cmd/compile: fix missing typecheck for static initialization slice

CL 440455 fixed missing walk pass for static initialization slice.
However, slicelit may produce un-typechecked node, thus we need to do
typecheck for sinit before calling walkStmtList.

Fixes #56727

Change-Id: I40730cebcd09f2be4389d71c5a90eb9a060e4ab7
Reviewed-on: https://go-review.googlesource.com/c/go/+/450215
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>

src/cmd/compile/internal/walk/complit.go

@@ -243,6 +243,7 @@ func fixedlit(ctxt initContext, kind initKind, n *ir.CompLitExpr, var_ ir.Node,
 					// confuses about variables lifetime. So making sure those expressions
 					// are ordered correctly here. See issue #52673.
 					orderBlock(&sinit, map[string][]*ir.Name{})
+					typecheck.Stmts(sinit)
 					walkStmtList(sinit)
 				}
 				init.Append(sinit...)

test/fixedbugs/issue56727.go

@@ -0,0 +1,45 @@
+// compile
+
+// Copyright 2022 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
+
+type I interface {
+	M()
+}
+
+type S struct{}
+
+func (*S) M() {}
+
+type slice []I
+
+func f() {
+	ss := struct {
+		i I
+	}{
+		i: &S{},
+	}
+
+	_ = [...]struct {
+		s slice
+	}{
+		{
+			s: slice{ss.i},
+		},
+		{
+			s: slice{ss.i},
+		},
+		{
+			s: slice{ss.i},
+		},
+		{
+			s: slice{ss.i},
+		},
+		{
+			s: slice{ss.i},
+		},
+	}
+}