Refuse a selector on a template before its level fence, give pathCheck one entry over its own tail, and scope the probe decision to descend

docs/decisions.md

@@ -688,8 +688,8 @@ though `hasRead` states the same stop rule. Valid while the two differ in where
 
 2026-09-28, larv-review on systems-architect's finding; awaiting approval. Goals 2 and
 11: `pathCheck`, `pathCover`, `pathProbe` and `pathDraw` each loop over `stepInto` and
-`table.route` themselves, and `descend` and `tableReadOf` build their probe in place, so
+`table.route` themselves, and `descend` builds its probe in place, so the probe's
-its `drawn` map stays on the stack. One walk calling them through an interface or a type parameter
+`drawn` map stays on the stack. One walk calling them through an interface or a type
-leaks the walker and the pins it holds, an allocation per reference read. Valid while Go's
+parameter leaks the walker and the pins it holds, an allocation per reference read.
-escape analysis treats a call through an interface or a type parameter as leaking its
+Valid while Go's escape analysis treats a call through an interface or a type parameter
-receiver.
+as leaking its receiver.

graph.go

@@ -165,7 +165,7 @@ func renderEdges(n node) []renderEdge {
 // already proved the tail resolves in every variant.
 func pathLeaves(n node, tail []string) []node {
 	w := &pathCheck{tail: tail}
-	_, _ = w.walk(n, tail)
+	_, _ = w.run(n)
 	return w.leaves
 }
 

path.go

@@ -196,6 +196,8 @@ type pathCheck struct {
 	leaves []node
 }
 
+func (w *pathCheck) run(n node) (node, error) { return w.walk(n, w.tail) }
+
 func (w *pathCheck) walk(n node, tail []string) (node, error) {
 	for descended := false; len(tail) > 0 || descended; {
 		var err error
@@ -215,6 +217,9 @@ func (w *pathCheck) walk(n node, tail []string) (node, error) {
 			n, tail, descended = r.next, r.rest, r.descends
 			continue
 		case *template:
+			if isSelector(tail[0]) {
+				break
+			}
 			if err := w.enter(x, tail); err != nil {
 				return nil, err
 			}
@@ -452,6 +457,6 @@ func unreachableInChoice(c *choice, want string) error {
 // checkPath proves a dotted tail as pathCheck does, so a path that validates here
 // resolves on every render, and a typo is a New-time error.
 func checkPath(n node, tail []string, level string) error {
-	_, err := (&pathCheck{level: level, tail: tail}).walk(n, tail)
+	_, err := (&pathCheck{level: level, tail: tail}).run(n)
 	return err
 }