cmd/fix: remove un-used code

Change-Id: Ibbd9da6fd1f3219c9c6103d8f858347ab3a21210
Reviewed-on: https://go-review.googlesource.com/c/go/+/250857
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

src/cmd/fix/fix.go

@@ -7,13 +7,9 @@ package main
 import (
 	"fmt"
 	"go/ast"
-	"go/parser"
 	"go/token"
-	"os"
 	"path"
-	"reflect"
 	"strconv"
-	"strings"
 )
 
 type fix struct {
@@ -323,160 +319,12 @@ func declImports(gen *ast.GenDecl, path string) bool {
 	return false
 }
 
-// isPkgDot reports whether t is the expression "pkg.name"
-// where pkg is an imported identifier.
-func isPkgDot(t ast.Expr, pkg, name string) bool {
-	sel, ok := t.(*ast.SelectorExpr)
-	return ok && isTopName(sel.X, pkg) && sel.Sel.String() == name
-}
-
-// isPtrPkgDot reports whether f is the expression "*pkg.name"
-// where pkg is an imported identifier.
-func isPtrPkgDot(t ast.Expr, pkg, name string) bool {
-	ptr, ok := t.(*ast.StarExpr)
-	return ok && isPkgDot(ptr.X, pkg, name)
-}
-
 // isTopName reports whether n is a top-level unresolved identifier with the given name.
 func isTopName(n ast.Expr, name string) bool {
 	id, ok := n.(*ast.Ident)
 	return ok && id.Name == name && id.Obj == nil
 }
 
