fix autoNames check importName

import.go

@@ -585,7 +585,6 @@ func (p *Package) big() PkgRef {
 type null struct{}
 type autoNames struct {
 	names   map[string]null
-	reqIdx  int
 	autoIdx int
 }
 
@@ -611,14 +610,14 @@ func (p *autoNames) hasName(name string) bool {
 	return ok
 }
 
-func (p *autoNames) requireName(name string) (ret string, renamed bool) {
+func (p *autoNames) importName(name string) (ret string, renamed bool) {
 	ret = name
+	var idx int
 	for p.hasName(ret) {
-		p.reqIdx++
-		ret = name + strconv.Itoa(p.reqIdx)
+		idx++
+		ret = name + strconv.Itoa(idx)
 		renamed = true
 	}
-	p.useName(ret)
 	return
 }
 

package.go

@@ -192,7 +192,7 @@ func (p astVisitor) Visit(node ast.Node) (w ast.Visitor) {
 		if id, ok := x.(*ast.Ident); ok && id.Obj != nil {
 			if used, ok := id.Obj.Data.(importUsed); ok && bool(!used) {
 				id.Obj.Data = importUsed(true)
-				if name, renamed := p.this.requireName(id.Name); renamed {
+				if name, renamed := p.this.importName(id.Name); renamed {
 					id.Name = name
 					id.Obj.Name = name
 				}

package_test.go

@@ -2563,6 +2563,88 @@ func main() {
 `)
 }
 
+func TestMultiFiles(t *testing.T) {
+	pkg := newMainPackage()
+
+	_, err := pkg.SetCurFile("a.go", true)
+	if err != nil {
+		t.Fatal("pkg.SetCurFile failed:", err)
+	}
+	fmt := pkg.Import("fmt")
+	pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg).
+		Val(fmt.Ref("Println")).Val("Hello").Call(1).EndStmt().
+		End()
+
+	_, err = pkg.SetCurFile("b.go", true)
+	if err != nil {
+		t.Fatal("pkg.SetCurFile failed:", err)
+	}
+	pkg.NewFunc(nil, "demo", nil, nil, false).BodyStart(pkg).
+		Val(fmt.Ref("Println")).Val("Hello").Call(1).EndStmt().
+		End()
+
+	domTestEx(t, pkg, `package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello")
+}
+`, "a.go")
+
+	domTestEx(t, pkg, `package main
+
+import "fmt"
+
+func demo() {
+	fmt.Println("Hello")
+}
+`, "b.go")
+}
+
+func TestImportMultiFiles(t *testing.T) {
+	pkg := newMainPackage()
+
+	_, err := pkg.SetCurFile("a.go", true)
+	if err != nil {
+		t.Fatal("pkg.SetCurFile failed:", err)
+	}
+	fmt := pkg.Import("fmt")
+	v := pkg.NewParam(token.NoPos, "v", types.NewSlice(gogen.TyByte))
+	pkg.NewFunc(nil, "fmt", gogen.NewTuple(v), nil, false).BodyStart(pkg).End()
+	pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg).
+		Val(fmt.Ref("Println")).Val("Hello").Call(1).EndStmt().
+		End()
+
+	_, err = pkg.SetCurFile("b.go", true)
+	if err != nil {
+		t.Fatal("pkg.SetCurFile failed:", err)
+	}
+	pkg.NewFunc(nil, "demo", nil, nil, false).BodyStart(pkg).
+		Val(fmt.Ref("Println")).Val("Hello").Call(1).EndStmt().
+		End()
+
+	domTestEx(t, pkg, `package main
+
+import fmt1 "fmt"
+
+func fmt(v []byte) {
+}
+func main() {
+	fmt1.Println("Hello")
+}
+`, "a.go")
+
+	domTestEx(t, pkg, `package main
+
+import fmt1 "fmt"
+
+func demo() {
+	fmt1.Println("Hello")
+}
+`, "b.go")
+}
+
 func TestImportUnused(t *testing.T) {
 	pkg := newMainPackage()
 	pkg.Import("fmt")