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-rw-r--r--src/reflect/value.go5
-rw-r--r--test/fixedbugs/issue77779.go45
2 files changed, 48 insertions, 2 deletions
diff --git a/src/reflect/value.go b/src/reflect/value.go
index 8c8acbaa9a..f192eb5974 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -1288,9 +1288,10 @@ func (v Value) Field(i int) Value {
// bunch of zero-sized fields. We must return the zero-sized
// fields indirectly, as only ptr-shaped things can be direct.
// See issue 74935.
- // We use nil instead of v.ptr as it doesn't matter and
+ // We use &zeroVal[0] instead of v.ptr as it doesn't matter and
// we can avoid pinning a possibly now-unused object.
- return Value{typ, nil, fl | flagIndir}
+ // Don't use nil, see issue 77779.
+ return Value{typ, unsafe.Pointer(&zeroVal[0]), fl | flagIndir}
}
// Either flagIndir is set and v.ptr points at struct,
diff --git a/test/fixedbugs/issue77779.go b/test/fixedbugs/issue77779.go
new file mode 100644
index 0000000000..1a61b2cbe0
--- /dev/null
+++ b/test/fixedbugs/issue77779.go
@@ -0,0 +1,45 @@
+// run
+
+// 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 main
+
+import (
+ "reflect"
+)
+
+type Renderer interface {
+ Render() error
+}
+
+type ZeroSize struct{}
+
+func (ZeroSize) Render() error { return nil }
+
+type Data struct {
+ X, Y, Z int
+}
+
+// Container is pointer-sized (8 bytes): zero-size embed + one pointer field.
+// This triggers Go 1.26 interface inlining, which produces a nil data pointer
+// for the zero-size field when extracted via reflect.Value.Interface().
+type Container struct {
+ ZeroSize
+ Data *Data
+}
+
+func main() {
+ render(Container{})
+ render(&Container{})
+}
+
+func render(iface any) {
+ if reflect.ValueOf(iface).Kind() == reflect.Ptr {
+ _ = reflect.ValueOf(iface).Elem().Field(0).Interface().(Renderer).Render()
+ return
+ }
+
+ _ = reflect.ValueOf(iface).Field(0).Interface().(Renderer).Render()
+}