-// isName reports whether n is an identifier with the given name.
-func isName(n ast.Expr, name string) bool {
-	id, ok := n.(*ast.Ident)
-	return ok && id.String() == name
-}
-
-// isCall reports whether t is a call to pkg.name.
-func isCall(t ast.Expr, pkg, name string) bool {
-	call, ok := t.(*ast.CallExpr)
-	return ok && isPkgDot(call.Fun, pkg, name)
-}
-
-// If n is an *ast.Ident, isIdent returns it; otherwise isIdent returns nil.
-func isIdent(n interface{}) *ast.Ident {
-	id, _ := n.(*ast.Ident)
-	return id
-}
-
-// refersTo reports whether n is a reference to the same object as x.
-func refersTo(n ast.Node, x *ast.Ident) bool {
-	id, ok := n.(*ast.Ident)
-	// The test of id.Name == x.Name handles top-level unresolved
-	// identifiers, which all have Obj == nil.
-	return ok && id.Obj == x.Obj && id.Name == x.Name
-}
-
-// isBlank reports whether n is the blank identifier.
-func isBlank(n ast.Expr) bool {
-	return isName(n, "_")
-}
-
-// isEmptyString reports whether n is an empty string literal.
-func isEmptyString(n ast.Expr) bool {
-	lit, ok := n.(*ast.BasicLit)
-	return ok && lit.Kind == token.STRING && len(lit.Value) == 2
-}
-
-func warn(pos token.Pos, msg string, args ...interface{}) {
-	if pos.IsValid() {
-		msg = "%s: " + msg
-		arg1 := []interface{}{fset.Position(pos).String()}
-		args = append(arg1, args...)
-	}
-	fmt.Fprintf(os.Stderr, msg+"\n", args...)
-}
-
-// countUses returns the number of uses of the identifier x in scope.
-func countUses(x *ast.Ident, scope []ast.Stmt) int {
-	count := 0
-	ff := func(n interface{}) {
-		if n, ok := n.(ast.Node); ok && refersTo(n, x) {
-			count++
-		}
-	}
-	for _, n := range scope {
-		walk(n, ff)
-	}
-	return count
-}
-
-// rewriteUses replaces all uses of the identifier x and !x in scope
-// with f(x.Pos()) and fnot(x.Pos()).
-func rewriteUses(x *ast.Ident, f, fnot func(token.Pos) ast.Expr, scope []ast.Stmt) {
-	var lastF ast.Expr
-	ff := func(n interface{}) {
-		ptr, ok := n.(*ast.Expr)
-		if !ok {
-			return
-		}
-		nn := *ptr
-
-		// The child node was just walked and possibly replaced.
-		// If it was replaced and this is a negation, replace with fnot(p).
-		not, ok := nn.(*ast.UnaryExpr)
-		if ok && not.Op == token.NOT && not.X == lastF {
-			*ptr = fnot(nn.Pos())
-			return
-		}
-		if refersTo(nn, x) {
-			lastF = f(nn.Pos())
-			*ptr = lastF
-		}
-	}
-	for _, n := range scope {
-		walk(n, ff)
-	}
-}
-
-// assignsTo reports whether any of the code in scope assigns to or takes the address of x.
-func assignsTo(x *ast.Ident, scope []ast.Stmt) bool {
-	assigned := false
-	ff := func(n interface{}) {
-		if assigned {
-			return
-		}
-		switch n := n.(type) {
-		case *ast.UnaryExpr:
-			// use of &x
-			if n.Op == token.AND && refersTo(n.X, x) {
-				assigned = true
-				return
-			}
-		case *ast.AssignStmt:
-			for _, l := range n.Lhs {
-				if refersTo(l, x) {
-					assigned = true
-					return
-				}
-			}
-		}
-	}
-	for _, n := range scope {
-		if assigned {
-			break
-		}
-		walk(n, ff)
-	}
-	return assigned
-}
-
-// newPkgDot returns an ast.Expr referring to "pkg.name" at position pos.
-func newPkgDot(pos token.Pos, pkg, name string) ast.Expr {
-	return &ast.SelectorExpr{
-		X: &ast.Ident{
-			NamePos: pos,
-			Name:    pkg,
-		},
-		Sel: &ast.Ident{
-			NamePos: pos,
-			Name:    name,
-		},
-	}
-}
-
 // renameTop renames all references to the top-level name old.
 // It reports whether it makes any changes.
 func renameTop(f *ast.File, old, new string) bool {
@@ -707,143 +555,3 @@ func rewriteImport(f *ast.File, oldPath, newPath string) (rewrote bool) {
 	}
 	return
 }
-
-func usesImport(f *ast.File, path string) (used bool) {
-	spec := importSpec(f, path)
-	if spec == nil {
-		return
-	}
-
-	name := spec.Name.String()
-	switch name {
-	case "<nil>":
-		// If the package name is not explicitly specified,
-		// make an educated guess. This is not guaranteed to be correct.
-		lastSlash := strings.LastIndex(path, "/")
-		if lastSlash == -1 {
-			name = path
-		} else {
-			name = path[lastSlash+1:]
-		}
-	case "_", ".":
-		// Not sure if this import is used - err on the side of caution.
-		return true
-	}
-
-	walk(f, func(n interface{}) {
-		sel, ok := n.(*ast.SelectorExpr)
-		if ok && isTopName(sel.X, name) {
-			used = true
-		}
-	})
-
-	return
-}
-
-func expr(s string) ast.Expr {
-	x, err := parser.ParseExpr(s)
-	if err != nil {
-		panic("parsing " + s + ": " + err.Error())
-	}
-	// Remove position information to avoid spurious newlines.
-	killPos(reflect.ValueOf(x))
-	return x
-}
-
-var posType = reflect.TypeOf(token.Pos(0))
-
-func killPos(v reflect.Value) {
-	switch v.Kind() {
-	case reflect.Ptr, reflect.Interface:
-		if !v.IsNil() {
-			killPos(v.Elem())
-		}
-	case reflect.Slice:
-		n := v.Len()
-		for i := 0; i < n; i++ {
-			killPos(v.Index(i))
-		}
-	case reflect.Struct:
-		n := v.NumField()
-		for i := 0; i < n; i++ {
-			f := v.Field(i)
-			if f.Type() == posType {
-				f.SetInt(0)
-				continue
-			}
-			killPos(f)
-		}
-	}
-}
-
-// A Rename describes a single renaming.
-type rename struct {
-	OldImport string // only apply rename if this import is present
-	NewImport string // add this import during rewrite
-	Old       string // old name: p.T or *p.T
-	New       string // new name: p.T or *p.T
-}
-
-func renameFix(tab []rename) func(*ast.File) bool {
-	return func(f *ast.File) bool {
-		return renameFixTab(f, tab)
-	}
-}
-
-func parseName(s string) (ptr bool, pkg, nam string) {
-	i := strings.Index(s, ".")
-	if i < 0 {
-		panic("parseName: invalid name " + s)
-	}
-	if strings.HasPrefix(s, "*") {
-		ptr = true
-		s = s[1:]
-		i--
-	}
-	pkg = s[:i]
-	nam = s[i+1:]
-	return
-}
-
-func renameFixTab(f *ast.File, tab []rename) bool {
-	fixed := false
-	added := map[string]bool{}
-	check := map[string]bool{}
-	for _, t := range tab {
-		if !imports(f, t.OldImport) {
-			continue
-		}
-		optr, opkg, onam := parseName(t.Old)
-		walk(f, func(n interface{}) {
-			np, ok := n.(*ast.Expr)
-			if !ok {
-				return
-			}
-			x := *np
-			if optr {
-				p, ok := x.(*ast.StarExpr)
-				if !ok {
-					return
-				}
-				x = p.X
-			}
-			if !isPkgDot(x, opkg, onam) {
-				return
-			}
-			if t.NewImport != "" && !added[t.NewImport] {
-				addImport(f, t.NewImport)
-				added[t.NewImport] = true
-			}
-			*np = expr(t.New)
-			check[t.OldImport] = true
-			fixed = true
-		})
-	}
-
-	for ipath := range check {
-		if !usesImport(f, ipath) {
-			deleteImport(f, ipath)
-		}
-	}
-	return fixed
-}