From: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Date: Mon, 31 May 2021 17:56:14 +0000 (+0700)
Subject: [dev.typeparams] cmd/compile: handle ONONAME in subster.node
X-Git-Tag: go1.18beta1~1818^2^2~468
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=4b10e4c547;p=gostls13.git

[dev.typeparams] cmd/compile: handle ONONAME in subster.node

Fixes #46472

Change-Id: I27802978fa0c3bb32a29e452165a6fcac93473bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/323731
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
---

diff --git a/src/cmd/compile/internal/noder/stencil.go b/src/cmd/compile/internal/noder/stencil.go
index e273a80b20..36a6f2e6d0 100644
--- a/src/cmd/compile/internal/noder/stencil.go
+++ b/src/cmd/compile/internal/noder/stencil.go
@@ -350,6 +350,9 @@ func (subst *subster) node(n ir.Node) ir.Node {
 				return v
 			}
 			return x
+		case ir.ONONAME:
+			// This handles the identifier in a type switch guard
+			fallthrough
 		case ir.OLITERAL, ir.ONIL:
 			if x.Sym() != nil {
 				return x
diff --git a/test/typeparam/issue46472.go b/test/typeparam/issue46472.go
new file mode 100644
index 0000000000..bab48e7d2f
--- /dev/null
+++ b/test/typeparam/issue46472.go
@@ -0,0 +1,20 @@
+// run -gcflags=-G=3
+
+// 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
+
+func foo[T any](d T) {
+	switch v := interface{}(d).(type) {
+	case string:
+		if v != "x" {
+			panic("unexpected v: "+v)
+		}
+	}
+
+}
+func main() {
+	foo("x")
+}