4f1a9738c7
Array-typed '::' consts as immutable globals (approved design: storage global + untyped inference + comptime-fold layer + const-write rejection covering the pre-existing struct-const write crash, issue 0116).
1.1 KiB
1.1 KiB
0116 — writes through module consts are not rejected (struct-const write bus-errors at runtime)
Symptom. Assigning through a module-level constant compiles silently. For a struct-literal const the store lands in read-only memory and the program crashes at runtime.
- Observed: compiles;
Bus errorat runtime on the store. - Expected: compile-time diagnostic —
cannot assign through constant 'WHITE'.
Reproduction
#import "modules/std.sx";
Color :: struct { r, g, b: s64; }
WHITE :: Color.{ r = 255, g = 255, b = 255 };
main :: () {
WHITE.r = 0; // compiles; bus error at runtime
print("{}\n", WHITE.r);
}
(Copies are fine and stay fine: w := WHITE; w.r = 0; mutates the copy.)
Fix
Scheduled as step 2 of current/PLAN-CONST-AGG.md (aggregate consts):
one rejection rule for assignment/compound-assignment targets whose ROOT
identifier resolves to a module const (module_const_map author) or a
const-flagged global (the array consts that plan introduces). Diagnose at
the assignment site; pin the repro above as a diagnostics example.