cmd/compile: lock in test for column numbers in unused error

Updates #21317

@mdempsky fixed issue #21317 with CL 66810,
so lock a test in to ensure we don't regress.

The test is manual for now before test/run.go
has support for matching column numbers so do
it old school and match expected output after
an exec.

Change-Id: I6c2a66ddf04248f79d17ed7033a3280d50e41562
Reviewed-on: https://go-review.googlesource.com/76150
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/test/fixedbugs/issue21317.go b/test/fixedbugs/issue21317.go
new file mode 100644 (file)
index 0000000..ae0e0b5
--- /dev/null
+++ b/test/fixedbugs/issue21317.go
@@ -0,0 +1,60 @@
+// run
+
+// Copyright 2017 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.
+
+// As of "Mon 6 Nov 2017", run.go doesn't yet have proper
+// column matching so instead match the output manually
+// by exec-ing
+
+package main
+
+import (
+       "fmt"
+       "io/ioutil"
+       "log"
+       "os"
+       "os/exec"
+       "runtime"
+       "strings"
+)
+
+func main() {
+       if runtime.Compiler != "gc" || runtime.GOOS == "nacl" {
+               return
+       }
+
+       f, err := ioutil.TempFile("", "issue21317.go")
+       if err != nil {
+               log.Fatal(err)
+       }
+       fmt.Fprintf(f, `
+package main
+
+import "fmt"
+
+func main() {
+        n, err := fmt.Println(1)
+}
+`)
+       f.Close()
+       defer os.RemoveAll(f.Name())
+
+       // compile and test output
+       cmd := exec.Command("go", "tool", "compile", f.Name())
+       out, err := cmd.CombinedOutput()
+       if err == nil {
+               log.Fatalf("expected cmd/compile to fail")
+       }
+       wantErrs := []string{
+               "7:9: n declared and not used",
+               "7:12: err declared and not used",
+       }
+       outStr := string(out)
+       for _, want := range wantErrs {
+               if !strings.Contains(outStr, want) {
+                       log.Fatalf("failed to match %q\noutput: %q", want, outStr)
+               }
+       }
+}