wcc/ww: document the unreachable N_TARRAY destructure arm

An array-typed tuple element cannot reach paramfieldsize: the checker
rejects composite tuple elements (check.ww:2150, the #60 gate), pinned
by test 832. The rule-7 note at the fall-through now records the proof
instead of an open task. Task #39 closes as unreachable.

selfhost/cmd/w6c/main.combined.ww

@@ -39263,11 +39263,17 @@ fn paramfieldsize(t: *node) i32 = {
 		let ps: i32 = primsize(nm);
 		if (ps > 0) { return ps; };
 	};
-	// rule-7: N_TARRAY (an array-typed tuple/struct field) is intentionally
-	// not sized here — deferred to task #39. No F7 repro or spec-§5-c4
-	// member feeds it, so it stays on the 8B default (mis-sized, latent)
-	// until a consumer surfaces; the divergence is pointed at the task, not
-	// silent.
+	// rule-7: N_TARRAY (an array-typed tuple field) is intentionally not
+	// sized here — and PROVABLY unreachable, not merely latent (#39).
+	// paramfieldsize's only callers are tuple-field contexts (the N_TTUPLE
+	// recursion above + the cgforrange destructure sizers below), and the
+	// checker loud-REJECTS an array/struct/nested-tuple tuple element at
+	// N_TTUPLE resolution (check.ww:2150, "composite element deferred to
+	// task #60"; pinned both-stage by test 832_tuple_elem_overlong). So no
+	// tuple field can carry an N_TARRAY type — this arm cannot be reached
+	// until #60's inline-composite layout lands and lifts that gate. The 8B
+	// fall-through is correct-by-vacuity; reopen WITH #60, adding the arm
+	// (read t.type_.size, twin of the #53 tagged arm above).
 	return 8;
 };
 

selfhost/cmd/wcc/cgenstmt.ww

@@ -3711,11 +3711,17 @@ fn paramfieldsize(t: *node) i32 = {
 		let ps: i32 = primsize(nm);
 		if (ps > 0) { return ps; };
 	};
-	// rule-7: N_TARRAY (an array-typed tuple/struct field) is intentionally
-	// not sized here — deferred to task #39. No F7 repro or spec-§5-c4
-	// member feeds it, so it stays on the 8B default (mis-sized, latent)
-	// until a consumer surfaces; the divergence is pointed at the task, not
-	// silent.
+	// rule-7: N_TARRAY (an array-typed tuple field) is intentionally not
+	// sized here — and PROVABLY unreachable, not merely latent (#39).
+	// paramfieldsize's only callers are tuple-field contexts (the N_TTUPLE
+	// recursion above + the cgforrange destructure sizers below), and the
+	// checker loud-REJECTS an array/struct/nested-tuple tuple element at
+	// N_TTUPLE resolution (check.ww:2150, "composite element deferred to
+	// task #60"; pinned both-stage by test 832_tuple_elem_overlong). So no
+	// tuple field can carry an N_TARRAY type — this arm cannot be reached
+	// until #60's inline-composite layout lands and lifts that gate. The 8B
+	// fall-through is correct-by-vacuity; reopen WITH #60, adding the arm
+	// (read t.type_.size, twin of the #53 tagged arm above).
 	return 8;
 };
 

selfhost/cmd/wwdump/main.combined.ww

@@ -39263,11 +39263,17 @@ fn paramfieldsize(t: *node) i32 = {
 		let ps: i32 = primsize(nm);
 		if (ps > 0) { return ps; };
 	};
-	// rule-7: N_TARRAY (an array-typed tuple/struct field) is intentionally
-	// not sized here — deferred to task #39. No F7 repro or spec-§5-c4
-	// member feeds it, so it stays on the 8B default (mis-sized, latent)
-	// until a consumer surfaces; the divergence is pointed at the task, not
-	// silent.
+	// rule-7: N_TARRAY (an array-typed tuple field) is intentionally not
+	// sized here — and PROVABLY unreachable, not merely latent (#39).
+	// paramfieldsize's only callers are tuple-field contexts (the N_TTUPLE
+	// recursion above + the cgforrange destructure sizers below), and the
+	// checker loud-REJECTS an array/struct/nested-tuple tuple element at
+	// N_TTUPLE resolution (check.ww:2150, "composite element deferred to
+	// task #60"; pinned both-stage by test 832_tuple_elem_overlong). So no
+	// tuple field can carry an N_TARRAY type — this arm cannot be reached
+	// until #60's inline-composite layout lands and lifts that gate. The 8B
+	// fall-through is correct-by-vacuity; reopen WITH #60, adding the arm
+	// (read t.type_.size, twin of the #53 tagged arm above).
 	return 8;
 };