fix: resolve embedded method on pointer types

Option "-e" allows to set the command to be executed:

```
echo '6001d5ff0000000003000000000107000000dcff' | \
	yaegi -e 'import "fmt"; import "os"; import "encoding/hex"; import "io/ioutil"; func main() { in, _ := ioutil.ReadAll(os.Stdin); decoded, _ := hex.DecodeString(string(in));fmt.Println(string(decoded)) }' 2>/dev/null | \
	hexdump -C
00000000  60 01 d5 ff 00 00 00 00  03 00 00 00 00 01 07 00  |`...............|
00000010  00 00 dc ff 0a                                    |.....|
00000015
```

.golangci.toml

@@ -37,6 +37,7 @@
     "funlen",
     "gocognit",
     "stylecheck",
+    "gomnd",
   ]
 
 [issues]

.travis.yml

@@ -19,8 +19,8 @@ cache:
 matrix:
   fast_finish: true
   include:
-    - go: 1.12.x
     - go: 1.13.x
+    - go: 1.14.x
       env: STABLE=true
 
 env:

README.md

@@ -129,6 +129,24 @@ $ yaegi cmd/yaegi/yaegi.go
 >
 ```
 
+Or for Go scripting in the shebang line:
+
+```console
+$ cat /tmp/test
+#!/usr/bin/env yaegi
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("test")
+}
+$ ls -la /tmp/test
+-rwxr-xr-x 1 dow184 dow184 93 Jan  6 13:38 /tmp/test
+$ /tmp/test
+test
+```
+
 ## Documentation
 
 Documentation about Yaegi commands and libraries can be found at usual [godoc.org][docs].

_test/a40.go

@@ -0,0 +1,23 @@
+package main
+
+import "fmt"
+
+type rule uint8
+
+const (
+	r0 rule = iota
+	r1
+	r2
+)
+
+var a = [...]int{
+	r0: 1,
+	r1: 12,
+}
+
+func main() {
+	fmt.Println(a)
+}
+
+// Output:
+// [1 12]

_test/a41.go

@@ -0,0 +1,10 @@
+package main
+
+var a = [...]bool{true, true}
+
+func main() {
+	println(a[0] && true)
+}
+
+// Output:
+// true

_test/and3.go

@@ -0,0 +1,10 @@
+package main
+
+var a = true && true
+
+func main() {
+	println(a)
+}
+
+// Output:
+// true

_test/assign1.go

@@ -9,5 +9,5 @@ func main() {
 	fmt.Println(buf)
 }
 
-// Output
+// Output:
 // []

_test/b1/foo/foo.go

@@ -0,0 +1,7 @@
+package foo
+
+import bar "github.com/containous/yaegi/_test/b2/foo"
+
+var Desc = "in b1/foo"
+
+var Desc2 = Desc + bar.Desc

_test/b2/foo/foo.go

@@ -0,0 +1,3 @@
+package foo
+
+var Desc = "in b2/foo"

_test/bad0.go

@@ -1,4 +1,4 @@
 println("Hello")
 
 // Error:
-// _test/bad0.go:1:1: expected 'package', found println
+// 1:1: expected 'package', found println

_test/bin3.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+func main() {
+	str := "part1"
+	str += fmt.Sprintf("%s", "part2")
+	fmt.Println(str)
+}
+
+// Output:
+// part1part2

_test/chan8.go

@@ -0,0 +1,12 @@
+package main
+
+func main() {
+	messages := make(chan bool)
+
+	go func() { messages <- true }()
+
+	println(<-messages && true)
+}
+
+// Output:
+// true

_test/complex3.go

@@ -7,5 +7,5 @@ func main() {
 	fmt.Printf("%T %v\n", s, s)
 }
 
-// Output
+// Output:
 // int 2

_test/composite5.go

@@ -0,0 +1,16 @@
+package main
+
+import "fmt"
+
+type T struct {
+	m uint16
+}
+
+var t = T{1<<2 | 1<<3}
+
+func main() {
+	fmt.Println(t)
+}
+
+// Output:
+// {12}

_test/composite6.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/containous/yaegi/_test/ct1"
+)
+
+type T struct {
+	m uint16
+}
+
+var t = T{1 << ct1.R}
+
+func main() {
+	fmt.Println(t)
+}
+
+// Output:
+// {2}

_test/composite7.go

@@ -0,0 +1,20 @@
+package main
+
+type T struct {
+	name string
+}
+
+var tab = []*T{{
+	name: "foo",
+}, {
+	name: "bar",
+}}
+
+func main() {
+	println(len(tab))
+	println(tab[0].name)
+}
+
+// Output:
+// 2
+// foo

_test/const10.go

@@ -0,0 +1,17 @@
+package main
+
+const (
+	a = 2
+	b = c + d
+	c = a + d
+	d = e + f
+	e = 3
+	f = 4
+)
+
+func main() {
+	println(b)
+}
+
+// Output:
+// 16

_test/const6.go

@@ -0,0 +1,22 @@
+package main
+
+const (
+	maxNonStarters = 30
+	maxBufferSize  = maxNonStarters + 2
+)
+
+type reorderBuffer struct {
+	rune [maxBufferSize]Properties
+}
+
+type Properties struct {
+	pos  uint8
+	size uint8
+}
+
+func main() {
+	println(len(reorderBuffer{}.rune))
+}
+
+// Output:
+// 32

_test/const7.go

@@ -0,0 +1,19 @@
+package main
+
+import "fmt"
+
+const (
+	a = iota
+	b
+	c
+	d
+)
+
+type T [c]int
+
+func main() {
+	fmt.Println(T{})
+}
+
+// Output:
+// [0 0]

_test/const8.go

@@ -0,0 +1,15 @@
+package main
+
+const (
+	a = 2
+	b = c + d
+	c = 4
+	d = 5
+)
+
+func main() {
+	println(a, b, c, d)
+}
+
+// Output:
+// 2 9 4 5

_test/const9.go

@@ -0,0 +1,17 @@
+package main
+
+const (
+	a = 2
+	b = c + d
+	c = a + d
+	d = e + f
+	e = b + 2
+	f = 4
+)
+
+func main() {
+	println(b)
+}
+
+// Error:
+// 5:2: constant definition loop

_test/ct1/ct1.go

@@ -0,0 +1,9 @@
+package ct1
+
+type Class uint
+
+const (
+	L Class = iota
+	R
+	AL
+)

_test/defer4.go

@@ -0,0 +1,23 @@
+package main
+
+import "sync"
+
+type T struct {
+	mu   sync.RWMutex
+	name string
+}
+
+func (t *T) get() string {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	return t.name
+}
+
+var d = T{name: "test"}
+
+func main() {
+	println(d.get())
+}
+
+// Output:
+// test

_test/fun11.go

@@ -0,0 +1,12 @@
+package main
+
+var f F
+
+type F func(int)
+
+func main() {
+	println("ok")
+}
+
+// Output:
+// ok

_test/import8.go

@@ -0,0 +1,10 @@
+package main
+
+import "github.com/containous/yaegi/_test/b1/foo"
+
+func main() {
+	println(foo.Desc)
+}
+
+// Output:
+// in b1/foo

_test/interface19.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+var I interface{}
+
+func main() {
+	fmt.Printf("%T %v\n", I, I)
+}
+
+// Output:
+// <nil> <nil>

_test/interface20.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+func main() {
+	var a interface{}
+	a = string("A")
+	fmt.Println(a)
+}
+
+// Output:
+// A

_test/interface21.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+func main() {
+	s := make([]interface{}, 1)
+	s[0] = 1
+	fmt.Println(s[0])
+}
+
+// Output:
+// 1

_test/interface22.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+func main() {
+	s := make([]interface{}, 0)
+	s = append(s, 1)
+	fmt.Println(s[0])
+}
+
+// Output:
+// 1

_test/interface23.go

@@ -0,0 +1,12 @@
+package main
+
+import "fmt"
+
+func main() {
+	m := make(map[string]interface{})
+	m["A"] = string("A")
+	fmt.Println(m["A"])
+}
+
+// Output:
+// A

_test/interface24.go

@@ -0,0 +1,11 @@
+package main
+
+import "fmt"
+
+func main() {
+	m := make(map[string]interface{})
+	fmt.Println(m["B"])
+}
+
+// Output:
+// <nil>

_test/interface25.go

@@ -0,0 +1,14 @@
+package main
+
+import "fmt"
+
+func main() {
+	m := make(map[string]interface{})
+	m["A"] = 1
+	for _, v := range m {
+		fmt.Println(v)
+	}
+}
+
+// Output:
+// 1

_test/interface26.go

@@ -0,0 +1,14 @@
+package main
+
+import "fmt"
+
+func main() {
+	s := make([]interface{}, 0)
+	s = append(s, 1)
+	for _, v := range s {
+		fmt.Println(v)
+	}
+}
+
+// Output:
+// 1

_test/map19.go

@@ -0,0 +1,19 @@
+package main
+
+import "fmt"
+
+type cmap struct {
+	servers map[int64]*server
+}
+
+type server struct {
+	cm *cmap
+}
+
+func main() {
+	m := cmap{}
+	fmt.Println(m)
+}
+
+// Output:
+// {map[]}

_test/map20.go

@@ -0,0 +1,10 @@
+package main
+
+var a = map[int]bool{1: true, 2: true}
+
+func main() {
+	println(a[1] && true)
+}
+
+// Output:
+// true

_test/map21.go

@@ -0,0 +1,15 @@
+package main
+
+var m = map[int]string{
+	1: "foo",
+}
+
+func main() {
+	var ok bool
+	if _, ok = m[1]; ok {
+		println("ok")
+	}
+}
+
+// Output:
+// ok

_test/map22.go

@@ -0,0 +1,14 @@
+package main
+
+var m = map[int]string{
+	1: "foo",
+}
+
+func main() {
+	var s string
+	s, _ = m[1]
+	println(s)
+}
+
+// Output:
+// foo

_test/map23.go

@@ -0,0 +1,13 @@
+package main
+
+var m = map[int]string{
+	1: "foo",
+}
+
+func main() {
+	_, _ = m[1]
+	println("ok")
+}
+
+// Output:
+// ok

_test/method29.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"context"
+	"net"
+)
+
+var lookupHost = net.DefaultResolver.LookupHost
+
+func main() {
+	res, err := lookupHost(context.Background(), "localhost")
+	println(len(res) > 0, err == nil)
+}
+
+// Output:
+// true true

_test/method30.go

@@ -0,0 +1,20 @@
+package main
+
+type T struct {
+	Name string
+}
+
+func (t *T) foo(a string) string {
+	return t.Name + a
+}
+
+var g = &T{"global"}
+
+var f = g.foo
+
+func main() {
+	println(f("-x"))
+}
+
+// Output:
+// global-x

_test/method31.go

@@ -0,0 +1,29 @@
+package main
+
+import "fmt"
+
+var db dbWrapper
+
+type dbWrapper struct {
+	DB *cmap
+}
+
+func (d *dbWrapper) get() *cmap {
+	return d.DB
+}
+
+type cmap struct {
+	name string
+}
+
+func (c *cmap) f() {
+	fmt.Println("in f, c", c)
+}
+
+func main() {
+	db.DB = &cmap{name: "test"}
+	db.get().f()
+}
+
+// Output:
+// in f, c &{test}

_test/or2.go

@@ -0,0 +1,10 @@
+package main
+
+var a = false || true
+
+func main() {
+	println(a)
+}
+
+// Output:
+// true

_test/ptr8.go

@@ -0,0 +1,10 @@
+package main
+
+var a = func() *bool { b := true; return &b }()
+
+func main() {
+	println(*a && true)
+}
+
+// Output:
+// true

_test/struct31.go

@@ -0,0 +1,14 @@
+package main
+
+type T struct {
+	bool
+}
+
+var t = T{true}
+
+func main() {
+	println(t.bool && true)
+}
+
+// Output:
+// true

_test/struct32.go

@@ -0,0 +1,39 @@
+package main
+
+type T0 struct {
+	name string
+}
+
+type lookupFunc func(s string) T0
+
+type T1 struct {
+	name string
+	info lookupFunc
+}
+
+func (t T0) F1() bool { println("in F1"); return true }
+
+type T2 struct {
+	t1 T1
+}
+
+func (t2 *T2) f() {
+	info := t2.t1.info("foo")
+	println(info.F1())
+}
+
+var t0 = T0{"t0"}
+
+func main() {
+	t := &T2{T1{
+		"bar", func(s string) T0 { return t0 },
+	}}
+
+	println("hello")
+	println(t.t1.info("foo").F1())
+}
+
+// Output:
+// hello
+// in F1
+// true

_test/struct33.go

@@ -0,0 +1,34 @@
+package main
+
+type T0 struct {
+	name string
+}
+
+type lookupFunc func(s string) T0
+
+type T1 struct {
+	name string
+	info lookupFunc
+}
+
+func (t T0) F1() bool { println("in F1"); return true }
+
+var t0 = T0{"t0"}
+
+func look(s string) T0 { println("in look"); return t0 }
+
+var table = []*T1{{
+	name: "bar",
+	info: look,
+},
+}
+
+func main() {
+	info := table[0].info
+	println(info("foo").F1())
+}
+
+// Output:
+// in look
+// in F1
+// true

_test/struct34.go

@@ -0,0 +1,16 @@
+package main
+
+type T struct {
+	f func(*T)
+}
+
