diff --git a/examples/171-pack-dynamic-type-name.sx b/examples/171-pack-dynamic-type-name.sx
new file mode 100644
index 0000000..174ef4a
--- /dev/null
+++ b/examples/171-pack-dynamic-type-name.sx
@@ -0,0 +1,34 @@
+// Variadic heterogeneous type packs — step 4A final-slice
+// follow-up. `type_name(<dynamic-arg>)` where the argument is
+// NOT a static type expression (e.g. `list[i]` indexing into
+// a `$args`-derived `[]Type` slice) silently folds to "s64"
+// today because `resolveTypeArg`'s index_expr fall-through
+// returns `.s64`. That's exactly the kind of silent unimplemented
+// arm the CLAUDE.md REJECTED PATTERNS section forbids.
+//
+// Next commit teaches `tryLowerReflectionCall` to detect "arg
+// not statically resolvable" and emit a `builtin_call` to the
+// new `.type_name` builtin. The interp's arm (already wired in
+// commit 9600ba5) reads the runtime `.type_tag` Value and
+// returns the per-position concrete type name.
+//
+// Expected output after fix:
+//   s64string
+
+#import "modules/std.sx";
+
+walk :: (..$args) -> string {
+    list := $args;
+    s := "";
+    i : s64 = 0;
+    while i < list.len {
+        s = concat(s, type_name(list[i]));
+        i = i + 1;
+    }
+    return s;
+}
+
+main :: () -> s32 {
+    print("{}\n", walk(42, "hi"));
+    return 0;
+}
diff --git a/tests/expected/171-pack-dynamic-type-name.exit b/tests/expected/171-pack-dynamic-type-name.exit
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/tests/expected/171-pack-dynamic-type-name.exit
@@ -0,0 +1 @@
+0
diff --git a/tests/expected/171-pack-dynamic-type-name.txt b/tests/expected/171-pack-dynamic-type-name.txt
new file mode 100644
index 0000000..d3a2664
--- /dev/null
+++ b/tests/expected/171-pack-dynamic-type-name.txt
@@ -0,0 +1 @@
+s64string