struct Fields {
pub field_1: u32,
pub field_2: (),
}
#[repr(i8)]
enum Enum {
VariantA = 0,
VariantB(Fields, Option<bool>) = -128,
VariantC {
field_1: u32,
field_2: (),
} = 127,
}
pub fn enum_test(e: Enum, v: u8) {
match v {
0 => {
let value = match e {
Enum::VariantA => {
0
}
Enum::VariantB(f, _) => {
f.field_1
}
Enum::VariantC { field_1, field_2 } => {
field_1
}
};
}
1 => {
let Enum::VariantB(a, b) = e else {
return;
};
}
2 => {
if let Enum::VariantC { field_1, field_2 } = e {
} else {
return;
}
}
_ => {
return;
}
}
}The errors are twofold.
First, at bb11[2] the e@VariantC is unnecessarily packed (and then unpacked again straight away on the next line):
Second (and worse), at the join point at bb14[0] the e@VariantB is left unpacked.
This is not sound since the unpacks along the edges of bb11 -> bb14 and bb13 -> bb14 cannot happen (the enum is not in VariantB in those branches).
When I run the pcg on the following example (not at all minimised), the
matchat thelet value = match e {line results in an incorrect pcg result.The errors are twofold.
First, at bb11[2] the
e@VariantCis unnecessarily packed (and then unpacked again straight away on the next line):Second (and worse), at the join point at bb14[0] the
e@VariantBis left unpacked.This is not sound since the
unpacks along the edges ofbb11 -> bb14andbb13 -> bb14cannot happen (the enum is not inVariantBin those branches).