+func f1(t *T) { t.f = f2 }
+
+func f2(t *T) { t.f = f1 }
+
+func main() {
+	println("ok")
+}
+
+// Output:
+// ok

_test/struct35.go

@@ -0,0 +1,16 @@
+package main
+
+type T struct {
+	f func(*T)
+}
+
+func f1(t *T) { t.f = f1 }
+
+func main() {
+	t := &T{}
+	f1(t)
+	println(t.f != nil)
+}
+
+// Output:
+// true

_test/struct36.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"net/http"
+	"strings"
+)
+
+type S struct {
+	http.Client
+}
+
+func main() {
+	var s S
+	if _, err := s.Get("url"); err != nil {
+		println(strings.Contains(err.Error(), "unsupported protocol scheme"))
+	}
+	return
+}
+
+// Output:
+// true

_test/struct37.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"net/http"
+	"strings"
+)
+
+type MyHttpClient struct {
+	*http.Client
+}
+
+func main() {
+	c := new(MyHttpClient)
+	c.Client = new(http.Client)
+	_, err := c.Get("url")
+	println(strings.Contains(err.Error(), "unsupported protocol scheme"))
+}

_test/switch23.go

@@ -0,0 +1,15 @@
+package main
+
+func getType() string { return "T1" }
+
+func main() {
+	switch getType() {
+	case "T1":
+		println("T1")
+	default:
+		println("default")
+	}
+}
+
+// Output:
+// T1

_test/switch24.go

@@ -0,0 +1,16 @@
+package main
+
+func main() {
+	a := 3
+	switch a + 2 {
+	case 5:
+		println(5)
+	default:
+		println("default")
+	}
+	println("bye")
+}
+
+// Output:
+// 5
+// bye

_test/switch25.go

@@ -0,0 +1,18 @@
+package main
+
+func main() {
+	a := 2
+	switch {
+	case a == 1:
+		println(1)
+	case a == 2:
+		println(2)
+	default:
+		println("default")
+	}
+	println("bye")
+}
+
+// Output:
+// 2
+// bye

_test/switch26.go

@@ -0,0 +1,18 @@
+package main
+
+func main() {
+	a := 1
+	switch a := 2; {
+	case a == 1:
+		println(1)
+	case a == 2:
+		println(2)
+	default:
+		println("default")
+	}
+	println(a)
+}
+
+// Output:
+// 2
+// 1

_test/type15.go

@@ -0,0 +1,9 @@
+package main
+
+func main() {
+	err := error(nil)
+	println(err == nil)
+}
+
+// Output:
+// true

_test/type16.go

@@ -0,0 +1,11 @@
+package main
+
+import "fmt"
+
+func main() {
+	a := uint8(15) ^ byte(0)
+	fmt.Printf("%T %v\n", a, a)
+}
+
+// Output:
+// uint8 15

_test/type17.go

@@ -0,0 +1,11 @@
+package main
+
+import "fmt"
+
+func main() {
+	a := int32(15) ^ rune(0)
+	fmt.Printf("%T %v\n", a, a)
+}
+
+// Output:
+// int32 15

_test/type18.go

@@ -0,0 +1,20 @@
+package main
+
+type T struct {
+	name string
+	size int
+}
+
+var table = []*T{{
+	name: "foo",
+	size: 2,
+}}
+
+var s = table[0].size
+
+func main() {
+	println(s)
+}
+
+// Output:
+// 2

_test/type19.go

@@ -0,0 +1,21 @@
+package main
+
+type T struct {
+	name string
+	size int
+}
+
+var table = map[int]*T{
+	0: {
+		name: "foo",
+		size: 2,
+	}}
+
+var s = table[0].size
+
+func main() {
+	println(s)
+}
+
+// Output:
+// 2

_test/var10.go

@@ -0,0 +1,11 @@
+package main
+
+var _ = true
+var _ = "hello"
+
+func main() {
+	println("hello")
+}
+
+// Output:
+// hello

_test/var11.go

@@ -0,0 +1,10 @@
+package main
+
+var a, _, _, b = 1, true, "foo", 2
+
+func main() {
+	println(a, b)
+}
+
+// Output:
+// 1 2

cmd/yaegi/yaegi.go

@@ -8,7 +8,7 @@ If invoked with no arguments, it processes the standard input
 in a Read-Eval-Print-Loop. A prompt is displayed if standard input
 is a terminal.
 
-Given a file, it operates on that file. if the first line starts with
+Given a file, it operates on that file. If the first line starts with
 "#!/usr/bin/env yaegi", and the file has exec permission, then the file
 can be invoked directly from the shell.
 
@@ -47,8 +47,10 @@ import (
 func main() {
 	var interactive bool
 	var tags string
+	var cmd string
 	flag.BoolVar(&interactive, "i", false, "start an interactive REPL")
 	flag.StringVar(&tags, "tags", "", "set a list of build tags")
+	flag.StringVar(&cmd, "e", "", "set the command to be executed (instead of script or/and shell)")
 	flag.Usage = func() {
 		fmt.Println("Usage:", os.Args[0], "[options] [script] [args]")
 		fmt.Println("Options:")
@@ -62,31 +64,41 @@ func main() {
 	i.Use(stdlib.Symbols)
 	i.Use(interp.Symbols)
 
-	if len(args) > 0 {
-		// Skip first os arg to set command line as expected by interpreted main
-		os.Args = os.Args[1:]
-		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+	if cmd != `` {
+		i.REPL(strings.NewReader(cmd), os.Stderr)
+	}
 
-		b, err := ioutil.ReadFile(args[0])
-		if err != nil {
-			log.Fatal("Could not read file: ", args[0])
-		}
-
-		s := string(b)
-		if s[:2] == "#!" {
-			// Allow executable go scripts, but fix them prior to parse
-			s = strings.Replace(s, "#!", "//", 1)
-		}
-
-		i.Name = args[0]
-		if _, err := i.Eval(s); err != nil {
-			fmt.Println(err)
-		}
-
-		if interactive {
+	if len(args) == 0 {
+		if interactive || cmd == `` {
 			i.REPL(os.Stdin, os.Stdout)
 		}
-	} else {
+		return
+	}
+
+	// Skip first os arg to set command line as expected by interpreted main
+	os.Args = os.Args[1:]
+	flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+
+	b, err := ioutil.ReadFile(args[0])
+	if err != nil {
+		log.Fatal("Could not read file: ", args[0])
+	}
+
+	s := string(b)
+	if s[:2] == "#!" {
+		// Allow executable go scripts, but fix them prior to parse
+		s = strings.Replace(s, "#!", "//", 1)
+	}
+
+	i.Name = args[0]
+	if _, err := i.Eval(s); err != nil {
+		fmt.Println(err)
+		if p, ok := err.(interp.Panic); ok {
+			fmt.Println(string(p.Stack))
+		}
+	}
+
+	if interactive {
 		i.REPL(os.Stdin, os.Stdout)
 	}
 }

interp/ast.go

@@ -75,8 +75,6 @@ const (
 	parenExpr
 	rangeStmt
 	returnStmt
-	rvalueExpr
-	rtypeExpr
 	selectStmt
 	selectorExpr
 	selectorImport
@@ -154,8 +152,6 @@ var kinds = [...]string{
 	parenExpr:        "parenExpr",
 	rangeStmt:        "rangeStmt",
 	returnStmt:       "returnStmt",
-	rvalueExpr:       "rvalueExpr",
-	rtypeExpr:        "rtypeExpr",
 	selectStmt:       "selectStmt",
 	selectorExpr:     "selectorExpr",
 	selectorImport:   "selectorImport",
@@ -204,7 +200,6 @@ const (
 	aCase
 	aCompositeLit
 	aDec
-	aDefer
 	aEqual
 	aGreater
 	aGreaterEqual
@@ -262,7 +257,6 @@ var actions = [...]string{
 	aCase:         "case",
 	aCompositeLit: "compositeLit",
 	aDec:          "--",
-	aDefer:        "defer",
 	aEqual:        "==",
 	aGreater:      ">",
 	aGetFunc:      "getFunc",
@@ -573,7 +567,7 @@ func (interp *Interpreter) ast(src, name string) (string, *node, error) {
 			st.push(addChild(&root, anc, pos, declStmt, aNop), nod)
 
 		case *ast.DeferStmt:
-			st.push(addChild(&root, anc, pos, deferStmt, aDefer), nod)
+			st.push(addChild(&root, anc, pos, deferStmt, aNop), nod)
 
 		case *ast.Ellipsis:
 			st.push(addChild(&root, anc, pos, ellipsisExpr, aNop), nod)

interp/cfg.go

@@ -10,7 +10,12 @@ import (
 )
 
 // A cfgError represents an error during CFG build stage
-type cfgError error
+type cfgError struct {
+	*node
+	error
+}
+
+func (c *cfgError) Error() string { return c.error.Error() }
 
 var constOp = map[action]func(*node){
 	aAdd:    addConst,
@@ -42,8 +47,8 @@ var identifier = regexp.MustCompile(`([\pL_][\pL_\d]*)$`)
 // and pre-compute frame sizes and indexes for all un-named (temporary) and named
 // variables. A list of nodes of init functions is returned.
 // Following this pass, the CFG is ready to run
-func (interp *Interpreter) cfg(root *node) ([]*node, error) {
-	sc, pkgName := interp.initScopePkg(root)
+func (interp *Interpreter) cfg(root *node, pkgID string) ([]*node, error) {
+	sc := interp.initScopePkg(pkgID)
 	var initNodes []*node
 	var iotaValue int
 	var err error
@@ -231,7 +236,13 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			}
 			// Propagate type to children, to handle implicit types
 			for _, c := range n.child {
-				c.typ = n.typ
+				switch c.kind {
+				case binaryExpr, unaryExpr:
+					// Do not attempt to propagate composite type to operator expressions,
+					// it breaks constant folding.
+				default:
+					c.typ = n.typ
+				}
 			}
 
 		case forStmt0, forRangeStmt:
@@ -410,7 +421,11 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 						if src.typ, err = nodeType(interp, sc, src); err != nil {
 							return
 						}
-						dest.typ = src.typ
+						if src.typ.isBinMethod {
+							dest.typ = &itype{cat: valueT, rtype: src.typ.methodCallType()}
+						} else {
+							dest.typ = src.typ
+						}
 					}
 					if dest.typ.sizedef {
 						dest.typ.size = arrayTypeLen(src)
@@ -419,7 +434,8 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					if sc.global {
 						// Do not overload existing symbols (defined in GTA) in global scope
 						sym, _, _ = sc.lookup(dest.ident)
-					} else {
+					}
+					if sym == nil {
 						sym = &symbol{index: sc.add(dest.typ), kind: varSym, typ: dest.typ}
 						sc.sym[dest.ident] = sym
 					}
@@ -448,7 +464,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 						err = n.cfgErrorf("illegal operand types for '%v' operator", n.action)
 					}
 				default:
-					// Detect invalid float truncate
+					// Detect invalid float truncate.
 					if isInt(t0) && isFloat(t1) {
 						err = src.cfgErrorf("invalid float truncate")
 						return
@@ -459,7 +475,8 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				// Propagate type
 				// TODO: Check that existing destination type matches source type
 				switch {
-				case n.action == aAssign && src.action == aCall:
+				case n.action == aAssign && src.action == aCall && dest.typ.cat != interfaceT:
+					// Call action may perform the assignment directly.
 					n.gen = nop
 					src.level = level
 					src.findex = dest.findex
@@ -467,7 +484,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 						src.typ = dest.typ
 					}
 				case n.action == aAssign && src.action == aRecv:
-					// Assign by reading from a receiving channel
+					// Assign by reading from a receiving channel.
 					n.gen = nop
 					src.findex = dest.findex // Set recv address to LHS
 					dest.typ = src.typ
@@ -476,16 +493,16 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					src.findex = dest.findex
 					src.level = level
 				case src.kind == basicLit:
-					// TODO: perform constant folding and propagation here
+					// TODO: perform constant folding and propagation here.
