From bd139dc09c2a66ffdd6bbff98ffbc197ac782e16 Mon Sep 17 00:00:00 2001
From: agra <alex@swipelab.co>
Date: Tue, 16 Jun 2026 19:01:03 +0300
Subject: [PATCH] =?UTF-8?q?xfail(reify):=20field=5Ftype=20=E2=80=94=20read?=
 =?UTF-8?q?=20struct/enum=20member=20types=20by=20index?=
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REIFY Phase 2.0. Add examples/0616: reflect a struct's fields (name via
field_name, type via field_type) and a tagged-union's variant payloads,
including field_type composed inside type_eq / type_name. Seed an empty
expected/*.exit marker. RED by design — field_type still bails ("not yet
implemented"); Phase 2.1 implements it over the type table and turns
this green.
---
 examples/0616-comptime-field-type.sx          | 29 +++++++++++++++++++
 .../expected/0616-comptime-field-type.exit    |  0
 2 files changed, 29 insertions(+)
 create mode 100644 examples/0616-comptime-field-type.sx
 create mode 100644 examples/expected/0616-comptime-field-type.exit

diff --git a/examples/0616-comptime-field-type.sx b/examples/0616-comptime-field-type.sx
new file mode 100644
index 00000000..846a5c92
--- /dev/null
+++ b/examples/0616-comptime-field-type.sx
@@ -0,0 +1,29 @@
+// REIFY Phase 2: `field_type($T, i) -> Type` — the type-only field projection
+// the value-level reflection (`field_value` / `type_of`) couldn't express.
+// Reflect a struct's fields by name (`field_name`) AND by type (`field_type`),
+// and a tagged-union's variant payloads. It folds at lower time, so it composes
+// inside `type_eq` / `type_name` / any type-arg slot.
+#import "modules/std.sx";
+#import "modules/std/meta.sx";
+
+Point :: struct { x: i64; y: f64; on: bool; }
+
+Msg :: enum { num: i64; tag: bool; quit; }
+
+main :: () -> i32 {
+    // Struct fields: name + type, position by position.
+    print("Point has {} fields\n", field_count(Point));
+    print("  0: {} : {}\n", field_name(Point, 0), type_name(field_type(Point, 0)));
+    print("  1: {} : {}\n", field_name(Point, 1), type_name(field_type(Point, 1)));
+    print("  2: {} : {}\n", field_name(Point, 2), type_name(field_type(Point, 2)));
+
+    // field_type composes in a type-arg slot (type_eq folds at comptime).
+    print("field 0 is i64: {}\n", type_eq(field_type(Point, 0), i64));
+    print("field 1 is f64: {}\n", type_eq(field_type(Point, 1), f64));
+
+    // Tagged-union variant payloads (the tagless `quit` → void).
+    print("Msg.num  payload: {}\n", type_name(field_type(Msg, 0)));
+    print("Msg.tag  payload: {}\n", type_name(field_type(Msg, 1)));
+    print("Msg.quit payload: {}\n", type_name(field_type(Msg, 2)));
+    return 0;
+}
diff --git a/examples/expected/0616-comptime-field-type.exit b/examples/expected/0616-comptime-field-type.exit
new file mode 100644
index 00000000..e69de29b