cmd/compile: don't emit inltree for closure within body of inlined func

When inlining functions with closures, ensure that we don't mark the
body of the closure with a src.Pos marker that reflects the inline,
since this will result in the generation of an inltree table for the
closure itself (as opposed to the routine that the func-with-closure
was inlined into).

Fixes #46234.

Change-Id: I348296de6504fc4745d99adab436640f50be299a
Reviewed-on: https://go-review.googlesource.com/c/go/+/320913
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Than McIntosh <thanm@google.com>

test/fixedbugs/issue46234.go

@@ -0,0 +1,103 @@
+// buildrun -t 30
+
+// +build !js
+
+// 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.
+
+// Ensure that runtime traceback does not infinite loop for
+// the testcase below.
+
+package main
+
+import (
+	"bytes"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+)
+
+const prog = `
+
+package main
+
+import "context"
+
+var gpi *int
+
+type nAO struct {
+	eE bool
+}
+
+type NAO func(*nAO)
+
+func WEA() NAO {
+	return func(o *nAO) { o.eE = true }
+}
+
+type R struct {
+	cM *CM
+}
+
+type CM int
+
+type A string
+
+func (m *CM) NewA(ctx context.Context, cN string, nn *nAO, opts ...NAO) (*A, error) {
+	for _, o := range opts {
+		o(nn)
+	}
+	s := A("foo")
+	return &s, nil
+}
+
+func (r *R) CA(ctx context.Context, cN string, nn *nAO) (*int, error) {
+	cA, err := r.cM.NewA(ctx, cN, nn, WEA(), WEA())
+	if err == nil {
+		return nil, err
+	}
+	println(cA)
+	x := int(42)
+	return &x, nil
+}
+
+func main() {
+	c := CM(1)
+	r := R{cM: &c}
+	var ctx context.Context
+	nnr := nAO{}
+	pi, err := r.CA(ctx, "foo", nil)
+	if err != nil {
+		panic("bad")
+	}
+	println(nnr.eE)
+	gpi = pi
+}
+`
+
+func main() {
+	dir, err := ioutil.TempDir("", "46234")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	file := filepath.Join(dir, "main.go")
+	if err := ioutil.WriteFile(file, []byte(prog), 0655); err != nil {
+		log.Fatalf("Write error %v", err)
+	}
+
+	cmd := exec.Command("go", "run", file)
+	output, err := cmd.CombinedOutput()
+	if err == nil {
+		log.Fatalf("Passed, expected an error")
+	}
+
+	want := []byte("segmentation violation")
+	if !bytes.Contains(output, want) {
+		log.Fatalf("Unmatched error message %q:\nin\n%s\nError: %v", want, output, err)
+	}
+}