Improve wording and add more reliable package check

Author: jespino

go/analysis/passes/initflagparse/initflagparse.go

@@ -8,16 +8,17 @@ package initflagparse
 
 import (
 	"go/ast"
+	"go/types"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/ast/inspector"
 )
 
-const Doc = `check for usage of flag.Parse during modules init
+const Doc = `check for calls to flag.Parse within packages init
 
-The initflagparse analyzer reports incorrect uses of flag.Parse during
-the init of the modules.`
+The initflagparse analyzer reports incorrect calls to flag.Parse within
+the init of the packages.`
 
 var Analyzer = &analysis.Analyzer{
 	Name:     "initflagparse",
@@ -59,8 +60,18 @@ func checkForFlagParse(pass *analysis.Pass, x ast.Node) {
 			return true
 		}
 
-		if ok && module.Name == "flag" && fun.Sel.Name == "Parse" {
-			pass.ReportRangef(x, "flag.Parse during package initialization")
+		obj := pass.TypesInfo.ObjectOf(module)
+		if obj == nil {
+			return true
+		}
+
+		pkgObj, ok := obj.(*types.PkgName)
+		if !ok || pkgObj.Imported() == nil {
+			return true
+		}
+
+		if ok && obj != nil && pkgObj.Imported().Name() == "flag" && fun.Sel.Name == "Parse" {
+			pass.ReportRangef(x, "flag.Parse call within package initialization")
 			return false
 		}
 		return true

go/analysis/passes/initflagparse/initflagparse_test.go

@@ -14,4 +14,5 @@ import (
 func Test(t *testing.T) {
 	testdata := analysistest.TestData()
 	analysistest.Run(t, testdata, initflagparse.Analyzer, "a")
+	analysistest.Run(t, testdata, initflagparse.Analyzer, "b")
 }

go/analysis/passes/initflagparse/testdata/src/a/a.go

@@ -7,7 +7,7 @@ package a
 import "flag"
 
 func init() {
-	flag.Parse() // want `flag.Parse usage during module initialization`
+	flag.Parse() // want `flag.Parse call within package initialization`
 }
 
 type Test struct{}

go/analysis/passes/initflagparse/testdata/src/b/b.go

@@ -0,0 +1,21 @@
+// Copyright 2014 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 b
+
+import x "flag"
+
+func init() {
+	x.Parse() // want `flag.Parse call within package initialization`
+}
+
+type Test struct{}
+
+func (_ *Test) init() {
+	x.Parse()
+}
+
+func main() {
+	x.Parse()
+}