 					switch {
 					case dest.typ.cat == interfaceT:
 					case isComplex(dest.typ.TypeOf()):
-						// value set in genValue
+						// Value set in genValue.
 					case !src.rval.IsValid():
-						// Assign to nil
+						// Assign to nil.
 						src.rval = reflect.New(dest.typ.TypeOf()).Elem()
 					default:
-						// Convert literal value to destination type
+						// Convert literal value to destination type.
 						src.rval = src.rval.Convert(dest.typ.TypeOf())
 						src.typ = dest.typ
 					}
@@ -499,9 +516,10 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				if isMapEntry(dest) {
 					dest.gen = nop // skip getIndexMap
 				}
-			}
-			if n.anc.kind == constDecl {
-				iotaValue++
+				if n.anc.kind == constDecl {
+					sc.sym[dest.ident].kind = constSym
+					iotaValue++
+				}
 			}
 
 		case incDecStmt:
@@ -739,7 +757,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				if isInt(n.child[0].typ.TypeOf()) && n.child[1].kind == basicLit && isFloat(n.child[1].typ.TypeOf()) {
 					err = n.cfgErrorf("truncated to integer")
 				}
-				if isInterface(n.child[0].typ) {
+				if isInterface(n.child[0].typ) && !n.child[1].isNil() {
 					// Convert to interface: just check that all required methods are defined by concrete type.
 					c0, c1 := n.child[0], n.child[1]
 					if !c1.typ.implements(c0.typ) {
@@ -759,10 +777,20 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			case isBinCall(n):
 				n.gen = callBin
 				if typ := n.child[0].typ.rtype; typ.NumOut() > 0 {
-					n.typ = &itype{cat: valueT, rtype: typ.Out(0)}
-					n.findex = sc.add(n.typ)
-					for i := 1; i < typ.NumOut(); i++ {
-						sc.add(&itype{cat: valueT, rtype: typ.Out(i)})
+					if funcType := n.child[0].typ.val; funcType != nil {
+						// Use the original unwrapped function type, to allow future field and
+						// methods resolutions, otherwise impossible on the opaque bin type.
+						n.typ = funcType.ret[0]
+						n.findex = sc.add(n.typ)
+						for i := 1; i < len(funcType.ret); i++ {
+							sc.add(funcType.ret[i])
+						}
+					} else {
+						n.typ = &itype{cat: valueT, rtype: typ.Out(0)}
+						n.findex = sc.add(n.typ)
+						for i := 1; i < typ.NumOut(); i++ {
+							sc.add(&itype{cat: valueT, rtype: typ.Out(i)})
+						}
 					}
 				}
 			default:
@@ -812,7 +840,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				n.findex = sc.add(n.typ)
 			}
 			// TODO: Check that composite literal expr matches corresponding type
-			n.gen = compositeGenerator(n)
+			n.gen = compositeGenerator(n, sc)
 
 		case fallthroughtStmt:
 			if n.anc.kind != caseBody {
@@ -897,10 +925,10 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			sc = sc.pop()
 			funcName := n.child[1].ident
 			if !isMethod(n) {
-				interp.scopes[pkgName].sym[funcName].index = -1 // to force value to n.val
-				interp.scopes[pkgName].sym[funcName].typ = n.typ
-				interp.scopes[pkgName].sym[funcName].kind = funcSym
-				interp.scopes[pkgName].sym[funcName].node = n
+				interp.scopes[pkgID].sym[funcName].index = -1 // to force value to n.val
+				interp.scopes[pkgID].sym[funcName].typ = n.typ
+				interp.scopes[pkgID].sym[funcName].kind = funcSym
+				interp.scopes[pkgID].sym[funcName].node = n
 			}
 
 		case funcLit:
@@ -908,13 +936,14 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			sc = sc.pop()
 			err = genRun(n)
 
-		case goStmt:
+		case deferStmt, goStmt:
 			wireChild(n)
 
 		case identExpr:
 			if isKey(n) || isNewDefine(n, sc) {
 				break
-			} else if sym, level, ok := sc.lookup(n.ident); ok {
+			}
+			if sym, level, ok := sc.lookup(n.ident); ok {
 				// Found symbol, populate node info
 				n.typ, n.findex, n.level = sym.typ, sym.index, level
 				if n.findex < 0 {
@@ -931,11 +960,6 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					case n.ident == "nil":
 						n.kind = basicLit
 					case sym.kind == binSym:
-						if sym.rval.IsValid() {
-							n.kind = rvalueExpr
-						} else {
-							n.kind = rtypeExpr
-						}
 						n.typ = sym.typ
 						n.rval = sym.rval
 					case sym.kind == bltnSym:
@@ -1097,7 +1121,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					n.val = method.Index
 					n.gen = getIndexBinMethod
 					n.recv = &receiver{node: n.child[0]}
-					n.typ = &itype{cat: valueT, rtype: method.Type}
+					n.typ = &itype{cat: valueT, rtype: method.Type, isBinMethod: true}
 				case n.typ.rtype.Kind() == reflect.Ptr:
 					if field, ok := n.typ.rtype.Elem().FieldByName(n.child[1].ident); ok {
 						n.typ = &itype{cat: valueT, rtype: field.Type}
@@ -1151,10 +1175,8 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				pkg := n.child[0].sym.typ.path
 				if s, ok := interp.binPkg[pkg][name]; ok {
 					if isBinType(s) {
-						n.kind = rtypeExpr
 						n.typ = &itype{cat: valueT, rtype: s.Type().Elem()}
 					} else {
-						n.kind = rvalueExpr
 						n.typ = &itype{cat: valueT, rtype: s.Type(), untyped: isValueUntyped(s)}
 						n.rval = s
 					}
@@ -1171,6 +1193,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					n.gen = nop
 					n.typ = sym.typ
 					n.sym = sym
+					n.rval = sym.rval
 				} else {
 					err = n.cfgErrorf("undefined selector: %s.%s", pkg, name)
 				}
@@ -1191,11 +1214,12 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					n.recv = &receiver{node: n.child[0], index: lind}
 				}
 			} else if m, lind, isPtr, ok := n.typ.lookupBinMethod(n.child[1].ident); ok {
-				if isPtr {
+				if isPtr && n.typ.fieldSeq(lind).cat != ptrT {
 					n.gen = getIndexSeqPtrMethod
 				} else {
 					n.gen = getIndexSeqMethod
 				}
+				n.recv = &receiver{node: n.child[0], index: lind}
 				n.val = append([]int{m.Index}, lind...)
 				n.typ = &itype{cat: valueT, rtype: m.Type}
 			} else if ti := n.typ.lookupField(n.child[1].ident); len(ti) > 0 {
@@ -1212,7 +1236,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					if n.typ.cat == funcT {
 						// function in a struct field is always wrapped in reflect.Value
 						rtype := n.typ.TypeOf()
-						n.typ = &itype{cat: valueT, rtype: rtype}
+						n.typ = &itype{cat: valueT, rtype: rtype, val: n.typ}
 					}
 				default:
 					n.gen = getIndexSeq
@@ -1220,7 +1244,7 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 					if n.typ.cat == funcT {
 						// function in a struct field is always wrapped in reflect.Value
 						rtype := n.typ.TypeOf()
-						n.typ = &itype{cat: valueT, rtype: rtype}
+						n.typ = &itype{cat: valueT, rtype: rtype, val: n.typ}
 					}
 				}
 			} else if s, lind, ok := n.typ.lookupBinField(n.child[1].ident); ok {
@@ -1303,14 +1327,8 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 			}
 			c := clauses[l-1]
 			c.tnext = c.lastChild().start
-			if n.child[0].action == aAssign &&
-				(n.child[0].child[0].kind != typeAssertExpr || len(n.child[0].child[0].child) > 1) {
-				// switch init statement is defined
-				n.start = n.child[0].start
-				n.child[0].tnext = sbn.start
-			} else {
-				n.start = sbn.start
-			}
+			n.start = n.child[0].start
+			n.child[0].tnext = sbn.start
 			sc = sc.pop()
 
 		case switchIfStmt: // like an if-else chain
@@ -1337,16 +1355,13 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				// If last case body statement is a fallthrough, then jump to next case body
 				if i < l-1 && len(body.child) > 0 && body.lastChild().kind == fallthroughtStmt {
 					body.tnext = clauses[i+1].lastChild().start
+				} else {
+					body.tnext = n
 				}
 			}
 			sbn.start = clauses[0].start
-			if n.child[0].action == aAssign {
-				// switch init statement is defined
-				n.start = n.child[0].start
-				n.child[0].tnext = sbn.start
-			} else {
-				n.start = sbn.start
-			}
+			n.start = n.child[0].start
+			n.child[0].tnext = sbn.start
 			sc = sc.pop()
 
 		case typeAssertExpr:
@@ -1439,8 +1454,14 @@ func (interp *Interpreter) cfg(root *node) ([]*node, error) {
 				}
 			}
 			for _, c := range n.child[:l] {
-				index := sc.add(n.typ)
-				sc.sym[c.ident] = &symbol{index: index, kind: varSym, typ: n.typ}
+				var index int
+				if sc.global {
+					// Global object allocation is already performed in GTA.
+					index = sc.sym[c.ident].index
+				} else {
+					index = sc.add(n.typ)
+					sc.sym[c.ident] = &symbol{index: index, kind: varSym, typ: n.typ}
+				}
 				c.typ = n.typ
 				c.findex = index
 			}
@@ -1526,13 +1547,13 @@ func childPos(n *node) int {
 	return -1
 }
 
-func (n *node) cfgErrorf(format string, a ...interface{}) cfgError {
+func (n *node) cfgErrorf(format string, a ...interface{}) *cfgError {
 	a = append([]interface{}{n.interp.fset.Position(n.pos)}, a...)
-	return cfgError(fmt.Errorf("%s: "+format, a...))
+	return &cfgError{n, fmt.Errorf("%s: "+format, a...)}
 }
 
 func genRun(nod *node) error {
-	var err cfgError
+	var err error
 
 	nod.Walk(func(n *node) bool {
 		if err != nil {
@@ -1570,7 +1591,7 @@ func isBinType(v reflect.Value) bool { return v.IsValid() && v.Kind() == reflect
 // isType returns true if node refers to a type definition, false otherwise
 func (n *node) isType(sc *scope) bool {
 	switch n.kind {
-	case arrayType, chanType, funcType, interfaceType, mapType, structType, rtypeExpr:
+	case arrayType, chanType, funcType, interfaceType, mapType, structType:
 		return true
 	case parenExpr, starExpr:
 		if len(n.child) == 1 {
@@ -1685,6 +1706,9 @@ func (n *node) isNatural() bool {
 	return false
 }
 
+// isNil returns true if node is a literal nil value, false otherwise
+func (n *node) isNil() bool { return n.kind == basicLit && !n.rval.IsValid() }
+
 // fieldType returns the nth parameter field node (type) of a fieldList node
 func (n *node) fieldType(m int) *node {
 	k := 0
@@ -1719,6 +1743,10 @@ func isKey(n *node) bool {
 		(n.anc.kind == fieldExpr && len(n.anc.child) > 1 && n.anc.child[0] == n)
 }
 
+func isField(n *node) bool {
+	return n.kind == selectorExpr && len(n.child) > 0 && n.child[0].typ != nil && isStruct(n.child[0].typ)
+}
+
 // isNewDefine returns true if node refers to a new definition
 func isNewDefine(n *node, sc *scope) bool {
 	if n.ident == "_" {
@@ -1783,13 +1811,6 @@ func getExec(n *node) bltn {
 	return n.exec
 }
 
-func fileNode(n *node) *node {
-	if n == nil || n.kind == fileStmt {
-		return n
-	}
-	return fileNode(n.anc)
-}
-
 // setExec recursively sets the node exec builtin function by walking the CFG
 // from the entry point (first node to exec).
 func setExec(n *node) {
@@ -1840,21 +1861,32 @@ func gotoLabel(s *symbol) {
 	}
 }
 
-func compositeGenerator(n *node) (gen bltnGenerator) {
+func compositeGenerator(n *node, sc *scope) (gen bltnGenerator) {
 	switch n.typ.cat {
 	case aliasT, ptrT:
 		n.typ.val.untyped = n.typ.untyped
 		n.typ = n.typ.val
-		gen = compositeGenerator(n)
+		gen = compositeGenerator(n, sc)
 	case arrayT:
 		gen = arrayLit
 	case mapT:
 		gen = mapLit
 	case structT:
-		if len(n.child) > 0 && n.lastChild().kind == keyValueExpr {
-			gen = compositeSparse
-		} else {
-			gen = compositeLit
+		switch {
+		case len(n.child) == 0:
+			gen = compositeLitNotype
+		case n.lastChild().kind == keyValueExpr:
+			if n.child[0].isType(sc) {
+				gen = compositeSparse
+			} else {
+				gen = compositeSparseNotype
+			}
+		default:
+			if n.child[0].isType(sc) {
+				gen = compositeLit
+			} else {
+				gen = compositeLitNotype
+			}
 		}
 	case valueT:
 		switch k := n.typ.rtype.Kind(); k {
@@ -1866,7 +1898,7 @@ func compositeGenerator(n *node) (gen bltnGenerator) {
 			log.Panic(n.cfgErrorf("compositeGenerator not implemented for type kind: %s", k))
 		}
 	}
-	return
+	return gen
 }
 
 // arrayTypeLen returns the node's array length. If the expression is an

interp/gta.go

@@ -8,8 +8,8 @@ import (
 // variables and functions symbols at package level, prior to CFG.
