diff --git a/src/cmd/compile/internal/rangefunc/rewrite.go b/src/cmd/compile/internal/rangefunc/rewrite.go
index 551e126af8..2421efbad8 100644
--- a/src/cmd/compile/internal/rangefunc/rewrite.go
+++ b/src/cmd/compile/internal/rangefunc/rewrite.go
@@ -994,7 +994,14 @@ func (r *rewriter) computeBranchNext() {
 				l := n.Label.Value
 				labels = append(labels, l)
 				f := forStack[len(forStack)-1]
-				r.labelLoop[l] = f
+				if _, existed := r.labelLoop[l]; existed {
+					// The typechecker has already validated that labels are unique within this scope.
+					// If a duplicate label 'X' is encountered, it must reside in a nested scope
+					// (e.g., inside a function literal). Because nested labels do not affect
+					// the current control flow analysis, they can be safely ignored.
+				} else {
+					r.labelLoop[l] = f
+				}
 			}
 		} else {
 			n := stack[len(stack)-1]
diff --git a/test/fixedbugs/issue78408.go b/test/fixedbugs/issue78408.go
new file mode 100644
index 0000000000..a43e5c23f1
--- /dev/null
+++ b/test/fixedbugs/issue78408.go
@@ -0,0 +1,18 @@
+// compile
+
+// Copyright 2026 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+func F() {
+A:
+	for range (func(func() bool))(nil) {
+		_ = func() {
+		A:
+			goto A
+		}
+		goto A
+	}
+}