From afd62a9187590d530b1a5049c39ebbe2f1b9bd76 Mon Sep 17 00:00:00 2001
From: Hojun-Cho <ghwns6743@gmail.com>
Date: Thu, 21 May 2026 21:14:08 +0900
Subject: [PATCH] selfhost/cmd/wcc: stamp e.type_ for N_SPREAD (A.6.2.0e)
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Port head-only of cstage cmd/wcc/check.c:1212-1213 to exprtype's
new N_SPREAD arm. The spread expression `xs...` carries the
operand's type — pass-through stamp, no structural synthesis.

A.6.2 step 5 of 8 (γ order). The smallest stamp arm in the
series; mirrors cstage's one-liner directly.

`make test-unit` green; full `make test` batched per option B.
---
 selfhost/cmd/w6c/main.combined.ww    | 7 +++++++
 selfhost/cmd/wcc/check.ww            | 7 +++++++
 selfhost/cmd/wwdump/main.combined.ww | 7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/selfhost/cmd/w6c/main.combined.ww b/selfhost/cmd/w6c/main.combined.ww
index 678a94b2..b9295e3a 100644
--- a/selfhost/cmd/w6c/main.combined.ww
+++ b/selfhost/cmd/w6c/main.combined.ww
@@ -8890,6 +8890,13 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		};
 		return nil;
 	};
+	if (k == nkind.N_SPREAD) {
+		// A.6.2.0e — pass-through stamp. Mirrors cstage check.c:1212-1213.
+		// The spread expression `xs...` carries the operand's type.
+		let t: *node = exprtype(c, e.lhs, nil);
+		if (t != nil) { e.type_ = tinfofornode(c, t): *void; };
+		return t;
+	};
 	if (k == nkind.N_TRYPROP) {
 		// success unwrap: the success-variant type of operand's
 		// tagged union.
diff --git a/selfhost/cmd/wcc/check.ww b/selfhost/cmd/wcc/check.ww
index 1b19efe1..96a332c2 100644
--- a/selfhost/cmd/wcc/check.ww
+++ b/selfhost/cmd/wcc/check.ww
@@ -1926,6 +1926,13 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		};
 		return nil;
 	};
+	if (k == nkind.N_SPREAD) {
+		// A.6.2.0e — pass-through stamp. Mirrors cstage check.c:1212-1213.
+		// The spread expression `xs...` carries the operand's type.
+		let t: *node = exprtype(c, e.lhs, nil);
+		if (t != nil) { e.type_ = tinfofornode(c, t): *void; };
+		return t;
+	};
 	if (k == nkind.N_TRYPROP) {
 		// success unwrap: the success-variant type of operand's
 		// tagged union.
diff --git a/selfhost/cmd/wwdump/main.combined.ww b/selfhost/cmd/wwdump/main.combined.ww
index 6352b51a..7554014f 100644
--- a/selfhost/cmd/wwdump/main.combined.ww
+++ b/selfhost/cmd/wwdump/main.combined.ww
@@ -8890,6 +8890,13 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		};
 		return nil;
 	};
+	if (k == nkind.N_SPREAD) {
+		// A.6.2.0e — pass-through stamp. Mirrors cstage check.c:1212-1213.
+		// The spread expression `xs...` carries the operand's type.
+		let t: *node = exprtype(c, e.lhs, nil);
+		if (t != nil) { e.type_ = tinfofornode(c, t): *void; };
+		return t;
+	};
 	if (k == nkind.N_TRYPROP) {
 		// success unwrap: the success-variant type of operand's
 		// tagged union.