 // All function bodies are skipped. GTA is necessary to handle out of
 // order declarations and multiple source files packages.
-func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
-	sc, _ := interp.initScopePkg(root)
+func (interp *Interpreter) gta(root *node, rpath, pkgID string) ([]*node, error) {
+	sc := interp.initScopePkg(pkgID)
 	var err error
 	var iotaValue int
 	var revisit []*node
@@ -21,6 +21,12 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 		switch n.kind {
 		case constDecl:
 			iotaValue = 0
+			// Early parse of constDecl subtree, to compute all constant
+			// values which may be necessary in further declarations.
+			if _, err = interp.cfg(n, pkgID); err != nil {
+				// No error processing here, to allow recovery in subtree nodes.
+				err = nil
+			}
 
 		case blockStmt:
 			if n != root {
@@ -44,6 +50,14 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 			for i := 0; i < n.nleft; i++ {
 				dest, src := n.child[i], n.child[sbase+i]
 				val := reflect.ValueOf(iotaValue)
+				if n.anc.kind == constDecl {
+					if _, err2 := interp.cfg(n, pkgID); err2 != nil {
+						// Constant value can not be computed yet.
+						// Come back when child dependencies are known.
+						revisit = append(revisit, n)
+						return false
+					}
+				}
 				typ := atyp
 				if typ == nil {
 					if typ, err = nodeType(interp, sc, src); err != nil {
@@ -52,7 +66,7 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 					val = src.rval
 				}
 				if typ.incomplete {
-					// Come back when type is known
+					// Come back when type is known.
 					revisit = append(revisit, n)
 					return false
 				}
@@ -60,7 +74,12 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 					err = n.cfgErrorf("use of untyped nil")
 					return false
 				}
-				sc.sym[dest.ident] = &symbol{kind: varSym, global: true, index: sc.add(typ), typ: typ, rval: val}
+				if typ.isBinMethod {
+					typ = &itype{cat: valueT, rtype: typ.methodCallType(), isBinMethod: true}
+				}
+				if sc.sym[dest.ident] == nil {
+					sc.sym[dest.ident] = &symbol{kind: varSym, global: true, index: sc.add(typ), typ: typ, rval: val}
+				}
 				if n.anc.kind == constDecl {
 					sc.sym[dest.ident].kind = constSym
 					iotaValue++
@@ -77,6 +96,11 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 				if n.typ, err = nodeType(interp, sc, n.child[l]); err != nil {
 					return false
 				}
+				if n.typ.incomplete {
+					// Come back when type is known.
+					revisit = append(revisit, n)
+					return false
+				}
 			}
 			for _, c := range n.child[:l] {
 				sc.sym[c.ident] = &symbol{index: sc.add(n.typ), kind: varSym, global: true, typ: n.typ}
@@ -117,6 +141,9 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 				// Add a function symbol in the package name space
 				sc.sym[n.child[1].ident] = &symbol{kind: funcSym, typ: n.typ, node: n, index: -1}
 			}
+			if n.typ.incomplete {
+				revisit = append(revisit, n)
+			}
 			return false
 
 		case importSpec:
@@ -143,7 +170,7 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 				default: // import symbols in package namespace
 					sc.sym[name] = &symbol{kind: pkgSym, typ: &itype{cat: binPkgT, path: ipath}}
 				}
-			} else if err = interp.importSrc(rpath, ipath, name); err == nil {
+			} else if err = interp.importSrc(rpath, ipath); err == nil {
 				sc.types = interp.universe.types
 				switch name {
 				case "_": // no import of symbols
@@ -194,3 +221,42 @@ func (interp *Interpreter) gta(root *node, rpath string) ([]*node, error) {
 	}
 	return revisit, err
 }
+
+// gtaRetry (re)applies gta until all global constants and types are defined.
+func (interp *Interpreter) gtaRetry(nodes []*node, rpath, pkgID string) error {
+	revisit := []*node{}
+	for {
+		for _, n := range nodes {
+			list, err := interp.gta(n, rpath, pkgID)
+			if err != nil {
+				return err
+			}
+			revisit = append(revisit, list...)
+		}
+
+		if len(revisit) == 0 || equalNodes(nodes, revisit) {
+			break
+		}
+
+		nodes = revisit
+		revisit = []*node{}
+	}
+
+	if len(revisit) > 0 {
+		return revisit[0].cfgErrorf("constant definition loop")
+	}
+	return nil
+}
+
+// equalNodes returns true if two slices of nodes are identical.
+func equalNodes(a, b []*node) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, n := range a {
+		if n != b[i] {
+			return false
+		}
+	}
+	return true
+}

interp/interp.go

@@ -11,6 +11,8 @@ import (
 	"os"
 	"os/signal"
 	"reflect"
+	"runtime"
+	"runtime/debug"
 	"strconv"
 	"sync"
 	"sync/atomic"
@@ -158,6 +160,24 @@ type _error struct {
 
 func (w _error) Error() string { return w.WError() }
 
+// Panic is an error recovered from a panic call in interpreted code.
+type Panic struct {
+	// Value is the recovered value of a call to panic.
+	Value interface{}
+
+	// Callers is the call stack obtained from the recover call.
+	// It may be used as the parameter to runtime.CallersFrames.
+	Callers []uintptr
+
+	// Stack is the call stack buffer for debug.
+	Stack []byte
+}
+
+// TODO: Capture interpreter stack frames also and remove
+// fmt.Println(n.cfgErrorf("panic")) in runCfg.
+
+func (e Panic) Error() string { return fmt.Sprint(e.Value) }
+
 // Walk traverses AST n in depth first order, call cbin function
 // at node entry and cbout function at node exit.
 func (n *node) Walk(in func(n *node) bool, out func(n *node)) {
@@ -216,7 +236,7 @@ func initUniverse() *scope {
 	sc := &scope{global: true, sym: map[string]*symbol{
 		// predefined Go types
 		"bool":        {kind: typeSym, typ: &itype{cat: boolT, name: "bool"}},
-		"byte":        {kind: typeSym, typ: &itype{cat: byteT, name: "byte"}},
+		"byte":        {kind: typeSym, typ: &itype{cat: uint8T, name: "uint8"}},
 		"complex64":   {kind: typeSym, typ: &itype{cat: complex64T, name: "complex64"}},
 		"complex128":  {kind: typeSym, typ: &itype{cat: complex128T, name: "complex128"}},
 		"error":       {kind: typeSym, typ: &itype{cat: errorT, name: "error"}},
@@ -228,7 +248,7 @@ func initUniverse() *scope {
 		"int32":       {kind: typeSym, typ: &itype{cat: int32T, name: "int32"}},
 		"int64":       {kind: typeSym, typ: &itype{cat: int64T, name: "int64"}},
 		"interface{}": {kind: typeSym, typ: &itype{cat: interfaceT}},
-		"rune":        {kind: typeSym, typ: &itype{cat: runeT, name: "rune"}},
+		"rune":        {kind: typeSym, typ: &itype{cat: int32T, name: "int32"}},
 		"string":      {kind: typeSym, typ: &itype{cat: stringT, name: "string"}},
 		"uint":        {kind: typeSym, typ: &itype{cat: uintT, name: "uint"}},
 		"uint8":       {kind: typeSym, typ: &itype{cat: uint8T, name: "uint8"}},
@@ -283,7 +303,7 @@ func (interp *Interpreter) resizeFrame() {
 func (interp *Interpreter) main() *node {
 	interp.mutex.RLock()
 	defer interp.mutex.RUnlock()
-	if m, ok := interp.scopes[mainID]; ok && m.sym[mainID] != nil {
+	if m, ok := interp.scopes[interp.Name]; ok && m.sym[mainID] != nil {
 		return m.sym[mainID].node
 	}
 	return nil
@@ -291,10 +311,17 @@ func (interp *Interpreter) main() *node {
 
 // Eval evaluates Go code represented as a string. It returns a map on
 // current interpreted package exported symbols
-func (interp *Interpreter) Eval(src string) (reflect.Value, error) {
-	var res reflect.Value
+func (interp *Interpreter) Eval(src string) (res reflect.Value, err error) {
+	defer func() {
+		r := recover()
+		if r != nil {
+			var pc [64]uintptr // 64 frames should be enough.
+			n := runtime.Callers(1, pc[:])
+			err = Panic{Value: r, Callers: pc[:n], Stack: debug.Stack()}
+		}
+	}()
 
-	// Parse source to AST
+	// Parse source to AST.
 	pkgName, root, err := interp.ast(src, interp.Name)
 	if err != nil || root == nil {
 		return res, err
@@ -307,19 +334,13 @@ func (interp *Interpreter) Eval(src string) (reflect.Value, error) {
 		}
 	}
 
-	// Global type analysis
-	revisit, err := interp.gta(root, pkgName)
-	if err != nil {
+	// Perform global types analysis.
+	if err = interp.gtaRetry([]*node{root}, pkgName, interp.Name); err != nil {
 		return res, err
 	}
-	for _, n := range revisit {
-		if _, err = interp.gta(n, pkgName); err != nil {
-			return res, err
-		}
-	}
 
 	// Annotate AST with CFG infos
-	initNodes, err := interp.cfg(root)
+	initNodes, err := interp.cfg(root, interp.Name)
 	if err != nil {
 		return res, err
 	}
@@ -336,7 +357,7 @@ func (interp *Interpreter) Eval(src string) (reflect.Value, error) {
 	interp.mutex.Lock()
 	if interp.universe.sym[pkgName] == nil {
 		// Make the package visible under a path identical to its name
-		interp.srcPkg[pkgName] = interp.scopes[pkgName].sym
+		interp.srcPkg[pkgName] = interp.scopes[interp.Name].sym
 		interp.universe.sym[pkgName] = &symbol{kind: pkgSym, typ: &itype{cat: srcPkgT, path: pkgName}}
 	}
 	interp.mutex.Unlock()
@@ -446,12 +467,15 @@ func (interp *Interpreter) REPL(in io.Reader, out io.Writer) {
 		v, err := interp.EvalWithContext(ctx, src)
 		signal.Reset()
 		if err != nil {
-			switch err.(type) {
+			switch e := err.(type) {
 			case scanner.ErrorList:
 				// Early failure in the scanner: the source is incomplete
 				// and no AST could be produced, neither compiled / run.
