cmd/compile: fix case where init info of OAS node is dropped

When an OAS node is converted to an OSELRECV2 node in tcSelect(), the
possible DCL node in the Init field was being dropped, since a
completely new node was being created and the Init field was not set. I
don't expect n.Init() to be set for the ORECV case, but the code now
deals with that too.

Fixed bug in both tcSelect() and transformSelect().

Fixes #48289

Change-Id: I09918a70f7cbaa4aa9a17546169f908a8787df15
Reviewed-on: https://go-review.googlesource.com/c/go/+/348569
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>

diff --git a/src/cmd/compile/internal/noder/transform.go b/src/cmd/compile/internal/noder/transform.go
index b278f3db09c7db4a8a4b4e65472ca5e57d44b260..8173bfc747f20ce59f8f36a858d0a0b1eb035e8b 100644 (file)
--- a/src/cmd/compile/internal/noder/transform.go
+++ b/src/cmd/compile/internal/noder/transform.go
@@ -554,6 +554,7 @@ func transformSelect(sel *ir.SelectStmt) {
                                }
                                selrecv.Def = def
                                selrecv.SetTypecheck(1)
+                               selrecv.SetInit(n.Init())
                                ncase.Comm = selrecv
                        }
                        switch n.Op() {

diff --git a/src/cmd/compile/internal/typecheck/stmt.go b/src/cmd/compile/internal/typecheck/stmt.go
index c322d490e5b2a07ac6524afd40900b182bd18392..9a02c1752caf13f6c89e26866e01ba553a767e62 100644 (file)
--- a/src/cmd/compile/internal/typecheck/stmt.go
+++ b/src/cmd/compile/internal/typecheck/stmt.go
@@ -395,10 +395,11 @@ func tcSelect(sel *ir.SelectStmt) {
                        n := Stmt(ncase.Comm)
                        ncase.Comm = n
                        oselrecv2 := func(dst, recv ir.Node, def bool) {
-                               n := ir.NewAssignListStmt(n.Pos(), ir.OSELRECV2, []ir.Node{dst, ir.BlankNode}, []ir.Node{recv})
-                               n.Def = def
-                               n.SetTypecheck(1)
-                               ncase.Comm = n
+                               selrecv := ir.NewAssignListStmt(n.Pos(), ir.OSELRECV2, []ir.Node{dst, ir.BlankNode}, []ir.Node{recv})
+                               selrecv.Def = def
+                               selrecv.SetTypecheck(1)
+                               selrecv.SetInit(n.Init())
+                               ncase.Comm = selrecv
                        }
                        switch n.Op() {
                        default:

diff --git a/test/fixedbugs/issue48289.go b/test/fixedbugs/issue48289.go
new file mode 100644 (file)
index 0000000..94dbeee
--- /dev/null
+++ b/test/fixedbugs/issue48289.go
@@ -0,0 +1,28 @@
+// run
+
+// 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
+
+import "fmt"
+
+func main() {
+       ch := make(chan int, 1)
+
+       var ptrs [2]*int
+       for i := range ptrs {
+               ch <- i
+               select {
+               case x := <-ch:
+                       ptrs[i] = &x
+               }
+       }
+
+       for i, ptr := range ptrs {
+               if *ptr != i {
+                       panic(fmt.Sprintf("got *ptr %d, want %d", *ptr, i))
+               }
+       }
+}