selfhost/cmd/wcc: stamp e.type_ for CAST/TRY/TYPEASSERT/TYPETEST (A.6.1.1)

Phase 1 A.6.1 commit 1. Extends A.6.0's literal+ident type_
population to the CAST + TRY family + TYPEASSERT/TYPETEST arms in
exprtype. Mirrors cstage cmd/wcc/check.c:737 (N_CAST) and
1332-1435 (TYPETEST/TYPEASSERT/TRYPROP/TRYUNW) where n->type is
stamped on each value-returning path.

N_TRYPROP / N_TRYUNW only stamp the value-returning paths
(success-variant match inside the for-loop, no-error tail at
ou.list); the three nil-returning early-outs are intentionally
left unstamped.

Verified 132/132 incl. 995_self_rebuild byte-identity.

selfhost/cmd/w6c/main.combined.ww

@@ -8255,7 +8255,9 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		return t;
 	};
 	if (k == nkind.N_CAST) {
-		// `expr: T` — explicit cast; the type expr is e.rhs.
+		// `expr: T` — explicit cast; the type expr is e.rhs. Mirrors
+		// cstage cmd/wcc/check.c:737 `n->type = resolve_type(c, n->rhs)`.
+		e.type_ = tinfofornode(c, e.rhs): *void;
 		return e.rhs;
 	};
 	if (k == nkind.N_CALL) {
@@ -8396,11 +8398,15 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		if (taggedhaserr(c, ou)) {
 			let v: *node = ou.list;
 			for (v != nil) {
-				if (!iserrvariant(c, ou, v)) { return v; };
+				if (!iserrvariant(c, ou, v)) {
+					e.type_ = tinfofornode(c, v): *void;
+					return v;
+				};
 				v = v.next;
 			};
 			return nil;
 		};
+		e.type_ = tinfofornode(c, ou.list): *void;
 		return ou.list;
 	};
 	if (k == nkind.N_TRYUNW) {
@@ -8414,20 +8420,28 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		if (taggedhaserr(c, ou)) {
 			let v: *node = ou.list;
 			for (v != nil) {
-				if (!iserrvariant(c, ou, v)) { return v; };
+				if (!iserrvariant(c, ou, v)) {
+					e.type_ = tinfofornode(c, v): *void;
+					return v;
+				};
 				v = v.next;
 			};
 			return nil;
 		};
+		e.type_ = tinfofornode(c, ou.list): *void;
 		return ou.list;
 	};
 	if (k == nkind.N_TYPEASSERT) {
-		// `e as T` → T
+		// `e as T` → T. Mirrors cstage cmd/wcc/check.c TYPEASSERT
+		// `n->type = resolve_type(c, n->rhs)`.
+		e.type_ = tinfofornode(c, e.rhs): *void;
 		return e.rhs;
 	};
 	if (k == nkind.N_TYPETEST) {
 		// `e is T` → bool
-		return mktname(c, "bool");
+		let tn: *node = mktname(c, "bool");
+		e.type_ = tinfofornode(c, tn): *void;
+		return tn;
 	};
 	return nil;
 };

selfhost/cmd/wcc/check.ww

@@ -1323,7 +1323,9 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		return t;
 	};
 	if (k == nkind.N_CAST) {
-		// `expr: T` — explicit cast; the type expr is e.rhs.
+		// `expr: T` — explicit cast; the type expr is e.rhs. Mirrors
+		// cstage cmd/wcc/check.c:737 `n->type = resolve_type(c, n->rhs)`.
+		e.type_ = tinfofornode(c, e.rhs): *void;
 		return e.rhs;
 	};
 	if (k == nkind.N_CALL) {
@@ -1464,11 +1466,15 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		if (taggedhaserr(c, ou)) {
 			let v: *node = ou.list;
 			for (v != nil) {
-				if (!iserrvariant(c, ou, v)) { return v; };
+				if (!iserrvariant(c, ou, v)) {
+					e.type_ = tinfofornode(c, v): *void;
+					return v;
+				};
 				v = v.next;
 			};
 			return nil;
 		};
+		e.type_ = tinfofornode(c, ou.list): *void;
 		return ou.list;
 	};
 	if (k == nkind.N_TRYUNW) {
@@ -1482,20 +1488,28 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		if (taggedhaserr(c, ou)) {
 			let v: *node = ou.list;
 			for (v != nil) {
-				if (!iserrvariant(c, ou, v)) { return v; };
+				if (!iserrvariant(c, ou, v)) {
+					e.type_ = tinfofornode(c, v): *void;
+					return v;
+				};
 				v = v.next;
 			};
 			return nil;
 		};
+		e.type_ = tinfofornode(c, ou.list): *void;
 		return ou.list;
 	};
 	if (k == nkind.N_TYPEASSERT) {
-		// `e as T` → T
+		// `e as T` → T. Mirrors cstage cmd/wcc/check.c TYPEASSERT
+		// `n->type = resolve_type(c, n->rhs)`.
+		e.type_ = tinfofornode(c, e.rhs): *void;
 		return e.rhs;
 	};
 	if (k == nkind.N_TYPETEST) {
 		// `e is T` → bool
-		return mktname(c, "bool");
+		let tn: *node = mktname(c, "bool");
+		e.type_ = tinfofornode(c, tn): *void;
+		return tn;
 	};
 	return nil;
 };

selfhost/cmd/wwdump/main.combined.ww

@@ -8255,7 +8255,9 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		return t;
 	};
 	if (k == nkind.N_CAST) {
-		// `expr: T` — explicit cast; the type expr is e.rhs.
+		// `expr: T` — explicit cast; the type expr is e.rhs. Mirrors
+		// cstage cmd/wcc/check.c:737 `n->type = resolve_type(c, n->rhs)`.
+		e.type_ = tinfofornode(c, e.rhs): *void;
 		return e.rhs;
 	};
 	if (k == nkind.N_CALL) {
@@ -8396,11 +8398,15 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		if (taggedhaserr(c, ou)) {
 			let v: *node = ou.list;
 			for (v != nil) {
-				if (!iserrvariant(c, ou, v)) { return v; };
+				if (!iserrvariant(c, ou, v)) {
+					e.type_ = tinfofornode(c, v): *void;
+					return v;
+				};
 				v = v.next;
 			};
 			return nil;
 		};
+		e.type_ = tinfofornode(c, ou.list): *void;
 		return ou.list;
 	};
 	if (k == nkind.N_TRYUNW) {
@@ -8414,20 +8420,28 @@ fn exprtype(c: *checker, e: *node, hint: *node) *node = {
 		if (taggedhaserr(c, ou)) {
 			let v: *node = ou.list;
 			for (v != nil) {
-				if (!iserrvariant(c, ou, v)) { return v; };
+				if (!iserrvariant(c, ou, v)) {
+					e.type_ = tinfofornode(c, v): *void;
+					return v;
+				};
 				v = v.next;
 			};
 			return nil;
 		};
+		e.type_ = tinfofornode(c, ou.list): *void;
 		return ou.list;
 	};
 	if (k == nkind.N_TYPEASSERT) {
-		// `e as T` → T
+		// `e as T` → T. Mirrors cstage cmd/wcc/check.c TYPEASSERT
+		// `n->type = resolve_type(c, n->rhs)`.
+		e.type_ = tinfofornode(c, e.rhs): *void;
 		return e.rhs;
 	};
 	if (k == nkind.N_TYPETEST) {
 		// `e is T` → bool
-		return mktname(c, "bool");
+		let tn: *node = mktname(c, "bool");
+		e.type_ = tinfofornode(c, tn): *void;
+		return tn;
 	};
 	return nil;
 };