 				// Get one more line, and retry
 				continue
+			case Panic:
+				fmt.Fprintln(out, e.Value)
+				fmt.Fprintln(out, string(e.Stack))
 			default:
 				fmt.Fprintln(out, err)
 			}

interp/interp_consistent_test.go

@@ -33,6 +33,7 @@ func TestInterpConsistencyBuild(t *testing.T) {
 	for _, file := range files {
 		if filepath.Ext(file.Name()) != ".go" ||
 			file.Name() == "bad0.go" || // expect error
+			file.Name() == "const9.go" || // expect error
 			file.Name() == "export1.go" || // non-main package
 			file.Name() == "export0.go" || // non-main package
 			file.Name() == "for7.go" || // expect error
@@ -138,6 +139,11 @@ func TestInterpErrorConsistency(t *testing.T) {
 			expectedInterp: "1:1: expected 'package', found println",
 			expectedExec:   "1:1: expected 'package', found println",
 		},
+		{
+			fileName:       "const9.go",
+			expectedInterp: "5:2: constant definition loop",
+			expectedExec:   "5:2: constant definition loop",
+		},
 		{
 			fileName:       "if2.go",
 			expectedInterp: "7:5: non-bool used as if condition",

interp/interp_eval_test.go

@@ -78,11 +78,11 @@ func TestEvalBuiltin(t *testing.T) {
 	i := interp.New(interp.Options{})
 	runTests(t, i, []testCase{
 		{src: `a := []int{}; a = append(a, 1); a`, res: "[1]"},
-		{src: `a := []int{1}; a = append(a, 2, 3); a`, res: "[1 2 3]"},
-		{src: `a := []int{1}; b := []int{2, 3}; a = append(a, b...); a`, res: "[1 2 3]"},
+		{src: `b := []int{1}; b = append(a, 2, 3); b`, res: "[1 2 3]"},
+		{src: `c := []int{1}; d := []int{2, 3}; c = append(c, d...); c`, res: "[1 2 3]"},
 		{src: `string(append([]byte("hello "), "world"...))`, res: "hello world"},
-		{src: `a := "world"; string(append([]byte("hello "), a...))`, res: "hello world"},
-		{src: `a := []byte("Hello"); copy(a, "world"); string(a)`, res: "world"},
+		{src: `e := "world"; string(append([]byte("hello "), e...))`, res: "hello world"},
+		{src: `f := []byte("Hello"); copy(f, "world"); string(f)`, res: "world"},
 	})
 }
 
@@ -525,7 +525,11 @@ func eval(t *testing.T, i *interp.Interpreter, src string) reflect.Value {
 	t.Helper()
 	res, err := i.Eval(src)
 	if err != nil {
-		t.Fatal(err)
+		t.Logf("Error: %v", err)
+		if e, ok := err.(interp.Panic); ok {
+			t.Logf(string(e.Stack))
+		}
+		t.FailNow()
 	}
 	return res
 }
@@ -541,7 +545,11 @@ func assertEval(t *testing.T, i *interp.Interpreter, src, expectedError, expecte
 	}
 
 	if err != nil {
-		t.Fatalf("got an error %v", err)
+		t.Logf("got an error: %v", err)
+		if e, ok := err.(interp.Panic); ok {
+			t.Logf(string(e.Stack))
+		}
+		t.FailNow()
 	}
 
 	if fmt.Sprintf("%v", res) != expectedRes {

interp/run.go

@@ -29,7 +29,6 @@ var builtin = [...]bltnGenerator{
 	aCase:         _case,
 	aCompositeLit: arrayLit,
 	aDec:          dec,
-	aDefer:        _defer,
 	aEqual:        equal,
 	aGetFunc:      getFunc,
 	aGreater:      greater,
@@ -216,7 +215,7 @@ func convert(n *node) {
 	typ := n.child[0].typ.TypeOf()
 	next := getExec(n.tnext)
 
-	if c.kind == basicLit && !c.rval.IsValid() { // convert nil to type
+	if c.isNil() { // convert nil to type
 		n.exec = func(f *frame) bltn {
 			dest(f).Set(reflect.New(typ).Elem())
 			return next
@@ -264,7 +263,9 @@ func assign(n *node) {
 			svalue[i] = genValueInterface(src)
 		case (dest.typ.cat == valueT || dest.typ.cat == errorT) && dest.typ.rtype.Kind() == reflect.Interface:
 			svalue[i] = genInterfaceWrapper(src, dest.typ.rtype)
-		case dest.typ.cat == valueT && src.typ.cat == funcT:
+		case src.typ.cat == funcT && dest.typ.cat == valueT:
+			svalue[i] = genFunctionWrapper(src)
+		case src.typ.cat == funcT && isField(dest):
 			svalue[i] = genFunctionWrapper(src)
 		case dest.typ.cat == funcT && src.typ.cat == valueT:
 			svalue[i] = genValueNode(src)
@@ -293,12 +294,17 @@ func assign(n *node) {
 	}
 
 	if n.nleft == 1 {
-		if s, d, i := svalue[0], dvalue[0], ivalue[0]; i != nil {
+		switch s, d, i := svalue[0], dvalue[0], ivalue[0]; {
+		case n.child[0].ident == "_":
+			n.exec = func(f *frame) bltn {
+				return next
+			}
+		case i != nil:
 			n.exec = func(f *frame) bltn {
 				d(f).SetMapIndex(i(f), s(f))
 				return next
 			}
-		} else {
+		default:
 			n.exec = func(f *frame) bltn {
 				d(f).Set(s(f))
 				return next
@@ -316,7 +322,6 @@ func assign(n *node) {
 			default:
 				t = typ.TypeOf()
 			}
-			//types[i] = n.child[sbase+i].typ.TypeOf()
 			types[i] = t
 		}
 
@@ -326,10 +331,16 @@ func assign(n *node) {
 		n.exec = func(f *frame) bltn {
 			t := make([]reflect.Value, len(svalue))
 			for i, s := range svalue {
+				if n.child[i].ident == "_" {
+					continue
+				}
 				t[i] = reflect.New(types[i]).Elem()
 				t[i].Set(s(f))
 			}
 			for i, d := range dvalue {
+				if n.child[i].ident == "_" {
+					continue
+				}
 				if j := ivalue[i]; j != nil {
 					d(f).SetMapIndex(j(f), t[i]) // Assign a map entry
 				} else {
@@ -345,16 +356,15 @@ func not(n *node) {
 	dest := genValue(n)
 	value := genValue(n.child[0])
 	tnext := getExec(n.tnext)
-	i := n.findex
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
 			if !value(f).Bool() {
-				f.data[i].SetBool(true)
+				dest(f).SetBool(true)
 				return tnext
 			}
-			f.data[i].SetBool(false)
+			dest(f).SetBool(false)
 			return fnext
 		}
 	} else {
@@ -379,17 +389,18 @@ func addr(n *node) {
 func deref(n *node) {
 	value := genValue(n.child[0])
 	tnext := getExec(n.tnext)
+	i := n.findex
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
-			if value(f).Elem().Bool() {
+			f.data[i] = value(f).Elem()
+			if f.data[i].Bool() {
 				return tnext
 			}
 			return fnext
 		}
 	} else {
-		i := n.findex
 		n.exec = func(f *frame) bltn {
 			f.data[i] = value(f).Elem()
 			return tnext
@@ -471,7 +482,6 @@ func genFunctionWrapper(n *node) func(*frame) reflect.Value {
 	if def, ok = n.val.(*node); !ok {
 		return genValueAsFunctionWrapper(n)
 	}
-	setExec(def.child[3].start)
 	start := def.child[3].start
 	numRet := len(def.typ.ret)
 	var rcvr func(*frame) reflect.Value
@@ -585,47 +595,6 @@ func genInterfaceWrapper(n *node, typ reflect.Type) func(*frame) reflect.Value {
 	}
 }
 
-func _defer(n *node) {
-	tnext := getExec(n.tnext)
-	values := make([]func(*frame) reflect.Value, len(n.child[0].child))
-	var method func(*frame) reflect.Value
-
-	for i, c := range n.child[0].child {
-		if c.typ.cat == funcT {
-			values[i] = genFunctionWrapper(c)
-		} else {
-			if c.recv != nil {
-				// defer a method on a binary obj
-				mi := c.val.(int)
-				m := genValue(c.child[0])
-				method = func(f *frame) reflect.Value { return m(f).Method(mi) }
-			}
-			values[i] = genValue(c)
-		}
-	}
-
-	if method != nil {
-		n.exec = func(f *frame) bltn {
-			val := make([]reflect.Value, len(values))
-			val[0] = method(f)
-			for i, v := range values[1:] {
-				val[i+1] = v(f)
-			}
-			f.deferred = append([][]reflect.Value{val}, f.deferred...)
-			return tnext
-		}
-	} else {
-		n.exec = func(f *frame) bltn {
-			val := make([]reflect.Value, len(values))
-			for i, v := range values {
-				val[i] = v(f)
-			}
-			f.deferred = append([][]reflect.Value{val}, f.deferred...)
-			return tnext
-		}
-	}
-}
-
 func call(n *node) {
 	goroutine := n.anc.kind == goStmt
 	var method bool
@@ -697,20 +666,40 @@ func call(n *node) {
 		}
 	}
 
+	if n.anc.kind == deferStmt {
+		// Store function call in frame for deferred execution.
+		value = genFunctionWrapper(n.child[0])
+		n.exec = func(f *frame) bltn {
+			val := make([]reflect.Value, len(values)+1)
+			val[0] = value(f)
+			for i, v := range values {
+				val[i+1] = v(f)
+			}
+			f.deferred = append([][]reflect.Value{val}, f.deferred...)
+			return tnext
+		}
+		return
+	}
+
 	n.exec = func(f *frame) bltn {
-		def := value(f).Interface().(*node)
+		var def *node
+		var ok bool
+		bf := value(f)
+		if def, ok = bf.Interface().(*node); ok {
+			bf = def.rval
+		}
 
 		// Call bin func if defined
-		if def.rval.IsValid() {
+		if bf.IsValid() {
 			in := make([]reflect.Value, len(values))
 			for i, v := range values {
 				in[i] = v(f)
 			}
 			if goroutine {
-				go def.rval.Call(in)
+				go bf.Call(in)
 				return tnext
 			}
-			out := def.rval.Call(in)
+			out := bf.Call(in)
 			for i, v := range rvalues {
 				if v != nil {
 					v(f).Set(out[i])
@@ -813,7 +802,7 @@ func pindex(i, variadic int) int {
 	return variadic
 }
 
-// Call a function from a bin import, accessible through reflect
+// Callbin calls a function from a bin import, accessible through reflect.
 func callBin(n *node) {
 	tnext := getExec(n.tnext)
 	fnext := getExec(n.fnext)
@@ -825,10 +814,12 @@ func callBin(n *node) {
 	if funcType.IsVariadic() {
 		variadic = funcType.NumIn() - 1
 	}
-	// method signature obtained from reflect.Type include receiver as 1st arg, except for interface types
+	// A method signature obtained from reflect.Type includes receiver as 1st arg, except for interface types.
 	rcvrOffset := 0
-	if recv := n.child[0].recv; recv != nil && recv.node.typ.TypeOf().Kind() != reflect.Interface {
-		rcvrOffset = 1
+	if recv := n.child[0].recv; recv != nil && !isInterface(recv.node.typ) {
+		if funcType.NumIn() > len(child) {
+			rcvrOffset = 1
+		}
 	}
 
 	for i, c := range child {
@@ -867,7 +858,6 @@ func callBin(n *node) {
 			case interfaceT:
 				values = append(values, genValueInterfaceValue(c))
 			default:
-				//values = append(values, genValue(c))
 				values = append(values, genInterfaceWrapper(c, defType))
 			}
 		}
@@ -875,8 +865,19 @@ func callBin(n *node) {
 	l := len(values)
 
 	switch {
+	case n.anc.kind == deferStmt:
+		// Store function call in frame for deferred execution.
+		n.exec = func(f *frame) bltn {
+			val := make([]reflect.Value, l+1)
+			val[0] = value(f)
+			for i, v := range values {
+				val[i+1] = v(f)
+			}
+			f.deferred = append([][]reflect.Value{val}, f.deferred...)
+			return tnext
+		}
 	case n.anc.kind == goStmt:
-		// Execute function in a goroutine, discard results
+		// Execute function in a goroutine, discard results.
 		n.exec = func(f *frame) bltn {
 			in := make([]reflect.Value, l)
 			for i, v := range values {
@@ -886,7 +887,7 @@ func callBin(n *node) {
 			return tnext
 		}
 	case fnext != nil:
-		// Handle branching according to boolean result
+		// Handle branching according to boolean result.
 		n.exec = func(f *frame) bltn {
 			in := make([]reflect.Value, l)
 			for i, v := range values {
@@ -899,8 +900,10 @@ func callBin(n *node) {
 			return fnext
 		}
 	default:
-		switch n.anc.kind {
-		case defineStmt, assignStmt, defineXStmt, assignXStmt:
+		switch n.anc.action {
+		case aAssign, aAssignX:
+			// The function call is part of an assign expression, we write results direcly
+			// to assigned location, to avoid an additional assign operation.
