os: convert poll.ErrFileClosed to ErrClosed for Stat

Fixes #66665

Change-Id: I3e3b7433d245daa997d7d502c2ef8978af6664fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/576119
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>

src/os/stat_test.go

@@ -5,6 +5,7 @@
 package os_test
 
 import (
+	"errors"
 	"internal/testenv"
 	"io/fs"
 	"os"
@@ -337,3 +338,26 @@ func TestStatConsole(t *testing.T) {
 		testStatAndLstat(t, `\\.\`+name, params)
 	}
 }
+
+func TestClosedStat(t *testing.T) {
+	// Historically we do not seem to match ErrClosed on non-Unix systems.
+	switch runtime.GOOS {
+	case "windows", "plan9":
+		t.Skipf("skipping on %s", runtime.GOOS)
+	}
+
+	t.Parallel()
+	f, err := os.Open("testdata/hello")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := f.Close(); err != nil {
+		t.Fatal(err)
+	}
+	_, err = f.Stat()
+	if err == nil {
+		t.Error("Stat succeeded on closed File")
+	} else if !errors.Is(err, os.ErrClosed) {
+		t.Errorf("error from Stat on closed file did not match ErrClosed: %q, type %T", err, err)
+	}
+}

src/os/stat_unix.go

@@ -19,7 +19,7 @@ func (f *File) Stat() (FileInfo, error) {
 	var fs fileStat
 	err := f.pfd.Fstat(&fs.sys)
 	if err != nil {
-		return nil, &PathError{Op: "stat", Path: f.name, Err: err}
+		return nil, f.wrapErr("stat", err)
 	}
 	fillFileStatFromSys(&fs, f.name)
 	return &fs, nil