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[bug] A poisoned cast argument cascades into SC063E naming '<literal>' #97
Description
Compiler version
kairo-0.1.1+dev.20261024
Compiler stage
Stage 1 (self-hosted)
Host platform
Linux (x86_64)
Minimal reproduction
// Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k
ffi "c" import "stdlib.h"
fn main() -> i32 {
var p: unsafe *const u8
unsafe { p = malloc(4) as unsafe *const u8 }
free(p as unsafe *void) // SC023E is right; the SC063E beside it is a cascade
return 0
}Command line
build/x86_64-linux-gnu/debug/bin/kairo --resource-dir=build/llvm/lib/clang/22 --builtins-dir=Lib/builtin --std-dir=Lib/std Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k --type-check-onlyActual behavior
error @ Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k:7
5 | var p: unsafe *const u8
6 | unsafe { p = malloc(4) as unsafe *const u8 }
7 | free(p as unsafe *void) // SC023E is right; the SC063E beside it is a cascade
| ^^^^^^^^^^^^^^^^^^^^^^^
| | [SC023E] cast to 'unsafe *void' requires an unsafe context
| [SC063E] no matching overload for call to 'free'
note @ build/x86_64-linux-gnu/release/sysroot/x86_64-linux-musl/include/stdlib.h:43
41 | void *calloc (size_t, size_t);
42 | void *realloc (void *, size_t);
43 | void free (void *);
| ^ candidate not viable: cannot convert argument of type '<literal>' to parameter '__arg0' of type 'unsafe *void'
note @ Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k:7
5 | var p: unsafe *const u8
6 | unsafe { p = malloc(4) as unsafe *const u8 }
7 | free(p as unsafe *void) // SC023E is right; the SC063E beside it is a cascade
| ^ wrap the expression in 'unsafe { ... }'; this cast discards pointer provenance
Exit code 1.Expected behavior
Only SC023E (with its unsafe { ... } note) is reported. The poisoned argument makes the call poisoned without a diagnostic.
Additional context
The SC063E is reported first; with --error-format=basic the order is:
Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k:7:5: error [SC063E]: no matching overload for call to 'free'
build/x86_64-linux-gnu/release/sysroot/x86_64-linux-musl/include/stdlib.h:43:1: note [I900N]: candidate not viable: cannot convert argument of type '<literal>' to parameter '__arg0' of type 'unsafe *void'
Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k:7:10: error [SC023E]: cast to 'unsafe *void' requires an unsafe context
Tests/Bugs/Triage/F15-poisoned-cast-argument-cascades-into-sc063e.k:7:10: note [I900N]: wrap the expression in 'unsafe { ... }'; this cast discards pointer provenance
The argument is poisoned, so overload resolution should treat it as unknown and stay silent, as check_convertible does for a poisoned expression. '' is also the wrong name for its type.
Fix: OverloadResolution skips viability reporting when an argument is poisoned (poison the call, no diagnostic). Test: the repro reports SC023E only.
Activity
Ze7111 commentedon Nov 9, 2026
a poisoned cast argument cascading into SC063E naming '' (only SC023E is reported now; the exact fixing commit was not pinpointed, it landed somewhere in the 2026-10-24..11-04 Sema work), fixed on origin/main