 			rvalues := make([]func(*frame) reflect.Value, funcType.NumOut())
 			for i := range rvalues {
 				c := n.anc.child[i]
@@ -967,21 +970,21 @@ func getIndexBinPtrMethod(n *node) {
 func getIndexArray(n *node) {
 	tnext := getExec(n.tnext)
 	value0 := genValueArray(n.child[0]) // array
+	i := n.findex
 
 	if n.child[1].rval.IsValid() { // constant array index
 		ai := int(vInt(n.child[1].rval))
 		if n.fnext != nil {
 			fnext := getExec(n.fnext)
 			n.exec = func(f *frame) bltn {
-				if value0(f).Index(ai).Bool() {
+				f.data[i] = value0(f).Index(ai)
+				if f.data[i].Bool() {
 					return tnext
 				}
 				return fnext
 			}
 		} else {
-			i := n.findex
 			n.exec = func(f *frame) bltn {
-				// Can not use .Set due to constraint of being able to assign an array element
 				f.data[i] = value0(f).Index(ai)
 				return tnext
 			}
@@ -993,16 +996,15 @@ func getIndexArray(n *node) {
 			fnext := getExec(n.fnext)
 			n.exec = func(f *frame) bltn {
 				_, vi := value1(f)
-				if value0(f).Index(int(vi)).Bool() {
+				f.data[i] = value0(f).Index(int(vi))
+				if f.data[i].Bool() {
 					return tnext
 				}
 				return fnext
 			}
 		} else {
-			i := n.findex
 			n.exec = func(f *frame) bltn {
 				_, vi := value1(f)
-				// Can not use .Set due to constraint of being able to assign an array element
 				f.data[i] = value0(f).Index(int(vi))
 				return tnext
 			}
@@ -1015,20 +1017,33 @@ func getIndexMap(n *node) {
 	dest := genValue(n)
 	value0 := genValue(n.child[0]) // map
 	tnext := getExec(n.tnext)
-	z := reflect.New(n.child[0].typ.TypeOf().Elem()).Elem()
+	z := reflect.New(n.child[0].typ.frameType().Elem()).Elem()
 
 	if n.child[1].rval.IsValid() { // constant map index
 		mi := n.child[1].rval
 
-		if n.fnext != nil {
+		switch {
+		case n.fnext != nil:
 			fnext := getExec(n.fnext)
 			n.exec = func(f *frame) bltn {
 				if v := value0(f).MapIndex(mi); v.IsValid() && v.Bool() {
+					dest(f).SetBool(true)
 					return tnext
 				}
+				dest(f).Set(z)
 				return fnext
 			}
-		} else {
+		case n.typ.cat == interfaceT:
+			z = reflect.New(n.child[0].typ.val.frameType()).Elem()
+			n.exec = func(f *frame) bltn {
+				if v := value0(f).MapIndex(mi); v.IsValid() {
+					dest(f).Set(v.Elem())
+				} else {
+					dest(f).Set(z)
+				}
+				return tnext
+			}
+		default:
 			n.exec = func(f *frame) bltn {
 				if v := value0(f).MapIndex(mi); v.IsValid() {
 					dest(f).Set(v)
@@ -1041,15 +1056,28 @@ func getIndexMap(n *node) {
 	} else {
 		value1 := genValue(n.child[1]) // map index
 
-		if n.fnext != nil {
+		switch {
+		case n.fnext != nil:
 			fnext := getExec(n.fnext)
 			n.exec = func(f *frame) bltn {
 				if v := value0(f).MapIndex(value1(f)); v.IsValid() && v.Bool() {
+					dest(f).SetBool(true)
 					return tnext
 				}
+				dest(f).Set(z)
 				return fnext
 			}
-		} else {
+		case n.typ.cat == interfaceT:
+			z = reflect.New(n.child[0].typ.val.frameType()).Elem()
+			n.exec = func(f *frame) bltn {
+				if v := value0(f).MapIndex(value1(f)); v.IsValid() {
+					dest(f).Set(v.Elem())
+				} else {
+					dest(f).Set(z)
+				}
+				return tnext
+			}
+		default:
 			n.exec = func(f *frame) bltn {
 				if v := value0(f).MapIndex(value1(f)); v.IsValid() {
 					dest(f).Set(v)
@@ -1068,26 +1096,77 @@ func getIndexMap2(n *node) {
 	value0 := genValue(n.child[0])     // map
 	value2 := genValue(n.anc.child[1]) // status
 	next := getExec(n.tnext)
+	typ := n.anc.child[0].typ
+	doValue := n.anc.child[0].ident != "_"
+	doStatus := n.anc.child[1].ident != "_"
 
+	if !doValue && !doStatus {
+		nop(n)
+		return
+	}
 	if n.child[1].rval.IsValid() { // constant map index
 		mi := n.child[1].rval
-		n.exec = func(f *frame) bltn {
-			v := value0(f).MapIndex(mi)
-			if v.IsValid() {
-				dest(f).Set(v)
+		switch {
+		case !doValue:
+			n.exec = func(f *frame) bltn {
+				v := value0(f).MapIndex(mi)
+				value2(f).SetBool(v.IsValid())
+				return next
+			}
+		case typ.cat == interfaceT:
+			n.exec = func(f *frame) bltn {
+				v := value0(f).MapIndex(mi)
+				if v.IsValid() {
+					dest(f).Set(v.Elem())
+				}
+				if doStatus {
+					value2(f).SetBool(v.IsValid())
+				}
+				return next
+			}
+		default:
+			n.exec = func(f *frame) bltn {
+				v := value0(f).MapIndex(mi)
+				if v.IsValid() {
+					dest(f).Set(v)
+				}
+				if doStatus {
+					value2(f).SetBool(v.IsValid())
+				}
+				return next
 			}
-			value2(f).SetBool(v.IsValid())
-			return next
 		}
 	} else {
 		value1 := genValue(n.child[1]) // map index
-		n.exec = func(f *frame) bltn {
-			v := value0(f).MapIndex(value1(f))
-			if v.IsValid() {
-				dest(f).Set(v)
+		switch {
+		case !doValue:
+			n.exec = func(f *frame) bltn {
+				v := value0(f).MapIndex(value1(f))
+				value2(f).SetBool(v.IsValid())
+				return next
+			}
+		case typ.cat == interfaceT:
+			n.exec = func(f *frame) bltn {
+				v := value0(f).MapIndex(value1(f))
+				if v.IsValid() {
+					dest(f).Set(v.Elem())
+				}
+				if doStatus {
+					value2(f).SetBool(v.IsValid())
+				}
+				return next
+			}
+		default:
+			n.exec = func(f *frame) bltn {
+				v := value0(f).MapIndex(value1(f))
+				if v.IsValid() {
+					dest(f).Set(v)
+				}
+				if doStatus {
+					value2(f).SetBool(v.IsValid())
+				}
+				return next
 			}
-			value2(f).SetBool(v.IsValid())
-			return next
 		}
 	}
 }
@@ -1144,17 +1223,28 @@ func getIndexSeq(n *node) {
 	value := genValue(n.child[0])
 	index := n.val.([]int)
 	tnext := getExec(n.tnext)
+	i := n.findex
+
+	// Note:
+	// Here we have to store the result using
+	//    f.data[i] = value(...)
+	// instead of normal
+	//    dest(f).Set(value(...)
+	// because the value returned by FieldByIndex() must be preserved
+	// for possible future Set operations on the struct field (avoid a
+	// dereference from Set, resulting in setting a copy of the
+	// original field).
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
-			if value(f).FieldByIndex(index).Bool() {
+			f.data[i] = value(f).FieldByIndex(index)
+			if f.data[i].Bool() {
 				return tnext
 			}
 			return fnext
 		}
 	} else {
-		i := n.findex
 		n.exec = func(f *frame) bltn {
 			f.data[i] = value(f).FieldByIndex(index)
 			return tnext
@@ -1172,17 +1262,18 @@ func getPtrIndexSeq(n *node) {
 	} else {
 		value = genValue(n.child[0])
 	}
+	i := n.findex
 
 	if n.fnext != nil {
 		fnext := getExec(n.fnext)
 		n.exec = func(f *frame) bltn {
-			if value(f).Elem().FieldByIndex(index).Bool() {
+			f.data[i] = value(f).Elem().FieldByIndex(index)
+			if f.data[i].Bool() {
 				return tnext
 			}
 			return fnext
 		}
 	} else {
-		i := n.findex
 		n.exec = func(f *frame) bltn {
 			f.data[i] = value(f).Elem().FieldByIndex(index)
 			return tnext
@@ -1194,17 +1285,38 @@ func getIndexSeqField(n *node) {
 	value := genValue(n.child[0])
 	index := n.val.([]int)
 	i := n.findex
-	next := getExec(n.tnext)
+	tnext := getExec(n.tnext)
 
-	if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
-		n.exec = func(f *frame) bltn {
-			f.data[i] = value(f).Elem().FieldByIndex(index)
-			return next
+	if n.fnext != nil {
+		fnext := getExec(n.fnext)
+		if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
+			n.exec = func(f *frame) bltn {
+				f.data[i] = value(f).Elem().FieldByIndex(index)
+				if f.data[i].Bool() {
+					return tnext
+				}
+				return fnext
+			}
+		} else {
+			n.exec = func(f *frame) bltn {
+				f.data[i] = value(f).FieldByIndex(index)
+				if f.data[i].Bool() {
+					return tnext
+				}
+				return fnext
+			}
 		}
 	} else {
-		n.exec = func(f *frame) bltn {
-			f.data[i] = value(f).FieldByIndex(index)
-			return next
+		if n.child[0].typ.TypeOf().Kind() == reflect.Ptr {
+			n.exec = func(f *frame) bltn {
+				f.data[i] = value(f).Elem().FieldByIndex(index)
+				return tnext
+			}
+		} else {
+			n.exec = func(f *frame) bltn {
+				f.data[i] = value(f).FieldByIndex(index)
+				return tnext
+			}
 		}
 	}
 }
@@ -1450,7 +1562,7 @@ func arrayLit(n *node) {
 		if c.kind == keyValueExpr {
 			convertLiteralValue(c.child[1], rtype)
 			values[i] = genValue(c.child[1])
-			index[i] = int(c.child[0].rval.Int())
+			index[i] = int(vInt(c.child[0].rval))
 		} else {
 			convertLiteralValue(c, rtype)
 			values[i] = genValue(c)
@@ -1581,12 +1693,12 @@ func destType(n *node) *itype {
 	}
 }
 
-// compositeLit creates and populates a struct object
-func compositeLit(n *node) {
+// doCompositeLit creates and populates a struct object
+func doCompositeLit(n *node, hasType bool) {
 	value := valueGenerator(n, n.findex)
 	next := getExec(n.tnext)
 	child := n.child
-	if !n.typ.untyped {
+	if hasType {
 		child = n.child[1:]
 	}
 	destInterface := destType(n).cat == interfaceT
@@ -1618,12 +1730,15 @@ func compositeLit(n *node) {
 	}
 }
 
-// compositeSparse creates a struct Object, filling fields from sparse key-values
-func compositeSparse(n *node) {
+func compositeLit(n *node)       { doCompositeLit(n, true) }
+func compositeLitNotype(n *node) { doCompositeLit(n, false) }
+
+// doCompositeSparse creates a struct Object, filling fields from sparse key-values
+func doCompositeSparse(n *node, hasType bool) {
 	value := valueGenerator(n, n.findex)
 	next := getExec(n.tnext)
 	child := n.child
-	if !n.typ.untyped {
+	if hasType {
 		child = n.child[1:]
 	}
 
@@ -1653,6 +1768,9 @@ func compositeSparse(n *node) {
 	}
 }
 
+func compositeSparse(n *node)       { doCompositeSparse(n, true) }
+func compositeSparseNotype(n *node) { doCompositeSparse(n, false) }
+
 func empty(n *node) {}
 
 var rat = reflect.ValueOf((*[]rune)(nil)).Type().Elem() // runes array type
@@ -1738,14 +1856,26 @@ func rangeMap(n *node) {
 	if len(n.child) == 4 {
 		index1 := n.child[1].findex  // map value location in frame
 		value = genValue(n.child[2]) // map
-		n.exec = func(f *frame) bltn {
-			iter := f.data[index2].Interface().(*reflect.MapIter)
-			if !iter.Next() {
-				return fnext
+		if n.child[1].typ.cat == interfaceT {
+			n.exec = func(f *frame) bltn {
+				iter := f.data[index2].Interface().(*reflect.MapIter)
+				if !iter.Next() {
+					return fnext
+				}
+				f.data[index0].Set(iter.Key())
+				f.data[index1].Set(iter.Value().Elem())
+				return tnext
+			}
+		} else {
+			n.exec = func(f *frame) bltn {
+				iter := f.data[index2].Interface().(*reflect.MapIter)
+				if !iter.Next() {
+					return fnext
+				}
+				f.data[index0].Set(iter.Key())
+				f.data[index1].Set(iter.Value())
+				return tnext
 			}
-			f.data[index0].Set(iter.Key())
-			f.data[index1].Set(iter.Value())
-			return tnext
 		}
 	} else {
 		value = genValue(n.child[1]) // map
@@ -1913,6 +2043,8 @@ func _append(n *node) {
 		values := make([]func(*frame) reflect.Value, l)
 		for i, arg := range args {
 			switch {
+			case n.typ.val.cat == interfaceT:
+				values[i] = genValueInterface(arg)
 			case isRecursiveStruct(n.typ.val, n.typ.val.rtype):
 				values[i] = genValueInterfacePtr(arg)
 			case arg.typ.untyped:
@@ -1933,6 +2065,8 @@ func _append(n *node) {
 	} else {
 		var value0 func(*frame) reflect.Value
 		switch {
+		case n.typ.val.cat == interfaceT:
+			value0 = genValueInterface(n.child[2])
 		case isRecursiveStruct(n.typ.val, n.typ.val.rtype):
 			value0 = genValueInterfacePtr(n.child[2])
 		case n.child[2].typ.untyped:
@@ -2066,7 +2200,7 @@ func _new(n *node) {
 func _make(n *node) {
 	dest := genValue(n)
 	next := getExec(n.tnext)
-	typ := n.child[1].typ.TypeOf()
+	typ := n.child[1].typ.frameType()
 
 	switch typ.Kind() {
 	case reflect.Array, reflect.Slice:
@@ -2159,16 +2293,18 @@ func reset(n *node) {
 func recv(n *node) {
 	value := genValue(n.child[0])
 	tnext := getExec(n.tnext)
+	i := n.findex
 
 	if n.interp.cancelChan {
 		// Cancellable channel read
 		if n.fnext != nil {
 			fnext := getExec(n.fnext)
 			n.exec = func(f *frame) bltn {
-				ch := value(f)
 				// Fast: channel read doesn't block
