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fix: optional-chain getter/field correctness from 0160 adversarial review

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Five adversarial reviews of the issue-0160 fix surfaced three more bugs in the
touched optional-chain / optional-coercion code; all fixed here:

1. A COLD generic-instance getter through `?.` (`?*Vec(i64)` `.getter`, never
   called directly first) panicked with "unresolved type reached LLVM emission":
   a cold instance method is absent from resolveFuncByName, so the getter's
   return type resolved to .unresolved → a ?unresolved merge type. lowerOptionalChain
   and getterReturnTypeOnDeref now warm the monomorph (ensureGenericInstanceMethodLowered)
   before querying its return type. (The 0907 test passed only by luck — List(i64)
   is warmed by stdlib use; 0907 now also exercises a cold user generic.)

2. A real-field read through a `?*T` chain (`op?.field`, op: ?*T) reinterpreted
   the pointer bits as the field (silent garbage) — the some-branch real-field
   path didn't load through the pointer. It now derefs `?*T` before the field
   access. (Pre-existing — the else-branch predates 0160 — but it's the same
   function and a silent miscompile, so fixed here.)

3. `?[]T = array` skipped the array→slice promotion (corrupt .len/.ptr): the
   lowerVarDecl optional arm wrapped the raw array. It now coerces the value to
   the optional's child type (array→slice) before wrapping.

Regression examples 0906/0907 extended to cover all three. Distinct PRE-EXISTING
bugs the reviews surfaced in untouched subsystems are filed as issues 0161
(struct-literal vs scalar), 0162 (#run returning an optional aggregate), 0163
(untagged-union payload-binding match).
This commit is contained in:
agra
2026-06-22 18:55:41 +03:00
parent 1b0c857b91
commit ff9e448f8c
10 changed files with 214 additions and 4 deletions
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6
examples/optionals/0906-optionals-struct-literal-into-optional.sx
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@@ -37,5 +37,11 @@ main :: () -> i64 {
// array element
arr : [2]?T = .[ .{ a = 20 }, .{ a = 21 } ];
if arr[0] != null { if arr[1] != null { print("arr: {} {}\n", arr[0]!.a, arr[1]!.a); } } // 20 21
// array value into an optional-of-slice `?[]T`: the array→slice promotion
// must run on the child BEFORE wrapping, or `.len`/`.ptr` are corrupted.
nums : [3]i64 = .[ 1, 2, 3 ];
os : ?[]i64 = nums;
if os != null { s := os!; print("optslice: {} {} {}\n", s.len, s[0], s[2]); } // 3 1 3
return 0;
}