diff --git a/src/cmd/compile/internal/reflectdata/reflect.go b/src/cmd/compile/internal/reflectdata/reflect.go
index f0a60998a1..d23ca6b839 100644
--- a/src/cmd/compile/internal/reflectdata/reflect.go
+++ b/src/cmd/compile/internal/reflectdata/reflect.go
@@ -1837,6 +1837,10 @@ func MarkTypeUsedInInterface(t *types.Type, from *obj.LSym) {
 // MarkUsedIfaceMethod marks that an interface method is used in the current
 // function. n is OCALLINTER node.
 func MarkUsedIfaceMethod(n *ir.CallExpr) {
+	// skip unnamed functions (func _())
+	if ir.CurFunc.LSym == nil {
+		return
+	}
 	dot := n.X.(*ir.SelectorExpr)
 	ityp := dot.X.Type()
 	tsym := TypeLinksym(ityp)
diff --git a/test/fixedbugs/issue45258.go b/test/fixedbugs/issue45258.go
new file mode 100644
index 0000000000..f4d6fccf17
--- /dev/null
+++ b/test/fixedbugs/issue45258.go
@@ -0,0 +1,28 @@
+// compile
+
+// Copyright 2021 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
+
+type Fooer interface {
+	Foo() Barer
+}
+
+type Barer interface {
+	Bar()
+}
+
+type impl struct{}
+
+func (r *impl) Foo() Barer {
+	return r
+}
+
+func (r *impl) Bar() {}
+
+func _() {
+	var r Fooer = &impl{}
+	r.Foo().Bar()
+}