-				if x, ok := ch.TryRecv(); ok {
-					if x.Bool() {
+				var ok bool
+				ch := value(f)
+				if f.data[i], ok = ch.TryRecv(); ok {
+					if f.data[i].Bool() {
 						return tnext
 					}
 					return fnext
@@ -2184,7 +2320,6 @@ func recv(n *node) {
 				return fnext
 			}
 		} else {
-			i := n.findex
 			n.exec = func(f *frame) bltn {
 				// Fast: channel read doesn't block
 				var ok bool
@@ -2206,7 +2341,7 @@ func recv(n *node) {
 		if n.fnext != nil {
 			fnext := getExec(n.fnext)
 			n.exec = func(f *frame) bltn {
-				if v, _ := value(f).Recv(); v.Bool() {
+				if f.data[i], _ = value(f).Recv(); f.data[i].Bool() {
 					return tnext
 				}
 				return fnext

interp/scope.go

@@ -78,6 +78,7 @@ type scope struct {
 	def         *node              // function definition node this scope belongs to, or nil
 	loop        *node              // loop exit node for break statement
 	loopRestart *node              // loop restart node for continue statement
+	pkgID       string             // unique id of package in which scope is defined
 	types       []reflect.Type     // Frame layout, may be shared by same level scopes
 	level       int                // Frame level: number of frame indirections to access var during execution
 	sym         map[string]*symbol // Map of symbols defined in this current scope
@@ -97,8 +98,8 @@ func (s *scope) push(indirect bool) *scope {
 		sc.global = s.global
 		sc.level = s.level
 	}
-	// inherit loop state from ancestor
-	sc.loop, sc.loopRestart = s.loop, s.loopRestart
+	// inherit loop state and pkgID from ancestor
+	sc.loop, sc.loopRestart, sc.pkgID = s.loop, s.loopRestart, s.pkgID
 	return &sc
 }
 
@@ -160,19 +161,15 @@ func (s *scope) add(typ *itype) (index int) {
 	return
 }
 
-func (interp *Interpreter) initScopePkg(n *node) (*scope, string) {
+func (interp *Interpreter) initScopePkg(pkgID string) *scope {
 	sc := interp.universe
-	pkgName := mainID
-
-	if p := fileNode(n); p != nil {
-		pkgName = p.child[0].ident
-	}
 
 	interp.mutex.Lock()
-	if _, ok := interp.scopes[pkgName]; !ok {
-		interp.scopes[pkgName] = sc.pushBloc()
+	if _, ok := interp.scopes[pkgID]; !ok {
+		interp.scopes[pkgID] = sc.pushBloc()
 	}
-	sc = interp.scopes[pkgName]
+	sc = interp.scopes[pkgID]
+	sc.pkgID = pkgID
 	interp.mutex.Unlock()
-	return sc, pkgName
+	return sc
 }

interp/src.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 )
 
-func (interp *Interpreter) importSrc(rPath, path, alias string) error {
+func (interp *Interpreter) importSrc(rPath, path string) error {
 	var dir string
 	var err error
 
@@ -29,6 +29,7 @@ func (interp *Interpreter) importSrc(rPath, path, alias string) error {
 	} else if dir, rPath, err = pkgDir(interp.context.GOPATH, rPath, path); err != nil {
 		return err
 	}
+
 	if interp.rdir[path] {
 		return fmt.Errorf("import cycle not allowed\n\timports %s", path)
 	}
@@ -46,7 +47,7 @@ func (interp *Interpreter) importSrc(rPath, path, alias string) error {
 	var root *node
 	var pkgName string
 
-	// Parse source files
+	// Parse source files.
 	for _, file := range files {
 		name := file.Name()
 		if skipFile(&interp.context, name) {
@@ -66,6 +67,9 @@ func (interp *Interpreter) importSrc(rPath, path, alias string) error {
 		if root == nil {
 			continue
 		}
+		if interp.astDot {
+			root.astDot(dotX(), name)
+		}
 		if pkgName == "" {
 			pkgName = pname
 		} else if pkgName != pname {
@@ -75,26 +79,24 @@ func (interp *Interpreter) importSrc(rPath, path, alias string) error {
 
 		subRPath := effectivePkg(rPath, path)
 		var list []*node
-		list, err = interp.gta(root, subRPath)
+		list, err = interp.gta(root, subRPath, path)
 		if err != nil {
 			return err
 		}
 		revisit[subRPath] = append(revisit[subRPath], list...)
 	}
 
-	// revisit incomplete nodes where GTA could not complete
+	// Revisit incomplete nodes where GTA could not complete.
 	for pkg, nodes := range revisit {
-		for _, n := range nodes {
-			if _, err = interp.gta(n, pkg); err != nil {
-				return err
-			}
+		if err = interp.gtaRetry(nodes, pkg, path); err != nil {
+			return err
 		}
 	}
 
 	// Generate control flow graphs
 	for _, root := range rootNodes {
 		var nodes []*node
-		if nodes, err = interp.cfg(root); err != nil {
+		if nodes, err = interp.cfg(root, path); err != nil {
 			return err
 		}
 		initNodes = append(initNodes, nodes...)
@@ -103,13 +105,7 @@ func (interp *Interpreter) importSrc(rPath, path, alias string) error {
 	// Register source package in the interpreter. The package contains only
 	// the global symbols in the package scope.
 	interp.mutex.Lock()
-	interp.srcPkg[path] = interp.scopes[pkgName].sym
-
-	// Rename imported pkgName to alias if they are different
-	if pkgName != alias {
-		interp.scopes[alias] = interp.scopes[pkgName]
-		delete(interp.scopes, pkgName)
-	}
+	interp.srcPkg[path] = interp.scopes[path].sym
 
 	interp.frame.mutex.Lock()
 	interp.resizeFrame()
@@ -189,7 +185,7 @@ func effectivePkg(root, path string) string {
 	for i := 0; i < len(splitPath); i++ {
 		part := splitPath[len(splitPath)-1-i]
 
-		if part == splitRoot[len(splitRoot)-1-rootIndex] {
+		if part == splitRoot[len(splitRoot)-1-rootIndex] && i != 0 {
 			prevRootIndex = rootIndex
 			rootIndex++
 		} else if prevRootIndex == rootIndex {

interp/type.go

@@ -17,7 +17,6 @@ const (
 	binPkgT
 	boolT
 	builtinT
-	byteT
 	chanT
 	complex64T
 	complex128T
@@ -33,7 +32,6 @@ const (
 	int64T
 	mapT
 	ptrT
-	runeT
 	srcPkgT
 	stringT
 	structT
@@ -54,7 +52,6 @@ var cats = [...]string{
 	arrayT:      "arrayT",
 	binT:        "binT",
 	binPkgT:     "binPkgT",
-	byteT:       "byteT",
 	boolT:       "boolT",
 	builtinT:    "builtinT",
 	chanT:       "chanT",
@@ -72,7 +69,6 @@ var cats = [...]string{
 	int64T:      "int64T",
 	mapT:        "mapT",
 	ptrT:        "ptrT",
-	runeT:       "runeT",
 	srcPkgT:     "srcPkgT",
 	stringT:     "stringT",
 	structT:     "structT",
@@ -103,22 +99,24 @@ type structField struct {
 
 // itype defines the internal representation of types in the interpreter
 type itype struct {
-	cat        tcat          // Type category
-	field      []structField // Array of struct fields if structT or interfaceT
-	key        *itype        // Type of key element if MapT or nil
-	val        *itype        // Type of value element if chanT, mapT, ptrT, aliasT, arrayT or variadicT
-	arg        []*itype      // Argument types if funcT or nil
-	ret        []*itype      // Return types if funcT or nil
-	method     []*node       // Associated methods or nil
-	name       string        // name of type within its package for a defined type
-	path       string        // for a defined type, the package import path
-	size       int           // Size of array if ArrayT
-	rtype      reflect.Type  // Reflection type if ValueT, or nil
-	incomplete bool          // true if type must be parsed again (out of order declarations)
-	untyped    bool          // true for a literal value (string or number)
-	sizedef    bool          // true if array size is computed from type definition
-	node       *node         // root AST node of type definition
-	scope      *scope        // type declaration scope (in case of re-parse incomplete type)
+	cat         tcat          // Type category
+	field       []structField // Array of struct fields if structT or interfaceT
+	key         *itype        // Type of key element if MapT or nil
+	val         *itype        // Type of value element if chanT, mapT, ptrT, aliasT, arrayT or variadicT
+	arg         []*itype      // Argument types if funcT or nil
+	ret         []*itype      // Return types if funcT or nil
+	method      []*node       // Associated methods or nil
+	name        string        // name of type within its package for a defined type
+	path        string        // for a defined type, the package import path
+	size        int           // Size of array if ArrayT
+	rtype       reflect.Type  // Reflection type if ValueT, or nil
+	incomplete  bool          // true if type must be parsed again (out of order declarations)
+	recursive   bool          // true if the type has an element which refer to itself
+	untyped     bool          // true for a literal value (string or number)
+	sizedef     bool          // true if array size is computed from type definition
+	isBinMethod bool          // true if the type refers to a bin method function
+	node        *node         // root AST node of type definition
+	scope       *scope        // type declaration scope (in case of re-parse incomplete type)
 }
 
 // nodeType returns a type definition for the corresponding AST subtree
@@ -142,7 +140,7 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 		}
 	}
 
-	var err cfgError
+	var err error
 	switch n.kind {
 	case addressExpr, starExpr:
 		t.cat = ptrT
@@ -175,7 +173,7 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 					}
 				} else {
 					// Evaluate constant array size expression
-					if _, err = interp.cfg(n.child[0]); err != nil {
+					if _, err = interp.cfg(n.child[0], sc.pkgID); err != nil {
 						return nil, err
 					}
 					t.incomplete = true
@@ -199,8 +197,8 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 			t.cat = boolT
 			t.name = "bool"
 		case byte:
-			t.cat = byteT
-			t.name = "byte"
+			t.cat = uint8T
+			t.name = "uint8"
 			t.untyped = true
 		case complex64:
 			t.cat = complex64T
@@ -226,8 +224,8 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 			t.name = "uint"
 			t.untyped = true
 		case rune:
-			t.cat = runeT
-			t.name = "rune"
+			t.cat = int32T
+			t.name = "int32"
 			t.untyped = true
 		case string:
 			t.cat = stringT
@@ -409,6 +407,20 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 			sc.sym[n.ident] = &symbol{kind: typeSym, typ: t}
 		}
 
+	case indexExpr:
+		var lt *itype
+		if lt, err = nodeType(interp, sc, n.child[0]); err != nil {
+			return nil, err
+		}
+		if lt.incomplete {
+			t.incomplete = true
+			break
+		}
+		switch lt.cat {
+		case arrayT, mapT:
+			t = lt.val
+		}
+
 	case interfaceType:
 		t.cat = interfaceT
 		if sname := typeName(n); sname != "" {
@@ -434,6 +446,9 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 			}
 		}
 
+	case landExpr, lorExpr:
+		t.cat = boolT
+
 	case mapType:
 		t.cat = mapT
 		if t.key, err = nodeType(interp, sc, n.child[0]); err != nil {
@@ -482,7 +497,7 @@ func nodeType(interp *Interpreter, sc *scope, n *node) (*itype, error) {
 			if m, _ := lt.lookupMethod(name); m != nil {
 				t, err = nodeType(interp, sc, m.child[2])
 			} else if bm, _, _, ok := lt.lookupBinMethod(name); ok {
-				t = &itype{cat: valueT, rtype: bm.Type}
+				t = &itype{cat: valueT, rtype: bm.Type, isBinMethod: true}
 			} else if ti := lt.lookupField(name); len(ti) > 0 {
 				t = lt.fieldSeq(ti)
 			} else if bs, _, ok := lt.lookupBinField(name); ok {
@@ -593,7 +608,6 @@ var zeroValues [maxT]reflect.Value
 
 func init() {
 	zeroValues[boolT] = reflect.ValueOf(false)
-	zeroValues[byteT] = reflect.ValueOf(byte(0))
 	zeroValues[complex64T] = reflect.ValueOf(complex64(0))
 	zeroValues[complex128T] = reflect.ValueOf(complex128(0))
 	zeroValues[errorT] = reflect.ValueOf(new(error)).Elem()
@@ -604,7 +618,6 @@ func init() {
 	zeroValues[int16T] = reflect.ValueOf(int16(0))
 	zeroValues[int32T] = reflect.ValueOf(int32(0))
 	zeroValues[int64T] = reflect.ValueOf(int64(0))
-	zeroValues[runeT] = reflect.ValueOf(rune(0))
 	zeroValues[stringT] = reflect.ValueOf("")
 	zeroValues[uintT] = reflect.ValueOf(uint(0))
 	zeroValues[uint8T] = reflect.ValueOf(uint8(0))
@@ -616,11 +629,13 @@ func init() {
 
 // if type is incomplete, re-parse it.
 func (t *itype) finalize() (*itype, error) {
-	var err cfgError
+	var err error
 	if t.incomplete {
 		sym, _, found := t.scope.lookup(t.name)
 		if found && !sym.typ.incomplete {
 			sym.typ.method = append(sym.typ.method, t.method...)
