Skip to content

fix(decode): accept signed enum tag scalars in _extract_tag #954

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Stevengre wants to merge 4 commits into
base: master
Choose a base branch
from
+142 −17
Open

fix(decode): accept signed enum tag scalars in _extract_tag #954

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
e60ca3f
fix(decode): accept signed enum tag scalars in _extract_tag
Stevengre Feb 28, 2026
1e130df
Align signed discriminant transmute test with passing semantics
Stevengre Feb 28, 2026
6167019
test(integration): drop signed discriminant case from show specs
Stevengre Mar 3, 2026
efc7edf
test(integration): remove stale signed-discriminant show snapshot
Stevengre Mar 3, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion kmir/src/kmir/decoding.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -445,10 +445,12 @@ def _extract_tag(*, data: bytes, tag_offset: MachineSize, tag: Scalar) -> tuple[
case Initialized(
value=PrimitiveInt(
length=length,
signed=False,
signed=_,
),
valid_range=_,
):
# Stable MIR enum discriminants are represented against the raw tag bits.
# Use unsigned decoding even when the scalar metadata marks the tag as signed.
tag_data = data[tag_offset.in_bytes : tag_offset.in_bytes + length.value]
tag_value = int.from_bytes(tag_data, byteorder='little', signed=False)
return tag_value, length
Expand Down
1 change: 1 addition & 0 deletions kmir/src/tests/integration/data/decode-value/enum-3-variants-0-fields-signed-tag.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Aggregate ( variantIdx ( 1 ) , .List )
138 changes: 138 additions & 0 deletions kmir/src/tests/integration/data/decode-value/enum-3-variants-0-fields-signed-tag.json
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,138 @@
{
"bytes": [
0
],
"types": [],
"typeInfo": {
"EnumType": {
"name": "OrderingLike",
"adt_def": 72,
"discriminants": [
255,
0,
1
],
"fields": [
[],
[],
[]
],
"layout": {
"fields": {
"Arbitrary": {
"offsets": [
{
"num_bits": 0
}
]
}
},
"variants": {
"Multiple": {
"tag": {
"Initialized": {
"value": {
"Int": {
"length": "I8",
"signed": true
}
},
"valid_range": {
"start": 255,
"end": 1
}
}
},
"tag_encoding": "Direct",
"tag_field": 0,
"variants": [
{
"fields": {
"Arbitrary": {
"offsets": []
}
},
"variants": {
"Single": {
"index": 0
}
},
"abi": {
"Aggregate": {
"sized": true
}
},
"abi_align": 1,
"size": {
"num_bits": 8
}
},
{
"fields": {
"Arbitrary": {
"offsets": []
}
},
"variants": {
"Single": {
"index": 1
}
},
"abi": {
"Aggregate": {
"sized": true
}
},
"abi_align": 1,
"size": {
"num_bits": 8
}
},
{
"fields": {
"Arbitrary": {
"offsets": []
}
},
"variants": {
"Single": {
"index": 2
}
},
"abi": {
"Aggregate": {
"sized": true
}
},
"abi_align": 1,
"size": {
"num_bits": 8
}
}
]
}
},
"abi": {
"Scalar": {
"Initialized": {
"value": {
"Int": {
"length": "I8",
"signed": true
}
},
"valid_range": {
"start": 255,
"end": 1
}
}
}
},
"abi_align": 1,
"size": {
"num_bits": 8
}
}
}
}
}
15 changes: 0 additions & 15 deletions ...on/data/prove-rs/show/transmute-u8-to-enum-changed-discriminant-signed-fail.main.expected
View file
Open in desktop

This file was deleted.

0 ...-enum-changed-discriminant-signed-fail.rs → ...u8-to-enum-changed-discriminant-signed.rs
View file
Open in desktop
File renamed without changes.
1 change: 0 additions & 1 deletion kmir/src/tests/integration/test_integration.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,6 @@
'assume-cheatcode-conflict-fail',
'raw-ptr-cast-fail',
'transmute-u8-to-enum-fail',
'transmute-u8-to-enum-changed-discriminant-signed-fail',
'assert-inhabited-fail',
'iterator-simple',
'unions-fail',
Expand Down