# 0083 — fixed array with a named-constant dimension is miscompiled

> **RESOLVED.** Root cause: `TypeResolver.resolveCompound`'s array arm resolved
> the dimension with `if (length.data == .int_literal) ... else 0` — a named
> const (`N :: 16`) hit the silent `else 0`, so `[N]T` became a 0-length / 0-byte
> array and element access ran out of bounds (garbage for scalars, bus error for
> slice/pointer/struct elements). Fix: the array arm now delegates the dimension
> to `inner.resolveArrayLen` (symmetric with `inner.resolveInner` for the element
> type). The stateful `Lowering.resolveArrayLen` evaluates the dimension as a
> compile-time integer across the comptime-constant, generic-value, and
> module-global const tables, and emits a diagnostic (no fabricated length) when
> it isn't one. Files: `src/ir/type_resolver.zig`, `src/ir/lower.zig`,
> `src/ir/type_bridge.zig`. Regression: `examples/0140-types-named-const-array-dim.sx`
> (s64 + string + struct element types).

## Symptom
A fixed array whose dimension is a module-global integer constant (`N :: 16;
a : [N]T`) miscompiles element access: reads/writes compute a wrong address.
With `s64` elements `a[0]` returns GARBAGE (silent); with slice/pointer element
types (`[N]string`) it Bus-errors. The identical program with a LITERAL dimension
(`a : [16]T`) is correct. Silent-miscompile class (cf. 0079–0082).

## Reproduction
```sx
#import "modules/std.sx";
N :: 16;
main :: () { a : [N]s64 = ---; a[0] = 7; print("a0={}\n", a[0]); }
```
`./zig-out/bin/sx run` prints `a0=8472789232` (garbage); want `a0=7`. Replacing
`[N]` with `[16]` prints `7`.

## Investigation prompt
A fixed-array TYPE whose dimension is a named const (`N :: 16; [N]T`) resolves to
a wrong element stride / array length in codegen — element address computation is
wrong (garbage for scalars, bad pointer for slice/pointer elements). Literal
dimensions are correct, so the defect is in resolving the array-type DIMENSION
from a constant expression (vs a literal) — the dim likely resolves to 0/unknown
or the element size is wrong. Look at array-type resolution where the length is a
const-expr (type lowering / sizeof / element-stride computation). Fix so a
named-const dimension yields the same layout as the literal. Verify with the
repro (expect 7) + a `[N]string`/`[N]struct` case (no bus error, correct reads),
and `zig build && zig build test && bash tests/run_examples.sh` green.