+			t.method = sym.typ.method
+			t.incomplete = false
 			return sym.typ, nil
 		}
 		m := t.method
@@ -809,6 +824,22 @@ func (t *itype) lookupBinField(name string) (s reflect.StructField, index []int,
 	return s, index, ok
 }
 
+// methodCallType returns a method function type without the receiver defined.
+// The input type must be a method function type with the receiver as the first input argument.
+func (t *itype) methodCallType() reflect.Type {
+	it := []reflect.Type{}
+	ni := t.rtype.NumIn()
+	for i := 1; i < ni; i++ {
+		it = append(it, t.rtype.In(i))
+	}
+	ot := []reflect.Type{}
+	no := t.rtype.NumOut()
+	for i := 0; i < no; i++ {
+		ot = append(ot, t.rtype.Out(i))
+	}
+	return reflect.FuncOf(it, ot, t.rtype.IsVariadic())
+}
+
 // getMethod returns a pointer to the method definition
 func (t *itype) getMethod(name string) *node {
 	for _, m := range t.method {
@@ -841,13 +872,11 @@ func (t *itype) lookupMethod(name string) (*node, []int) {
 }
 
 // lookupBinMethod returns a method and a path to access a field in a struct object (the receiver)
-func (t *itype) lookupBinMethod(name string) (reflect.Method, []int, bool, bool) {
-	var isPtr bool
+func (t *itype) lookupBinMethod(name string) (m reflect.Method, index []int, isPtr bool, ok bool) {
 	if t.cat == ptrT {
 		return t.val.lookupBinMethod(name)
 	}
-	var index []int
-	m, ok := t.TypeOf().MethodByName(name)
+	m, ok = t.TypeOf().MethodByName(name)
 	if !ok {
 		m, ok = reflect.PtrTo(t.TypeOf()).MethodByName(name)
 		isPtr = ok
@@ -874,7 +903,7 @@ func exportName(s string) string {
 
 var interf = reflect.TypeOf(new(interface{})).Elem()
 
-func (t *itype) refType(defined map[string]bool) reflect.Type {
+func (t *itype) refType(defined map[string]*itype, wrapRecursive bool) reflect.Type {
 	if t.rtype != nil {
 		return t.rtype
 	}
@@ -885,50 +914,56 @@ func (t *itype) refType(defined map[string]bool) reflect.Type {
 			panic(err)
 		}
 	}
-	if t.val != nil && defined[t.val.name] && !t.val.incomplete && t.val.rtype == nil {
+	if t.val != nil && defined[t.val.name] != nil && !t.val.incomplete && t.val.rtype == nil {
 		// Replace reference to self (direct or indirect) by an interface{} to handle
 		// recursive types with reflect.
 		t.val.rtype = interf
+		defined[t.val.name].recursive = true
 	}
 	switch t.cat {
 	case aliasT:
-		t.rtype = t.val.refType(defined)
+		t.rtype = t.val.refType(defined, wrapRecursive)
 	case arrayT, variadicT:
 		if t.sizedef {
-			t.rtype = reflect.ArrayOf(t.size, t.val.refType(defined))
+			t.rtype = reflect.ArrayOf(t.size, t.val.refType(defined, wrapRecursive))
 		} else {
-			t.rtype = reflect.SliceOf(t.val.refType(defined))
+			t.rtype = reflect.SliceOf(t.val.refType(defined, wrapRecursive))
 		}
 	case chanT:
-		t.rtype = reflect.ChanOf(reflect.BothDir, t.val.refType(defined))
+		t.rtype = reflect.ChanOf(reflect.BothDir, t.val.refType(defined, wrapRecursive))
 	case errorT:
 		t.rtype = reflect.TypeOf(new(error)).Elem()
 	case funcT:
 		in := make([]reflect.Type, len(t.arg))
 		out := make([]reflect.Type, len(t.ret))
+		//wrap := false
 		for i, v := range t.arg {
-			in[i] = v.refType(defined)
+			in[i] = v.refType(defined, true)
 		}
 		for i, v := range t.ret {
-			out[i] = v.refType(defined)
+			out[i] = v.refType(defined, true)
 		}
 		t.rtype = reflect.FuncOf(in, out, false)
 	case interfaceT:
 		t.rtype = interf
 	case mapT:
-		t.rtype = reflect.MapOf(t.key.TypeOf(), t.val.TypeOf())
+		t.rtype = reflect.MapOf(t.key.refType(defined, wrapRecursive), t.val.refType(defined, wrapRecursive))
 	case ptrT:
-		t.rtype = reflect.PtrTo(t.val.refType(defined))
+		t.rtype = reflect.PtrTo(t.val.refType(defined, wrapRecursive))
 	case structT:
 		if t.name != "" {
-			defined[t.name] = true
+			defined[t.name] = t
 		}
 		var fields []reflect.StructField
 		for _, f := range t.field {
-			field := reflect.StructField{Name: exportName(f.name), Type: f.typ.refType(defined), Tag: reflect.StructTag(f.tag)}
+			field := reflect.StructField{Name: exportName(f.name), Type: f.typ.refType(defined, wrapRecursive), Tag: reflect.StructTag(f.tag)}
 			fields = append(fields, field)
 		}
-		t.rtype = reflect.StructOf(fields)
+		if t.recursive && wrapRecursive {
+			t.rtype = interf
+		} else {
+			t.rtype = reflect.StructOf(fields)
+		}
 	default:
 		if z, _ := t.zero(); z.IsValid() {
 			t.rtype = z.Type()
@@ -939,7 +974,7 @@ func (t *itype) refType(defined map[string]bool) reflect.Type {
 
 // TypeOf returns the reflection type of dynamic interpreter type t.
 func (t *itype) TypeOf() reflect.Type {
-	return t.refType(map[string]bool{})
+	return t.refType(map[string]*itype{}, false)
 }
 
 func (t *itype) frameType() (r reflect.Type) {
@@ -1003,7 +1038,17 @@ func isInterface(t *itype) bool {
 func isStruct(t *itype) bool {
 	// Test first for a struct category, because a recursive interpreter struct may be
 	// represented by an interface{} at reflect level.
-	return t.cat == structT || t.TypeOf().Kind() == reflect.Struct
+	switch t.cat {
+	case structT:
+		return true
+	case aliasT, ptrT:
+		return isStruct(t.val)
+	case valueT:
+		k := t.rtype.Kind()
+		return k == reflect.Struct || (k == reflect.Ptr && t.rtype.Elem().Kind() == reflect.Struct)
+	default:
+		return false
+	}
 }
 
 func isBool(t *itype) bool { return t.TypeOf().Kind() == reflect.Bool }

interp/value.go

@@ -90,9 +90,6 @@ func genValue(n *node) func(*frame) reflect.Value {
 			v = reflect.ValueOf(n.val)
 		}
 		return func(f *frame) reflect.Value { return v }
-	case rvalueExpr:
-		v := n.rval
-		return func(f *frame) reflect.Value { return v }
 	default:
 		if n.rval.IsValid() {
 			v := n.rval
@@ -167,7 +164,7 @@ func genValueInterface(n *node) func(*frame) reflect.Value {
 	return func(f *frame) reflect.Value {
 		v := value(f)
 		nod := n
-		for {
+		for v.IsValid() {
 			// traverse interface indirections to find out concrete type
 			vi, ok := v.Interface().(valueInterface)
 			if !ok {
@@ -180,11 +177,23 @@ func genValueInterface(n *node) func(*frame) reflect.Value {
 	}
 }
 
+func zeroInterfaceValue() reflect.Value {
+	n := &node{kind: basicLit, typ: &itype{cat: nilT, untyped: true}}
+	v := reflect.New(reflect.TypeOf((*interface{})(nil)).Elem()).Elem()
+	return reflect.ValueOf(valueInterface{n, v})
+}
+
 func genValueInterfaceValue(n *node) func(*frame) reflect.Value {
 	value := genValue(n)
 
 	return func(f *frame) reflect.Value {
-		return value(f).Interface().(valueInterface).value
+		v := value(f)
+		if v.Interface().(valueInterface).node == nil {
+			// Uninitialized interface value, set it to a correct zero value.
+			v.Set(zeroInterfaceValue())
+			v = value(f)
+		}
+		return v.Interface().(valueInterface).value
 	}
 }
 

stdlib/go1_14_archive_tar.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports archive/tar'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_archive_zip.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports archive/zip'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_bufio.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports bufio'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_bytes.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports bytes'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 
@@ -54,6 +54,7 @@ func init() {
 		"ToTitleSpecial":  reflect.ValueOf(bytes.ToTitleSpecial),
 		"ToUpper":         reflect.ValueOf(bytes.ToUpper),
 		"ToUpperSpecial":  reflect.ValueOf(bytes.ToUpperSpecial),
+		"ToValidUTF8":     reflect.ValueOf(bytes.ToValidUTF8),
 		"Trim":            reflect.ValueOf(bytes.Trim),
 		"TrimFunc":        reflect.ValueOf(bytes.TrimFunc),
 		"TrimLeft":        reflect.ValueOf(bytes.TrimLeft),

stdlib/go1_14_compress_bzip2.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports compress/bzip2'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_compress_flate.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports compress/flate'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_compress_gzip.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports compress/gzip'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_compress_lzw.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports compress/lzw'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_compress_zlib.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports compress/zlib'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_container_heap.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports container/heap'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_container_list.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports container/list'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_container_ring.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports container/ring'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_context.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports context'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_aes.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/aes'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_cipher.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/cipher'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_des.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/des'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_dsa.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/dsa'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_ecdsa.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/ecdsa'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_ed25519.go

@@ -0,0 +1,28 @@
+// Code generated by 'goexports crypto/ed25519'. DO NOT EDIT.
+
+// +build go1.14,!go1.15
+
+package stdlib
+
+import (
+	"crypto/ed25519"
+	"reflect"
+)
+
+func init() {
+	Symbols["crypto/ed25519"] = map[string]reflect.Value{
+		// function, constant and variable definitions
+		"GenerateKey":    reflect.ValueOf(ed25519.GenerateKey),
+		"NewKeyFromSeed": reflect.ValueOf(ed25519.NewKeyFromSeed),
+		"PrivateKeySize": reflect.ValueOf(ed25519.PrivateKeySize),
+		"PublicKeySize":  reflect.ValueOf(ed25519.PublicKeySize),
+		"SeedSize":       reflect.ValueOf(ed25519.SeedSize),
+		"Sign":           reflect.ValueOf(ed25519.Sign),
+		"SignatureSize":  reflect.ValueOf(ed25519.SignatureSize),
+		"Verify":         reflect.ValueOf(ed25519.Verify),
+
+		// type definitions
+		"PrivateKey": reflect.ValueOf((*ed25519.PrivateKey)(nil)),
+		"PublicKey":  reflect.ValueOf((*ed25519.PublicKey)(nil)),
+	}
+}

stdlib/go1_14_crypto_elliptic.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/elliptic'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_hmac.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/hmac'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_md5.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/md5'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_rand.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/rand'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_rc4.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/rc4'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_rsa.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/rsa'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib
 

stdlib/go1_14_crypto_sha1.go

@@ -1,6 +1,6 @@
 // Code generated by 'goexports crypto/sha1'. DO NOT EDIT.
 
-// +build go1.12,!go1.13
+// +build go1.14,!go1.15
 
 package stdlib